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HomeMy WebLinkAboutMINUTES - 12142004 - D5 EIR DRAF .. f s� r. C z h 11 S EE 1=11hawl"llbra %,VwaIIe%'%%j#P Eb&-T-"-a"E'--e 7 ental Irnw%act Repftor-g- raft Environrn i: County File #SD028634, RZ023112 SCH# 2003032026 E March 20£14 Contra Costa County Community Deveiopment Department Administrative Bu "ing 651 Pine Street,Second Floor,North Wing Martinez,CA 94553 CommunityContra DennisommBarry,ACCP Community Development Director Development Costa Department CIII / County Administration Building 651 Pine Street f" 4th Floor, North wing Martinez, California 94558-0095 t , Phone; 41. 2004 1 # l ,[ ,� � , , I f'4 TY l NOTICE OF COMPLETION AND AVAIr`BI : TN - �wWl~l'�rT AND NOTICE OF PUBLIC HEARING FOR DRAFT ENVIRONMENTAL IMPACT REPORT STATE CLEARINGHOUSE #2003032026 FOR ALHAMBRA VALLEY ESTATES County Files#SD028634 and #RZ023112 Notice is hereby given pursuant to the California Environmental Quality Act(CEQA)that a document entitled "Draft Environmental Impact Report" has been prepared for the proposed Alhambra Valley Estates project. This is a request to subdivide a 15.02-acre parcel of land (project site) into 23 lots for the subsequent development of single family detached residential units, and rezone 4.5 acres of the project site from A-2 (General Agriculture District, 5-Acre Minimum) to R--20 (Single Family Residential District, 20,000 Square-Foot Minimum). The subject property is located at the northwest corner of Alhambra Valley Road and Reliez Valley Road in the Alhambra Valley area in the unincorporated area of Martinez. REVIEW AND COMMENT PERIOD: There will be a forty-five (45) day review and comment period for the Draft EIR document. These comments should be submitted before 5:00 PM on Monday, April 19, 2004 to: Contra Costa County Community Development Department 651 Pine Street, 4 t floor North Wing Martinez, CA 94553 Attention: Christine Gregory For accuracy of record, written comments are desirable and encouraged and should be supported by factual information whenever possible. During the 45-day review period, The County Zoning Administrator will conduct a PUBLIC HEARING to take testimony on the adequacy of the Draft EIR. This hearing will be held MONDAY APRIL 5 2004 at 3:30 PM in Room 107, McBrien Administration Building, 651 Pine Street, Martinez, California. Office Hours Monday - Friday:8:00 a.m. - 5:00 p.m. Office is closed the 1 st, 3rd & 5th Fridays of each month REPORT AVAILABILITY: Copies of the Draft EIR copies available for review or purchase at the Contra Costa County Community Development Department at the address listed above. In addition to copies of the Draft EIR, supplemental maps and other supporting material related to the project are also available for public review at the offices of the Community Development Department. The Draft EIR is also available for purchase in printed ($25.00) and CD format ($5.00), and is also on the County Web Site at http://www.cocoplans.org, The Draft EIR is also available for review at the following locations: Martinez Library Office of Supervisor Gayle Uilkema District II 740 Court Street, 651 Pine Street, Room 108 A Martinez, CA 94553 Martinez, CA 94553 Pleasant Hill (Main) Library 1750 Oak Park Blvd. Pleasant Hill, CA 94523 Environmental Effects of the Project: Potentially significant environmental impacts will be mitigated to less than significant impacts. MORE INFORMATION: For more information on the Draft EIR, please contact Christine Gregory at the Contra Costa Community Development Department by telephone at (925) 335-1210, fax at (925) 335-1222 or by email at cgreg@cd.cccounty.us NOTICE ISSUED 3/5/04 GACurrent Planninglcurr-planlah EliMnotice of AvaEiabMty.doc ...................................................... ......_.........._ .......................................................................... ES2 EXECUTIVE SUMMARY ES-1 introduction and Overview Security Owners Corporation (applicant) is proposing to subdivide a 15.02-acre parcel of land {project site) Into 23 lots for the subsequent development of single family detached residential units'.The triangularly-shaped project site is located south of the City of Martinez, at the northwest corner of the Intersection of Alhambra Valley Road and Rellez Valley Road, in unincorporated Contra Costa County(Figure ESA-1). On October 17, 2001, the applicant filed an application with the Contra Costa County Community Development Department(County) seeking approval of a Vesting Tentative Subdivision Map (Subdivision 8634) and a rezoning for the project site. The applicant is seeking approval to rezone 4.5 acres of the project site from A-2 (General Agriculture District, 5-Acre Minimum)to R-20 (Single Family Residential District, 20,000 Square-Foot Minimum), and to subdivide the project site into 23 residential lots. The County deemed the application complete for processing on November 20, 2002. Residential Lots The 23 lots (Lots 1 through 23) are intended for the future development of single family detached residential units (Figure ES.1-2).The proposed lots would range from 20,002 to 37,358 gross square feet. Residential Unit Design Parameters The proposed project dries not Include the specific design or development of residential units. The following parameters have been proposed by the applicant to guide the future development: Residential Units. -- 3,000 to 4,500 square feet In size, excluding garages — Lots 1,5,6,and 22 would be developed with 1-story residential units — 1-story units would not exceed 27 feet in freight i Development of the proposed lots with single family detached residential units is not a part of the current entitlement process.Separate,subsequent applications for development of the lots will be submitted to the County after action is taken on the proposed subdivision and Rezoning. Alhambra Valley Estates Draft EIR Es-1 [March 2004 ES: EXECUTIVE SUMMARY Figure ES.1-1: Alhambra Valley Estates Development Location _ rO DOWAIrOWN MARTINEZ t � 14WAY A 1 y 4 L SNS R IZ RO q p ¢ F' OPEN 8PACE JON MUIR . NAT70NAt HIS?-OR/0 SITE lox LN Ul VIA df �yQ yrPt 3 flaw a LN x fie'' ' REL IE7 m 0 ,c VA L PROJECT SITE INIUKIF SOURCE: P/A Design Resources,Inc. ES-2 Alhambra Valley Estates Draft 6k March 2004 E5: EXECUTIVE SUMMARY Figure ES.1-2: Alhambra Valley Estates—Proposed Lot Design NO IIS Iii { I 0 a SOURCE:PIA Design Resources,Inc.and MHA 2009 Alhambra Valley Emotes Drat EIR ES-3 March 2004 f ES: EXECUTIVE SUMMARY Lots 2-4, 7-21,and 23 would be developed with either 1-or 2-story residential units - 2-story units would not exceed 35 feet in height Garages: - All residential units would be developed with three-car garages Off-Site Wastewater Pipeline A 5,400-foot long wastewater pipeline from the pump station on Parcel C to a connection paint at Sage Drive is the proposed method of wastewater disposal. The proposed alignment of the wastewater pipeline would be within the existing rights-sof-way of Alhambra Valley and Rell z Valley Roads. On and Off-Site Storm Water Pipeline The applicant has proposed the installation of an on-site storm water collection and drainage system to serve the proposed project, The on-site system (to be owned and maintained by the project's homeowners association)would connect via a proposed 48-inch storm drain pipeline to be located within the existing right-of-way of Alhambra Valley Road. The on-site system would connect to the proposed 48-Inch pipeline at several locations along the project site's Alhambra Valley Road frontage. The pipeline would discharge through a h+eadwalt into Alhambra Creek near the intersection of Alhambra Valley Road and Wanda Way. The off-sits storm water pipeline would be maintained by Contra Costa County. Project Site Access and tan-Site Circulation The applicant proposes that vehicular access to the project site be from Alhambra Valley Road. Vehicular access to the Individual lots would be from the proposed private roadway system consisting of a single central cul-de-sac(Greek Court) and two shorter cut-de-sacs(Fawn Court and Fox Court). The on-site roadways would be situated on Parcel S. Ownership and maintenance of the three carr-site roadways would be by a homeowners association to be established for the subdivision by the applicant. Bicycle/Pedestrian and Equestrian Trait .The applicant proposes the development and dedication of a 22-foot wide right-of-way along the west side of Alhambra Valley Road for trail uses. The right-of-way would include construction of an 8-foot wide paved bicycle/pedestrian trail and a separate 6-foot wide wood chip equestrian trait as depicted In the Alhambra Valley Specific Plan. The applicant has proposed that the right-cif-way be owned and maintained by the County, Fencing A 5-foot high open wood rail fence with opera-wire mesh behind the rails would be constructed along the site's Alhambra Valley Road frontage. The proposed fence wouldbe situated between the bicycle/pedestrian and equestrian trail easement and the lots along Alhambra Valley Road. Project plans also illustrate installation of 6-foot high fences along the project site's southern and northern project boundaries and between all lets. The proposed fences would be a combination of shiplap (to 4 feet above grade)and open wire mesh (18 inches)with a wooden cap. ES-4 Alhambra Valley Estates Draft EIR March 2004 ES:EXECUTIVE SUMMARY The proposed project also Includes Installation of a 6-foot high open-wire mesh fence along the rear of lots adjacent to Vaca Creek. Landscaping The applicant has proposed a preliminary landscaping,pian for the project that Includes interior roadway and Alhambra Valley Road frontage landscaping. Proposed interior roadway landscaping includes a variety of trees, including. • Sycamore = Raywood ash = Chinese pistache = Cork oak = Aristocrat pear = Idaho locust = Purpleleaf plum = Crape myrtle The applicant has proposed the Installation of a total of Sly trees along the project's Alhambra Valley Road frontage and along the project's interior roadway system. ES-2 Approach to Environmental Review Contra Costa County Is conducting its review of the potential environmental Impacts that could result from implementation of the project.The review Is being conducted in accordance with CEQA andtheCEQA Guidelines.All government agencies In California are required to consider whether their decisions would result In significant Impacts on the environment and, if so,to take actions to eliminate, avoid, compensate for, or reduce those Impacts to a less than significant level. In conducting the environmental review,the County, and its consultants,first examined and verified Information provided by the applicant in its applications.The County then consulted with government agencies that have permitting or statutory authority over all or part of the project or who have specialized knowledge of the project area.The County also consulted with the public about the scope of Issues this EIR should cover.The County and its:consultants conducted additional studies and analyses as needed to identify any potentially significant Impacts and identified measures, called mitigation measures, that would avoid, eliminate,compensate for, or reduce any such impacts to a less than significant level. In reading this EIR, it Is important to understand the assumption used throughout the document to evaluate the potential environmental impacts of the project. Each environmental issue in this EIR is analyzed based on significance criteria established in the GENA Guidelines.When no specific guidelines are suggested by the CEQA Guidelines, professional judgment was used to develop appropriate significance thresholds.The significance criteria are defined at the beginning of each impact analysis section, following the discussion of the environmental and regulatory setting. Potential impacts are categorized as follows. significant and unavoidable;significant, but mltigable to a less than significant level; or less than significant. Feasible mitigation measures areidentifiedIn this EIR for impacts that could be considered potentially significant. The measures are designed to reduce the Impact to a less than significant level, This EIR also includes an analysis of the environmental effects of feasible project alternatives. The County is seeking comments on this EIR. The County will respond to comments on this EIR, conduct additional analysis as necessary, and modify mitigation measures as appropriate. If the County approves the project, County staff would monitor the applicant's compliance with the requirements Imposed by the mitigation measures. Alhambra Valley Estates Draft EIR ES-5 March 2004 ES: EXECUTIVE SUMMARY ES-3 Impacts and Mitigation Measures This EIR presents the conclusions that the project has the potential to result in significant environmental impacts. Table ES-1, located at the end of the Executive Summary, summarizes the environmental impacts that could result from implementation of the proposed project.Table ES-1 also summarizes mitigation measures that have been identified to minimize or avoid these impacts, and identifies the significant effects and unavoidable significant environmental effects associated with the proposed project. Among the potentially significant impacts are those in the areas of. • Aesthetics a Agriculture + Air quality * Biological resources • Guttural resources * Geology,soils, and seismicity * Hazards and hazardous materials * Hydrology and water quality • Noise * Utilities and service systems ES-4 Significant and Unavoidable Impacts All potentially significant impacts are mitigable to less-than-significant levels with implementation of mitigation measures outlined in this EIR. ES-5 Opportunities for Public Comment The County invites all interested persons to provide comments on the accuracy and completeness of this EIR. Comments can be provided in writing to the County at the address identified on the cover sheet of this EIR.All written comments on this EIR received during the public comment period will be addressed in the Final EIR. ES-6 Craft Mitigation Monitoring and Reporting urogram The mitigation measures identified In this EIR must be implemented to assure the stated impacts associated with project implementation are brought to less than significant levels. The purpose of the Mitigation, Monitoring,and Reporting Program (MMRP") is to summarize the mitigation, monitoring, and reporting process for the proposed project and the role and responsibilities of the County in ensuring the effective implementation of mitigation for potential adverse effects and cumulatively considerable effects. This MMRP Is a draft program, and would be finalized if the County approves the project. At that time final mitigation measures world be incorporated into the program and the rales and responsibilities for their implementation refined. ENVIRONMENTAL. SECTORS AND MITIGATION Construction, operation,and maintenance of the proposed project could result in potentially significant environmental impacts. Mitigation measures identified in this EIR have been developed to reduce those potential impacts to a less than significant level. The numbers of the mitigation measures summarized in Table ES.10-1 correspond with the mitigation measure numbers outlined in Section 3, Environmental Impact Analyses. ES-6 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Table ES,6-9: Summary of impacts and Mitigation Measures Impact Mitigation Measure Aesthetics Potential Impact 3.1-1.Substantial Mitigation Measure 3.1.1. Prior to recordation of the Final Map and adverse effect on a scenic vista approval of Improvement Pians,the applicant shall submit a revised landscape plan to the Zoning Administrator for review and approval. a. The revised plan shall illustrate the use of a greater range of plant species that are native to the area. b. The revised plan shall Include non-linear plantings of all landscape materials.The plan shall indicate the installation of all landscape materials in Informal,naturally appearing groupings. The overall goal of the revised plan shall be to portray a design that Is natural In appearance. c. The applicant shall Implement the revised landscape plan. Mitigation Measure 3.1-2. Prior to recordation of the Final Map, the applicant shall submit improvement Plans to the Contra Costa County Public Works Department that delineate a revised vehicular access for Lot 6 in a manner such that It takes its vehicular access of off the subdivision's internal roadway system and not off of Alhambra Valley Road. Mitigation Measure 3.1-3. Prior to recordation of the Final Map,the applicant shall submit Improvement Plans to the Contra Costa County Public Works department that delineate a revised entry to the project site off of Alhambra Valley Road. The entryway shall delete the center Island. Mitigation Measure 3.1-4. Residential units constructed on tots 1, 3 through 6,22,and 23 shall be limited to one-story and a maximum height of 27 feet. Potential Impact 3.1-3.Substantially Mitigation Measure 3.1.6.Prior to recordatlon of the Final Map and degrade the existing visual character approval of Improvement Plans,the applicant shall submit a revised or quality of the site and Its Gateway design plan to the Zoning Administrator for review and surroundings approval.The revised pian shall illustrate the exclusive use of plant species that are native to the area. Mitigation Measure 3.1-6. Prior to issuance of building permits,the applicant shall submit architectural plans, color schemes, and elevations of the residential units to the Zoning Administrator for review and approval.The plans and elevations shall demonstrate the following: a. Exterior wall colors shall be limited to muted earth tones.The use of bright colors shall be avoided. b. Roof colors shall be limited to muted earth tones.' Highly reflective materials shall be prohibited. Alhambra Valley Estates Draft EIR ES-7 March 2004 ES.EXECUTIVE SUMMARY Impact Mitigation Measure c. Materials and colors shall be less than 60% reflectivity. Mitigation Measure 3.1-7.Prior to recordation of the Final Map,the applicant shall submit to the Zoning Administrator for review and approval language to be incorporated into a Deed Restrict€on for each of the lots and the project-wide Covenants, Codes,and Restrictions(CC&Rs).The Deed Restriction or project CC&Rs shall state that future home improvements must comply with the requirements Identified in Mitigation Measure 3.1-6 and the design Guidelines In the Alhambra Valley Specific Plan. Potential Impact 3.1-4.Creation of Mitigation Measure 3.1-8. Prior to recordation of the Final Map and a new source of light and glare approval of Improvement Plans,the applicant shall submit a revised street light fixture plan to the Zoning Administrator for review and approval.The revised plan shall include the use of shielded fixtures/globes that direct light downward, and have an Incandescent light color. Aar#culture Potential Impact 3.2-1.Conversion Mitigation Measure 3.2-1. Prior to recordation of the final map,the of Prime Farmland,Unique applicant shall dedicate to Contra Costa County or to an Agricultural Farmland,or Farmland of Statewide Trust a conservation easement for a minimum of 15 acres of existing Importance(Farmland),as shown on agricultural land located In the County, unless Land Evaluation and the maps prepared pursuant to the Site Assessment(LESA)modeling demonstrates that the impact of Farmland Mapping and Monitoring the agricultural conversion would not be significant.The purpose of Program of the California Resources the conservation easement shall be to assure that the land remains Agency,to non-agricultural use available for farming.The land shall be available as closely as possible to the project area,to the satisfaction of the Zoning Administrator.The dedication and proposed conservation easement for the property shall be submitted to the County for review and approval. Potential Impact 3.2-4.Other Mitigation Measure 3.2-2.Concurrent with recordation of the changes in the existing environment, Final Map,the following statement shall be recorded at the County which,due to their location or nature, Recorder's Office for each parcel within the subdivision to notify could result in conversion of owners of the lots that they own property in an agricultural area: Farmland to nonagricultural use "This document shall serve as notification that you have purchased land In an agricultural area where you may regularly find farm equipment using local roads;farm equipment causing dust;crop dusting and spraying occurring regularly; burning associated with agricultural activities; noise associated with farm equipment and aerial crop dusting and certain animals and files may existing on surrounding properties.This statement is,again,notification that this Is part of the agricultural way of life in the open space areas of Contra Costa County and you should be fully aware of this at the time of purchase." Air_4uality Potential Impact 3.3-1.The Mitigation Measure 3.3-1. Prior to Issuance of a grading permit the potential to generate a nuisance or applicant shall submit a grading plan to the Zoning Administrator for Increase air emissions from on-and review and approval.The grading plan shall include measures to ES-8 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure off-site sources associated with the reduce emissions from construction equipment and wind blown sails project that shall Include, but shall not be limited to: a. Watering of disturbed soils as needed during dry periods b. Provisions requiring that all construction trucks leaving the project site carrying excavation spoils shall be covered c. Provisions to require the sweeping of Alhambra Valley Road and Rellez Valley Road If visible soil material Is carried onto the roads d. On-site construction speed limit of 15 miles per hour e. Suspending excavation and grading activity when winds(instantaneous gusts)exceed 25 miles per hour(mph) f. Implementing other Best Management Practices to minimize particulate emissions as required by the County O,Ioioafcal Resources Potential Impact 3.4-1.Taking or Mitigation Measure 3.4-1. Prior to commencement of any site work, harassment of sensitive plant and the applicant shall conduct preconstructlon surveys for the presence animal species or damage to their of big tarplant,fragrant fritillary, Mount Diablo fairy lantern,Alameda habitats whipsnake,western pond turtle,and California red-legged frog.All surveys shall follow the standardized protocols as specified by the U.S.Fish and Wildlife Service(USFWS)and/or the California Department of Fish and game(CDFG),where applicable. If any of the Identified sensitive species are discovered on site during the preconstruction surveys,the applicant shall enter into consultations with the USFWS(whlpsnake and California red legged frog)and/or the CDFG(western pond turtle)to determine appropriate measures for Implementation to ensure the complete protection of the species and Its habitat. Measures may Include, but are not limited to,construction restrictions, avoidance of species, and off-site relocation or replacement. Potential Impact 3.4.2.Destruction Mitigation Measure 3.4-2. No alterations of Vaca Creek within the or degradation of sensitive habitats creek setback along the project site shall be allowed. or plant communities, such as wetlands and riparian areas Alhambra Valley Estates Draft EIR ES-9 March 2004 ES:EXECUTIVE SUMMARY Impact Mitigation Measure Mitigation Measure 3.4-3. Prior to recordation of the final reap,the applicant shall submit a deed restriction to the Zoning Administrator for review and approval. The deed restriction shall prohibit, In perpetuity,use and improvements within the Creek Setback. Specifically,the deed restriction shall prohibit any physical alterations within the Creek Setback, including vegetation removal, vegetation planting,landform alterations, or construction of structures or improvements.The deed restriction shall be recorded concurrently with the final map. Cultural Resources Potential impact 3.5-1.Potential to Mitigation Measure 3.5-1. Prior to recordation of the Final Map,the cause a substantial adverse change applicant shall submit a Dead Restriction to be recorded against In the significance of a historical each lot within the Subdivision to the Zoning Administrator for review resource, archaeological resource, and approval. The Deed Restriction shall alert each property owner directly or Indirectly destroy a unique to the possible presence of buried human remains and/or artifacts. paleontological resource or site or The Deed restriction shall require that If any of these cultural unique geologic feature,or disturb remains are discovered during ground disturbing activities,work any human remains, Including those shall be halted within 50 feet of the discovery until a qualified interred outside of formal cemeteries archaeologist Is retained to inspect the discovery. If the archaeologist determines that the find is Important,no additional construction shall take place until the find can be fully evaluated according to procedures outlined in Section 106 of the Historic Preservation Act. If human remains are uncovered,the Contra Costa County Coroner shall be notified Immediately. If the remains are determined to be Native American, a qualified Native American representative shall be contacted, and the Native American Heritage Commission(NAHC)shall be notified within 24 hours.The most likely descendents of the deceased shall be given the chance to make recommendations for the remains. If no recommendations are made within 24 hours,remains may be reinterred elsewhere. If recommendations are made and not accepted,the NAHC shall mediate the problem. Mitigation Measure 3.5-2.Prior to issuance of a Grading Permit, the applicant shall submit to the Zoning Administrator grading plans that Include the following notation on the first sheet of those plans; "There exists on the property that is the subject of this Grading Plan the possible presence of buried human remains and/or artifacts. If any of these cultural remains are discovered during ground disturbing activities,work shall be halted within 50 feet of the discovery until a qualified archaeologist Is retained to Inspect the discovery. In the event of discovery of Native American Remains, a qualified Native American representative shall be contacted, and Native American monitors meeting their standards shall be retained to observe conditions. If the archaeologist determines that the find is Important, no additional construction shall take place until the find can be fully evaluated according to procedures outlined in Section 106 of the Historic Preservation Act. ES-10 � Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure Geology.Soils,and Seismicity Potential impact 3.6-1. Surface fault Mitigation Measure 3.6.1. Prior to recordation of the final reap, the rupture applicant shall submit an updated project geologic and geotechnical report to the Zoning Administrator for review and approval. The updated report shall: a. Include a geologic map of the site b. Present the tog of one deep borehole In the area of the suspected bedrock fault or geologic contact (between boreholes CPT-1 and CPT-2)to an approximate depth of 60 feet below ground surface (borehole will be sampled sufficiently to confirm/refine the Interpretation of geologic contacts In PRA's CPT cross section and provide data on the depth to"hard"bedrock, along with data on lithology,engineering properties,structure and age of the units penetrated) c. Reafftrm/modlfy PRA's Interpretation of fault hazards on the site Should the updated report conclude that there Is a potential Impact of surface fault rupture,then a greater setback from the Identified fault may be required by the Zoning Administrator.The setback will be designed to protect structures for human occupancy from the hazard of surface fault rupture. Potential impact 3.6.9.Expansive Mitigation Measure 3.6-2.All recommendations of the Geotechnical Solis Study shall be Implemented during construction and shall be performed under the observation and testing of the Geotechnical Engineer: HoW_dl and Hazartious Materials Potential Impact 3.7.2.Cause injury Mitigation Measure 3.7-1.At least 30 days prior to Issuance of a or harm to employees,the public or grading permit the applicant shall submit an agrlchernical survey of the environment from construction the entire site to the Zoning Administrator for review and approval. activities that may release hazardous The agrichemical survey shall be conducted In accordance with Substances potentially present in the guidelines established by the Contra:Costa County Environmental soils at the project site Health Department.The survey shall Include the area beneath the floor of the former agrichemicai storage area, located at the southeastern portion of the barn. If the survey reveals the presence of any agrichemicals.In amounts that exceed accepted standards for exposure, no grading activities shall be commenced until a specific plan for mitigating the concentrations has been developed and approved by the Zoning Administrator. Such a plan shall include,but shall not be limited to,the following: a. Identification of a method for the removal of contaminated soils b. Identification of a disposal site for the soils Alhambra Valley Estates Draft EIR _ ES-11 March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure c. identification of a removal method that ensures that no contaminated soils are cast into the surrounding air shed or Into adjacent waterways. Mitigation Measure 3.7-2. Prior to demolition of any existing structure on the project site, all such structures shall be surveyed for the potential presence of asbestos. If the surveys reveal the presence of asbestos,the applicant shall first obtain a permit from the San Francisco Bay Area Air Quality Management District for the safe removal of any asbestos contaminated material. Mitigation Measure 3.7-3. Prior to issuance of a grading permit the applicant shall contact the Contra Costa County Health Services Department, Hazardous Materials Program or the San Francisco Regional Water Quality Control Board,whichever is determined to have jurisdiction,to obtain a Clean Closure Letter for the former fuel storage tank site, Mitigation Measure 3.7-4. During site demolition and pre-grading activities the applicant shall retain an environmental professional,as deemed appropriate and acceptable by the Zoning Administrator,to view areas of the property obscured from access and review during the Modified Prase I Site Assessment, and to evaluate the nature of the fi#i material observed along the western property boundary.The applicant shall submit a report to the Zoning Administrator describing the results of the study. The applicant shall follow all recommendations In the report prior to property transfer. Mitigation Measure 3.7-5.Prior to Issuance of a grading permit the applicant shall decommission any on-site septic systems In accordance with state and County requirements and provide evidence of decommissioning to the Zoning Administrator. Mitigation Measure 3.7-6. Prior to issuance of a grading permit the applicant shall submit a construction safety plan to the Director of Community Development for review and approval.The purpose of the plan will be to minimize the exposure of the public to potentially hazardous materials during all phases of project construction through. a. Implementing appropriate control methods(e.g., Best Management Practices)and approved containment and spill-control practices(e.g.,spill control plan)for construction chemical and materials on-site b. Installing temporary safety fencing to restrict or prevent public access to active on-site construction materials or chemicals ES-12 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure Hydrpio,gy and Wetor Quality Potential impact 3.8-2.Alterations Mitigation Measure 3.8-1. Prior to Issuance of a Grading Permit, In drainage patterns and grading the applicant shall submit to the Building inspection Department, during the construction period could Grading Division,for review and approval a detailed erosion control result In construction-related erosion plan (ECP). The ECP shall define measures that the applicant will problems Implement to mitigate erosion and sedimentation impacts during the construction period. Mitigation Measure 3.8-2.Prior to issuance of a Grading Permit, the applicant shall submit evidence to the Director of Public Works that coverage under the statewide General Construction Activities Storm Water Permit(General Permit)has been obtained. The applicant shall comply with NPDES General Construction Activities Storm Water Permit Requirements established by the CWA. The applicant can obtain coverage under the General Permit by filing a'Notice of intent(NOI)with the State Water Resource Control Board's(SWRCB)Division of Water Quality.The filing shall describe erosion control and storm water treatment measures to be Implemented during and following construction and provide a schedule for monitoring performance. These BMPs will serve to control point and non-point source(NPS) pollutants in storm water and constitute the project's SWPPP for construction activities.While the SWPPP will Include several of the same components as the ECP,the SWPPP will also Include BMPs for preventing the discharge of other NPS pollutants besides sediment(such as paint, concrete,etc.)to downstream waters. Potential impact 3.8.3. Mitigation Measure 3,8.3.The project applicant shall provide the Development of the proposed project Department of Public Works with information that shows the could result In an increase In peak relationship between peak discharge from the project site and peak discharge at downstream drainage discharge from the upper watershed. If it is found that these two facilities discharges occur at the same time downstream of the site,the detention structures shall be redesigned such that post-development discharge is equal to,or less than the peak discharge under existing conditions at the point of discharge into Alhambra Creek at Wanda Way. Mitigation Measure 3.8-4.The project applicant shall demonstrate to the satisfaction of the Contra Costa County Public Works Department that 100-year flows can be safely conveyed through the project site. If it Is found that the 100-year storm event cannot be safely conveyed through the project site,the drainage plan for the proposed project shall be revised such that this performance criteria can be met. Potential impact 3.8.4.Project Mitigation Measure 3.8-5. Prior to Issuance of a Grading Permit, development could result In an the applicant shall submit to Public Works for review and,approval IncreaseIn Non-Point Source the results of percolation tests for site soils.The tests shall be Pollutants to receiving waters. conducted at the project site to demonstrate that site soils are suitable for Infiltration. If percolation tests have already been conducted,the results of these tests shall be presented,along with a brief summary,to the Contra Costa County Public Works Department to ensure that Infiltration Is feasible at the project site.If It Is determined that site soils are suitable for Infiltration,specific design criteria for the structures shall be prepared and submitted to Alhambra Malley Estates Draft EIR ES-13 March 2004 ES:EXECUTIVE SUMMARY Impact Mitigation Measure the Director of Public Works for approval. If the soils are deemed unsuitable for infiltration,the applicant shall design a suitable system for filtering pollutants found in storm water to submit to the Department of Public Works for approval. Mitigation Measure 3.8-6.A Homeowners Association shall be developed and shall be responsible for the maintenance of drainage structures on the project site.The Homeowners Association shall be responsible for the proper maintenance of the low-flow infiltration structures. Mitigation Measure 3.8.7. Prior to Issuance of a Grading Permit, the applicant shall submit to Public works for review and approval a long-term storm water pollution prevention plan(SWPPP)to protect storm water quality after the construction period.The SWPPP shall Include the fallowing additional BMPs to protect storm water quality: a. Proper maintenance of other paved areas can eliminate the majority of litter and debris washing into storm drains and thus,entering local waterways. Regular sweeping is a simple and effective BMP aimed at reducing the amount of litter in storm drain inlets(to prevent clogging)and public waterways(for water quality).The Homeowners Association shall enter into an agreement with Contra Costa County or other street sweeping contractor to ensure this maintenance Is completed. b. Proper maintenance of low-flow Infiltration structures Is necessary to ensure their effectiveness. Improper maintenance of the structures could result In a reduction of storm water conveyance capacity to overlying drainage structures as well as interfere with the infiltration capabilities of the structures.The maintenance of the low-flow infiltration structures will be the responsibility of the Homeowners Association. Necessary maintenance Includes: regular Inspection during the wet season for sediment buildup and clogging of inlets and outlets,and regular (approximately once a year)removal of sediment.A maintenance schedule shall be submitted to the Contra Costa Public Works Department prior to project approval. c. The applicant shall prepare informational literature and guidance on residential BMPs to minimize pollutant contributions from the proposed development.This Information shalt be distributed to all future residents at the project site by the Homeowners Association.At a minimum the Information should cover: 1)General Information on the low-flow Infiltration structures for residents concerning their purpose and Importance of maintaining them;2)Proper disposal of household and commercial chemicals; 3)Proper use of landscaping chemicals;4)Clean-up and appropriate ES-14 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure disposal of yard cuttings and leaf fitter;and 5) Prohibition of any washing and dumping of materials and chemicals into storm drains. Potential Impact 3.8.4.Project Mitigation Measure 3.8-8. Project design shall comply with the development could expose proposed County Flood Plain Management Ordinance requirements. structures on Lots 15 and 16 to 100- year flood hazards. olse Potential Impact 3.10-1.Generation Mitigation Measure 3.16-1. Noise generation associated with of construction noise grading construction activities shall be minimized by Implementation of the following noise control measures: a. All noise producing grading and construction activities shall be limited to the hours of 7:30 AM to 5:00 PM, Monday through Friday. b. Feasible,appropriate noise-reducing technology shall be used on all on-site grading and construction equipment,and toots. c. The delivery of construction materials and equipment shall occur only during the hours of 7:30 AM and 5:00 PM on construction days.Construction materials shall not be delivered on Saturdays, Sundays,or federal holidays. d. All stationary construction equipment shall be sited as far as practical from Alhambra Valley Road and Hill Girt Ranch Road. Potential Impact 3.10-2.Exposure Mitigation Measure 3.90-2.Prior to recordation of the final map the of persons to or the generation of applicant shall submit CC&Rs to the Zoning Administrator for review noise levels In excess of standards and approval.The CCBRs shall state that all residential units established by the General Plan constructed on lots 1,3,4. 5,6, 22,and 23 shall provide outdoor areas that are exposed to noise levels from Alhambra Valley Road at levels no greater than 60 dB.The outdoor areas must be: 1)a 100-feet minimum from the center of Alhambra Valley Road or;2} enclosed within a courtyard that places the residential unit between the courtyard and Alhambra Valley Road or;3)protected from Alhambra Valley Road noise levels by the use designs that shield exterior spaces to levels from Alhambra Valley Road no greater than 60 dB, Mitigation Measure 3.10-3.Any residential unit constructed less than 100 feet from the centerline of Alhambra Valley Road shall be constructed with forced air mechanical ventilation systems, air conditioning,or as approved by the Zoning Administrator Potential Impact 3.12-2.Traffic Mitigation Measure 3.12-1. Prior to recordation of the Final conditions that could be considered Map,the applicant shall submit Improvement Plans to the hazardous or dangerous Contra Costa County Public Works Department that delineate a revised vehicular access for Lot 6 In a manner such that It takes its vehicular access off of the subdivision's Alhambra Valley Estates Draft EIR E -15 March 2004 ES:EXECUTIVE SUMMARY Impact Mitigation Measure Internal roadway system and not off of Alhambra Valley Road. Mitigation Measure 3.12-2.Prior to recordation of the Final Map, the applicant shall submit improvement Pans to the Contra Costa County Public Works Department that delineate a revised entry to the project site off of Alhambra Valley Road.The entryway shall delete the center island. Potential Impact 3.12.3.Conflict Mitigation Measure 3.92-3.Prior to recordation of the Final Map, with established transportation the applicant shall submit Improvement Plans to the Contra Costa policies County Public Works Department that illustrate the widening of Alhambra Valley Road per the Alhambra Valley Specific Plan. Utilities and Service Systems Potential Impact 3.1342. Demand Mitigation Measure 3.13.1.Prior to recordation of the Final Map, for wastewater treatment services In the applicant shall apply to and receive approval from the Contra excess of current capacity Costa County LAFCO for annexation of the project site and the alignment of the off-site wastewater pipeline to the Central Contra Costa Sanitary District. ES-16 Alhambra Valley Estates Draft EIR March 2004 TABLE CE CONTENTS Table of Contents ES: Executive Summary..........................................................................................................ES-1 1: Introduction............................................................................................................................1-1 2: Project Description.................................................................................................................2-1 3: Environmental Impact Analyses............................................................................................3-1 3.0 Introduction.................... .......................................... ....................................................3-1 3.1 Aesthetics.........................................................................................................................3-2 3.2 Agriculture ......................................................................................................................3-25 3.3 Air Quality.......................................................................................................................3-29 3.4 Biological Resources.......................................................................................................3-33 3.5 Cultural Resources .........................................................................................................3-43 3.6 Geology, Soils, and Seismicity........................................................................................3-48 3.7 Hazards and Hazardous Materials........................................................................... .......3-56 3.8 Hydrology and Water Quality...........................................................................................3-60 3.9 Land Use and Planning...................................................................................................3-74 3.10 Noise......... ........................................................................... . ................................3-79 3.11 Population and Housing ...............................................................................................3-86 3.12 Transportation and Traffic.............................................................................................3-88 3.13 Utilities and Service Systems ........................................................................................3-97 4: Cumulative and Growth-inducing Impacts............................................................................4-1 5: Alternatives to the Project......................................................................................................5-1 6: List of Preparers & Distribution.............................................................................................6-1 7: References..............................................................................................................................7-1 APPENDIX A: NOTICE OF PREPARATION ...............................................................................A-1 APPENDIX B: LEVEL OF SERVICE CALCULATIONS/SIGNAL WARRANT GRAPHS..............B-1 Alhambra Valley Estates Graft EIR TQC-1 March 2004 TABLE OF CONTENTS LIST OF TABLES Table ES.6-1: Summary of Impacts and Mitigation Measures ....................................................ES-7 Table 2.3-1: Alhambra Valley Estates Lot Areas .--.................—.................................. .........—.2.5 Table 2.4-1: Summary of Agencies Involved in Permitting the Proposed Project......................2-11 Table 3.1-1: Key Viewing Areas........................................ .............................................. ......3-13 Table 3.3-1: Federal and State Ambient Air Quality Standards...............................................-3-31 Table 3.3-2: Thresholds of Significance for Project Operations................................................3-33 Table 3.3-3: Estimated Project Emissions..................................... ......... ............. 3-33 Table 3.4-1: Plant Species Observed........................................... ................................ .......3-35 Table 3.4-2: Sensitive Plant Species Potentially Occurring within the Project Site ................... 3-37 Table 3.4-3: Wildlife Species Observed ..... ......... ..................... ................................ ....—3-37 Table 3.4-4: Sensitive Wildlife Species Potentially Occurring within the Project Site................ 3-38 Table 3.6-1: Regional Faults and Activity........................................... ...................... ......... ... 3-50 Table 3.8-1: Potential Increases in Peak Discharge Without Detention.................................... 3-73 Table 3.10-1: Typical Residential/Commercial Noise Sources and Levels.................................3-80 Table 3.11-1: Historic Annual Population Growth/Decline for Contra Costa County.......... .....— 3-87 Table 3.12-1: Existing and Projected Intersection Operation (LOS and Seconds of Delay) ........3-92 Table 3.12-2: Project Trip Generation.......................................................................................3-93 TOC-2 Alhambra Valley Draft EIR March 2004 TABLE OF CONTENTS LIST OF FIGURES Figure ES.1-1: Alhambra Valley Estates Development Location ..............................................ES-2 Figure ES.1-2: Alhambra Valley Estates-Proposed Lot Design..............................................ES-3 Figure 1.0-1: Alhambra Valley Estates Development Location .................................................1-2 Figure 2.0-1: Alhambra Valley Estates-Proposed Lot Design.................................................2-3 Figure 2.3-1: Alhambra Valley Estates- Proposed Gateway Treatment Detail.........................2-6 Figure 2.3-2: Preliminary Landscape Plan ..................................................... .........................2-9 Figure 3.1-1: Key Viewing Areas ..................................... .....................................................3-14 Figure 3.1-2: Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road Looking Southwest(KVA 1A) ........................................3-15 Figure 3.1-3: Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road Looking Northwest (KVA IS).........................................3-16 Figure 3.1-4: Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road and Reliez Valley Road Looking Northwest(KVA 2)......................3-17 Figure 3.1-5: Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road west of Reliez Valley Road Looking North (KVA 3)........................3-18 Figure 3.1-6: Trees Proposed for Removal Along Alhambra Valley Road...............................3-20 Figure 3.1-7: Proposed Entry Island .......... ............................. .............................................3-22 Figure 3.1-8: Alhambra Valley Estates-Proposed Gateway Treatment Detail.......................3-24 Figure 3.1-9: Proposed Landscape Design at Alhambra Valley Road.....................................3-24 Figure 3.1-10: Proposed Street Light Fixture .................................................................... ......3-25 Figure 3.6-1: Geologic Map of the Project Site and Vicinity....................................................3-51 Figure 3.8-1: Project Area Drainage Subbasins.......... .................... .............................. ......3-63 Figure 3.8-2: 100-Year Floodplain of Vaca Creek Adjacent to the Project Site........................3-64 Figure 3.8-3: Proposed On-Site Drainage System ............... ............................. ...................3-68 Figure 3.8-4: Proposed Off-Site Drainage System .......... ................ .....................................3-69 Figure 3.8-5: Proposed Storm Water Inlet and Low-Flow Infiltration Structure........................3-70 Figure 3.9-1: Alhambra Valley Specific Plan Land Use Plan...................................................3-77 Figure 3.9-2: Existing Zoning Districts....... ......................................................... ..................3-78 Figure 3.10-1: Noise Levels 50 Feet from the Centerline of Alhambra Valley Road ..................3-84 Figure 3.10-2: Approximate Location of 60 dB Noise Contour from Alhambra Valley Road.......3-85 Figure 3.12-1: Existing Volumes AM and (PM) Peak Hour.......................................................3-90 Figure 3.12-2: Peak Hour Project Trips AM and (PM) (PROJECT TRIPS ONLY) .....................3-94 Figure 3.12-3: Alhambra Valley Specific Plan Trails.................................................................3-96 Figure 3.13-1: Central Contra Cost Sanitary District Boundaries and Sphere of Influence ........3-99 Figure 3.13-2: ,Proposed Off-Site Wastewater Pipeline ..........................................................3-103 Alhambra Valley Estates Draft EIR TOC-3- March 2004 ES : EXECUTIVE S ES-1 Introduction and Overview Security Owners Corporation (applicant) is proposing to subdivide a 15.02-acre parcel of land (project site) into 23 lots for the subsequent development of single family detached residential units'. The triangularly-shaped project site is located south of the City of Martinez, at the northwest corner of the intersection of Alhambra Valley Road and Reliez Valley Road, in unincorporated Contra Costa County (Figure ES.1-1). On October 17, 2001, the applicant riled an application with the Contra Costa County Community Development department (County) seeking approval of a Vesting Tentative Subdivision Map (Subdivision 3634) and a rezoning for the project site. The applicant is seeking approval to rezone 4.5 acres of the project site from A-2 (General Agriculture District, 5-Acre Minimum) to R-20 (Single'Family Residential District, 20,000 Square-Foot Minimum), and to subdivide the project site into 23 residential lots. The County deemed the application complete for processing on November 20, 2002 Residential Lots The 23 lots (Lots 1 through 23) are intended for the future development of single family detached residential units (Figure ES.1-2). The proposed lots would range from 20,002 to 37,338 gross square feet. Residential Unit Design Parameters The proposed project does not include the specific design or development of residential units. The following parameters have been proposed by the applicant to guide the future development: Residential Units: -- 3,000 to 4,500 square feet in size, excluding garages — Lots 1, 5, 6, and 22 would be developed with 1-story residential units — 1-story units would not exceed 27 feet in height ' Development of the proposed lots with single family detached residential units is not a part of the current entitlement process.Separate,subsequent applications for development of the lots will be submitted to the County after action is taken on the proposed Subdivision and Rezoning. Alhambra Valley Estates Draft EIR ES-1 March 2004 ES, EXECUTIVE SUMMARY Figure E5.1.1: Alhambra Valley Estates�+� y Devehilopment Location '� _ A MEZ 19 I RC � rt � ;r Hv WR NA 770ML MS TOR1,0 97F t . �r p1 Atl to LEZ r- . 0 AZ��� �� X1.0 SITE NORIH SOURCE:P/A Design Resources,Inc. ES-2 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Figure ES.1-2: Alhambra Valley Estates—Proposed Lot Design r. i m. e y SOURCE: PIA Design Resources, Inc.and MHA 2003 Alhambra Valley'Estates Draft ElR ES-3 March 2004 ES: EXECUTIVE SUMMARY — Lots 24, 7-29, and 23 would be developed with either'i-or 2-story residential units — 2-story units would not exceed 35 feet in height Garages: — All residential units would be developed with three-car garages Off-Site Wastewater Pipeline A 5,440-foot long wastewater pipeline from the pump station on Parcel C to a connection point at Sage Drive is the proposed method of wastewater disposal. The proposed alignment of the wastewater pipeline would be within the existing rights-of-way of Alhambra Valley and Reliez Valley Roads. On and Off-Site Storm Water Pipeline The applicant has proposed the installation of an on-site storm water collection and drainage system to serve the proposed project. The on-site system (to be owned and maintained by the project's homeowners association)would connect via a proposed 48-inch storm drain pipeline to be located within the existing right-of-way of Alhambra Valley Rood. The on-site system would connect to the proposed 48-inch pipeline at several locations along the project site's Alhambra Valley Road frontage. The pipeline would discharge through a headwall into Alhambra Creek near the intersection of Alhambra Valley Road and Wanda Way. The off-site storm water pipeline would be maintained by Contra Costa County. Project Site Access and On-Site Circulation The applicant proposes that vehicular access to the project site be from Alhambra Valley Road. Vehicular access to the individual lots would be from the proposed private roadway system consisting of a single central cul-de-sac(Creek Court)and two shorter cul-de-sacs (Fawn Court and Fox Court). The on-site roadways would be situated on Parcel B. Ownership and maintenance of the three on-site roadways would be by a homeowners association to be established for the subdivision by the applicant. Bicycle/Pedestrian and Equestrian Trail The applicant proposes the development and dedication of a 22-foot wide right-of-way along the west side of Alhambra Valley Road for trail uses. The right-of-way would include construction of an 8-foot wide paved bicycle/pedestrian trail and a separate 6-foot wide wood chip equestrian trail as depicted in the Alhambra Valley Specific Plan. The applicant has proposed that the right-of-way be owned and maintained by the County. Fencing A 5-font high open wood rail fence with open-wire mesh behind the rails would be constructed along the site's Alhambra Valley Road frontage.The proposed fence would be situated between the bicycle/pedestrian and equestrian trail easement and the lots along Alhambra Valley Road. Project plans also illustrate installation of 6-foot high fences along the project site's southern and northern project boundaries and between all lots. The proposed fences would be a combination of shiplap (to 4 feet above grade) and open wire mesh (18 inches) with a wooden cap. ES4 Alhambra Valley Estates draft E€R March 2004 .......................... - ............................................................................._.. ES: EXECUTIVE SUMMARY The proposed project also includes installation of a 6-foot high open-wire mesh fence along the rear of lots adjacent to Vaca Creek. Landscaping The applicant has proposed a preliminary landscaping plan for the project that includes interior roadway and Alhambra Valley Road frontage landscaping. Proposed interior roadway landscaping includes a variety of trees, including: • Sycamore * Raywood ash * Chinese pistache • Cork oak * Aristocrat pear * Idaho locust • Purpleleaf plum * Crape myrtle The applicant has proposed the installation of a total of 90 trees along the project's Alhambra Valley Road frontage and along the project's interior roadway system. ES-2 Approach to Environmental Review Contra Costa County is conducting its review of the potential environmental impacts that could result from implementation of the project. The review is being conducted in accordance with CEQA and the CEQA Guidelines. All government agencies in California are required to consider whether - their decisions would result in significant impacts on the environment and, if so, to take actions to eliminate, avoid, compensate for, or reduce those impacts to a less than significant level. In conducting the environmental review, the County, and its consultants, first examined and verified information provided by the applicant in its applications. The County then consulted with government agencies that have permitting or statutory authority over all or part of the project or who have specialized knowledge of the project area. The County also consulted with the public about the scope of issues this EIR should cover. The County and its consultants conducted additional studies and analyses as needed to identify any potentially significant impacts and identified measures, called mitigation measures, that would avoid, eliminate, compensate for, or reduce any such impacts to a less than significant level. In reading this EIR, it is important to understand the assumption used throughout the document to evaluate the potential environmental impacts of the project. Each environmental issue in this EIR is analyzed based on significance criteria established in the CEQA Guidelines. When no specific guidelines are suggested by the CEQA Guidelines, professional judgment was used to develop appropriate significance thresholds. The significance criteria are defined at the beginning of each impact analysis section, following the discussion of the environmental and regulatory setting. Potential impacts are categorized as follows: significant and unavoidable; significant, but mitigable to a less than significant level; or less than significant. Feasible mitigation measures are identified in this EIR for impacts that could be considered potentially significant. The measures are designed to reduce the impact to a less than significant level. This EIR also includes an analysis of the environmental effects of feasible project alternatives. The County is seeking comments on this EIR. The County will respond to comments on this EIR, conduct additional analysis as necessary, and modify mitigation measures as appropriate. If the County approves the project, County staff would monitor the applicant's compliance with the requirements imposed by the mitigation measures. Alhambra Valley Estates!haft EIR ES-5 March 2004 ES: EXECUTIVE SUMMARY ES-3 Impacts and Mitigation Measures This EIR presents the conclusions that the project has the potential to result in significant environmental impacts. Table ES-1, located at the end of the Executive Summary, summarizes the environmental impacts that could result from implementation of the proposed project. Table ES-1 also summarizes mitigation measures that have been identified to minimize or avoid these impacts, and identifies the significant effects and unavoidable significant environmental effects associated with the proposed project. Among the potentially significant impacts are those in the areas of; • Aesthetics • Agriculture • Air quality • Biological resources • Cultural resources • Geology, soils, and seismicity • Hazards and hazardous materials • Hydrology and water quality • Noise • Utilities and service systems ES-4 Significant and Unavoidable Impacts All potentially significant impacts are mitigable to less-than-significant levels with implementation of mitigation measures outlined in this EIR. ES-5 Opportunities for Public Comment The County invites all interested persons to provide comments on the accuracy and completeness of this EIR. Comments can be provided in writing to the County at the address identified on the cover sheet of this EIR. All written comments on this EIR received during the public comment period will be addressed in the Final EIR. ES-6 Draft (Mitigation Monitoring and Reporting Program The mitigation measures identified in this EIR must be implemented to assure the stated impacts associated with project implementation are brought to less than significant levels. The purpose of the Mitigation, Monitoring, and Reporting Program (MMRP) is to summarize the mitigation, monitoring, and reporting process for the proposed project and the role and responsibilities of the County in ensuring the effective implementation of mitigation for potential adverse effects and cumulatively considerable effects. This MMRP is a draft program, and would be finalized if the County approves the project. At that time final mitigation measures would be incorporated into the program and the roles and responsibilities for their implementation refined. ENVIRONMENTAL. SECTORS AND MITIGATION Construction, operation, and maintenance of the proposed project could result in potentially significant environmental impacts. Mitigation measures identified in this EIR have been developed to reduce those potential impacts to a less than significant level. The numbers of the mitigation measures summarized in Table ES.10-1 correspond with the mitigation measure numbers outlined in Section 3, Environmental Impact Analyses. ES-6 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Table ES.6-1: Summary of Impacts and Mitigation Measures Impact Mitigation Measure Aesthetics Potential Impact 3.1-1.Substantial Mitigation Measure 3.1-1. Prior to recordation of the Final Map and adverse effect on a scenic vista approval of Improvement Plans, the applicant shall submit a revised landscape plan to the Zoning Administrator for review and approval. a. The revised plan shall illustrate the use of a greater range of plant species that are native to the area. b. The revised plan shall include non-linear plantings of all landscape materials. The plan shall indicate the installation of all landscape materials in informal, naturally appearing groupings.The overall goal of the revised plan shall be to portray a design that is natural in appearance. c. The applicant shall implement the revised landscape plan. Mitigation Measure 3.1-2. Prior to recordation of the Final Map, the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that delineate a revised vehicular access for Lot 6 in a manner such that it takes its vehicular access of off the subdivision's internal roadway system and not off of Alhambra Valley Road. Mitigation Measure 3.1-3. Prior to recordation of the Final Map, the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that delineate a revised entry to the project site off of Alhambra Valley Road. The entryway shall delete the center island. Mitigation Measure 3.1-4. Residential units constructed on Lots 1, 3 through 6, 22, and 23 shall be limited to one-story and a maximum height of 27 feet. Potential Impact 3.1-3.Substantially Mitigation Measure 3.1-5. Prior to recordation of the Final Map and degrade the existing visual character approval of Improvement Plans,the applicant shall submit a revised or quality of the site and its Gateway design plan to the Zoning Administrator for review and surroundings approval.The revised plan shall illustrate the exclusive use of plant species that are native to the area. Mitigation Measure 3.1-6. Prior to issuance of building permits,the applicant shall submit architectural plans, color schemes, and elevations of the residential units to the Zoning Administrator for review and approval. The plans and elevations shall demonstrate the following: a. Exterior wall colors shall be limited to muted earth tones.The use of bright colors shall be avoided. b. Roof colors shall be limited to muted earth tones. Highly reflective materials shall be prohibited. Alhambra Valley Estates Craft EIR I=S-7 March 2004 E :EXECUTIVE SUMMARY Impact Mitigation Measure c. Materials and colors shall be less than 50% reflectivity. Mitigation Measure 3.1-7. Prior to recordation of the Final Map,the applicant shall submit to the Zoning Administrator for review and approval language to be incorporated into a Deed Restriction for each of the lots and the project-wide Covenants, Codes, and Restrictions(CC&Rs).The deed Restriction or project CC&Rs shall state that future home improvements must comply with the requirements identified in Mitigation Measure 3.1-5 and the Design Guidelines in the Alhambra Valley Specific Plan. Potential Impact 3.1-4.Creation of Mitigation Measure 3.1-8. Prior to recordation of the Final Map and a new source of light and glare approval of Improvement Plans,the applicant shall submit a revised street light fixture plan to the Zoning Administrator for review and approval.The revised pian shall include the use of shielded fixtures/globes that direct light downward, and have an incandescent light color. Agriculture Potential Impact 3.2-1. Conversion Mitigation Measure 3.2-1.Prior to recordation of the final map,the of Prime Farmland, Unique applicant shall dedicate to Contra Costa County or to an Agricultural Farmland,or Farmland of Statewide Trust a conservation easement for a minimum of 15 acres of existing Importance (Farmland), as shown on agricultural land located in the County, unless Land Evaluation and the maps prepared pursuant to the Site Assessment(LSSA)modeling demonstrates that the impact of Farmland Mapping and Monitoring the agricultural conversion would not be significant. The purpose of Program of the California Resources the conservation easement shall be to assure that the land remains Agency,to non-agricultural use available for farming.The land shall be available as closely as possible to the project area,to the satisfaction of the Zoning Administrator. The dedication and proposed conservation easement for the property shall be submitted to the County for review and approval. Potential Impact 3.2-4. Other Mitigation Measure 3.2-2. Concurrent with recordation of the changes in the existing environment, Final Map,the following statement shall be recorded at the County which, due to their location or nature, Recorder's Office for each parcel within the subdivision to notify could result in conversion of owners of the lots that they own property in an agricultural area: Farmland to non-agricultural use "This document shall serve as notification that you have purchased land in an agricultural area where you may regularly find farm equipment using local roads;farm equipment causing dust; crop dusting and spraying occurring regularly; burning associated with agricultural activities; noise associated with farm equipment and aerial crop dusting and certain animals and flies may existing on surrounding properties.This statement is, again, notification that this is part of the agricultural way of life in the open space areas of Contra Costa County and you should be fully aware of this at the time of purchase." Air uality Potential Impact 3.3-1.The Mitigation Measure 3.3-1. Prior to issuance of a grading permit the potential to generate a nuisance or applicant shall submit a grading plan to the Zoning Administrator for increase air emissions from on-and review and approval.The grading plan shall include measures to ES-8 Alhambra Valley Estates Draft EIR March 2004 ES:EXECUTIVE SUMMARY Impact Mitigation Measure off-site sources associated with the reduce emissions from construction equipment and wind blown soils project that shall include, but shall not be limited to: a. Watering of disturbed soils as needed during dry periods b. Provisions requiring that all construction trucks leaving the project site carrying excavation spoils shall be covered c. Provisions to require the sweeping of Alhambra Valley Road and Reliez Valley Road if visible soil material is carried onto the roads d. On-site construction speed limit of 15 miles per hour e. Suspending excavation and grading activity when winds(instantaneous gusts)exceed 25 miles per hour(mph) f. Implementing other Best Management Practices to minimize particulate emissions as required by the County Biological Resources Potential Impact 3.4-1.'Taking or Mitigation Measure 3.4-1. Prior to commencement of any site work, harassment of sensitive plant and the applicant shall conduct preconstruction surveys for the presence animal species or damage to their of big tarplant,fragrant fritillary, Mount Diablo fairy lantern,Alameda habitats whipsnake,western pond turtle, and California red-legged frog.All surveys shall follow the standardized protocols as specified by the U.S. Fish and Wildlife Service(USFWS)and/or the California Department of Fish and Came(CDFG), where applicable. If any of the identified sensitive species are discovered on site during the preconstruction surveys,the applicant shall enter into consultations with the USFWS (whipsnake and California red legged frog)and/or the CDFG(western pond turtle)to determine appropriate measures for implementation to ensure the complete protection of the species and its habitat. Measures may include, but are not limited to, construction restrictions, avoidance of species, and off-site relocation or replacement. Potential Impact 3.4-2. Destruction Mitigation Measure 3.4.2. No alterations of Vaca Creek within the or degradation of sensitive habitats creek setback along the project site shall be allowed. or plant communities, such as wetlands and riparian areas Alhambra Valley Estates Draft EIR ES-9 March 2004 ES:EXECUTIVE SUMMARY Impact Mitigation Measure Mitigation Measure 3.4-3.Prior to recordation of the final map,the applicant shall submit a deed restriction to the Zoning Administrator for review and approval.The deed restriction shall prohibit, in perpetuity, use and improvements within the Creek Setback. Specifically, the deed restriction shall prohibit any physical alterations within the Creek Setback, including vegetation removal, vegetation planting, landform alterations, or construction of structures or improvements.The deed restriction shall be recorded concurrently with the final map. Cultural Resources Potential Impact 3.5-1. Potential to Mitigation Measure 3.5-1.Prior to recordation of the Final Map,the cause a substantial adverse change applicant shall submit a Deed Restriction to be recorded against in the significance of a historical each lot within the Subdivision to the Zoning Administrator for review resource, archaeological resource, and approval.The Deed Restriction shall alert each property owner directly or indirectly destroy a unique to the possible presence of buried human remains and/or artifacts. paleontological resource or site or The Deed Restriction shall require that if any of these cultural unique geologic feature,or disturb remains are discovered during ground disturbing activities,work any human remains, including those shall be halted within 50 feet of the discovery until a qualified interred outside of formal cemeteries archaeologist is retained to inspect the discovery. If the archaeologist determines that the find is important, no additional construction shall take place until the find can be fully evaluated according to procedures outlined in Section 106 of the Historic Preservation Act. if human remains are uncovered,the Contra Costa County Coroner shall be notified immediately. If the remains are determined to be Native American, a qualified Native American representative shall be contacted, and the Native American Heritage Commission(NAHC)shall be notified within 24 hours.The most likely descendents of the deceased shall be given the chance to make recommendations for the remains. If no recommendations are made within 24 hours, remains may be reinterred elsewhere. If recommendations are made and not accepted, the NAHC shall mediate the problem. Mitigation Measure 3.5-2. Prior to issuance of a Grading Permit, the applicant shall submit to the Zoning Administrator grading plans that include the following notation on the first sheet of those plans. "There exists on the property that is the subject of this Grading Plan the possible presence of buried human remains and/or artifacts. If any of these cultural remains are discovered during ground disturbing activities, work shall be halted within 50 feet of the discovery until a qualified archaeologist is retained to inspect the discovery. In the event of discovery of Native American Remains, a qualified Native American representative shall be contacted, and Native American monitors meeting their standards shall be retained to observe conditions. If the archaeologist determines that the find is important, no additional construction shall take place until the find can be fully evaluated according to procedures outlined in Section 106 of the Historic Preservation Act. ES-10 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure Geology,Soils and Seismicity Potential Impact 3.6-1. Surface fault Mitigation Measure 3.6-1. Prier to recordation of the final map,the rupture applicant shall submit an updated project geologic and geotechnical report to the Zoning Administrator for review and approval.The updated report shall: a. include a geologic map of the site b. Present the log of one deep borehole in the area of the suspected bedrock fault or geologic contact {between boreholes CPT-1 and CPT-2}to an approximate depth of 60 feet below ground surface {borehole will be sampled sufficiently to confirm/refine the interpretation of geologic contacts in PIRA's CPT cross section and provide data on the depth to"hard"bedrock,along with data on lithology, engineering properties, structure and age of the units penetrated} c. Reaffirm/modify PRA's interpretation of fault hazards on the site Should the updated report conclude that there is a potential impact of surface fault rupture,then a greater setback from the identified fault may be required by the Zoning Administrator. The setback will be designed to protect structures for human occupancy from the hazard of surface fault rupture. Potential Impact 3.6-9. Expansive Mitigation Measure 3.6-2.All recommendations of the Geotechnical soils Study shall be implemented during construction and shall be performed under the observation and testing of the Geotechnical Engineer: H aards and Hazardous Materials Potential impact 3.7-2. Cause injury Mitigation Measure 3.7-1.At least 30 days prior to issuance of a or harm to employees,the public or grading permit the applicant shall submit an agrichemical survey of the environment from construction the entire site to the Zoning Administrator for review and approval. activities that may release hazardous The agrichemical survey shall be conducted in accordance with substances potentially present in the guidelines established by the Contra Costa County Environmental soils at the project site Health Department.The survey shall include the area beneath the floor of the former agrichemical storage area, located at the southeastern portion of the barn. If the survey reveals the presence of any agrichemicals in amounts that exceed accepted standards for exposure, no grading activities shall be commenced until a specific plan for mitigating the concentrations has been developed and approved by the Zoning Administrator. Such a plan shall include, but shall not be limited to, the following: a. Identification of a method for the removal of contaminated soils b. Identification of a disposal site for the soils Alhambra Valley Estates Draft EIR ES-11 March 2004 ES. EXECUTIVE SUMMARY Impact Mitigation Measure c. Identification of a removal method that ensures that no contaminated soils are cast Into the surrounding air shed or Into adjacent waterways. Mitigation Measure .7-2. Prior to demolition of any existing structure on the project site, all such structures shall be surveyed for the potential presence of asbestos. If the surveys reveal the presence of asbestos,the applicant shall first obtain a permit from the San Francisca Bay Area Air Quality Management District for the safe removal of any asbestos contaminated material. Mitigation Measure 3.7-3.Prior to issuance of a grading permit the applicant shall contact the Contra Costa County Health Services Department, Hazardous Materials Program or the San Francisco Regional Water Quality Control Board,whichever is determined to have jurisdiction,to obtain a Clean Closure Letter for the former fuel storage tank site. Mitigation Measure 3.7-4. During site demolition and pre-grading activities the applicant shall retain an environmental professional, as deemed appropriate and acceptable by the Zoning Administrator, to view areas of the property obscured from access and review during the Modified Phase I Site Assessment, and to evaluate the nature of the fill material observed along the western property boundary. The applicant shall submit a report to the Zoning Administrator describing the results of the study. The applicant shall follow all recommendations in the report prior to property transfer. Mitigation Measure 3.7-5. Prior to issuance of a grading permit the applicant shall decommission any on-site septic systems in accordance with state and County requirements and provide evidence of decommissioning to the Zoning Administrator. Mitigation Measure 3.7-6. Prior to issuance of a grading permit the applicant shall submit a construction safety plan to the Director of Community development for review and approval.The purpose of the plan will be to minimize the exposure of the public to potentially hazardous materials during all phases of project construction through: a. Implementing appropriate control methods (e.g., Best Management Practices)and approved containment and spill-control practices(e.g., spill control plan)for construction chemical and materials on-site b. Installing temporary safety fencing to restrict or prevent public access to active on-site construction materials or chemicals ES-12 -- i� Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure Hydroiony and WaterQuality Potential impact 3.8-2.Alterations Mitigation Measure 3.8-1. Prior to issuance of a Grading Permit, in drainage patters and grading the applicant shall submit to the Building Inspection Department, during the construction period could Grading Division,for review and approval a detailed erosion control result in construction-related erosion plan(ECP). The ECP shall define measures that the applicant will problems implement to mitigate erosion and sedimentation impacts during the construction period. Mitigation Measure 3.8-2. Prior to issuance of a Grading Permit, the applicant shall submit evidence to the Director of Public Works that coverage under the statewide General Construction Activities Storm Water Permit(General Permit) has been obtained. The applicant shall comply with NPDES General Construction Activities Storm Water Permit Requirements established by the CWA. The applicant can obtain coverage under the General Permit by filing a Notice of Intent(NO])with the State Water Resource Control Board's (SWRCB) Division of Water Quality. The filing shall describe erosion control and storm water treatment measures to be implemented during and following construction and provide a schedule for monitoring performance.These BMPs will serve to control point and non-point source(NPS)pollutants in storm water and constitute the project's SWPPP for construction activities. While the SWPPP will include several of the same components as the ECP,the SWPPP will also include BMPs for preventing the discharge of other NPS pollutants besides sediment(such as paint, concrete, etc.)to downstream waters. Potential impact 3.8-3. Mitigation Measure 3.8-3. The project applicant shall provide the Development of the proposed project Department of Public Works with information that shows the could result in an increase in peak relationship between peak discharge from the project site and peak discharge at downstream drainage discharge from the upper watershed. if it is found that these two facilities discharges occur at the same time downstream of the site,the detention structures shall be redesigned such that post-development discharge is equal to, or less than the peak discharge under existing conditions at the point of discharge into Alhambra Creek at Wanda Way. Mitigation Measure 3.8-4.The project applicant shall demonstrate to the satisfaction of the Contra Costa County Public Works Department that 9 00-year flows can be safely conveyed through the project site. If it is found that the 900-year storm event cannot be safely conveyed through the project site, the drainage plan for the proposed project shall be revised such that this performance criteria can be met. Potential impact 3.8-4. Project Mitigation Measure 3.8-5.Prior to issuance of a Grading Permit, development could result in an the applicant shall submit to Public Works for review and approval increase in Non-Point Source the results of percolation tests for site soils. The tests shall be Pollutants to receiving waters. conducted at the project site to demonstrate that site soils are suitable for infiltration. If percolation tests have already been conducted, the results of these tests shall be presented, along with a brief summary,to the Contra Costa County Public Works Department to ensure that infiltration is feasible at the project site. If it is determined that site soils are suitable for infiltration, specific design criteria for the structures shall be prepared and submitted to Alhambra Valley Estates Draft EIR ES-93 March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure the Director of Public Works for approval. If the soils are deemed unsuitable for infiltration, the applicant shall design a suitable system for filtering pollutants found in storm water to submit to the Department of Public Works for approval. Mitigation Measure 3.8-6.A Homeowners Association shall be developed and shall be responsible for the maintenance of drainage structures on the project site.The Homeowners Association shall be responsible for the proper maintenance of the low-flow infiltration structures. Mitigation Measure 3.8-7. Prior to issuance of a Grading Permit, the applicant shall submit to Public works for review and approval a long-term storm water pollution prevention plan (SWPPP)to protect storm water quality after the construction period. The SWPPP shall include the following additional BMPs to protect storm water quality: a. Proper maintenance of other paved areas can eliminate the majority of litter and debris washing into storm drains and thus, entering local waterways. Regular sweeping is a simple and effective BMP aimed at reducing the amount of litter in storm drain inlets(to prevent clogging)and public waterways(for water quality).The Homeowners Association shall enter into an agreement with Contra Costa County or other street sweeping contractor to ensure this maintenance is completed. b. Proper maintenance of low-flow infiltration structures is necessary to ensure their effectiveness. improper maintenance of the structures could result in a reduction of storm water conveyance capacity to overlying drainage structures as well as interfere with the infiltration capabilities of the structures. The maintenance of the low-flow infiltration structures will be the responsibility of the Homeowners Association. Necessary maintenance incudes: regular inspection during the wet season for sediment buildup and clogging of inlets and outlets; and regular (approximately once a year) removal of sediment.A maintenance schedule shall be submitted to the Centra Costa Public Works Department prior to project approval. c. The applicant shall prepare informational literature and guidance on residential BMPs to minimize pollutant contributions from the proposed development.This information shall be distributed to all future residents at the project site by the Homeowners Association.At a minimum the information should cover: 1)General information on the low-flow infiltration structures for residents - concerning their purpose and importance of maintaining them; 2) Proper disposal of household and commercial chemicals; 3) Proper use of landscaping chemicals;4)Clean-up and appropriate ES-14 Alhambra Valley Estates Draft EIR March 2004 ES: EXECUTIVE SUMMARY Impact Mitigation Measure disposal of yard cuttings and leaf litter; and 5) Prohibition of any washing and dumping of materials and chemicals into storm drains. Potential Impact 3.8-4. Project Mitigation Measure 3.8-8. Project design shall comply with the development could expose proposed County Flood Plain Management Ordinance requirements. structures on Lots 15 and 16 to 100- year flood hazards. Noise Potential Impact 3.10-1. Generation Mitigation Measure 3.10-1. Noise generation associated with of construction noise grading construction activities shall be minimized by implementation of the following noise control measures: a. All noise producing grading and construction activities shall be limited to the hours of 7:30 AM to 5:00 Pit, Monday through Friday. b. Feasible, appropriate noise-reducing technology shall be used on all on-site grading and construction equipment, and tools. c. The delivery of construction materials and equipment shall occur only during the hours of 7.30 Ari and 5:00 Pm on construction days. Construction materials shall not be delivered on Saturdays, Sundays, or federal holidays. d. All stationary construction equipment shall be sited as far as practical from Alhambra Valley Road and Mill Girt Ranch Road. Potential Impact 3.10-2. Exposure Mitigation Measure 3.10.2. Prior to recordation of the final map the of persons to or the generation of applicant shall submit CC&Rs to the Zoning Administrator for review noise levels in excess of standards and approval. The CC&Rs shall state that all residential units established by the General Plan constructed on lots 1, 3,4, 5, 6, 22, and 23 shall provide outdoor areas that are exposed to noise levels from Alhambra Valley Road at levels no greater than 60 dB. The outdoor areas must be: 1)a 100-feet minimum from the center of Alhambra Valley Road or; 2) enclosed within a courtyard that places the residential unit between the courtyard and Alhambra Valley Road or; 3)protected from Alhambra Valley Road noise levels by the use designs that shield exterior spaces to levels from Alhambra Valley Road no greater than 60 dB. Mitigation Measure 3.90-3.Any residential unit constructed less than 100 feet from the centerline of Alhambra Valley Road shall be constructed with forced air mechanical ventilation systems, air conditioning, or as approved by the Zoning Administrator Potential Impact 3.12-2. Traffic Mitigation Measure 3.12-1. Prior to recordation of the Final conditions that could be considered hazardous or dangerous Map, the applicant shall submit improvement Plans to the Centra Costa County Public Works Department that delineate a revised vehicular access for Lot 6 in a manner such that it takes its vehicular access off of the subdivision's Alhambra Valley Estates Craft EIR ES-15 March 2004 ES; EXECUTIVE SUMMARY _ Impact Mitigation Measure Internal roadway system and not off of Alhambra Valley Road. Mitigation Measure 3.12-2. Prior to recordation of the Final Map, the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that delineate a revised entry to the project site off of Alhambra Valley Road.The entryway shell delete the center island. Potential Impact 3.12-3.Conflict Mitigation Measure 3.12-3. Prior to recordation of the Final Map, with established transportation the applicant shall submit Improvement Plans to the Contra Costa policies County Public Works Department that illustrate the widening of Alhambra Valley Road per the Alhambra Valley Specific Plan. Utilities and Service Systems Potential Impact 3.13-2. Demand Mitigation Measure 3.13-1. Prior to recordation of the Final Map, for wastewater treatment services in the applicant shall apply to and receive approval from the Contra excess of current capacity Costa County L.AFCO for annexation of the project site and the alignment of the off-site wastewater pipeline to the Central Contra Costa Sanitary District. ES-16 � Alhambra Valley Estates Draft EIR March 2004 ■ ■ INTRODUCTION 1.0 Introduction and Purpose of the EIR Security Owners Corporation (applicant) is proposing to subdivide a 15.02-acre parcel of land (project site) into 23 lots for the subsequent development of single family detached residential units'. The triangularly-shaped project site is located south of the City of Martinez, at the northwest corner of the intersection of Alhambra Valley Road and Reliez Valley Road, in unincorporated Contra Costa County(Figure 1.0-1). On October 17, 2001, the applicant filed an application with the Contra Costa County Community Development Department(County) seeking approval of a Vesting Tentative Subdivision Map (Subdivision 3634) and a rezoning for the project site. The applicant is seeking approval to rezone 4.5 acres of the project site from A-2 (General Agriculture District, 5-Acre Minimum) to R-20 (Single Family Residential District, 20,000 Square-Foot Minimum), and to subdivide the project site into 23 residential lots. The County deemed the application complete for processing on November 20, 2002. 1 .1 EIR Process CALIFORNIA ENVIRONMENTAL QUALITY ACT The California Environmental Quality Act(CEQA) and the Guidelines for implementation of the California Environmental Quality Act(CEQA Guidelines) require all government agencies in California to assess potential impacts to the environment prior to making a discretionary decision. Contra Costa County is the lead agency for preparation of this EIR. As lead agency, the County must determine if the proposed project could result in significant impacts to the environment, and whether those impacts could be avoided, eliminated, compensated for, or reduced to less-than- significant levels. ' Development of the proposed lots with single family detached residential units is not a part of the current entitlement process.Separate,subsequent applications for development of the lots will be submitted to the County after action is taken on the proposed Subdivision and Rezoning. Alhambra Valley Estates Draft EIR 1-1 March 2004 1: INTRODUCTION Figure 1.0-1:Alhambra Valley Estates Development Location TO DOWNTOWN MARI'IWZ . � C3 fir• I ��� � O WAY t JPF`N SFAS' jow 44w NATIONAL WWWO SITE J� 311 .,a CT VC qj�`� ivy rE A R&S9Z i'q � , w `-- tC ,1 ` ECT t SITE NORTH 6 E SOURCE:P/A Design Resources, Inc. 1-2 - — _ Afharnbra Valley Estates Draft EIR March 2004 1: INTRODUCTION NOTICE OF PREPARATION In accordance with Section 15082 of the CEQA Guidelines, the County prepared a Notice of Preparation (NOP) for this EIR(Appendix A). The NOP was mailed on March 6, 2003, to local, state, and federal agencies, the State Clearinghouse, and potentially affected property owners for a 30-day review period. The NOP provided a general description of the proposed project and a summary of the main regulations and permit conditions applicable to development and operation of the proposed project. The agency and public comments on the NOP helped to determine the relevant environmental issues associated with the project that would be analyzed and described in this EIR. PUBLIC SCOPING The County conducted a scoping meeting to explain the environmental review process and to receive public comments on the scope of this EIR. The meeting was conducted at the Contra Costa County Board of Supervisors Chambers, located in the City of Martinez, on March 24, 2003. The County sent notices of the scoping meeting to potentially interested agencies and adjacent property owners. The comments received at the scoping meeting helped to determine the relevant environmental issues analyzed and described in this EIR. DRAFT EIR This document is the Draft EIR for the Rezoning and Vesting Tentative Subdivision Map application described above. Applications for the construction of single family residential units on the proposed lots have not been filed, however this EIR presents an evaluation of the expected environmental impacts that may be generated by the future development of the individual residential lots. This EIR contains a description of the project, a description of the environmental setting, an identification of direct and cumulative impacts, mitigation measures for impacts found to be significant, as well as an analysis of project alternatives. FINAL EIR Written and oral comments received in response to this EIR will be addressed in a Response to Comments document that, together with the Draft EIR, will constitute the Final EIR. The Final EIR will also include any changes to the Draft EIR that may result from public or agency comments. The Final EIR will be released for public review prior to certification of the EIR by the Zoning Administrator, and prior to final decisions on whether to approve or deny the rezoning and Vesting Tentative Subdivision Map applications. The Final EIR may also be used by responsible or trustee agency with authority to review or make decisions on aspects of the proposed project. MITIGATION MONITORING AND REPORTING PROGRAM CEQA and the CEQA Guidelines require lead agencies to "adopt a reporting and mitigation monitoring program for the changes to the project which it has adopted or made a condition of project approval in order to mitigate or avoid significant effects on the environment" (CEQA Guidelines Article 7, Sections 15091(d)and 15097). A final reporting and monitoring program is not required to be included in the EIR. Throughout the EIR mitigation measures have been clearly identified and presented in language that will facilitate establishment of a monitoring program. The Mitigation Monitoring and Reporting Program (MMRP) for the project will be a stand-alone document separate from the Final EIR. Alhambra Valley Estates Graft EIR 1-3 March 2004 1: INTRODUCTION 1.2 Key Areas of Environmental Concern This Ela presents an analysis of all potential environmental impacts of the proposed project and alternatives to the project. The key areas of environmental concern described in this document include: • Aesthetics • Air Quality • Agriculture • Biological Resources • Cultural Resources + Geology/Soils • Hazards& Hazardous Materials • Hydrology/Water Quality • Land Use/Planning • Noise • Population/Housing • Transportation/Traffic • Utilities/Service Systems -1.3 Organization of the EIR This EIR has been organized into the following sections: Executive Summary:Presents a summary of the proposed project, required permits, environmental setting, impacts of the proposed project,and mitigation measures identified to reduce or eliminate significant impacts to the proposed project. Chapter 1. Introduction: Provides an introduction and overview that describes the proposed project and the purpose of the EIR, summarizes the EIR review and certification process, identifies key areas of environmental concern, and outlines the EIR process. Chapter 2. Project Description: Presents the project objectives, provides a detailed description of the proposed project, including facilities and construction methods, and the permits required for the proposed project's implementation. Chapter 3. Environmental Impact Analyses: Includes a description of the existing conditions, analysis of the proposed project's potential environmental impacts, and identifies mitigation measures for the impacts identified in this EIR. Chapter 4. Cumulative and Growth-Inducing Impacts: Describes cumulative and growth- inducing impacts resulting from implementation of the project.The analysis describes reasonably anticipated future projects that may have related or cumulative impacts. Chapter 5.Alternatives: Provides an evaluation of a reasonable range of project options that would reduce or avoid environmental impacts. The alternatives section describes alternative ways of meeting the project objectives and alternative locations for certain proposed facilities. In addition,the No Project Alternative is evaluated. Chapter 6.Report Preparation: Lists preparers of this EIR and identifies public agencies that were consulted in Its preparation. Chapter 7. References: Lists sources of information used in the preparation of this EIR. Appendix: Includes the Notice of Preparation(NOP)for this EIR,and recent traffic counts in the project area. 1„4 Alhambra Valley Estates©raft EIR March 2004 1: INTRODUCTION 1.4 Incorporated References The following documents are incorporated by reference into this EIR: • Alhambra Valley Estates Subdivision 8634(Traverso Tree Service 2002) • Archeological Field inspection of the Plummer Property(Holman&Associates 2401) • Biological Resources Inventory at the 16+1-Acre Plummer Property(Moore Biological Consultants 2001) • California Red-legged Frog Habitat Assessment for the Alhambra Valley Estates Project (LSA Associates, Inc.2003) • Geotechnical Study, Proposed Single Family Home Subdivision, Plummer Property (Purcell, Rhoades&Associates 2002) • Supplemental Geotechnical Study, Proposed Single Family Home Subdivision, Plummer Property(Purcell, Rhoades&Associates 2003) • Modified Phase One Environmental Site Assessment, Plummer Property(ENGEO Incorporated 2000) • Plummer Property Subdivision(Illingworth & Rodkin, Inc. 2002) • Tree Survey at the Plummer Property on Alhambra Valley Road (Traverso Tree Service 2002) • Facilities Plan for Wastewater Utility Services to Alhambra Valley(Central Contra Costa Sanitary District 2003) These references are available for review at the Contra Costa County Community Development Department, 651 Pine Street, North Wing, 2nd Floor, Martinez, California. Several Maps are included in this EIR that were sourced from PA Design Resources, Inc. (2002), Alhambra Valley Estates Vesting Tentative Neap- Subdivision 8634, Plan Sheets 1-10. The following figures were taken from the Plan Sheets: • 2.3-2 Preliminary Landscape Design • 3.8-3 Proposed do-Site Drainage System • 3.8-4 Proposed Off-Site Drainage System • 3.13-2 Proposed Off--Site Wastewater Pipeline Full size copies of the Plan Sheets referenced in this EIR are available for review at the Contra Costa County Planning Department address listed above. Alhambra Valley Estates Draft EIR 1-5 March 2004 ■ ■ INTRODUCTION 1.0 Introduction and Purpose of the EIR Security Owners Corporation (applicant) is proposing to subdivide a 15.02-acre parcel of land (project site) into 23 lots for the subsequent development of single family detached residential units'. The triangularly-shaped project site is located south of the City of Martinez, at the northwest comer of the intersection of Alhambra Valley Road and Reliez Valley Road, in unincorporated Contra Costa County(Figure 1.0-1). On October 17, 2001, the applicant filed an application with the Contra Costa County Community Development Department(County) seeking approval of a Vesting Tentative Subdivision Map (Subdivision 8634) and a rezoning for the project site. The applicant is seeking approval to rezone 4.5 acres of the project site from A-2 (General Agriculture District, 5-Acre Minimum) to R-20 (Single Family Residential District, 20,000 Square-Foot Minimum), and to subdivide the project site into 23 residential lots. The County deemed the application complete for processing on November 20, 2002. 1 .1 Elft Process CALIFORNIA ENVIRONMENTAL QUALITY ACT The California Environmental Quality Act(CEQA) and the Guidelines for Implementation of the California Environmental Quality Act(CEQA Guidelines) require all government agencies in California to assess potential impacts to the environment prior to making a discretionary decision. Contra Costa County is the lead agency for preparation of this EIR. As lead agency, the County must determine if the proposed project could result in significant impacts to the environment, and whether those impacts could be avoided, eliminated, compensated for, or reduced to less-than- significant levels. ' Development of the proposed tats with single family detached residential units is not a part of the current entitlement process. Separate,subsequent applications for development of the lots will be submitted to the County after action is taken on the proposed Subdivision and Rezoning. Alhambra Valley Estates draft EIR 1-1 March 2004 1: INTRODUCTION Figure 1.0-1: Alhambra Valley Estates Development Location h 7-0 00w')Vr0WN)WARTkYez 4 . `N$PACE ttHsYR �AI7�rYAL t��'?'C?AIC �1�'E IN s Olt f �. T A £N„ �* 7 � pPROJECT i!d SITE NORTfi— SOURCE; P/A Design Resources, Inc. 1-2 Alhambra Valley Estates Draft EIR March 2004 1: INTRODUCTION NOTICE OF PREPARATION In accordance with Section 15082 of the CEQA Guidelines, the County prepared a Notice of Preparation (NOP) for this EIR (Appendix A). The NOP was mailed on March 6, 2043, to local, state, and federal agencies, the State Clearinghouse, and potentially affected property owners for a 30-day review period. The NOP provided a general description of the proposed project and a summary of the main regulations and permit conditions applicable to development and operation of the proposed project. The agency and public comments on the NOP helped to determine the relevant environmental issues associated with the project that would be analyzed and described in this EIR. PUBLIC SCOPING The County conducted a scoping meeting to explain the environmental review process and to receive public comments on the scope of this EIR. The meeting was conducted at the Contra Costa County Board of Supervisors Chambers, located in the City of Martinez, on March 24, 2403. The County sent notices of the scoping meeting to potentially interested agencies and adjacent property owners. The comments received at the scoping meeting helped to determine the relevant environmental issues analyzed and described in this EIR. DRAFT EIR This document is the Draft EIR for the Rezoning and Vesting Tentative Subdivision Map application described above. Applications for the construction of single family residential units on the proposed lots have not been filed, however this EIR presents an evaluation of the expected environmental impacts that may be generated by the future development of the individual residential lots. This EIR contains a description of the project, a description of the environmental setting, an•identification of direct and cumulative impacts, mitigation measures for impacts found to be significant, as well as an analysis of project alternatives. FINAL EIR Written and oral comments received in response to this EIR will be addressed in a Response to Comments document that, together with the Draft EIR, will constitute the Final EIR. The Final EIR will also include any changes to the Draft EIR that may result from public or agency comments. The Final EIR will be released for public review prior to certification of the EIR by the Zoning Administrator, and prior to final decisions on whether to approve or deny the rezoning and Vesting Tentative Subdivision Map applications. The Final EIR may also be used by responsible or trustee agency with authority to review or make decisions on aspects of the proposed project. MITIGATION MONITORING AND REPORTING PROGRAM CEQA and the CEQA Guidelines require lead agencies to "adopt a reporting and mitigation monitoring program for the changes to the project which it has adapted or made a condition of project approval in order to mitigate or avoid significant effects on the environment" (CEQA Guidelines Article 7, Sections 15091(4) and 15497). A final reporting and monitoring program is not required to be included in the EIR. Throughout the EIR mitigation measures have been clearly identified and presented in language that will facilitate establishment of a monitoring program. The Mitigation Monitoring and Reporting Program (MMRP) for the project will be a stand-alone document separate from the Final EIR. Alhambra Valley Estates Draft EIR 143 March 2004 1: INTRODUCTION 1.2 Key Ares of Environmental Concern This EIR presents an analysis of all potential environmental impacts of the proposed project and alternatives to the project. The key areas of environmental concern described in this document include: • Aesthetics • Air Quality • Agriculture • Biological Resources • Cultural Resources + Geology/Soils • Hazards& Hazardous Materials • Hydrology/Water Quality • Land Use/Planning • Noise • Population/Housing • Transportation[Traffic • Utilities/Service Systems 1.3 Organization of the EIR This EIR has been organized into the following sections, Executive Summary: Presents a summary of the proposed project, required permits, environmental setting, impacts of the proposed project, and mitigation measures identified to reduce or eliminate significant impacts to the proposed project. Chapter 1. Introduction: Provides an introduction and overview that describes the proposed project and the purpose of the EIR, summarizes the EIR review and certification process, identifies key areas of environmental concern,and outlines the EIR process. Chapter 2. Project Description: Presents the project objectives, provides a detailed description of the proposed project, including facili.Jes and construction methods, and the permits required for the proposed project's implementation . Chapter 3. Environmental Impact Analyses: Includes a description of the existing conditions, analysis of the proposed project's potential environmental impacts, and identifies mitigation measures for the impacts identified in this EIR. Chapter 4. Cumulative and Growth-Inducing Impacts: Describes cumulative and growth- inducing impacts resulting from implementation of the project. The analysis describes reasonably anticipated future projects that may have related or cumulative impacts. Chapter 5.Alternatives: Provides an evaluation of a reasonable range of project options that would reduce or avoid environmental impacts.The alternatives section describes alternative ways of meeting the project objectives and alternative locations for certain proposed facilities. In addition,the No Project Alternative is evaluated. Chapter 6. Report Preparation: Lists preparers of this EIR and identifies public agencies that were consulted in its preparation. Chapter 7. References: Lists sources of Information used in the preparation of this EIR. Appendix: Includes the Notice of Preparation(NOP)for this EIR, and recent traffic counts in the project area. 1-4 Alhambra valley Estates Draft EIR March 2004 1: INTRODUCTION 1.4 Incorporated References The fallowing documents are incorporated by reference into this EIR: • Alhambra Valley Estates Subdivision 8634(Traverso Tree Service 2002) • Archeological Field inspection of the Plummer Property(Holman &Associates 2001) • Biological Resources Inventory at the 16+/-Acre Plummer Property(Moore Biological Consultants 2001) • California Red-legged Frog Habitat Assessment for the Alhambra Valley Estates Project (LSA Associates, Inc.2003) • Geotechnical Study, Proposed Single Family Home Subdivision, Plummer Property (Purcell, Rhoades&Associates 2002) • Supplemental Geotechnical Study, Proposed Single Family Home Subdivision, Plummer Property(Purcell, Rhoades&Associates 2003) • Modified Phase One Environmental Site Assessment, Plummer Property(ENGE© Incorporated 2000) • Plummer Property Subdivision (Illingworth& Rodkin, Inc.2002) • Tree Survey at the Plummer Property on Alhambra Valley Road (Traverso Tree Service 2002) • Facilities Plan for Wastewater Utility Services to Alhambra Valley(Central Contra Costa Sanitary District 2003) These references are available for review at the Centra Costa County Community Development Department, 661 Pine Street, North Wing, 2"d Floor, Martinez, California. Several Maps are included in this EIR that were sourced from PA Design Resources, Inc. (2002), Alhambra Valley Estates Vesting Tentative Map- Subdivision 8634, Pian Sheets 1-10. The following figures were taken from the Plan Sheets: + 2.3-2 Preliminary Landscape Design + 3.8-3 Proposed On-Site Drainage System • 3.8-4 Proposed Off-Site Drainage System • 3.13-2 Proposed Off Site Wastewater Pipeline Full size copies of the Plan Sheets referenced in this EIR are available for review at the Contra Costa County Planning Department address listed above. Alhambra Valley Estates Draft EIR 1.5 March 2004 2 ■ PROJECT DESCRIPTION 2.0 Introduction BACKGROUND AND PROJECT OVERVIEW Security Owners Corporation (applicant) is proposing subdivision of a 15.02 acre parcel of land (project site) into 23 lots for the subsequent development of single family detached residential units in unincorporated Contra Costa County(Figure 1.0-1). On October 17, 2001, the applicant filed an application for a Vesting Tentative Subdivision Map (Subdivision 8534) and a Rezoning with the Contra Costa County Community Development Department. The applicant is seeking approval to rezone 4.5 acres of the project site from A-2 (General Agriculture District, 5-Acre Minimum) to R-20 (Single Family Residential District, 20,000 Square'-Foot Minimum), and to subdivide the project site into 23 buildable residential lots. The County deemed the application complete for processing on November 20, 2002. In early 2003, the County commissioned the preparation of an Initial Study for the proposed project. The Initial Study, which summarized the findings of a preliminary environmental assessment, presented the conclusion that the proposed project could result in potentially significant environmental impacts. The County, in accordance with provisions of CEQA and the CEQA Guidelines, commissioned the preparation of this EIR before considering whether to approve, approve with conditions, or deny the project. PROJECT DEFINITION For the purposes of evaluating the project under CEQA and the CEQA Guidelines, the"proposed project" identified in this EIR is the project presented in the application submitted to the County. This section of the EIR presents information that describes the proposed project at a level of detail that provides the reader with a basic understanding of the proposed project_This project description presents the following relevant information about the proposed Alhambra Valley Estates: Alhambra Valley Estates Draft EIR 2-1 March 2004 2: PROJECT DESCRIPTION • Project purpose • Project location and site features • Project description Additional information about the existing conditions is included in Section 3.0, Environmental Impact Analyses, of this EIR. 2.1 Project Purpose The purpose of the proposed project is to create residential building lots on the project site for the subsequent development of single family detached residential units. 2.2 Project Location and Site Features PROJECT LOCATION The undeveloped 15.02-acre triangularly-shaped project site is located at the northwest corner of the intersection of Alhambra Valley Road and Reliez Valley Road. The project site is located in unincorporated Contra Costa County on Assessor's Parcel Number 357-130-033 (Figures 1.0-1 and 2.0-1). PROJECT SITE FEATURES The project site is bounded by Alhambra Valley Road on the east, by an approximately 7-acre undeveloped parcel on the south, by the Arroyo del Hambre (referred to as Vaca Creek in this EIR) on the west, and by Hill Girt Ranch Road on the north (Figure 2.0-1). The project site is relatively flat, with the exception of some topographic relief on proposed Lots 14-16, adjacent to the Vaca Creek. Current site vegetation includes non-native grasses, a limited amount of cultivated hay pasture, a variety of mature trees, and blackberry bushes. ADJACENT LAND USES AND DEVELOPMENT The majority of the properties surrounding the project site are developed with single family detached residential units. The approximately 7-acre parcel to the south of the project site is currently undeveloped. 2.3 Project Description INTRODUCTION The project description is a critical element in the preparation of the environmental analysis for the proposed Alhambra Valley Estates EIR. Section 15278 (a)of the CEQA Guidelines defines "project"as follows: "Project"means the whole of an action, which has a potential for resulting in either a direct physical change in the environment,or a reasonably foreseeable indirect physical change in the environment... 2-2 Alhambra Valley Estates Draft EIR March 2004 2: PROJECT DESCRIPTION Figure 2.0-1: Alhambra Valley Estates—Proposed Lot Design i3Y Y9 a Y b � � SOURCE: PJA Design Resources,Inc. and MHA 2003 Alhambra Valley Estates Draft EIR 2-3 March 2004 2: PROJECT DESCRIPTION The environmental analysis conducted for Alhambra Valley Estates examined the proposed activities associated with the project if it were to be approved and developed. The current condition of the project area is referred to as the baseline condition, or the environmental setting, for the purposes of environmental analysis. The following discussion presents the key elements that constitute the proposed project, Residential Lots The proposed vesting tentative subdivision map would subdivide the 15.02-acre project site into 23 lots (Figure 2.0-1). The 23 lots(Lots I through 23)are intended for the future development of single family detached residential units. The proposed lots range from 20,002 to 37,388 gross square feet(Table 2.3-1). Residential Unit Design Parameters The proposed project does not include the specific design or development of residential units. The following parameters have been proposed by the applicant to guide the future development. • Residential Units - 3,000 to 4,500 square feet in size,excluding garages - Lets 1, 5,6,and 22 would be developed with 1-story residential units - 1-story units would not exceed 27-feet in height -- Lots 2-4,7-21,and 23 would be developed with either 1-car 2-story residential units - 2-story units would not exceed 35-feet in height • Garages. - All residential units would be developed with three-car garages Alhambra Valley Gateway (Parcel A) In addition to the 23 residential lots, three additional lots are proposed for various subdivision improvements.A 633 square foot parcel (Parcel A) is proposed at the intersection of Alhambra Valley and Reliez Valley Roads (Figure 2.0-1). This lot would be improved to create a visual gateway for Alhambra Valley, in accordance with provisions of the Alhambra Valley Specific Plan. Improvements wouldinclude a mixture of drought tolerant flowering shrubsandgroundcover and crape myrtle trees set against a backdrop of a 5-foot high wood rail fence with a low stonewall in the foreground (Figure 2.3-1). The applicant has proposed dedication of Parcel A to the County for ownership and maintenance. On-Site Roadways (Parcel B) On-site roadways would be constructed on Parcel S. For a description of the art-site circulation system refer to Project Site Access and On-Site Circulation later in Section 2.3. Ownership and maintenance of the on-site roadways would be by`a homeowners association. The homeowners association for the subdivision would be established by the applicant. Wastewater Pump Station (Parcel C) The proposed 500 square foot Lot C is located at the project site's northern boundary, adjacent to Alhambra Valley Road and Lot 23 (Figure 2:0-1). The applicant has proposed construction of the project's wastewater collection system pump station on the Parcel. The pump station would consist 2-4 Alhambra Valley Estates Draft EIR March 2004 2. PROJECT DESCRIPTION Table 2.3-1: Alhambra Valley Estates Lot Areas' Lot No. Gross Area Net Area Basis for Lesser (sq.ft.) (sq.ft.) Net Area 1 25,713 25,713 2 23,235 20,236 3 25,005 25,005 4 21,549 21,549 5 20,103 20,103 6 21,818 21,818 7 20,181 20,181 8 22,101 22,101 9 20,592 20,592 10 20,002 20,002 11 24,221 24,221 12 24,776 24,776 13 22,476 22,476 14 32,426 20,001 The lot's gross area is reduced due to the restriction imposed by a creek setback 15 37,388 20,694 The lot's gross area is reduced due to the restriction imposed by a creek setback 16 25,722 22,331 The lot's gross area is reduced due to the restriction imposed by a creek setback 17 23,123 23,123 18 23,261 23,261 19 31,126 26,686 The lot's gross area is reduced due to the restriction imposed by a creek setback 20 32,420 22,918 The let's gross area is reduced due to the restriction imposed by an access easement 21 20,253 203,253 22 20,589 20,589 23 36,885 31,273 The lot's gross area is reduced due to the restriction imposed by an access easement SOURCE:Lot Calculations,Sheet 3 of 10,Alhambra Valley Estates Vesting Tentative Subdivision Map-Subdivision Map 8634,PfA Design Resources, Inc.2003 'The areas of Parcels A,3,and C are not depicted in Table 2.3-1. Alhambra Valley Estates Draft EIR 2-5 March 2004 2:PROJECT DESCRIPTION Figure 2.3-1: Alhambra Valley Estates—Gateway Treatment Detail }r' r *w-, *4+ � 't T d TA1 6 SOURCE:PIA Design Resources, Inc.and MHA 2003 of a grinder-pump that would transform solids within the wastewater stream into a consistency that could be pressurized and pumped, along with liquids, through the proposed off'-site wastewater pipeline. The applicant has proposed dedication of the pump station and Parcel C to the Central Contra Costa Sanitary District (CCCSD)for ownership and maintenance. Off-Site Wastewater Pipeline A 5,400-foot long wastewater pipeline from the pump station on Parcel C to a connection point at Sage Drive is the proposed method of wastewater disposal. The proposed alignment of the wastewater pipeline would be within the existing rights-of-way of Alhambra Valley and Reliez Valley Roads. The applicant has indicated that the off-site wastewater pipeline would be dedicated to and maintained by the CCCSD. Off-Site Storm Water Pipeline The applicant has proposed the installation of an on-site storm water collection and drainage system to serve the proposed project. The on-site system (to be owned and maintained by the _ project's homeowners association)would connect via a proposed 48-inch storm drain pipeline to 2-6 Alhambra Valley Estates draft E€R March 2004 -. 2: PROJECT DESCRIPTION be located within the existing right-cif-way of Alhambra Valley Road. The on-site system would connect to the proposed 48-inch pipeline at several locations along the project site's Alhambra Valley Read frontage. The pipeline would discharge through a headwall into Alhambra Creek near the intersection of Alhambra Valley Road and Wanda Way. The off-site storm water pipeline would be dedicated to and maintained by Contra Costa County. Project Site Access and On-Site Circulation The applicant proposed that vehicular access to the project site be off of Alhambra Valley Road (Figure 2.0-1). Vehicular access to the individual lots would be off of a proposed private roadway system consisting of a single central cul-de-sac (Creek Court) and two shorter cul-de-sacs (Fawn Court and Fox Court). The on-site roadways would be situated on Parcel B. Ownership and maintenance of the three on-site roadways would be by a homeowners association to be established for the subdivision by the applicant. Two (2)of the proposed lots (Lots 11 and 23) are a flag-lot design with vehicular access to those lots off of private driveways, that would be in turn off of the nearest on-site private roadways. The applicant has proposed that vehicular access to Lot 6 be directly off of Alhambra Valley Road. The on-site roadways would have a 32-foot wide paved section with County standard curbs and gutters. There are no paved or unpaved sidewalks proposed along the private roadways. An emergency vehicular access drive is proposed off of the end of the Fawn Court cul-de-sac across lot 20 to Hill Girt Ranch Road. This access drive would have a 20-foot wide paved section with curb and gutter on one side. Removal of Existing Site Vegetation There area total of 54 trees currently on the project site, including the following species: • Valley oak • Coast live oak • California black walnut • Camphor • California bay laurel • Olive • Black walnut • California sycamore • California buckeye • Coast redwood • Redwood • Deodar cedar • English walnut • Eucalyptus Project plans include the proposed the removal of 14 of the existing trees: • Valley oak(4) • Coast live oak(3) • California black walnut(1) • Camphor(1) • Olive(1) • Deodar cedar(1) • Eucalyptus(1) • Black walnut(1) • English walnut(1) Alhambra Valley Estates Graft EIR 2-7 March 2004 2: PROJECT DESCRIPTION Bicycle/Pedestrian and Equestrian Trail The applicant proposes the development and dedication of a 22-foot wide right-of-way along the west side of Alhambra Valley Road for trail uses. The right-of-way would include construction of an 8-foot wide paved bicycle/pedestrian trail and a separate 6-foot wide wood chip equestrian trail. The applicant proposes that the right-of-way be owned and maintained by the County. Fencing A 5-foot high open wood rail fence with open-wire mesh behind the rails would be constructed along the site's Alhambra Valley Road frontage. The proposed fence would be situated between the bicycle/pedestrian and equestrian trail easement and the lots along Alhambra Valley Road. Project plans also illustrate installation of 6-foot high fences along the project site's southern and northern project boundaries and between all lots. The proposed fences would be a combination of shiplap (to 4 feet above grade) and open wire mesh (18 inches) with a wooden cap. The proposed project also includes installation of a 6-foot high open-wire mesh fence along the rear of lots adjacent to Vaca Creek. Landscaping The applicant has proposed a preliminary landscaping plan for the project that includes interior roadway and Alhambra Valley Road frontage landscaping (Figure 2.3-2). Proposed interior roadway landscaping includes a variety of trees including: • Sycamore • Raywood ash • Chinese pistache • Cork oak • Aristocrat pear • Idaho locust • Purpleleaf plum • Crape myrtle The applicant has proposed the installation of a total of 90 trees along the project's Alhambra Valley Road frontage, and along the project's interior roadway system. Street Lighting The applicant proposes the installation of Victorian-style luminaire pole lights along the project's interior roadway system. The applicant has not indicated the specific locations of street lighting. Entry Island Project plans include the construction of an entry island at the project's vehicular entry at Alhambra Valley Road (a portion of Parcel B). The island would include the installation of two oak trees, shrubs, and decorative rocks and boulders. A 3- to 5-foot high decorative stonewall and shrubs would flank the sides of the entry roadway. 2-8 Alhambra Valley Estates Draft EIR March 2004 2: PROJECT DESCRIPTION Figure 2.3-2. Preliminary Landscape Plan . r �Lj { 3 Y d d! f aea u i ' ffi a � a y , 3 x I a+ d of fel o SOURCE:P/A Design Resources, Inc.2003 Alhambra Valley Estates Draft EIR 2-9 March 2004 2: PROJECT DESCRIPTION ._ Grading Implementation of the proposed project would require grading to create the individual building pads, to construct the on-site roadways, and for the installation of utilities (including trench spoils for the off-site utility pipelines). An on-site balanced grading plan is proposed that would require the total movement of approximately 12,500 cubic yards of earth material, including on-site and off-site trench spoils. Utilities Water Supply. The applicant proposes that domestic water supplies for the proposed project be provided by the City of Martinez. Wastewater. Each of the proposed 23 lots would be connected to an on-site wastewater collection system, which would connect to the proposed wastewater pump station and off-site sewer pipeline. Wastewater treatment and disposal would be provided by the Central Contra Costa Sanitary District. Storm Water Drainage. The applicant proposes an on-site system of storm water drainage flow (surface features and curb and gutter), collection (drain inlets), and on-site storm water pipelines. The on-site system would connect to the proposed 48-inch off-site storm drain pipeline. The on- site drainage system would be private, and maintained by the Homeowners Association. The off- site drainage system would be dedicated to and maintained by Contra Costa County. Electricity, Natural Gas,Telephone, and Cable Television. Electricity, natural gas, telephone, and cable television services would be extended to each of the lots via underground conduits. 2.4 Permits and Approvals The site is currently unoccupied and undeveloped; no development-associated permits exist for _ the project site. In addition-to the rezoning and Vesting Tentative Subdivision approval from the County, the applicant may be required to obtain permits and approvals from several agencies or jurisdictions for implementation of the project as outlined in Table 2.4-1. 2-10 Alhambra Valley Estates Draft EIR March 2004 2: PROJECT DESCRIPTION Table 2.4-1: Summary of Agencies Involved in Permitting the Proposed Project Agency Action, Permit, or Decision Contra Costa County Approval or denial of the proposed rezoning and Vesting Tentative Subdivision Map U.S. Fish and Wildlife Service Consultation, if required U.S.Army Corps of Engineers Approval or denial of a Wetlands Delineation, a Wetlands Permit, or a Section 404 (Clean Water Act) Kermit, if required State Water Resources Control Board Approval or denial of a General Construction Activity Storm Water Permit,if required California Department of Fish and Game Approval or denial of a Streambed Alteration Agreement, if required San Francisco Bay Regional Water Quality Approval or denial of a Section 401 (Clean Water Act) Permit, Control Board if required Bay Area Air Quality Management District Approval or denial of permits to demolish on-site structures Contra Costa County Local Agency Approval or denial of annexation of the project site and the Formation Commission alignment of the temporary wastewater pipeline within the rights-of-ways of Alhambra Valley and Reliez Valley Roads to the Central Contra Costa Sanitary District Central Contra Costa Sanitary District Agreement to annexation of the project site and the alignment of the temporary wastewater pipeline within the rights-of- ways of Alhambra Valley and Reliez Valley Roads to the District Acceptance of ownership and maintenance of the on-site wastewater pump station and off-site temporary wastewater pipelines Approval or denial of a permit to connect the off-site temporary wastewater pipeline to the District's existing wastewater system at Sage Drive City of Martinez Approval or denial of a permit to connect on-site water supply pipelines to the City of Martinez's existing water main in Alhambra Valley Road Alhambra Valley Estates Draft EIR 2-11 March 2004 3 ■ ENVIRONMENTAL IMPACT ANALYSES 3.0 Introduction This section present the findings of the environmental analyses conducted for the proposed Alhambra Valley Estates development. Each of these sections identifies the: • Environmental Setting • Regulatory Setting • Environmental Analysis ENVIRONMENTAL SETTING The environmental setting sections present a description of the physical environment for each of the thirteen environmental parameters analyzed for the proposed project. The discussion of environmental setting varies among the parameters. As appropriate, separate environmental settingdiscussions are presented for federal, state, regional, and local environments. REGULATORY SETTING Similar to the Environmental Setting discussions, current regulatory settings are presented for thirteen environmental parameters. Federal, state, regional, district, and local regulations applicable to the project site are identified. ENVIRONMENTAL ANALYSIS The results of the environmental analyses conducted for the proposed project are presented in these portions of Sections 3.1 through 3.13. Each of the environmental analysis discussions present: • Thresholds of significance « Impact discussion Alhambra Malley Estates Draft EIR 3-1 March 2004 3. ENVIRONMENTAL IMPACT ANALYSES + Mitigation measures(as appropriate to mitigate significant effects) The thresholds of significance discussions identify the criteria against which the impact was compared to determine if the project would cause a potentially significant impact. Each of the environmental analysis sections presents discussions of the potential effects of the proposed project on the environment. Analyses are presented for each area of potential environmental concern. For each potential effect, a determination is made as to whether or not the proposed project would result in a significant environmental impact. Mitigation measures are identified to reduce significant or potentially significant impacts to a less than significant level. if warranted by the environmental parameter, the area of potential environmental concern, or the threshold of significance, the impact analyses are divided into construction and operation phases of the proposed project. 3.1 Aesthetics ENVIRONMENTAL SETTING Regional Setting The project site is located at the western end of the Alhambra Valley, in an unincorporated area of northern Contra Costa County, south of the City of Martinez. The Alhambra Valley is part of the Alhambra Creek watershed, which is generally defined by the hills to the south and west. The valley floor varies in width, with the adjacent hillsides rising from drainages and Vaca Greek. The landform of the region is defined largely by a series of low to moderate hills and valleys,with somewhat steep hillsides and rounded ridgelines and peaks. For most of the region, the surrounding hills define the visible limits and serve as a visual backdrop. Some of these ridgelines and hills to the south and west are specifically identified as scenic resources in the Alhambra Valley Specific Plan. The regional landscape is primarily rural, with scattered rural-residential development visible in the valleys and at the lower hillside elevations. Briones RegionalPark retains an open space visual character south of the Alhambra Valley. Local Setting Surrounding Visual Character. The project site is located at the northwest corner of the intersection of Alhambra Valley Road and Reliez Valley Road. The visual character surrounding the project site can generally be described as an undulating oak woodland landscape with rural residential development. Land use within the immediate vicinity of the project site includes single family detached residential units across Alhambra Valley Road to the east, a few residences to the north on bill Girt Ranch Road, Vaca Creek to the northwest,and scatteredresidential development to the south along Alhambra Valley Road. Five of the 7 homes along the site's Alhambra Valley Road frontage are single story units.A triangular vacant lot adjoins the project site immediately to the south along Alhambra Valley Road. The visual character of the area surrounding the site is mostly defined by mature vegetation. Native trees and shrubs are part of the foreground view and the hillside backdrop to the site, providing visual continuity to the area. The adjacent residences are generally well landscaped and blend somewhat with the natural setting of the surrounding hills. From the project site, views of the hillsides can be seen mostly to the south and west. Some residential development is visible on the background hills. Vaca Creek is adjacent to the northwest corner of the project site, which provides a more densely vegetated, natural character to the project setting. 3-2. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Viewers experience a transition from the urban development associated with the Interstate 680 corridor to the rural and residential rural landscape of the Alhambra Valley as they approach the project site from the east. Reliez Valley Road at Alhambra Valley Road is defined as a "Gateway" to the Alhambra Valley by the Alhambra Valley Specific Plan, coinciding with a change from suburban to rural visual character. West of the project site, Alhambra Valley Road becomes more curvilinear as it winds further into the valley. Although development is visible throughout the region and project vicinity, the area retains a rural ambiance due mostly to the undulating landform, continuity of native vegetative patterns, and generally low density of development. Present Site Visual Character, The project site is approximately fifteen acres of currently undeveloped land (several agricultural outbuildings are located on the northwest portion of the site on proposed Lots 16 and 19). One area of the site is currently cultivated with hay, and the remainder is primarily tilled soil or naturalized grasses. The topography of the project site is mostly flat and ranges in elevation from approximately 236 to 255 feet above sea level..The landform of the site slopes gently toward Vaca Creek, a portion of which borders the site to the northwest.A large portion of the site slopes towards the northeast cornier of the site. Existing on-site vegetation includes approximately 54 mature trees, most of them native oaks. Although a few trees are scattered throughout the site, the majority of the existing vegetation, including redwoods, bay laurel, and sycamore are located near the riparian corridor along Vaca Creek. A planted row of redwood trees defines the northern perimeter of the site along Hill Girt Ranch Road, and a blackberry hedge parallels the eastern fence line along Alhambra Valley Road. The existing site is characterized as rural, and is visually supported by the current agricultural use and the Vaca Creek riparian corridor to the northwest. REGULATORY SETTING The proposed project is located within the jurisdiction of Contra Costa County. The regulatory setting pertaining to visual resources includes review of the proposed development's consistency with the Contra Costa County General Plan, the Alhambra Valley Speck Plan, and Title 8 of the County Zoning Ordinance. Contra Costa County General Plan The County's Board of Supervisors adopted the General Flan in July 1996. The purpose of the Plan is to "express the broad goals and policies, and specific implementation measures, which will guide decisions on future growth, development, and the conservation of natural resources through the year 2010."Among the Plan's relevant direction applicable to the proposed project are the following. Open Space Element The General Plan Scenic Ridgelines and Waterways map identifies hills visible from the project site as "scenic ridgellnes." The General Plan section includes the following statement regarding visual resources and views of major ridgelines: From throughout much of Contra Costa County,there are significant topographic variations in the landscape. The largest and most prominent of these hills form the backdrop for much of the developed portions of the area.Views of these major ridgelines help to reinforce the rural feeling of the County's rapidly growing communities.These major ridges provide an important balance to current and planned development. Circulation Element As mentioned above, Alhambra Valley and Reliez Valley Roads are identified as Scenic Routes. The Circulation Element of the General Plan states that: Alhambra Valley Estates Draft EIR 3-3 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Controls should be applied to retain and enhance scenic qualities, restrict unsightly use of land, control height of structures, and provide site design and architectural guidance along the entire scenic Corridor. Scenic Routes Policies. 5-34.Scenic corridors shall be maintained with the intent of protecting attractive natural qualities adjacent to various roads throughout the county. 5-35.The planning of scenic corridors shall be coordinated with and maximize access to public parks, recreation areas, bike trails,cultural attractions,and other related public developments. 5-36. Scenic views observable from scenic routes shall be conserved, enhanced, and protected to the extent possible. 5-42. Provide special protection for natural topographic features, aesthetic views,vistas, hills, and prominent ridgelines at"gateway"sections of scenic routes. Such "gateways',are located at unique transition paints in topography or land use, and serve as entrances to regions of the County. Alhambra Valley Specific Plan The Board of Supervisors adopted the Alhambra Valley Specific Plan on October 6, 1992. The Alhambra Valley Specific Plan sets forth a series of goals and policies designed to guide use of the land and development within the Valley at a level of detail greater than that afforded by the County's General Plan. The following goals and policies are relevant to analysis of the proposed project's potential aesthetic effects. Section ll. Goals and Policies A.The Environment Goal 1: Preserve and enhance both the natural and man-made environment in Alhambra Valley, Policy 1: Structures shall be designed to blend into, rather than dominate the natural setting, especially on ridgelines. The massing of new dwellings should be compatible with the natural setting. Policy 2: Only allow development which is sensitive to available natural resources and features. New development shall generally conform with natural conforms and avoid excessive grading. Policy 4: Require development proposals to include an environmentally-superior design alternative as part of the environmental review process. Goal 2: Restrict development in environmentally sensitive areas. Policy 1: Avoid conventional development in flood inundation zones; prohibit development in Federal Emergency Management Act 100-year flood zones. Goal 3: Enhance watercourses and associated riparian habitat to their natural state to restore water quality,wildlife diversity, aesthetic values, and recreation opportunities. 3-4. Alhambra Valley Estates Draft EIR March 2004 .............................................. - 3: ENVIRONMENTAL IMPACT ANALYSES Policy 1: Require a creek setback for any development proposal along a creek or natural waterway. Policy 2: Require a Creek Preservation plan to restore and enhance this resource. Policy 3: Ensure that any new parcels which are proposed along watercourses meet the minimum lot size requirements of that General Plan description. B. New Development Goal 1:Allow development in accord with the goals and policies of the Countywide General Plan as it pertains to Alhambra Valley. Policy 1: Establish regulations for new development that ensure compatibility with General Plan designated land uses. Policy 2: Ensure that the applicable rules for environmental protection are applied to both major and minor subdivisions. C. Public Services&Facilities Goal 2: Minimize soil erosion and runoff throughout Alhambra Valley. Policy 1: Require new development to provide on-site storm water and drainage facilities which accommodates full buildout and considers a range of design alternatives. Policy 2: Control erasion in natural watercourses where creek capacity and bank stability necessitate,while maintaining consistency with the Greek Preservation plan for that development. Minor structural improvements, e.g. drop structures, may be allowed if consistent with the concepts of the Creek Preservation Plan. Goad 3: Ensure that adequate and a quality water supply system is available to areas designated for new homes. Policy 1:The service area for the Martinez water system shall be limited to the area outside the Briones Hills Agricultural Preserve Area. Policy 2: Water service systems for new development shall be required to meet State and County regulatory standards for water delivery,water storage and emergency water supplies. Policy 3: Prior to approval of development entitlements, new development shall obtain verification from the appropriate water service agency, be it the City of Martinez or the County Health Services Department,that an adequate and safe water supply can be provided to serve development. All new subdivisions created after adoption of Specific Plan within Urban Limit tine shall be connected to Martinez Water Department. Policy 4: Require all new development to be served by a public sewer service or to provide an adequate and safe septic system which meets the standards of the County Health Department, Alhambra Valley Estates Draft EIR 3-5 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Policy 5: The establishment of small community well water systems to serve proposed subdivisions shall be prohibited. D.Agricultural Resources Goal 1: To encourage and enhance agriculture and to maintain and promote a healthy and competitive agricultural economy in Alhambra Valley. Policy 1: Agriculture shall be protected to maintain the semi-rural atmosphere and to retain a balance of land uses in Alhambra Valley. Policy 2: The County shall encourage agriculture to continue operating adjacent to areas of planned urban development. Goal 2: To minimize and resolve conflicts between agricultural and urban uses. Policy 1: Establish regulations for new development that ensure its compatibility with agricultural uses. Policy 2: Allow only development that is compatible with existing agricultural, residential and open space uses. Policy 3: Require adequate(a minimum 60 foot) setbacks for structures located within or adjacent to areas with either an Agricultural Lands or Parks and Recreation land use designation. Policy 4: inform and educate prospective home buyers in or near agricultural areas regarding the nuisance and hazards associated with nearby agricultural practices. Policy 5:Agriculture shall be protected from nuisance complaints by non-agricultural land uses. E. Traffic, Circulation and Scenic Routes Goal 1: Maintain Alhambra Valley and Reliez Valley Roads to two travel lanes as a way to reduce through traffic and as a way to preserve the scenic qualities of these corridors. Policy 1: Establish an 80 foot right-of-way for Alhambra Valley Road and an 84 foot right-of-way for Reliez Valley Road. Policy 2: To the extent possible, improve and maintain the aesthetic views from and natural features, which occur along scenic corridors. Policy 3:To the extent practical, enhance public access from scenic routes to parks, trails and other public attractions. Policy 4: Enhance views from designated Valley Gateways, which include Alhambra Avenue at Alhambra Valley Road;Alhambra Valley Road at Reliez Valley Road; and Alhambra Valley Road at the Vaca CreekCrossing. Policy 5: Limit Reliez Valley and Alhambra Valley Roads to one travel lane in each direction while allowing safety features such as turning lanes while providing for separated trails within the rights-of- ways of those roads. 3-6• Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Policy 6: Acknowledge that the existing trees along Alhambra Valley and Reliez Valley Reads significantly contribute to these scenic corridors and all efforts shall be made to preserve them. Policy 7: Prohibit the installation of any solid board fences along Alhambra Valley and Reliez Valley Roads.Allow only open rail fencing within the front yard setback on all properties fronting these roadways. Goal 2: Maintain safe road conditions throughout the Specific Plan area. Policy 1: underground overhead electrical and telephone transmission lines as part of any major road improvement or utility project. Policy 2: Minimize access points along Alhambra Valley and Reliez Valley Roads. Policy 4: Give priority, in terms of road Improvements,to the continuous segment of Alhambra Valley Road and Alhambra Avenue from the Rellez Valley Road intersection to the Santa Fe Railroad trestle. Policy 5: Mitigate any public safety hazards caused by new development which relate to traffic,circulation and parking. Policy 6: Establish a road signage program which discourages through traffic and maintains safe travel speeds. Policy 7: Provide adequate sight distance at entryways to new development. Policy 8:To the fullest extent possible, reduce traffic-related impacts of new development on adjacent property owners and neighboring jurisdictions. F.,Scenic Resources and Community Design Goal 1: Preserve and protect areas of identified high scenic value. Goal 2: Preserve the rural-residential atmosphere in the area. Policy 1: Develop and adopt design standards to regulate new residential development and which maintains the rural-residential atmosphere in Alhambra Valley. Policy 2: To the extent feasible, scenic features should be protected or maintained, either through land dedication to a public agency or through the granting of scenic or conservation easements. Policy 4: In order to conserve the scenic beauty of Alhambra Valley,developers shall generally be required to restore the natural contours and vegetation of the land after grading and other land disturbances. Public and private projects shall be designed to minimize damages to significant trees and other visual landmarks. Policy 7: Enhance and protect access to established scenic routes through the development of trails and other facilities. Alhambra Valley Estates graft EIR 3-7 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Policy 8 New projects shall be designed to blend in with the rural setting of Alhambra Valley as much as possible-,the use of fire resistant materials shall be encouraged. Policy 9. New buildings which are proposed in highly visible areas, such as on hillsides, shall be sited,designed and landscaped so that supporting columns, piers and building undersides are not visually dominant. Section ill. Plan Elements B. Speck Plan land Use Element: Land Use Designations and Compatible Zoning Categories. Single Family Residential,Low Density(SQ.While the County General Plan allows a density range between 1.0—2.9 units per net acre. This specific Plan restricts new parcel sizes to 20,000 square feet or larger. Unique environmental characteristics of a parcel may warrant larger minimum lot sizes. This designation has been applied to lands on the valley floor along Reliez Valley Road and along ether side of the northern leg of Alhambra Valley Road. Compatible zoning designations for this General Plan land use category are R-20(20,000 square feet minimum net parcel size), R-40, R-65, R-100, P-1 and all Agricultural districts. E. Scenic Routes Element. The Alhambra Valley Specific Plan designates Alhambra Valley Road and Reliez Valley Road as scenic routes. The Plan states"Scenic routes provide a dramatic viewing experience of the surrounding area for residents and those traveling through the valley."In addition, the Scenic Routes Element of the Specific Plan designates the intersection of Alhambra Valley Road at Reliez Valley Road as a "Valley Gateway."A Valley Gateway is defined as an area that will help frame the driver's perception of the area as the car passes through the area. The Specific Plan states that its intent is to"preserve the existing views from these gateways." Section IV. Land Use Regulations A. Preserving the Physical and Aesthetic Characteristics of Alhambra Valley "...new development should complement the existing environment in terms of form, scale, and physical appearance. Structures should complement the existing topography to the greatest extent possible while reducing visual impacts of such development through the use of landscaping and siting techniques." 11. Scenic Route Tree Planting-As a way to enhance the aesthetic and scenic qualities along the Alhambra Valley/Reliez Valley Road (AVRD/RVRD) Scenic Corridor, new subdivisions shall be required to plant along their road frontage new specimen trees according to the following. a) Beginning at either and of the parcel's frontage,trees should be a minimum 50 foot intervals; b) Trees shall be a minimum 24-inch boxed Live Oaks; and c) Shall be located approximately 10-feet from the road shoulder area. Section V. Design Guidelines The Design Guidelines are intended to"provide a framework for high quality residential development that will complement and be compatible with the existing residential community", and to"provide guidance for the County planning staff and the County Planning Commission when reviewing future 3-8. Alhambra Valley Estates Draft EIR March 2004 ................. 3: ENVIRONMENTAL IMPACT ANALYSES residential development proposals".The two principal goals of the Guidelines are to reduce the effective balk of development, and to reduce the environmental impact of development. All applicable principals defined in the Design Guidelines are considered, however the following principals may be particularly Important for this project: 8.Site buildings to avoid prominence 9.Weight limits 10.Protection of Rldgellne View-Design of new residential structures should be located and designed so as to minimize the obstruction of any ridge silhouette as viewed from scenic routes on the valley floor. ENVIRONMENTAL ANALYSIS Project Characteristics The potentially most identifiable visual characteristics associated with the proposed project are described below: Structures.The project would create lots for the future construction of 23 new single family detached residential units.The homes are proposed to be between 3,000 and 4,560 square feet in size, excluding garages. Current zoning allows for structures to be built at 35 feet above natural grade. Nineteen of the residences could be two story units with a height of 35 feet(for the purposes of this analysis, all nineteen are presumed to be two story units).The remaining four units would be single story with a maximum height of 27 feet. Roadway Improvements along Alhambra Valley Road.The project plans include streetscape improvements along Alhambra Valley Road including an 8 foot wide paved pedestrian/bicycle path and a separate 6 foot wide wood chip equestrian trail. Landscaping and fencing is also proposed along this road frontage. In addition, special landscaping is proposed at the corner of Alhambra Valley Road and Reliez Valley Road to serve as a gateway treatment. Tree removal.The proposed project would remove 14 of the existing 54 mature trees (approximately 25 percent)from the project site. Of these trees, several are in the vicinity of Alhambra Valley Road and removal would likely be noticed by viewers along that roadway. Trees removed along the western portion of the site would be less noticeable because of the viewing distance and the number of trees remaining in place. Landscaping. It is reasonable to expect that the owners of each of the 23 new residences would improve their homes with landscaping.These landscapes may take on a wide variety of appearances, which by style and contrast may be a noticeable visual element of the completed project. Developer-installed street landscaping would also be a new visual component of the site. Night lighting.The only existing sources of light originating from the site are from the residence at the western side of the parcel.The project proposes the installation of street fights along the interior roadways. Lights associated with the completed residential units are expected to be a visible aspect of the development.Two-story units have the potential for greater visible nighttime illumination. Sensitive Viewers A change in perceived visual character must be evaluated in terms of viewer response to that change. Planning policies and guidelines are indicators of the general level of community sensitivity regarding the aesthetic character of the region and of the project area. The local policies Alhambra Valley Estates Draft EIR 3-9 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES identified in the Regulatory Setting section illustrate that the community,places a high value on the scenic qualities of the area. Because of community sentiments expressed in local planning documents, it is reasonable to conclude that project characteristics which alter scenic qualities such as rural character of the landscape, views of the surrounding hillside, ridgelines and waterways may cause a high degree of local interest and concern. Considering the typical activities of potential viewers in the area, generalizations can be made regarding their relative awareness and likely visual perceptions of the proposed project. Due to its somewhat prominent location at the intersection of two well-traveled arterials, and its proximity to a gateway node,the project has the potential to be seen by many community residents and visitors, including bicyclists and motor vehicle users. The sensitivity of the viewer group depends on the specific activity, but all viewers are generally expected to have a high degree of appreciation for existing scenic qualities and a negative response to changes that are inconsistent with the present visual character. The community's priorities and interest regarding the overall aesthetic character of the area can be determined by reviewing all applicable planning documents and guidelines. Review of planning documents shows that residents of Contra Costa County place a high value on retention of existing visual resources. Areas of Potential Environmental Concern The following are areas of potential environmental concern that may be associated with implementation of the proposed project: • The potential to have a substantial adverse effect on a scenic vista • The potential to substantially degrade the existing visual character or quality of the site and its surroundings • The potential to create a new source of substantial light or glare which would adversely affect nighttime views in the area. Determination of the project's potential effect on these three areas of environmental concern is based in part on focused analysis of the following elements: • Overall visibility of the project • View blockage of surrounding hillsides and ridgelines • Tree removal • Site layout • Residential and other structures • Landscape improvements • Lighting and glare • Cumulative impacts to the community The following topics are areas of potential environmental concern that may be associated with implementation of the proposed project: • The potential to have a substantial adverse effect on a scenic vista • The potential to substantially damage scenic resources, including trees, rock outcroppings, and historic buildings 3_10, Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES • The potential to substantially degrade the existing visual character or quality of the site and its surroundings • The potential to create a new source of light and glare Thresholds of Significance The determination of significance for the proposed project was based on applicable policies, regulations, goals, and guidelines defined by CEQA, the CEQA Guidelines, and Contra Costa County. CEQA Thresholds. Section 15064.7 of the CEQA Guidelines states that each public agency is encouraged to develop thresholds that the agency uses in the determination of the significance of environmental effects. The section further states that uA threshold of significance is an identifiable quantitative, qualitative or performance level of a particular environmental effect, non-compliance with which means the effect would normally be determined to be significant by the agency and compliance with which means the effect normally would be determined to be less than significant". According to Section 15382 of the CEQA Guidelines, an effect on the environment is considered to be significant if it is a substantial, or potentially substantial adverse change in any of the physical conditions within the area being studied, "Including...objects of aesthetic significance."Appendix G of the CEQA Guidelines defines a project as having a significant visual effect on the environment if it would "have a substantial, demonstrable, negative aesthetic effect." Contra Costa County. Contra Costa County planning documents do not contain specific criteria for determining thresholds of significance regarding visual resources. The community's standards for determining aesthetic impacts, policies and goals are found in the Open Space Element and Circulation Element of the General Plan,the Alhambra Valley Specific flan, and the Zoning Ordinance. The visual impact assessment conducted for the proposed project determined which specific criteriacontribute most to the existing quality of available views, and if change would occur to that criteria as a result of the project. If a change in visual criteria was identified, this change was analyzed for its potential affect on the existing scenic character. This analysis was combined with the potential number of viewers, their sensitivities, and viewing duration in order to determine the overall level of impacts. Specifically, the project would be considered to have a significant effect on the environment if the effects exceed the significance criteria described below. Substantial adverse effect on a scenic vista. If the proposed project could significantly degrade the scenic landscape as viewed from public roads, or in particular designated scenic routes,or from other public areas,this would be considered a potentially significant impact on the scenic vista. The scenic landscape in this case includes views of identified scenic ridgelines as a backdrop to the project site and community setting.The degree of potential impact on scenic vistas would vary with factors such as viewing distance, duration, viewer sensitivity, and the visual context of the surrounding area. Degradation of visual character or quality of the site. Project related actions would be considered to have a significant impact on the visual character of the site if they altered the area in a way that significantly altered,detracted from,or degraded the visual quality of the site for moderately sensitive viewers in the area and was inconsistent with community policies regarding visual character.A fundamental change in visual character is inevitable with the conversion of vacant land to a residential subdivision. The degree to which that change reflects documented community values and meets neighbors'and other viewers' aesthetic expectations is the basis for determining levels of significance.Visual contrast may Alhambra Valley Estates Draft EIR 3-11 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES be used as a measure of the potential impact that the project may have on the visual quality of the site. Project components that are not subordinate to the landscape sating could result in a significant change in the composition of the landscape. If a strong contrast occurred where project activities attract attention and dominate the landscape setting,this would be considered a potentially significant impact on visual character or quality of the site. Create substantial new source of lighting adversely affecting nighttime views.The project would result in a significant impact if it subjected adjacent residents to a substantial amount of point-source lighting visibility at night,or if the collective lamination of the project resulted in a noticeable spillover effect into the nighttime sky,increasing the ambient light over the region.The degree of impact caused by night lighting would consider the type of lighting proposed by the project applicant along with the lighting reasonably expected to be generated by the future residential occupants. The placement of lighting,source of illumination, and fixture types combined with viewer locations,adjacent reflective elements, and atmospheric conditions can affect the degree of change to nighttime views. If the project results in direct visibility of a substantial number of lighting sources,or allows a substantial amount of light to project toward the sky,significant impacts on nighttime views and rural aesthetic character will result. Analysis Methodology To ensure a thorough analysis of the project's potential effects,visual resources both on and off- site were inventoried and potentially sensitive viewer groups and viewing locations were identified. Locations and heights of proposed residences were identified by surveyed placement of reference pylons, and by comparison with the known dimensions of existing on-site elements. The project applicant prepared a tree removal plan and specific trees proposed for removal were tagged in the field. The project applicant provided surveyed locations and ground elevations of project features. Based on overall visual access to the site, dominance of the site within the view, duration of views, expected sensitivity of the viewer group, and community interests as defined in local planning policy, Key Viewing Areas (KVAs)were selected for further analysis (Table 3.1-'1 and Figure 3.1- 1). Photographs were taken from the Key Viewing Areas, and photo-simulations were prepared illustrating a likely appearance of the project as proposed. The emphasis of the photo-simulations was on structure massing, tree removal, roadside improvements and the project's relationship to the surroundings. The photomontages illustrate three photos from each Key viewing Area: * Existing • Proposed Project • Proposed project with mitigation The baseline photographs for the photomontages were taken from the travel lanes of Alhambra Valley Read. The massing of single family residential units along in each of the four views of the project site were based on the setbacks for each of the depicted lots as established by the R-20 Zoning district: • 25 foot setback from the property line along the north-south segment of Alhambra Valley Road(KVA 1A,KVA IS, and KVA 2) « 15 foot setback from the property line along the east-west segment of Alhambra Valley Road(KVA 3) The depiction of one and two story single family detached residential units along the project site's Alhambra Valley frontage in the "View of Proposed Project"photomontage were based on the applicant's proposed limitation of one and two story units: 3-12. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSI=S Table 3.1-1: Key Viewing Areas KVA Location Figure No. KVA 1A From Alhambra Valley Read looking southwest 3.1-2 KVA 113 From Alhambra Valley Road looking northwest 3.1-3 KVA 2 From the intersection of Alhambra Valley and Reliez Valley Roads looking 3.1-4 northwest KVA 3 From Alhambra Valley Road west of Reliez Valley Road looking north 3.1-5 SOURCE:Carr 2003 • Lots 1, 5, 6, and 22 would be developed with 1-story residential units • Lots 2-4,7-21,and 23 would be developed with either 1-or 2-story residential units The residential unit attributes depicted in the "View of Proposed Project"and "Proposed Project with Mitigation" photomontages were based on the applicants proposed limitations for development of the lots: • 3,0100 to 4,500 square feet in size,excluding garages • 1-story units would not exceed 27-feet in height • 2-story units would not exceed 35-feet in height • All residential units would be developed with three-car garages A preliminary concept rendering was provided by the applicant illustrating how the proposed residences might appear along Alhambra Valley Road'. The concept elevations were used as a basis for understanding the general potential structure massing and architectural styles that might be constructed upon approval of the proposed subdivision. Based on these elevations, images of existing residences in the region with similar size and form were included in the photo-simulations. The photo-simulations were analyzed and used to assist in quantifying potential project and visual resource visibility, to assess related character impacts, and to develop mitigation measures if necessary. Project Visibility. Determining the extent of the proposed project's visibility is a critical step in analyzing its potential visual impacts. Field review shows that visibility of the project is limited to sections of Alhambra Valley Road and the intersection of Alhambra Valley and Reliez Valley Roads. Because of existing residential development and landscaping, views from the north-south oriented Alhambra Valley Road are limited to the segment immediately adjacent to the project site. Project visibility from the east-west segment of Alhambra Valley Road (west of the intersection with Reliez Valley Road) is generally unimpeded across the intervening undeveloped parcel that fronts on that',east-west segment of Alhambra Valley Road. Existing development and planting screen views from other locations. As part of the project visibility determination, three key viewing locations were selected to illustrate the appearance of the proposed project as seen from the adjacent roadways. These viewing locations are shown on Figure 3.1-1. Photo-simulations from these locations, depicting landscape materials at approximately 8 to 10 years of growth, can be seen in Figures 3.1-2 through 3.1-5. 1 The applicant has not proposed construction of the residential units on the project site,nor has the applicant proposed specific architectural designs for the future residential units. Alhambra Valley Estates Draft EIR 3-13 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-1: Key Viewing Areas 12 k W 4g, �. x - "Y 'e Y2 t j a \ J/d+Kw�t�' � '..� 'S•R �.'`i A s __... 22 a x � 4 Fm KVA � via n � hY x aa.4 F � � h '-- .•ai-',` `w" g w :. e -. .,-,K ,.�-_-.r-... fi a A..t;,., a ,, .d� ,.. S. '& r� X- s .::-, �ffi..,.....�.r_.:,--.•---'-A .. SOURCE: PIA Design Resources, Inc. and carr 2003 Potential Impacts and Mitigation The potential effects of the project on scenic vistas, visual character, and overall visual quality are identified through analysis of the relevant project actions and characteristics. The following discussion addresses the potential effects of the proposed project by individual resource or project related actions: Potential Impact 3.1-1: Substantial adverse effect on a scenic vista Within the context of the project site, scenic vistas include the project site and the hillsides beyond the site to the north. The interior portions of the project site are openly visible from the east-west leg of Alhambra Valley Read. Views to the site's interior from the north-south portion of Alhambra Valley Road are partially filtered by the project's existing edge landscape. Views beyond the site to the northern hills are generally unobstructed from the east-west leg of Alhambra Valley Road and filtered as described above along the north-south roadway segment.. Views of the hills are also available from westbound travel along Rellez Valley Road as it descends a shallow grade to its intersection with Alhambra Valley Road. Among the proposed project's attributes that could alter scenic vistas are tree removal, site design, residential structures, and landscape improvements. 3-14. Alhambra Valley Estates Draft EIR March 2004 ........................................................ _ 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-2o Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road Looking Southwest(KVA 1A) -Existing view View of proposed projject r. Lot 6 Lot 5 Lot 4 all Proposed project with mitigation L11 9 Mill SOURCE:Garr 2003 Alhambra Valley Estates Draft EIR 3-15 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-3: Pre, Post; and Mitigated Development Views of the Project from Alhambra Valley Road Looking Northwest(KVA 9 B) Existin, view View of proposed project of 3 Lot'2. Lot 22 Proposed prqject with,rz3iti Iation SOURCE:Carr 20013 3-16. Alhambra Valley Estates Draft E1R March 2004 3. ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-4. Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road and Reliez Valley Road Looking Northwest(KVA 2) Existing view a., 3 View of proposed project } E k 6 r " i Proposed project with mitigation N-� mommm 'r i SOURCE:Carr 2003 Alhambra Valley Estates Draft EIR 3.17 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-5 Pre, Post, and Mitigated Development Views of the Project from Alhambra Valley Road west of Reliez Valley Road Looking North (KVA 3) Existing View 1 View of Proposed Project F71 , i WE - i. f , Proposed Project with Mitigation 3-s , SOURCE:Carr 2003 3`18• Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Tree Removal. Fourteen trees are proposed for removal: 3 along the site's Alhambra Valley Road Frontage, and 11 throughout the interior. The proposed removal would temporarily open views to and across the site to the hills beyond, although those views would be modified by the construction of new residential units and by new landscaping along the Alhambra Valley Road frontage. The widening of the roadway per the Alhambra Valley Specific flan will result in the removal of 3 trees. The trees are located along the site's Alhambra Valley Road frontage near the existing paved roadway. The proposed removal of these trees would be highly visible. The trees are shown in Figure 3.1-6. The size and canopy of the Valley Oak, California Black Walnut, and Camphor trees (identified as trees 4, S, and 6 respectively on the Existing Trees Exhibit(February 20, 2002)) would be immediately noticeable to viewers along the north-south portion of Alhambra Valley Road. `hese trees presently contribute to a canopy and spatial quality that supports the rural visual character valued in planning documents for the Alhambra Valley.Although each of these trees contribute to the visual quality of the corridor, the 43-inch diameter Valley Oak located at the proposed intersection of peer Creek Court and Alhambra Valley Road has the most scenic value. One 40-inch diameter Valley Oak(tree number 1)may be preserved along Alhambra Valley Road and would maintain some of the existing vegetated dualities of the area. Based primarily on their size and location, removal of the existing roadside trees would result in a substantial reduction of visual quality along Alhambra Valley Road, and thus, the generation of a significant visual impact. Landscape Improvements. The project proposes to provide landscaping along the internal roadways and along Alhambra Valley Road. Street trees are proposed along the internal roads. A combination of native and non-native trees, shrubs, and ground cover would be included with the roadside improvements along the Alhambra Valley Road frontage. The entry island at the proposed intersection of Deer Creek Court and Alhambra Valley Road, and the"gateway" treatment near the corner of Alhambra Valley Road and Reliez Valley Road would receive special landscaping. A wide variety of landscape plantings and amenities would be associated with the individual residences. The visibility of this landscaping would in time re-establish some of the vegetated character along Alhambra Valley Road and the project site, although this landscaping could also contribute to a more suburban-style appearance than what currently exists, and could detract from the rural character of the Valley. This could be regarded as a potentially significant visual impact. Mitigation Measure 3.1-1 would reduce the potential impact associated with the proposed removal of trees along the site's Alhambra Valley Road frontage to a less than significant level. Mitigation Measure 3.1-1. Prior to recordation of the Final Map and approval of Improvement flans,the applicant shall submit a revised landscape plan to the Zoning Administrator for review and approval. a) The revised plan shall illustrate the use of a greater range of plant species that are native to the area. b) The revised plan shall include non-linear plantings of all landscape materials. The plan shall indicate the installation of all landscape materials in informal, naturally appearing groupings. The overall goal of the revised plan shall be to portray a design that is natural in appearance. c) The applicant shall implement the revised landscape plan. Site design. The proposed lots range from 20,0302 to 37,388 gross square feet in size, which is visually consistent with other development in the area and along this segment of Alhambra Valley Road. Because of the relative flatness of the site, the lots along Alhambra Valley Road are the most directly visible. The remainder of the lots to the west would be noticeable by the visibility of the residential units on them and would define the perceived density of the development. Alhambra Valley Estates Craft EIR 3-19 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Figure 3,1-6: Trees Proposed for Removal Along Alhambra Valley Road x #4 Valley Oak r: Y_ Y #6 California Black Walnut #6 Camphor SOURCE:Contra Costa County 2404 3-20. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL. IMPACT ANALYSES The overall site layout appears to respond to the setting in a way that minimizes visual impacts with two exceptions: the connection point of the proposed neer Creek Court at Alhambra Valley Road, and the driveway access from Lot 6 onto Alhambra Valley Road. The site design isolates Lot 6 from access to the interior circulation system, requiring a driveway to be constructed onto Alhambra Valley Road. This driveway connection would slightly increase the built characteristic of the project as seen from Alhambra Valley Road, and to a lesser extent, from Reliez Valley Road, yet does not comply with the Alhambra Valley Specific Plan's Goal 2, Policy 2. Entry Island. The applicant has proposed an entry island design at Deer Creek Court that is visually reminiscent of entry islands typically associated with formal urban/suburban subdivisions (Figure 3.1-7). This would be in direct contrast to the area's existing and planned rural character. The formal design of the entry island is in direct contrast to the area's existing aesthetic, and would represent a potentially significant visual impact. Both of these proposed project elements would result in a visual impact that can be mitigated to less than significant levels with the implementation of Mitigation Measures 3.1-2 and 3.1-3. Mitigation Measure 3.1-2. Prior to recordation of the Final Map, the applicant shall submit Improvement Flans to the Contra Costa County Public Warks Department that delineate a revised vehicular access for Lot 6 in a manner such that it takes its vehicular access of off the subdivision's internal roadway system and not off of Alhambra Valley Road. Mitigation Measure 3.1-3.Prior to recordation of the Final Map, the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that delineate a revised entry to the project site off of Alhambra Valley Roam.The entryway shall delete the center island. - Residential Structures, The applicant has proposed that 1-story residential units should be limited to a maximum height of 27-feet, while 2-story units should be limited to a maximum height of 35-feet. Review of scaled photomontages suggests that residences constructed along the Alhambra Valley Road frontage would block views of the hills to the southwest, west and northwest as seen from the Alhambra Valley Road frontage. Both one and two story structures would silhouette above the ridgelines looking from various locations along the Alhambra Valley Road frontage. The space between residential structures is expected to allow for some visibility to the hills beyond because of the size of the lots. Although the proposed residences would block some views to the hills, the removal of existing trees along Alhambra Valley Road would open up similar views. As a result no net loss of hillside views is expected, although as the proposed edge landscaping matures those views may incrementally diminish. When viewed from Alhambra Valley Road, the materials and details of the residences along the _ site's Alhambra Valley road frontage would be visible to the average viewer. The preliminary residential unit design concepts suggested by the applicant show a range of architectural styles somewhat typical of recent residential construction through the region. The applicant favored a mostly California bungalow style, with hip and gable roof forms. Exteriors appear to include horizontal siding, stone facades, and stucco finishes. The visibility of these structures and their proximity to the viewing corridor would inherently alter the visual character of the site. The two- story residences would have a greater effect on the visual character of the site and its setting than the single-story residences. This could be regarded as a potentially significant impact on a scenic vista. Mitigation Measure 3.1-4 would reduce that potential impact to a less than significant level. Mitigation Measure 3.1-4. Residential units constructed on Loots 1, 3 through 6, 22, and 23 shall be limited to one-story and a maximum height of 27 feet Alhambra Valley Estates Draft EIR 3.21 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-7: Proposed Entry Island r Z OAKS f." , 71 E . ., I rt y✓1 s z SOURCE: P/A Design Resources, Inc. 2003 Potential Impact 3.1-2: Substantial damage to scenic resources, including trees, rock outcroppings, and historic buildings The proposedproject would not result in significant damage to scenic resources. Implementation of the proposed project would require removal of 14 trees; however, 40 mature trees will remain and additional landscaping will be implemented. After full development of the project site horticultural practices could lead to the premature demise of trees proposed for retention or to be installed as part of the project. Demise of these trees could be considered a significant impact on scenic resources; however, implementation of Mitigation Measure 3,1-1 would reduce these impacts to less than significant levels. There are no significant rock outcroppings on the.project site. There are also no structures of historic significance that would be affected by the project's implementation. Potential Impact 3.1-3: Substantially degrade the existing visual character or quality of the site and its surroundings The project site and the area's visual quality can be summarized as principally rural in character, as evidenced by the random pattern of residential development and associated improvements, the rural design of Alhambra Valley Road (no curb and gutter, unpaved shoulders, encroaching vegetation),and the intermittent open parcels of land. There are a variety of architectural styles exhibited by existing residential units. There are elements of the proposed project that could negatively impact the existing visual character of the area Gateway. The Alhambra Valley Specific Plan designates the intersection of Alhambra Valley and Reliez Valley as a "Valley Gateway"that requires'special treatment that would help to frame a viewer's perception as they pass through the area, The Specific Plan also states that its intent is to "preserve the existing views from these gateways." 3-22. Alhambra Valley Estates draft EIR March 2004 ................................ 3: ENVIRONMENTAL IMPACT ANALYSES The applicant has proposed a landscape design for the Gateway (proposed Lot A) that includes a mixture of drought tolerant flowering shrubs and groundcover and crape myrtle trees set against a backdrop of a 5-foot nigh wood rail fence with a low stonewall in the foreground (Figure 3.1-8). The proposed design would not be expected to significantly obstruct views of the site. The proposed Gateway design includes elements that would appear more comparable with those found in a typical urban/suburban setting, rather than with the rural character that is favored by the Specific Plan. Those elements include ornamental landscape materials and the stonewall. This could be considered a potentially signif=icant impact on the area's visual character. Mitigation Measure 3.1-5 would reduce the potential impact to a less than significant level. Mitigation Measure 3.1-5.Prior to recordation of the Final Map and approval of Improvement Plans, the applicant shall submit a revised Gateway design plan to the Zoning Administrator for review and approval. The revised plan shall illustrate the exclusive use of plant species that are native to the area. Building Finish Color. The applicant has not proposed a specific range of finish colors for the future residential units. The potential exists for the use of colors that would not be muted and which would not compliment and blend with the rural setting of the project site. This could be regarded as a potentially significant impact. Mitigation Measure 3.1-6 would reduce this impact to a less than significant level. Mitigation Measure 3.1-6. Prior to issuance of building permits,the applicant shall submit architectural plans, color schemes, and elevations of the residential units to the Zoning Administrator for review and approval. The plans and elevations shall demonstrate the following: a) Exterior wall colors shall be limited to muted earth tones.The use of bright colors shall be avoided. b) Roof colors shall be limited to muted earth tones. Highly reflective materials shall be prohibited. c) Materials and colors shall be less than 50%reflectivity. Mitigation Measure 3.1-7. Prior to recordation of the Final Map,the applicant shall submit to the Zoning Administrator for review and approval language to be incorporated into a Geed Restriction for each of the lots and the project-wide Covenants, Godes, and Restrictions (CC&Rs).The Deed Restriction or project CC&Rs shall state that future home improvements must comply with the requirements identified in Mitigation Measure 3.1-6 and the Design Guidelines in the Alhambra Valley Specific Plan. Potential Impact 3.1-4: Creation of a new source of light and glare Development of the proposed project would add two new sources of light and glare. Nighttime lighting associated with the individual residential units, particularly those on the project site's edges, would be expected to be similar to residential lighting already in use throughout the Valley and would not represent a potentially significant impact. The proposed installation of streetlights throughout the project site's interior would represent a potentially significant new source of light and glare (Figure 3.1-9). The applicant has proposed the installation of streetlights that feature a glass globe atop a 14-foot past. If unshielded, the globes would allow light to leave the project site in the horizontal and vertical direction, which represent a significant impact with respect to the addition of light and glare within the Valley. Mitigation Measure 3.1-8 would reduce that impact to a less than significant level. Alhambra Valley Estates Draft EIR 3023 March 2004 3. ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-8; Alhambra Valley Estates— Proposed Gateway Treatment Detaii F, \ ^.rte 4 H,.�� } •�'i � F 3 *..r«_sM -. -�,;yn ' t r,' ,. va.x m:.rsE.'C- -^�'x�'. mow,-ti,✓sr w, SOURCE: P/A Design Resources, Inc, 2003 Figure 3.1-9; Proposed Landscape Design at Alhambra Valley Road r' F4 { �k. .� d a _. SOURCE: PIA Design Resources, Inc. -- ... _-- `_._..._ _.._._.___..... _. ........... .__ _.. ---_..... ._. . .._.._ 3-24. Alhambra Valley Estates.Craft EER March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-10: Proposed Street Light Fixture L—UM 3 AP* t i i E i 3 u SOURCE:PIA Design Resources, Inc. Mitigation Measure 3.1-8. Prior to recordation of the Final Map and approval of Improvement Plans,the applicant shall submit a revised street light fixture plan to the Zoning Administrator for review and approval.The revised plan shall include the use of shielded futures/globes that direct light downward, and have an incandescent light color. 3.2 Agricultural Resources ENVIRONMENTAL SETTING Contra Costa County has experienced a decreasing tread in the amount of acreage in agricultural production since 1940. Much of this decline is attributable to regional increases in urbanization, a process that over time gradually converts agricultural lands to housing and other urban uses. The project site has historically been used for a variety of agricultural pursuits, and currently, with the exception of a small planting of hay, is not actively farmed. REGULATORY SETTING Contra Costa County General plan The County General Plan's Conservation Element outlines goals, policies, and implementation measures designed to conserve and preserve agricultural resources. The Element's direction that is applicable to the project site and the proposed project follows: Alhambra Valley Estates daft EIR 3-25 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Agricultural Resources Policies 8.31. Urban development in the future shall take place within the Urban Limit Line and areas designated by this plan for urban growth. 8.34. Urban developments shall be required to establish effective barriers between them and land planned for agricultural uses. Lands defined by the County as agriculturally important are identified on Figure 8-2 of the Conservation Element. The project site is defined as agriculturally important on Figure 8-2 of the Conservation Element. Alhambra Valley Specific Plan The Alhambra Valley Specific Plan fully encourages the retention and maintenance of existing agricultural uses, as long as they prove to be viable economic pursuits.Among the Specific Plan's goals and policies that lend support to agricultural activities are: Goal 1: To encourage and enhance agriculture and to maintain and promote a healthy and competitive agricultural economy in Alhambra Valley. Policy 1.Agriculture shall be protected to maintain the semi-rural atmosphere and to retain a balance of land uses in Alhambra Valley. Policy 2. The County shall encourage agriculture to continue operating adjacent to areas of planned urban development. Goal 2: To minimize and resolve conflicts between agricultural and urban uses. Policy 1: Establish regulations for new development that ensure its compatibility with agricultural uses. Policy 2: Allow only development that is compatible with existing agricultural, residential and open space uses. Policy 4: Inform and educate prospective homebuyers in or near agricultural areas regarding the nuisance and hazards associated with nearby agricultural practices. Policy 5: Agriculture shall be protected from nuisance complaints by non- agricultural land uses. ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following are areas of potential environmental concern that may be associated with implementation of the proposed project: • The potential to convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance(Farmland), as shown on maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use • The potential to conflict with existing zoning for agricultural use • The potential to conflict with a Williamson Act contract • The potential to Involve other changes in the existing environment, which,due to their location or nature, could result in conversion of Farmland to non-agricultural use 3-26. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Thresh'ol'd of Significance The following threshold of significance is used to determine the level of impact for areas of potential environmental concern. The project would have a significant effect if it would: • Irreversibly convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance to non-agricultural use + Convert agricultural resources to non-agricultural uses in conflict with the Contra Costa County General Plan or the Alhambra Valley Specific Plan Impacts and Mitigation Impact .2-1: Conversion of Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use. The project site is rated as Unique Farmland on the Contra Costa County Important Farmland 2002 map, by the Farmland Mapping and Monitoring Program, California department of Conservation, Division of Land Resource Protection. Implementation of the proposed project would irreversibly convert the site to non-agricultural uses, and in so doing, would convert 15.02 acres of land defined by the State,as unique farmland to non-agricultural uses. This conversion of agricultural land would be considered a potentially significant impact. The Department of Conservation Farmland Mapping and Monitoring Program (NRCS) indicates that: "Unique Farmland is land of lesser quality soils used for the production of specific high economic value craps (as listed in California Agriculture produced by the California Department of Food and Agriculture)at some time during the two update cycles prior to the mapping date. It has the special combination of soil quality,location, growing season, and moisture supply needed to produce sustained high quality or high yields of a specific crop when treated and managed according to current farming methods. Unique Farmland is usually irrigated, but may include nonirrigated orchards or vineyards as found in some climatic zones in California. Examples of crops on Unique Farmland include oranges, olives, avocados, rice,grapes, and cut flowers. Unique Farmland does not include publicly owned lands for which there is an adopted policy preventing agricultural use." Irrigated row crops have not been planted on the property, and the project is surrounded by residential development. The Alhambra Valley Specific Plan has designated the parcel for Single Family Residential, Low Density land use. The Specific flan also designates areas for agricultural preservation, and the proposed project site is not designated for protection. The project site is not listed as "Important Agricultural Lands"on Figure 8-2 of the General Plan. General Plan Policy 8-H directs the County"To conserve prime productive agricultural land outside the Urban Limit Line jULLj exclusively for agriculture."The project parcel is not outside the Urban Limit Line. General Plan Policies 8;31 and 8.84 state that urban development in the future shall take place withintheUrban Limit Line and areas designated by this plan for urban growth, and projects shall be required to establish effective barriers between them and land planned for agricultural uses. Irrigated row crops or agricultural crops have not been planted on the property for years. The site previously had a Christmas tree farm on a portion of the site, however those trees are no longer there. The project is surrounded by residential development. The following mitigation measure will ensure land elsewhere in the county is available to farming. Alhambra Valley Estates draft EIR 3-27 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Mitigation Measure 3.2-1. Prior to recordation of the final map, the applicant shall dedicate to Contra Costa County or to an Agricultural Trust a conservation easement for a minimum of 15 acres of existing agricultural land located in the County, unless Land Evaluation and Site Assessment(LESA) modeling demonstrates that the impact of the agricultural conversion would not be significant.The purpose of the conservation easement shall be to assure that the land remains available for farming. The land shall be available as closely as possible to the project area,to the satisfaction of the Zoning Administrator. The dedication and proposed conservation easement for the property shall be submitted to the County for review and approval. Impact 3.2-2: Conflict with existing zoning for agricultural use The project site is situated within two zoning districts—the R-20 Single-Family Residential District and the A-2 General Agricultural District. Both zoning districts are consistent with the Alhambra Valley Specific Plan's Single Family Residential, Low Density land use designation. The A-2 District would not allow the creation and development of the proposed 20,000 square foot residential lots. The proposed project is shown on the Alhambra Valley Specific Plan Land Use Map as Single Family Residential–Low. The applicant is seeking approval of a Rezoning of the 4.6 acres of A-2 District lands with the project area to the R-20 District, which if approved, would allow full project implementation. If the Rezoning is approved, there would not be an associated environmental impact due to conflict with agricultural zoning. No mitigation would be required inasmuch as the Rezoning would represent the mitigation for the current zoning conflict and would comply with the Alhambra Valley Specific Plan Land Use Map. Impact 3.2-3: Conflict with a Williamson Act contract The project site is not under a Williamson Act contract, and therefore, implementation of the proposed project would not result in any impacts associated with provisions of such a contract. Impact 3.2-4: Other changes In the existing environment,which, due to their location or nature, could result in conversion of Farmland to non-agricultural use Implementation of the proposed project would site urban uses immediately adjacent to lands designated for agriculture and open space uses. The immediate proximity of urban uses to agricultural activities (existing or future)would subject the site's future residents to the effects of agricultural activities, including noise, dust, odors, smoke, and the application of agricultural chemicals. Contra Costa County has established a "right to farm"ordinance, which in essence is designed to protect and promote agricultural activities, especially at the urban/agriculture interface (Contra Costa County Code, Title 8, Chapter 820-2). In part, the right to farm ordinance is designed to: "...promote a good-neighbor policy by requiring notification of purchasers and users of property adjacent to or near agricultural operations of the inherent potential problems associated with such purchase or residential use. Such concerns may include, but are not limited to, the noise, odors, dust, chemicals, smoke, and hours of operation that may accompany agricultural operations. It is intended that,through mandatory disclosures, purchasers and users will better understand the impact of living near agricultural operations and be prepared to accept attendant conditions as the natural result of living in or near rural areas." While implementation of the proposed project will place urban uses in close proximity to lands designated for agricultural use, the "right to farm" ordinance is designed to adequately mitigate any potential conflicts between the uses. In so doing, the "right to farm" ordinance is intended to halt, or 3-28. Alhambra Valley Estates Draft EIR March 2004 ............................................................. 3: ENVIRONMENTAL IMPACT ANALYSES at the very least slow, the potential conversion of agricultural lands to urban use, and therefore, a significant impact is not expected to occur. Further, the following mitigation measure would further the Code's intent with regard to notification to all affected property owners of the existence of active, nearby agricultural activities. Mitigation pleasure 3.2-2.Concurrent with recordation of the Final Map, the following. statement shall be recorded at the County Recorder's Office for each parcel within the subdivision to notify owners of the lots that they own property in an agricultural area: "This document shall serve as notification that you have purchased land in an agricultural area where you may regularly find farm equipment using local roads;farm equipment causing dust;crop dusting and spraying occurring regularly; burning associated with agricultural activities; noise associated with farm equipment and aerial crop dusting and certain animals and flies may existing on surrounding properties. This statement is,again, notification that this is part of the agricultural way of life in the open space areas of Contra Costa County and you should be fully aware of this at the time of purchase." 3.3 Air Quality ENVIRONMENTAL SETTING The climate of the project vicinity, like much of the San Francisco Bay Area region, is generally semiarid and temperate. The San Francisco Bay Area climate is Mediterranean in character, with mild, rainy weather from November through April, and warm, dry weather from May through October. Average monthly temperatures in the project vicinity generally range from about 50OF in winter to 72°F in summer. The average annual precipitation its the vicinity of the proposed project is about 19 inches per year(World Climate 2003). Under certain atmospheric conditions, dispersion of air pollution can be restricted. Rainy periods usually'coincide with the rapid movement of pressure systems, causing increased horizontal movement, increased vertical mixing of air, and thus lower pollution levels, however, dry periods also occur during the winter, resulting in less ventilation, and the build up of pollutants. Elevated pollutant levels are also common during hot, sunny summer afternoons, when temperature inversions limit vertical mixing. REGULATORY SETTING Federal The federal Clean Air Act(CAA) requires the U.S. Environmental Protection Agency(EPA)to identify ambient air quality standards (AAQS)to protect public health and welfare. Federal AAQS have been set for the following pollutants: • Particulate matter less than 10 microns in diameter(PM10) • Particulate matter less than 2.5 microns in diameter(PM2.5) • Carbon monoxide(CO) • Oxides of nitrogen: (NOx) • Ozone(03) + Sulfur dioxide(SO2) • Lead(Pb) Alhambra Valley Estates Draft EIR 3_29 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES These pollutants are called "criteria" pollutants because the standards satisfy criteria specified in the CAA. Pursuant to the CAA, the EPA has classified air basins (i.e., distinct geographic regions) as either "attainment" or"non-attainment'for each criteria pollutant, based on whether or not the federal AAQS have been achieved. Some air basins have not received sufficient analysis for certain criteria air pollutants and are designated as "unclassified"for those pollutants. Contra Costa County is located in the San Francisco Bay Area Air Basin. At the federal level, the Bay Area has been designated as attainment for CO, NOX, SO2, and Pb and as non-attainment for 03, PM10, and PM2.5 (BAAQMD 2003). State The California Air Resources Board (CARS) is the state agency responsible for regulating mobile source (vehicle) emissions and overseeing the activities of local air pollution control districts (APCDs). In addition, CARS has established state AAQS. The state AAQS are generally more stringent than the federal AAQS. Under the California Clean Air Act(which was patterned after the federal CAA), areas have been designated as attainment, non-attainment, or unclassified with respect to state ambient air quality standards. The federal and California state ambient air quality standards for criteria pollutants are summarized in Table 3.3-1. Bay Area Air Quality Management district. The San Francisco Bay Area Air Basin is under the jurisdiction of the Bay Area Air Quality Management District (BAAQMD). BAAQMD regulates air quality through its permit authority over most types of stationary emission sources and through its planning and review activities. BAAQMD no longer monitors for lead in the air basin due to extremely law levels, and has ceased monitoring for S02 at selected monitoring stations in the air basin for the same reason. At the state level, the Bay Area has been designated as attainment for CO, NOx, S02, and Pb and as non-attainment for 03 and PM10 (BAAQMD 2003). In response to the California Clean Air Act, BAAQMD developed the Bay Area `94 Clean Air Plan (CAP).The CAP describes the Bay Area's current plans for meeting state clean air laws. The goal of the CAP is to improve air quality in the region, especially for ozone,through the year 2000 and beyond through tighter industry controls, cleaner cars and trucks, cleaner fuels, and increased commute alternatives. The `94 CAP includes an integrated set of transportation control measures (TCMs) designed to meet the specific needs of the Bay Area. Measures include improved bicycle access and facilities, mobility improvements, employer-based trip reductions, user incentives, and implementation support measures. The District operates two air quality monitoring stations in the vicinity of the Alhambra Valley project site: one is located in Martinez(on Jones Street)and a second is located in Concord (on Treat Boulevard). The Martinez station only monitors sulfur dioxide (SO2). The Concord station monitors ozone (03), carbon monoxide (CO), nitrogen dioxide (NOZ), sulfur dioxide(SO2), and particulates (PM,a). Pollutant monitoring results for the years 199€3 to 2001 at the Concord station indicate that air quality in the Concord area has generally been good. Wind data for the nearby Diablo-San Ramon Valley shows a strong influence of terrain on wind. Winds are channeled by terrain, and the area is very sheltered, with relatively low average wind speeds and a very high frequency of calm conditions. The potential for air pollution in this area is high because of reduced ventilation and warm temperatures, which promote the formation of ozone. This area is also downwind from the highly urbanized areas of western Contra Costa and 3-30. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Table 3!3-1: Federal and State Ambient Air Quality Standards Pollutant Averaging Time Federal Primary Standard State Standard Ozone 1-Hour 0.12 ppm 0.09 ppm 8-Hour 0.08 ppm — Carbon Monoxide 8-Hour 9.0 ppm 9.0 ppm 1-Hour 35.0 ppm 20.0 ppm Nitrogen Dioxide Annual 0.05 ppm -- 1-Hour — 0.25 ppm Sulfur Dioxide Annual 0.03 ppm — 24-Hour 0.14 ppm 0.05 ppm 1-Hour — 0.5 ppm PM10 Annual 50µg/m3 30 gg/m3 24-Hour 150 Rg/m3 50µg/m3 Lead 30-Day Avg. — 1.5 Ag/m3 Month Avg. 1.5 gg/ms Ppm=parts per million µgtm3 r Micrograms per cubic meter SOURCE:US EPA 2001,GARB 2002 Alameda counties. As a result, ozone levels exceed the federal ambient air quality standard a few days each year. The standard for carbon monoxide is not exceeded, but the State particulate (PM,o) standard is exceeded several days per year(Contra Costa County 1995). Contras Costa County General Plan The Conservation Element of the Contra Costa County General Flan established several goals aimed at improving air quality within the County: 8-AA.To meet federal Air Quality Standards for all air pollutants 8-AS.To continue to support federal, State and regional efforts to reduce air pollution in order to protect human and environmental health 8-AC.To restore air quality in the area to a more healthful level 8-AD.To reduce the percentage of Average Daily Trak(ADT)trips occurring at peak hours ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following topics are areas of potential environmental concern that may be associated with implementation of the proposed project: The potential to generate a nuisance or increase air emissions from on-and off-site sources associated with the project Alhambra Valley Estates Draft EIR 3-31 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Thresholds of Significance The following thresholds of significance are used to determine the level of impact to areas of potential environmental concern. The project would have a significant effect if it would: • Conflict with or obstruct implementation of applicable air quality plans • Violate any air quality standard or contribute substantially to an existing or projected air quality violation • Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard(including releasing emissions that exceed quantitative thresholds for ozone precursors) • Create objectionable odors affecting a substantial number of people The BAAQMD has established thresholds of significance for certain air borne pollutants associated with project operations, as outlined in Table 3.3-2. Impacts and Mitigation Impact 3,3-1: The potential to generate a nuisance or increase air emissions from on-and off-site sources associated with the project Construction. Construction related emissions are generally short-term in duration, but may stili cause adverse air quality impacts. l=ine particulate matter(PM,Q) is the pollutant of greatest concern with respect to construction activities. PM,n emissions can result form a variety of construction activities, including excavation, grading, demolition, vehicle travel on paved and unpaved roads, and vehicle and equipment exhaust. Construction related emissions could cause substantial increases in localized concentrations of PM,o. Particulate emissions can lead to adverse health effects as well as nuisance concerns such as reducedvisibility and soiling of exposed surfaces. Implementation of the following measure would ensure that dust emissions from construction would not contribute substantially to a currently projected air quality violation. Mitigation Measure 3.3"1: Prior to issuance of a grading permit the applicant shall submit a grading plan to the Zoning Administrator for review and approval. The grading plan shall include measures to reduce emissions from construction equipment and wind blown soils that shall include, but shall not be limited to: a) Watering of disturbed soils as needed during dry periods b) Provisions requiring that all construction trucks leaving the project site carrying excavation spoils shall be covered c) Previsions to require the sweeping of Alhambra Valley Road and Reliez Valley Road if visible soil material is carried onto the roads d) On-site construction speed limit of 15 miles per hour e) Suspending excavation and grading activity when winds(instantaneous gusts) exceed 25 miles per hour(mph) f) Implementing other Best Management Practices to minimize particulate emissions as required by the County 3-32• Alhambra Valley Estates Draft EIR March 2004 ........................... - 3: ENVIRONMENTAL IMPACT ANALYSES Table 3.3-2: Thresholds of Significance for Project Operations Pollutant Tons/Year Pounds/Day Kilograms/Day Reactive Organic Gasses(ROG) 15 80 36 Nitrogen Dioxide(NO),) 15 80 36 Fine Particulate Matter(PM,o) 15 80 36 SOURCE:BAAQMD CEQA Guidelines 1999 Post Construct!on/Operation. Approval of the proposed project is expected to lead to the development of 23 single family detached residential units, which would lead to the generation of vehicular trips. Vehicular trips are the single greatest generator of air borne emissions for residential development. The traffic analysis conducted for this EIR projects that 2203 daily traffic trips would be generated after completion of residential construction. The expected increase of 220 trips would include 17 trips during the AM peak commute hour, and 23 trips occurring during the PM peak commute hour. Traffic effects are discussed in detail in Section 3.12, Transportation and Traffic. BAAQMD CEQA Guidelines were used to calculate emission effects from increased trips to and from the project site for the air borne pollutants of concern. Table 3.3-3 presents the results of the emission calculations. Table 3.3-2 identifies the thresholds for any of the air borne pollutants as 80 pounds per day for each individual pollutant. The proposed project would generate airborne pollutants at levels less than the BAAQMD's established thresholds, and therefore, a potentially significant environmental impact would not result from project operation. Table 3.3-3: Estimated Project Emissions Pollutant Emission Estimate ROG 1.97 lbs/day NO, 4.06 lbs/day PM,O 1.50 lbs/day SOURCE:MHA 2002 3.4 Biological Resources Section 3.4 of this EIR is based in pert on the peer review of the following biological resource reports prepared on behalf of the applicant: • LSA Associates, Inc. 2003,California Red-legged Frog Habitat Assessment for the Alhambra Valley Estates Project near Martinez, Contra Costa County May 2003. • Moore Biological Consultants. 2000. Biological resources inventory at the 16+/-acre Plummer property(Assessor's parcel No. 357-130-33), Martinez, CA. December 2001. • Traverso Tree Service 2002,Alhambra Valley Estates subdivision 8634.June 2002 • Traverso Tree Service 2002, Tree Survey @ the Plummer Property on Alhambra Valley Road. February 2002 Alhambra Valley Estates Draft EIR 3-33 March 2004 3; ENVIRONMENTAL IMPACT ANALYSES The listed references are available for review at the Contra Costa County Community Development Department, 6151 Pine Street, North Wing, 2nd Floor, Martinez, California. ENVIRONMENTAL SETTING Sensitive Species Sensitive Species.are defined as. • Species afforded protection under the Federal Endangered Species Act(FESA)and/or California Endangered Species Act(CESA) • Species proposed for listing under the FESA and/or CESA • Species afforded protection under sections of the California Fish and Game Code • Birds afforded protection under the Migratory Bird Treaty Act of 1918 • Species considered either Federal Special Concern species or California Special Concern species • Species that meet the definitions of rare or endangered species under CEQA • Plants considered sensitive by the California Native Plant Society • Species considered sensitive or important by local resource groups/agencies or the scientific community The following section includes a brief discussion of those sensitive plants and animals with the potential to occur within the project site. More information on these species' general and local ecologies can be found in the reports prepared on behalf of the applicant and listed in Section 7, References, of this EIR. Vegetation The majority of the project site has been used as pasture and formerly as a conifer tree farm. Non- native annual grassland species dominated the site's vegetation in the late Spring of 20022. Bull thistle (Cirsium vulgere), black mustard (Brassica nigra), and bristly ox-tongue (Picris echioides), is common. Several individual spruce (Picea sp.) remain from tree-farming operations along the periphery of the site. Grasses on-site are comprised mainly of oats (Avena sp.), soft chess brome (Bromus hordeaceus), and foxtail barley (Hordeum marinum). Large blue gum (Eucalyptus sp.), ornamental cedar(Cedrus sp.), valley oak (Quercus lobata), and coastal live oak(Quercus agrifolia) are scattered throughout the site. A well-developed riparian corridor borders the northwestern edge of the project site along the Vaca Creek reach. Vegetation associated with the corridor includes valley oaks, willow (Slalix sp.), sycamores(Platanus racemosa), and Himalayanblackberry(Rebus discolor). Table 3.4-1 lists the plant species observed during site assessments, many of which are typically associated with highly or moderately disturbed areas. Sensitive Plants. The California Natural Diversity Data Base (NDDB) (2003) lists 10 sensitive plant species within the Briones Valley 7.5-minute USGS quadrangle (project vicinity). Many of these species are not found on-site due to unfit habitat conditions(e.g., lack of vernal pools or 2 Since the biological reconnaissance conducted during preparation of this EIR the majority of the grasses on the site have been mowed/plowed in compliance with the county's weed abatement/fire protection requirements. 3-34. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Tabu 34-1: Plant Species Observed COMMON NAME SCIENTIFIC NAME Frees Box elder Acernegundo Tree of heaven Ailanthus altissima Deodar cedar Cedrus deodara Poison hemlock Conium maculatum Red iron bark eucalyptus Eucalyptus sideroxlon California black walnut Juglans califomica Sycamore Platanus racemose Coastal live oak Quercus agrifolia Valley oak Quercus lobeta Red willow Salix laevigata Blue elderberry Sambucus mexicana Redwood Sequoia sempervirens Shrubs Coyote brush Bacchads pilularis Bristle ox-tongue Picris echioides Wild rose Ross califomica Himalayan blackberry Rubus discolor Blackcap raspberry Rubus leucodermis Milk thistle Silybum marianum Poison oak 7`6xicodendron diversiloburn California bay umbellularis Herbs Scarlet pimpernel Anagallis arvenis Plgweed Amaranthus sp. Field mustard- Brassica raps Curly dock-herb Rumex crispus Grasses Wild oat Avane fatua Rip-out brume Bromus diandrus Soft chess brume Bromus hordeaceus Perennial ryegrass Lolium perenne Vines Morning glary Convolvulus arvenis Puncture vine Ribulus terrestris California wild grape Mitis califomica SOURCE: Moore Biological Consultants 2001 and MHA 2003 Alhambra Valley Estates Draft EtR 3-35 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES marine terraces) and include: • Contra Costa goldfields(Lasthenia conjugens) • Diablo helianthella (Helianthella castanea) • Robust monardella (Monardella villosa ssp giobosa) • Western leatherwood (Dirca occidentalis) • Santa Cruz.tarplant(Holocarpha macradenia) • Pallid manzanita (Arctostaphylos paliida) • Congdon's tarplant(Centromadia parryi ssp. Condonii) The remaining three plant species have a low potential to be found on the project site because of marginal habitat conditions (Table 3.4-2). The status of these sensitive plant taxa are listed in Table 3.4-2 and descriptions of the plants are available in the various reports prepared on behalf of the applicant and other reports listed in Section 7, References, of this EIR. Wildlife A limited number of wildlife species were observed during surveys conducted by qualified biologists on behalf of the applicant and the County. All species observed were common species typically found in the urban environments of Contra Costa County(Table 3.4-3). Steller's jay(Cyanositta stellen), California quail (Callipepla californica), and black-tailed deer (Odocoilius hemionus columbianus) are the most common species observed at the project site. Several large stick nests were observed in the trees along Vaca Creek. These nests could potentially become raptor nests in the future. A limited number of mammals are likely to occur on the project site. Black-tailed deer(©docoillus hemionus columbianus) and fox squirrel (5ciurus niger)were observed during site surveys. Raccoon (Procyon lotor) and stripped skunk (Mephtis mephtis) are expected to occur on the project site. A number of species of small rodents including mice (Mus musculus, Reithrodontomys megalotis, and Peramyscus maniculatus) and voles (Microtus califvrnicus) are likely commonplace. Sensitive Wildlife. A total of seven sensitive wildlife species were identified as having the potential to occur within the project vicinity using the CNDDB (2003), other reference literature, and site surveys. Five of these species are not found in the vicinity of the project site because key habitat requirements (e.g., vernal pools, forest) are lacking: • Sacramento perch (Archoplites interruptus) • Berkeley kangaroo rat (Dipodomys heermanni berkeleyensis) • California tiger salamander(Ambystoma califomiense) • Bridge's Coast range shoulderband snail (Helminthoglypta nickliniana bridgesi) • Cooper's hawk(Accipiter cooperii) Three sensitive species, listed in Table 3.4-4, could be found within the project site based on the specific location and habitat characteristics of the project site. The ecologies of all of the species listed in the table are discussed in detail in the various reports prepared by or on behalf of the applicant and other reports listed in Section 7, References, of this EIR. 3-36. Alhambra Valley Estates Graft EIR March 2004 _.._... 3: ENVIRONMENTAL IMPACT ANALYSES Table 3.4-2: Sensitive Plant Species Potentially Occurring within the Project Site Common Name Scientific Name Legal Status Federal/State/CNPS Big tarplant Slepharizonia plumose ssp. --/--/ B plumose Fragrant fritillary Fritillaria liliacea 4-41 B Mount Diablo fairy lantern Calochorfus pulchellus --/--/1 B Nates: California Native Plant Society{CLAPS} List 1B =rare,threatened, or endangered in California and elsewhere SOURCE:NDDB 2003 Table 3.4-3: Wildlife Species Observed Common Name Scientific Name Turkey vulture Cathartes aura Red-shouldered hawk Buteo tineatus Red-tailed hawk Buteo jamaicensis California quail Callipepia calffibmica Anna's hummingbird Calypte anna Black phoebe Sayornis nigricans Steller's jay Cyanocitta stelled Western scrub jay Aphelocoma coerulescens American robin Turdus migratorius California towhee Pipifo crissalis House finch Carpodacus mexicanus American goldfinch Cardue/is tristis Fox squirrel Sciurus niger Black-tailed deer Odocolleus hemionus SOURCE:Moore Biological Consultants 2001 and MHA 2003 Alhambra Valley Estates draft EIR _ 3-37 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Table 3.4-4: Sensitive Wildlife Species Potentially Occurring within the Project Site Common Name Scientific Name legal Status Federal/State/other Alameda whipsnake Masticophis lateralis euryxanthus FT/ST/-- Western pond turtle Clemmys marmorata --/CSC/-- California red-legged frog Rama aurora draytonli FT/CSC/-- FT:federally threatened ST:California threatened CSC:California species of special concern SOURCE: NDDB 2003 Habitats on and adjacent to the project site provide opportunities for a limited number of amphibians and reptiles, including the California red-legged frog (Dana aurora draytonir), the Western pond turtle (Clemmys marmorata), and the Alameda whipsnake (Masticophis lateralis euryxanthus). Western pond turtles are generally found in slack or slow water habitats where there are dense stands of submergent or emergent vegetation. These turtles could potentially be found along Vaca Creek where there may be suitable habitat. Alameda whipsnake live primarily in northern coastal scrub and chaparral habitats in Contra Costa and Alameda Counties. Alameda whipsnake have a very low potential of occurring throughout the project site. The most likely inhabitant is the California red-legged frog (CRLF). Suitable habitat for the CRLF is located upstream within one-mile of the project site within the Vaca Creek watershed. Lands within one-mile of the site likely to provide suitable for the CRLF include portions of the Vaca Creek and Alhambra Creek, at least two stock ponds, and several segments of unnamed tributaries to Vaca Creek. No records have been identified that document the occurrence of the CRLF on the project site although large, stable populations of the CRLF have been documented in the Sindicich and Maricich Lagoons, located within Briones Regional Park, approximately 2-miles upstream of the project site. Vaca Creek provides suitable habitat for adult CRLF along its project site reach, but is not suitable for CRLF breeding. The Creek could function as a movement corridor even though no species were identified during surveys conducted by qualified biologists on behalf of the applicant and the County. CRLF have been documented downstream of the Creek and so it is assumed that the species migrate from Briones Regional Park down the reach of the creek along the project site. Sensitive Habitats Sensitive habitats are defined as: • Habitats recognized by the California department of Fish and Game (CDFG)as rare, sensitive, important, or meriting further study(Holland 1986) • Wetlands,as defined by the U.S.Army Corps of Engineers(Corps; Environmental Laboratory 1987) and classified by Cowardin et al. (1979) • Creek bed-Watercourses, as defined by the Alhambra Valley Specific Plan(Contra Costa County Community Development Dept. 1992) • Ecologically significant areas or habitats, as defined by the Contra Costa County General Plan Conservation Element(Contra Costa County 1996) 3-38. — Alhambra Valley Estates Craft E€R Match 2004 3: ENVIRONMENTAL IMPACT ANALYSES The California Natural Diversity Database (NDDB 2003) lists two sensitive habitat types within the Eriones Valley and Walnut Creek USGS 7.5-minute quadrangles (project vicinity). These include Northern maritime chaparral and Northern coastal saltmarsh, neither of which is present in the project vicinity based on site surveys. Riparian habitat, a sensitive habitat recognized by CDFG, is found along the Vaca Creek, which is adjacent to the northwest corner of the project site, and is the only sensitive habitat within the potential disturbance area of the project. REGULATORY SETTING Clean Water Act of 1977 Regulatory protection for water resources throughout the United States is under the jurisdiction of the U.S.Army Carps of Engineers. Section 404 of the Clean Water Act and prohibits the discharge of dredged or fill material into Waters of the U.S. without formal consent from the Corps. Waters of the U.S. include marine waters, tidal areas, stream channels, and associated wetlands. Wetlands often include freshwater marshes, vernal pools, freshwater seeps, and riparian areas. Policies regulating the loss of wetlands generally stress the need to compensate for wetland acreage losses by creating wetlands from non-wetland habitat on at least an acre-for-acre basis. Section 7 of The Federal Endangered Species Act The Federal Endangered Species Act(FESA) provides legislation to protect federally listed plant and animal species. Impacts to listed species resulting from the implementation of a project would require the responsible agency to consult the United States Fish and Wildlife Service (USFWS). Section 7 of the FESA requires that all federal agencies must, in consultation with the USFWS or National Marine Fisheries Service (NMFS), ensure that its(the agency's) actions do not jeopardize the continued existence of a listed species, or destroy or adversely modify the listed species' "critical habitat." For this project the Corps would be the lead federal agency to consult with the USFWS. Section 10 of the Act describes the process by which take permits are issued by USFWStNMF'S for take of listed species incidental to an otherwise lawful activity. State of California Endangered Species Act The State of California Endangered Species Act(CESA) ensures legal protection for plants listed as rare or endangered and species of wildlife formally listed as endangered or threatened. The state also lists "Species of Special Concern" based on limited distribution, declining populations, diminishing habitat, or unusual scientific, recreational, or educational value. Under State law, the CDFG is empowered to review projects for their potential to impact state-listed species and Species of Special Concern, and their habitats. Impacts to the state-listed species would be evaluated and identification of mitigation measures would likely be required. California Department of Fish and Game Code California Fish and Marne Code governs state-designated wetlands, including riparian and stream habitat, and mandates that mitigation be implemented to replace wetland extent and value lost to development. Sections 1600-1607 of the California Fish and Game Code regulate activities that would alter the flow, bed, channel or bank of streams and lakes. Activities that affect these areas, as well as associated riparian habitats, would require a Streambed Alteration Permit from the CDFG. in addition, Section 3503 of the California Fish and Game Code prohibits impacts to actively nesting birds, their nests, or their eggs. Alhambra Valley Estates Draft EIR 3-39 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Contra Costa County General Plan The Conservation Element of the Contra Costa County General plan outlines a series of goals and policies aimed at protecting and enhancing vegetation and wildlife. The following selected policies are directly applicable to the proposed project: Vegetation and Wildlife Policies • 8-6.Significant tress, natural vegetation, and wildlife populations generally shall be preserved. • 8-7. Important wildlife habitats that would be disturbed by major development shall be preserved,and corridors for wildlife migration between undeveloped lands shall be retained. • 8.24. The planning of native trees and shrubs shall be encouraged in order to preserve the visual integrity of the landscape, provide habitat conditions suitable for native wildlife,and ensure that a maximum number and variety of well-adapted plants are sustained in urban areas. Alhambra Valley Specific Plan The Alhambra Valley Specific Plan includes provisions for the preservation,protection,and enhancement of natural resources within the Plan's area,including Vaca Greek.Among the Plan's development regulations applicable to the proposed project is the following: 2.Creek Setbacks and Creek Preservation C.The appropriate width of the creek setbacks will be determined as part of the review of the tentative subdivision map.The creek setback width shall be a minimum of 50 feet, but may be expanded by the County Community development Department if necessary to protect the creek or is adjacent riparian habitat. ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following areas of potential environmental concern may be associated with implementation of the proposed project: • The potential for the taking or harassment of sensitive plant and animal species or damage to their habitats • The potential for the destruction or degradation of sensitive habitats or plant communities, such as wetland and riparian areas • The potential for the interference with movement or nursery sites of native, resident,or migratory wildlife Thresholds of Significance Impacts to biological resources of the project site were evaluated by determining the sensitivity, significance, or rarity of each resource that could be adversely affected {either directly or indirectly} by the proposed project, and by using thresholds of significance to determine if the impact constitutes a significant impact. The significance threshold may be different for each habitat or species and is based upon the rarity or sensitivity of the resource and the level of impact that would result from the proposed project. Guidance for determining significance thresholds is based 3-40. Alhambra Valley Estates draft EIR March 2004 3 ENVIRONMENTAL IMPACT ANALYSES on Appendix G of the CEQA Guidelines,the Contra Caste County General Plan, and the Alhambra Valley Specific Plan. Using these guidelines, implementation of the proposed project would have a significant impact on biological resources if it were to: • Adversely and substantially affect a sensitive species • Have a substantial adverse effect on any important or sensitive habitat • Interfere substantially with the movement of any resident or migratory species of wildlife or with established native resident or migratory wildlife corridors • Conflict with any local policies or ordinances protecting biological resources • Conflict with the provisions of an adopted HCP, Natural Community Conservation Plan, or other approved local, regional, or state habitat or conservation plan • Conflict with adopted City General Plan policy associated with the protection and preservation of biological resources Based on these guidelines, as well as pertinent state and federal policies and regulations, the following thresholds of significance will be applied to project-related impacts to biological resources within the proposed project area: • Loss of individuals or habitat for sensitive species • Project-related loss or degradation of wetland habitat or riverine habitat(other waters of the U.S.)associated with on-site drainages • Introduction of invasive/exotic species at the project site • Disruption or degradation of wildlife migration or movement corridors Potential impacts and Mitigation Impacts to biological resources on the project site could occur where proposed construction or development activities could result in temporary or permanent modification of sensitive communities or habitats occupied or potentially occupied by sensitive species. These activities could also result in direct impacts (e.g., loss or injury) to special status species. The following significant or potentially significant impacts would be associated with the proposed projectdevelopment. The outlined mitigation measures would reduce these impacts to less than significant levels Potential Impact 3.4-1: Taking or harassment of sensitive plant and animal species or damage to their habitats Six sensitive species have the potential for occurring on the project site (Tables 3.4-2 and 3.4-4): • Sig tarplant • Fragrant fritillary • Mount Diablo fairy lantern • Alameda whipsnake • Western pond turtle • California red-legged frog Alhambra Valley Estates draft EIR 3-41 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Development of the proposed project through construction of single-family detached homes and other on-and off-site improvements has the potential to negatively affect sensitive species that may occur in the area. Negative effects to sensitive species could occur through removal of vegetation, harassment of wildlife species, or disruption of habitat within the Creek. Although none of the identified sensitive species were observed on or near the project site, the species could still exist at the site and therefore the potential for their taking or harassment also exists.Application of the following mitigation measures would ensure that project development would not result in the taking or harassment of sensitive plant or animal specials, nor damage to their habitats. Mitigation Measure.3.4-1. Prior to commencement of any site work,the applicant shall conduct preconstruction surveys for the presence of big tarplant,fragrant fritillary, Mount Diablo fairy lantern,Alameda whipsnake, western pond turtle, and California red-legged frog.All surveys shall follow the standardized protocols as specified by the U.S. Fish and Wildlife Service(USFWS) and/or the California Department of Fish and Game (CDFG), where applicable. If any of the identified sensitive species are discovered on site during the preconstruction surveys,the applicant shall enter into consultations with the USFWS (whipsnake and California red legged frog)and/or the CDFG(westem pond turtle)to determine appropriate measures for implementation to ensure the complete protection of the species and its habitat. Measures may include, but are not limited to,construction restrictions,avoidance of species,and off-site relocation or replacement. Potential Impact 3.4-2: Destruction or degradation of sensitive habitats or plant communities, such as wetlands and riparian areas The applicant has proposed the establishment of a 50-foot wide creek setback on those lots that abut Vaca Creek. The setback is mandated by the Alhambra Valley Specific Plan for the purpose of protecting the Creek and its habitats and wildlife. The Specific Plan also provides for a greater setback if warranted. No body of evidence to suggest biological resources would benefit from a greater than 50 ft setback exists. Absent from the Specific Plan and from the applicant's proposed setback provisions is the type of activities and/or improvements that may occur within the setback. The riparian environment, and in particular the potential use of the Creek as a movement corridor by the CRILF, could be affected if any construction activities occurred in or near the Creek within the 50 ft setback. The following mitigation measures would ensure the preservation of the habitats and species within the Creek Setback: Mitigation Measure 3.4-2. No alterations of Vaca Creek within the creek setback along the project site shall be allowed. Mitigation Measure 3.4-3. Prior to recordation of the final map,the applicant shall submit a deed restriction to the Zoning Administrator for review and approval-The dead restriction shall prohibit, in perpetuity, use and improvements within the Creek Setback. Specifically, the deed restriction shall prohibit any physical alterations within the Creek Setback, including vegetation removal, vegetation planting, landform alterations, or construction of structures or improvements.The deed restriction shall be recorded concurrently with the final map. Potential Impact 3.4-3: Interference with movement or nursery sites of native, resident, or migratory wildlife Construction of the proposed project does not have the potential to interfere with the movement of CRLF and western pond turtles within Vaca Creek if construction were to occur in proximity to the Creek during periods of movement or if project development were to modify elements of the Creek. 3-42. Alhambra Valley Estates DraftEIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES 3,5 Cultural Resources ENVIRONMENTAL, SETTING The project area is situated in Alhambra Valley, a narrow upland valley along Vaca Creek and Alhambra Creek, streams that empty into the Carquinez Strait approximately 5 miles to the north. The project area is located at an elevation of 250-300 ft, at a point in which the valley orientation turns from east to north. Inspection of the 1997 Quaternary Geology Map of Contra Costa County (Helley and Graymer 1997) shows the valley bottom is filled with Holocene basin deposits, while surrounding margins are Pleistocene alluvial fan deposits. Key plant resources for native peoples using the project-area habitat would have included oak acorns, bay nuts (Umbellularfa calffomfca), walnut(Juglans calffornfca), manzanita (Arctostaphylos sp.), hazelnuts (Corylus cornuta var. calffornfca), and a variety of small-seeded annuals and perennials(Wohlgemuth 2002). Primary game animals were deer(Odocofleus hemfonfus) and rabbits( ylvilagus sp. and L,epus callfomicus), with less use of game birds like quail (Callfpepla calffornfca)and mourning doves (Zenafda rnacroura). The streams in the project vicinity did not support significant fish resources. In general,the small upland valley where the current project is situated is not as attractive a location for either native or historic American occupation as the nearby bay shore, or the larger valleys to the east around Walnut Creek, Cultural Background Brief reviews of the history, ethnography, and archaeology of the project area place it within a broader context of human use of the eastern San Francisco Bay Area. The name "Alhambra Valley" is derived from the original Canada del Hambre, or valley of hunger. This earlier name is still applied to a major tributary of Alhambra Creek, the Vaca Creek, which flaws through the western margin of the subdivision parcel, A variety of stories purport to explain the naming of this small valley for hard times, but none can be supported by documentary evidence as reported by Gudde (1969:7). The name was applied on diseno maps for land grants in 1842, and appears on maps dating to 1868 and 1873. John Mules mother-in-law, Mrs. John Strentzel, settled in the valley in the 1880s, "and renamed the valley because she disliked the old name"(Gudde 1969:7). The valley remained in agricultural use until small housing developments were constructed. John Swett started a winery in 1853 and the remains can be seen outside the project on the northwest side of Vaca Creek. Native American Presence. Several ethnographles have been written about peoples of the San Francisco Bay Area, notably by Kroeber(1925), Levy (1978), Margolin (1978), and Milliken (1995). Milliken's detailed study of native ethnogeography(1995) shows the project area lies between the principal village locations of the Saclan and the Chupcan, both speakers of Bay Mlwok languages. The Saclan lived in small inland valleys in the East Bay hills, while the Chupcan controlled the lower reaches of Diablo Valley, with a principal village at Concord (Milliken 1995:241, 253). The Saclan and Chupcan were organized as independent sociopolitical groups known as tribelets, or groups of allied villages controlling a territory and its resources (Kroeber 1962). Tribelet territories in the Say Area were approximately 6 to 10 miles in diameter(Milliken 1995). The principal village of a tribelet was the home of the tribelet chief. Chieftainship was patrilineally inherited, but could be passed to a man's sister or daughter if there was no male heir. It was the chief s responsibility to provide for visitors and the poor, direct ceremonial activities, and arrange expeditions and tabor for hunting, fishing, gathering, and warfare (Levy 1978). Bay Miwok were organized in households of patrilineally extended families, ranging in size from 10-15 members. Houses were usually dome-shaped structures constructed of willow poles, and thatched with leaves and grasses. Alhambra Valley Estates Draft EIR 3-43 March 2004 3.ENVIRONMENTAL IMPACT ANALYSES Archeology. Detailed overviews of the archaeology of the eastern Bay Area have been written by Rosenthal(2001, 2002). The focus here is to describe the most current view of the cultural sequence of the region. Lower Archaic Period. The Lower Archaic period is represented only at Los Vaqueros Reservoir east of Mount Diablo, where sites CCO-637 and -696 have produced artifact assemblages and human remains dated between 9,870 and 6,600 years ago (Meyer and Rosenthal1997). Characteristic artifacts include handstones and millingslabs, cobble-core tools, and a wide- stemmed projectile point. The subsequent Initial Middle Archaic Period, dating to 6,000-4,500 years ago, is similarly documented only at the Los Vaqueros locality, again at CCO-637. This component featured a grinding assemblage exclusively composed of mortars and pestles, and an early Offvella shell-bead lot (Meyer and Rosenthal 1997). Terminal Middle Archaic, Several Terminal Middle Archaic(4,500-2,500 years ago)sites have been documented in contrast to the scant earlier record. Initial use of the lame shell-mound sites alone the bayshore began during this period (Lightfoot and Luby 2003), and interior habitats also are well-represented, including CCO-308 In San Ramon Valley(Fredrickson 1966). All sites have produced human remains. Artifacts associated with this period include side-notched and stemmed projectile points, rectangular abalone ornaments, mortars and pestles, and rectangular Ofivella shell beads. Upper Archaic. The Upper Archaic(2,500-1,300 years ago) sites are found throughout the lowland valleys and along bay shores, and may reflect a population increase in the area. Upper Archaic sites usually have well-developed midden deposits with abundant human burials and residential features, both indicating long-term residential villages. Artifacts typical of this period include saucer and saddle Olfvella beads, numerous and varied bone tools and ornaments, shouldered lanceolate projectile points, and mortars and pestles. Emergent Period.The Emergent Period (1,300-200 years ago)sites have been documented from most interior valleys, bayshore locations, and upland contexts.Artifacts characteristic of the Emergent Period include small, arrow-sized projectile points,well-made fancy mortars, flanged pestles, flanged soapstone pipes, and bird-bone tubes with intricate chevron designs. Sites usually feature well-developed middens, human burials and cremations, and residential features like house floors (Rosenthal 2002). Cultural Resource Studies Records searches were conducted. The proposed project would not be expected to result in significant damage to scenic resources to identify archaeological resources and Native American sacred sites of the project area. Field studies were conducted following these contacts. Native American consultation was completed following fieldwork. Research Considerations. While the current project is small and only a limited research consideration is necessary, the following points were made: • A small upland location like Alhambra Valley could only support smaller populations compared to the bayshore or the larger valleys of the East Bay interior.This assertion would apply for bath Native American and historic settlement. • There is evidence to suggest that Native American occupation of remote upland valleys was more prevalent during the most recent Emergent Period (1,300-200 years ago), and that substantial occupation of Alhambra Valley may have been limited to relatively recent prehistory(Rosenthal 2002). 3-44. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES PrefieldStudies. A records search conducted for this project at the Northwest Information Center of the California Historical Resources Information System (NWIC CHRIS)files held at Sonoma State University revealed that six impact-related cultural resource inventory studies have been conducted within 0.5 miles of the current project. Five of these surveys are of parcels ranging from 1 to 24 acres in area (Baldrica 1980; Chavez 1981; Self 1999; Smith and Baker 1993; Werner and Zahniser 1991); the last is of approximately 3 linear miles of a gas line (Shoup et al. 1991). None of these inventories Identifies discovered and recorded cultural resources. The Native American Heritage Commission (NAHC)was contacted prior to fieldwork. A search of sacred lends files, and consultation with local Native Americans who might have knowledge of cultural resources in the project area was requested. The NAHC identified no sacred lands or known Native American cultural resources within or near the project area. The NAHC also identified Ms. Katherine Perez, of Stockton, as the Native American contact for Contra Costa County.'07n April 25, 2003, a letter and accompanying project vicinity and location maps were sent to Ms. Perez. Holman and Associates, consulting archeologists, inventoried the subdivision parcel of the current project area in August 2000, after most of the property had recently been disked. The remaining portion was in a Christmas tree farm. The entire parcel had excellent ground surface visibility. Parallel,transects spaced 20 meters apart were walked over the entire area. No cultural resources were noted during this survey. The Holman and Associates survey serves as an adequate cultural resources inventory. Survey transect spacing was sufficiently narrow to ensure that no significant cultural resources were missed. There was no impedance to ground-surface visibility. No further cultural resource inventory of the subdivision is necessary; however, the storm water and wastewater line routes outside the subdivision area require additional field study. Field Studies. Fieldwork was conducted on May 4, 2003. As noted above, since the subdivision parcel had received adequate cultural resource inventory by Holman and Associates in 2000, only the storm-and waste-water line routes were surveyed.The entire 1.5 miles of water lines was walked. The bulk of the alignment follows Alhambra Valley Road and Reliez Valley Road, along which little native soil was visible for inventory. Results. No cultural resources were noted during either the 2000 Holman and Associates survey of the proposed subdivision parcel, or in the survey of storm water and wastewater lines adjacent to Alhambra Valley and Reliez Valley roads in 2003. Consultation. The contact letter to Native American contact Katherine Perez was followed by a telephone call on May 7, 2003. She was informed that no archaeological sites had been found on the surface of either the subdivision or the water lines. IVIS. Perez was satisfied with these findings, but expressed two concerns about the possibility of project activities impacting buried archaeological sites. She requested a 100-2070 foot buffer zone between the subdivision developments and Vaca Creek during the construction phase of each lot, and Native American consultation throughout the construction phase if buried archaeological sites are discovered during construction. REGULATORY SETTING The need for a 404 Permit from the U.S. Army Corps of Engineers mandates cultural resource inventory and reporting to standards of Section 106 of the National Historic Preservation Act, as amended. Consultation with representatives of the Native American community is necessary in addition to adequate archaeological and historical research. Alhambra Valley Estates Draft EIR 3-45 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The location of the proposed development within the bottom of Alhambra Valley suggests that the entire subdivision area and the total length of storm water and wastewater lines are in potentially sensitive cultural resources areas. Thresholds of Significance Criteria for defining significant cultural resources are stipulated in the National Historic Preservation Act (NHPA; new regulations issued 1999)and the California Environmental Quality Act(CEQA, revised January 1999). The NHPA, which is applicable to all undertakings that involve federal lands, permits, or funds, defines a significant cultural property as one that is eligible for listing on the National Register of Historic Places. Eligible properties are those that: "(a)...are associated with events that have made a significant contribution to the broad patterns of our history; or (b) that are associated with the lives of persons significant in our past;or (c) that embody the distinctive characteristics of a type, period,or method of construction, or that represent a significant and distinguishable entity whose components may lack individual distinction; or (d) that have yielded,or may be likely to yield, information important in prehistory or history" (36 CFR 60.4). Typically, historic-era properties are evaluated under each of these criteria, while prehistoric properties are evaluated under Criterion D only. Unevaluated resources are usually are treated as potentially significant in practice. Under the NHPA,the lead federal agency must consider effects to eligible or potentially eligible properties from the proposed undertaking. This consideration includes identification of eligible properties (usually through archival research, field inventories, public interpretation, and/or test evaluations), assessment of potential adverse effects to eligible properties, and development of mitigation measures to offset those effects. The new regulations emphasize consultation with appropriate Native American communities, in the case of prehistoric or ethnographic properties, or Traditional Cultural Properties; and the preparation of Memoranda of Agreement(MOA) between all involved agencies and parties. Potential Impacts and Mitigation Because surface cultural resource inventories of the subdivision area and water lines documented no cultural resources,the project would have no effect on known important cultural resources. In alluvial settings like Alhambra Valley; however,there is always a possibility for discovery of deeply buried archaeological sites potentially eligible to the NRHP, which could be adversely impacted by construction activities. Native American representatives have also expressed concerns about the presence and protection of buried archaeological sites. Potential Impact 3.5-1: Potential to cause a substantial adverse change in the significance of a historical resource, archaeological resource, directly or indirectly destroy a unique paleontological resource or site or unique geologic feature, or disturb any human remains, Including those interred outside of formal cemeteries No cultural resources were found during surveys of the subdivision and water lines of the project area. The proposed project would not affect known archaeological resources. The project can be 346. Alhambra Valley Estates Draft EIR March 2004 3. ENVIRONMENTAL IMPACT ANALYSES considered to have no effect on important cultural resources eligible or potentially eligible to the National Register of Historic Places, or under the California Environmental Quality Act. It is possible, however, that buried archaeological sites may be present within the project area, and that such sites could be exposed by deep trenching or grading (cf. Meyer and Rosenthal 1997). The following guidelines set out by Holman (2000), recommend that construction crews be alerted to the possible presence of buried human remains andlor artifacts. Should any of these cultural remains be discovered during construction, it is recommended that work be halted within 50 ft. of the discovery until a qualified archaeologist is retained to inspect the discovery, Native American representative Katherine Perez should be contacted, and Native American monitors meeting her standards should be allowed to observe conditions following any such discovery, Finally, if the archaeologist determines that the find is important, it is recommended that no additional construction take place until the find can be fully evaluated according to procedures outlined in Section 105 of the Historic Preservation Act. Undiscovered archeological resources could be significantly affected by project activities. Implementation of the following mitigation measures would ensure that these impacts are reduced to less than significant levels. Mitigation Measure 3.5-1. prior to recordation of the Final Map, the applicant shall submit a Deed Restriction to be recorded against each lot within the Subdivision to the Zoning Administrator for review and approval.The Deed Restriction shall alert each property owner to the possible presence of buried human remains and/or artifacts.The Heed Restriction shall require that if any of these cultural remains are discovered during ground disturbing activities,work shall be halted within 50 feet of the discovery until a qualified archaeologist is retained to inspect the discovery. If the archaeologist determines that the find is important, no additional construction shall take place until the find can be fully evaluated according to procedures outlined in Section 106 of the Historic Preservation Act. If human remains are uncovered,the Contra Costa County Coroner shall be notified immediately. If the remains are determined to be Native American, a qualified Native American representative shall be contacted,and the Native American Heritage Commission(NAHC)shall be notified within 24 hours.The most likely descendents of the deceased shall be given the chance to make recommendations for the remains. If no recommendations are made within 24 hours, remains may be reinterred elsewhere. if recommendations are made and not accepted,the NAHC shall mediate the problem. Mitigation Measure 3.5-2. Prior to Issuance of a Grading Permit,the applicant shall submit to the Zoning Administrator grading plans that include the following notation on the first sheet of those plans: "There exists on the property that is the subject of this Grading Plan the,possible presence of buried human remains and/or artifacts. If any of these cultural remains are discovered during ground disturbing activities, work shall be halted within 50 feet of the discovery until a qualified archaeologist is retained to inspect the discovery. In the event of discovery of Native American Remains, a qualified Native American representative shall be contacted, and Native American monitors meeting their standards shall be retained to observe conditions. If the archaeologist determines that the find is important, no additional construction shall take place until the find can be fully evaluated according to procedures outlined in Section 106 of the Historic Preservation Act. Alhambra Valley Estates Draft EIR _ 3-47 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES 3.6 Geology, Sails, and Seismicity Section 3.6 of this EIR is based in part on the peer review of the following geology, sails, and seismicity reports prepared on behalf of the applicant; • Purcell, Rhoades&Associates 2003 Geotechnical Study Proposed Single f=amily Home Subdivision Plummer Property January 2002 • Darwin Myers Associates 2002 Review letter for Geotechnical Study Proposed Single Family Horne Subdivision Plummer Property,May 13, 2002 • Purcell,Rhoades&Associates 2003 Supplemental Geotechnical Study Proposed Single Family Nome Subdivision Plummer Property June 2003 • Darwin Myers Associates 2003 Review letter for Supplemental Geotechnical Study Proposed Single Family Nome Subdivision Plummer Property July 21,2003 The listed references are available for review at the Contra Costa County Community Development Department, 651 Pine Street, North Wing, 2nd Floor, Martinez,California. ENVIRONMENTAL SETTING The project site is located within the Coast Ranges Geomorphic Province in the East Bay Hills region of the San Francisco Bay Area. The site lies to the south and east of Vaca Creek, which intersects the southeastern terminus of Franklin Ridge, a northwest to southeast trending ridge. Regional Geology and Seismicity. The project site is locatedin the central Coast Range geomorphic province of California. The structure of the Coast Ranges in this region consists of northwest-trending folds and faults resulting from the collision and subduction of the Farallon Plate beneath the North American Plate and the subsequent, translational shearing along the contact between the Pacific and North American tectonic plates, the San Andreas fault system. Landslides and other slope stability problems are pervasive in the province but vary significantly in intensity depending on climate, topography,bedrock geology, and other local factors. The San Francisca Bay Area, including western Contra Costa County, is recognized as one of the most active seismic regions in the United States. Each year low to moderate sized'earthquakes occur within or near the region. There are several active and potentially active fault zones that affect development in the project vicinity. Faults that have been active during the Holocene period, approximately the last 10,000 years (the last 11,000 according to the Alquist-Prlolo Earthquake Fault Zone Act of 1972), are considered to be active. Faults that have been active during the Quaternary geologic period, approximately the last 3 million years(1.6 million years according to the California Geological Survey), are consideredpotentiallyactive faults. Active faults are considered to be known geologic hazards. The Hayward fault, the Calaveras fault, the Concord-Green Valley fault, and the San Andreas fault (major features of the San Andreas fault system) are historically active faults. Of the major fault zones in the area, the northern section of the San Andreas Fault is capable of generating the largest maximum credible earthquake (MCE), estimated at a magnitude of 8.3 on the Richter scale (Borcherdt 1975). The Hayward and the Calaveras faults can generate an MCE of magnitude 7.5, and the Concord fault can generate an MCE of magnitude 7.0 (Borcherdt 1975). Earthquakes of this magnitude are sufficient to create ground accelerations in bedrock and unconsolidated 3-48. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES deposits that are severe enough to potentially cause major damage to structures, foundations, and underground utility lines (Greens#elder 1974). The County has been subjected to numerous seismic events, originating both on faults within the County and in other parts of the region. Six major San Francisco Bay Area earthquakes have occurred since 1800 that affected the County, and at least two of the faults that produced these earthquakes run through or into the County. Project Site Faulting and Seismicity. The East Bay Hills region is characterized by northwest to southeast trending ridges that parallel the overall structural trend of the region. The structural trend is primarily controlled by the active faulting and folding related to movement within the San Andreas fault system. This portion of the East Bay Hills lays between two major active structures within the fault system, the active Hayward fault approximately 8 miles to the southwest, and the active Concord-Green Valley fault approximately 4.5 miles to the northeast. Faults zoned as active by the California Geological Survey(formerly the Division of Mines and Geology) are those that have undergone surface rupture or seismic activity within the past 11,000 years (Holocene time). tither active faults in the region include the San Andreas fault, located approximately 28 miles to the southwest, the Calaveras fault, approximately 18 miles to the south, and the Greenville-Marsh Creek-Clayton fault, approximately 11 miles to the east (CDMG 1997). These faults are capable of producing major earthquakes, which may result in strong to violent ground shaking at the project site. Other faults are present in the project vicinity including the Franklin fault, considered potentially active in the Contra Costa County General Plan Seismic Safety Element(1996), the Southampton fault as mapped by Dibblee (1980), and several other unnamed faults. These faults are not considered active by the California Geological Survey, and are not considered a potential source of earthquake shaking. However, during a major earthquake on a nearby active fault, sympathetic movement can occur on these faults. These types of movements are generally small offsets of several inches that can cause damage to structures and utilities, but are generally not life threatening. Table 3.6-1 summarizes the fault locations relative to the subject site and the status of fault activity. Regional Geology. The regional geology of the East Bay Hills in this area is primarily composed of Cretaceous and Tertiary age sedimentary and volcanic rock sequences with overlying Quaternary alluvium in stream valleys, Quaternary colluvium on hillslopes and Quaternary landslide deposits locally. In the project vicinity, formations include the Viae Hill Sandstone (also known as the Martinez Formation), Las Juntas Shale, and unnamed sandstones of the Great Valley Sequence. The site is mapped on regional geologic maps as undifferentiated alluvial deposits of Quaternary age(Graymer et al 1994). A map of the regional geology is presented as Figure 3.6-1. Site Soils. Quaternary geologic maps of the area characterize the site as predominantly Holocene alluvial fan deposits with minor Pleistocene alluvial deposits in the southeast corner(Helley and Graymer 1997). The Soil Survey of Contra Costa County(U.S. Department of Agriculture 1977) indicates that the site soils are composed primarily of Botelle clay loam and silty clay loam (Sandy Clay-CL-on Unified Scrip Classification System) with minor Clear Lake Clay (Silty Clay-CL) about the southeast corner of the site. These sails are moderately to highly expansive, with liquid limits ranging from 30 to 50 and plasticity indexes of 15 to 30. Investigation of the site by PRA(2002) penetrated silty clay and clayey silt soils in boreholes consistent with the soils mapping. Alhambra Valley Estates Draft EIR 3-49 March 2004 3;ENVIRONMENTAL IMPACT ANALYSES Table 3.6-1: Regional Faults and Activity Fault Distance From Direction From Activity Maximum Credible Site(miles) Site Earthquake (Richter Magnitude) Concord-Green Valley 4.5 Northeast Active 7.6*** Hayward 8 Southwest Active 7.5*** Greenville-Marsh Creek- 11 Southeast Active 7.2 Clayton Calaveras 12 South Active 7.5*** San Andreas 28 Southwest Active Unnamed 0 Crosses site Inactive* -- northwest to southeast Southampton 0.04 West Inactive -- (200 fl) Franklin 0.5 Southwest Potentially 6.25** active** According to Purcell Rhoades&Associates 2063 "According to Contra Costa County General Plein Seismic Safety Element 1996 Borcherdt, 1975 SOURCE:CDMG 1997;Contra Costa County 1996;Dibblee 1980 Slope Stability. The site lies on a relatively flat to gently sloping alluvial area within the sediments of the Alhambra Valley adjacent to Vaca Creek, No landslides are mapped on the proposed project property and the site is considered to have very low landslide and debris flow susceptibility. Several types of slope instabilities have been mapped on the relatively steep slopes adjacent to the site, but do not appear to pose a risk to the proposed project property from landslide or debris flow deposition. Instabilities identified include debris flows and gullies west of the site and Vaca Creek, and a landslide south of the site across Alhambra Valley Road (CDMG 1995). Any landslides or debris flaws generated from the upland areas wast of the site would be intercepted by the drainage of Vaca Creek and are unlikely to reach the project site. The landslide to the south would be extremely unlikely to reach the project site due to the distance from the site and the intervening areas of lowtopographic relief. The landslide would lose momentum before reaching the site. Surface Fault Rupture. No faults zoned as active by the State of California Geological Survey traverse the site,although a northwest-southeast trending, unnamed fault is shown on published maps as passing through the site in a northwest to southeast direction. The fault is mapped as being'concealed beneath the alluvial deposits on the site. Exposures in the banks of Vaca Creek include contacts between sandstone/shale bedrock and sandy clay sediments. Unusual geomorphic features are also present at the site that suggests the possibility of a fault. An investigation of the potential for surface fault rupture was performed by Purcell, Rhoades & Associates (PRA 2003) based on the State map that shows a concealed fault and unusual geomorphic features observed on the project site's surface and along the creek bank. Trenches excavated perpendicular to the mapped fault trend and creek bank exposures encountered a continuous sequence of sediments with no apparent fault offset. If a fault is present, it is buried beneath the sediments exposed by the trenching at the site, and predates the sediments that 3-50. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.6-1: Geologic Map of the Project Site and Vicinity 4 te {r Mw 4 x, { y Map Legend Surficial Deposits Qs Landslide deposits Qu Undivided Quaternary deposits Tbl Lower Briones formation-sandstone Th Harnbre sandstone Tij Los Juntas Shale Tr Rodeo shale Tvh Vine Hill Sandstone Tvhi Lower Vine Hill Sandstone-glauconitic sandstone SOURCE:Graymer,R.W.,Jones,D.[..,and Brabb, E.E., 1994 overlie it. The age of the sediments is uncertain, but PRA suggests that they are older sediments based on the presence of weathering rinds of clay on gravel clasts (PRA 2403), However, the PRA study did not include detailed bagging of upper sails pedogenic horizons. The occurrence of well- developed sail profiles is also an indication of older deposits. Subsequent investigation of the possible fault involved drilling Cone Penetration Test(CPT) boreholes to determine the depth to bedrock adjacent to the Vaca Creek and to evaluate the sediments encountered for the potential for seismic related ground failure, including liquefaction. The depth to hard bedrock varied in these boreholes from approximately 22 to 60 feet below around surface(BGS). A distinct drop in the hard bedrock surface was found between two of the boreholes, CPT-1 and CPT-3. These holes were located within 50 feet of one another(Figure 3.6- 1). CPT-1 penetrated hard bedrock at approximately 60 feet BGS and CPT-3 penetrated hard Alhambra Valley Estates Draft EIR 3-51 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES bedrock at approximately 25 feet BGS. PRA states that this could be the location of a deep bedrock fault, but they do not consider it to be an active fault(PRA 2003). The County's Peer Review Geologist recommended further studies to investigate the potential for fault rupture(see Mitigation Measure 3.6-1). Ground Shaking. The intensity of ground shaking felt in the site vicinity from future earthquakes will depend on several factors, including the distance of the site to the earthquake focus, the magnitude and the duration of the earthquake, and the response of the underlying soil and/or bedrock. Strong to very strong (Modified Mercalli Intensity, MMI, of Vll to VI11) ground shaking at the site could be generated in response to large magnitude earthquakes on the Concord-Green Valley, Hayward or northern Calaveras faults. More distant earthquakes, centered on the San Andreas or Greenville faults, could generate>moderate to strong (MMI of Vt to V11)groundshaking; (http://quake.abag.ca.gov/).The CDMG has predicted peak ground acceleration for the region of the site to be in the range of 0.6 to greater than 9.7 of gravity(G). These values for peak ground acceleration are estimated by the CDMG to have a 10 percent probability of being exceeded within the next 50 years (CDMG Map Sheet 48, 1999). Liquefaction, Liquefaction susceptibility of the project area is estimated as high by the Association of Bay Area Governments(http://quake.abag.ca.gov). However,the Seismic Safety Element of the Contra Costa County General Plan(199£0 indicates a"generally moderate to love" potential for liquefaction (PRA 2002). The potential for liquefaction of site soils was examined in the PRA Geotechnical Study(2002). Based on the cohesive alluvial soils and relatively deep groundwater conditions encountered, PRA concluded that the risk of liquefaction is low(PRA 2002). Specifically, presence of non-liquefiable silty and sandy clay soils within 20 feet of the ground surface, and the depth to of the water table(approximately 29 feet). An additional detailed evaluation was to determine the potential for liquefaction of site sediments was performed during June 2003 by PRA. Performed adjacent to the modern creek channel, the investigation included logging of trenches, test pits, the results of cane penetration test boreholes (to depths of approximately 50 to 60 feet below ground surface), and laboratory testing of selected samples. Results of this testing confirmed that the site soils have a low potential for liquefaction(PRA 2993). Off-Site infrastructure The proposed off-site storm drain and wastewater pipelines would follow the alignments of Alhambra Malley and Reliez Valley Roads. The pipelines would be constructed underlying the pavement section. Both Alhambra Valley Road and Reliez Valley Road are shown on geologic maps of the area as being constructed over the Quaternary alluvial deposits of Alhambra Creek and Vaca Creek. The proposed pipeline would traverse the area of one or more mapped faults,all of which are mapped as concealed below the Quaternary alluvial deposits. No landslides are mapped as crossing the proposed alignment, but landslides may occur in upslope areas adjacent to the reds. Liquefiable sediments may be present in the alluvial deposits beneath the pipeline and roadway section. REGULATORY SETTING There are no specific regulations applicable to geology, soils, and seismicity within the context of this EIR and the proposed project. Information about the site's geologic characteristics would be used by engineers and architects to guide development of designs and construction techniques appropriate to those characteristics.Contra Costa County has adopted the California Building Code, which by reference incorporates the Uniform Building Cade, The Codes provide the regulatory environment to ensure that structural designs are specific to site conditions.The County has also adopted a grading ordinance that regulates a variety of grading activities`including excavating, grading, earthwork construction, Including fills or embankments and related work. 3-52. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Contra Costa County General Pian.The Safety Element of the County's General Plan addresses hazardsrelated to seismic hazards, as follows: Seismic Hazard Policies Policy 10-8. Structure for human occupancy, and structures and facilities whose loss would substantially affect the public safety or the provision of needed services, shall not be erected in areas where there is a high risk of sever damage in the event of an earthquake. Policy 10-7.The County should encourage cooperation between neighboring government agencies and public and private organizations to dive an appropriate attention to seismic hazards to increase the effectiveness of singular and mutual efforts to increase seismic safety. Ground Shaking Policies Policy 10-8. Ground conditions shall be a primary consideration in the selection of land use and in the design of development projects. Policy 10-9. In areas susceptible to high damage from ground shaking(1.e., Zone IV on Map 10-4), geologic seismic and soils studies shall be required prior to authorization of major land developments and significant structures*(public or private). Policy 10-10. Policies regarding liquefaction shall apply to other ground failures which might result from ground shaking:but which are not subject to such well-defined field and laboratory analysis. Faults and Fault Displacement Policies Policy 10-11. Classify as active faults those faults which have ruptured the ground surface during Holocene geologic time, roughly the last 10,000 years.Classify as potentially active faults which displace Quaternary geologic units, those formed during approximately the last 2 to 3 million years. ENVIRONMENTAL ANALYSIS Areas'of Potential Environmental Concern The following are areas of potential environmental concern that may be associated with implementation of the proposed project: * The potential of surface fault rupture • The potential for strong seismic ground shaking The potential for human exposure to seismic hazards The potential for seismic related ground failure, including liquefaction • The potential for landslides or mudflows * The potential for soil erosion * The potential for the destruction of unique geologic features * The potential for the loss of mineral resources * The potential for the construction of buildings or structures atop expansive soils Alhambra Valley Estates draft EIR 3-53 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Thresholds of Significance The CEQA Guidelines state that the exposure of people or structures to major geological hazards is considered a significant adverse impact. The potential geologic, soils, and seismic effects of the proposed project can be considered from two points of view: (9) construction impacts; and, (2) geologic hazards to people or structures. The basic criterion applied to the analysis of construction impacts is whether construction of the project would create unstable geologic conditions that would last beyond the short-terra construction period. The analysis of geological hazards is based on the degree to which the site geology could produce hazards to people or structures from earthquakes, ground shaking, ground movement, fault rupture, or other geologic hazards, features or events. The following thresholds of significance are used to determine the level of impact to areas of potential environmental concern. The project would have a significant effect if it would. Expose people or structures to potential substantial adverse,effects, including risk of loss, injury, or death involving rupture of a known earthquake fau=lt, Strong seismic ground shaking, seismic-related ground failure, including liquefaction, or landslides Result in substantial soil erosions or the loss of topsail Expose people or structures to a geologic unit or sail that is unstable, or would become unstable as a result of the project, and would result in on-or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse Expose people or structures to soils characterized by high shrink-swell potential and which would have the potential for expansion and/or settlement Impacts and Mitigation Although projects can have impacts on the local geologic environment through induced slope instability and soil erosion, most projects do not affect the regional geologic environment. However, projects can be affected by regional and area wide geologic conditions. Many seismic events, particularly large magnitude earthquakes, are felt regionally. Injury, damages and property loss tend to occur along and near linear earthquake fault zones of regional extent and in areas of soil and geologic conditions susceptible to high amplitude ground motion, settlement, or instability, Most seismic experts agree that for planning and project,evaluation purposes, a large, damaging earthquake event should be anticipated to occur within the design life of all projects in the San Francisco Bay Area. Regional and local geologic impacts that could significantly impact the project will primarily be damages to the infrastructure (utilities, roads, etc.). Potential Impact 3.6-1: Surface fault rupture There are no faults zoned as active by the State of California Geological Survey that cross the project site. An unnamed fault has been mapped crossing the project site, but is shown on regional geologic reaps as concealed by Quaternary sediments that blanket the site. The Southampton fault, as mapped by Qibbiee (9980), crosses 2034 feet west of the site. The State of California Geological Survey has not zoned either fault as active (CDMG, 2404). An investigation of a possible fault on the subject property was performed by Purcell Rhoades and Associates (PRA 2403). After that investigation PRA concluded that e continuous sequence of sediments in the near surface show no evidence of having been cut by surface fault rupture. However, borehole data suggest the possibility of a fault beneath the surface sediments. PRA interprets the subsurface'data as a possible bedrock fault or contact between geologic units. In a peer review of the PRA report, Darwin Myers Associates recommends additional study to verify the ..__........_ _ _ _.._... ....... ............... __..______ --_..._....._.____ 3-54. Alhambra Valley Estates Draft EIR March 2004 - _ 3.ENVIRONMENTAL IMPACT ANALYSES preliminary interpretation of the data gathered, Surface fault rupture is considered a potentially significant impact. Mitigation Measure 3.6-1. Prior to recordation of the final map,the applicant shall submit an updated project geologic and geotechnical report to the Zoning Administrator for review and approval. The updated report shall: • Include an original geologic map of the site • Present the log of one deep borehole in the area of the suspected bedrock fault or geologic contact(between boreholes CPT-1 and CPT-2)to an approximate depth of 60 feet below ground surface(borehole will be sampled sufficiently to confirm/refine the interpretation of geologic Contacts in PRA's CPT cross section and provide data on the depth to"hard"bedrock, along with data on lithology, engineering properties, structure and age of the units penetrated) • Reaffirm/modify PRA's interpretation of fault hazards on the site Should the updated report conclude that there is a potential impact of surface fault rupture, then a setback from the identified fault will be determined by the Zoning Administrator.The setback will be designed to protect structures for human occupancy from the hazard of surface fault rupture. Potential impact 3.6-2. Strong seismic ground shaking Seismic shaking levels for the site are anticipated to exceed an acceleration of 50 percent of gravity ( ) to greater than 70 percent G, which is considered moderate to very strong ground shaking. All construction will follow currently adopted building codes, which include provisions for seismicdesign. These codes include the Uniform Building Code (UBC) and the more recent International Building Cade (IBC).As of the spring of 2003, the building code of record in Contra Costa County is the 2001 edition of the California Building Code(California Code of Regulations, Title 24, Part 2, Volumes 1 and 2 [based on the 1997 Uniform Building Code, published by the International Conference of Building Officials]), including Appendix chapter 3, division 11; chapter 12, divisions I and 11; chapter 15, sections 1514, 1515, 1517, 1518, 1519, and 1520; chapter 29; chapter 31, divisions 11 and 111; chapter 34, division I (sections 3406.1, 3407, 3408, 3409, 3410, 3411 and 3412)and division III; and the 1997 Uniform Building Code. Based on the ordinance- required implementation of provisions of the Building Codes, strong seismic ground shaking is considered a less than significant impact. However, the building codes do not necessarily address the construction of onsite utilities, which could also be impacted by strong seismic ground shaking. All on-site utility systems will be designed and constructed in accordance with applicable provisions of the Uniform Building Code, established County standards and regulations, and accepted engineering practice. Potential Impact 3.6-3; Human exposure to seismic hazards It is projected that a local earthquake along the Concord-Green Valley, Hayward, Greenville or Calaveras faults will result in moderate to very strong ground shaking in the project site area. Moderate ground motions can be expected during earthquakes of lesser magnitude on nearby faults and during larger magnitude earthquakes on more distant faults. Violent ground shaking can be expected to occur during peak magnitude earthquakes on nearby sections of the San Andreas or Hayward faults. New structures with more occupants than the current structures in the proposed area will increase the number of people exposed to local and regional seismic hazards. This is a significant unavoidable risk for every property in the San Francisco Bay region. Implementation of Mitigation Measures 3,6-1 and 3.6-2 would reduce the impact of the seismic hazards on humans. Alhambra Valley Estates Draft EIR 3-55 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Potential Impact 3.6-4: Seismic related ground failure,including liquefaction Soils and sediments were analyzed for the potential for liquefaction in the Supplemental Geotechnical Study by PRA (2003). The study results indicated that the potential for liquefaction at the site is low. The current project calls for a 50-foot setback from the creek. This setback is considered sufficient mitigation for the potential for lurch cracking or lateral spreading due to liquefaction of confined layers. With incorporation of this existing mitigation, seismic related ground failure is considered a less than significant impact. Potential Impact 3.6.5: Landslides or mudflows No landslides are present on the subject property. Therefore, landslides and mudflows are considered a less than significant impact. Potential Impact 3.6-6: Soil erosion Soil erosion impacts are discussed in Section 3.8, Hydrology and Water Quality. Potential Impact 3.6-7: Destruction of unique georgic features No unique geologic features exist at the site.The project would have no effect on,unique geologic features. Potential Impact 3.6-8: Loss of mineral resources No known mineral resource of value to the region or the State would be lust. The project would have no effect on mineral resources. Potential impact 3.6-9: Expansive soils Potentially expansive soils underlie the site. Expansive soils shrink and swell in volume during changes in moisture contents such as occur seasonally or due to irrigation. Expansive soils can cause damage to foundations and pavement sections. Expansive clay soils will likely be penetrated during project and tiff-site infrastructure construction. The presence of expansive soils is considered a potentially significant impact. The following mitigation measures would reduce the potential impactto a less than significant level. Mitigation Measure 3.6-2.All recommendations of the Geotechnical Study shall be implemented during construction and shall be performed under the observation and testing of the Geotechnical Engineer. 3.7 Hazards and Hazardous Materials ENVIRONMENTAL SETTING Fire Current site vegetation includes non-native grasses, a limited amount of cultivated' hay pasture,a variety of mature tree species, and blackberry bushes. The California Department of Forestry and Fire Protection characterizes the project area as a "wildland area that may contain substantial forest fire risks and hazards" (CDF 2000). Hazardous Materials A Modified Phase One Environmental Site Assessment was conducted on the project site (ENGEO Inc. 2000). That study found no documentation or physical evidence of soil or 3-56. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES groundwater impairments associated with the historic use of the property. A review of regulatory agency records did not lead to the identification of contaminated facilities within 1 mile of the site that would be expected to impact the site. Additional research found that there are no known leaking underground storage tanks within one-half mile of the site, nor are there any underground tank facilities or hazardous waste generators documented within one-quarter mile of the site. An undocumented underground fuel storage tank was removed from the site in the early 1980s. A soil sample was collected from the base of the former tank pit for analysis for the presence of total petroleum hydrocarbons such as gasoline, diesel, benzene, toluene, ethyl benzene, and xylenes (BTEX),,and methyl tertiary butyl(MtBE) ether. Concentrations of gasoline range petroleum hydrocarbons, BTEX, and MtBE were found to be below laboratory reporting limits. Residual diesel range hydrocarbons were reported at 11 parts per million (ppm)for the soil sample beneath the former tank location (ENGEO Inc. 2000). REGULATORY SETTING Federal Clean Water Act(CWA). The CWA provides the framework through which permits to discharge wastes to surface waters are authorized. The National Pollutant Discharge Elimination System (NPDES) permit typically has conditions specific to the permitted operation and may set limits on variousconstituents. The CWA also prohibits the discharge of pollutants to storm water. State California Water Code (CWC).The CWC includes provisions of the federal CWA and water quality programs specific to California. The CWC requires reporting, investigation, and cleanup of hazardous material releases that could affect waters of the state (including storm water). Alquist-Priolo Special Studies Zones Act. The purpose of this Act is to regulate development near active faults to mitigate the hazard of surface fault rupture. Under the Act,the State Geologist is required to delineate "special study zones" along known active faults in California. Cities and counties affected by the zones must regulate certain development projects within the zones. They must withhold development permits for sites within the zones until geologic investigations demonstrate that the sites are not threatened by surface displacement from future faulting. Local Contra'Costa County General Plan. The Safety Element and the Public Facilities/Services Element of the County's General Plan address hazards related to fire and hazardous materials by defining goals and policies that serve to: • Reduce the severity of structural fires and minimize overall fire loss * Minimize flood hazards The following policy of the Conservation Element applies to hazards from pesticides, herbicides, and fertilizer use: * Policy 8-37. The use of toxic and nutritive chemicals by agricultural operators shall be minimized. Some impacts related to hazards and health and safety are addressed in other sections of this EIR: geological and earthquake hazards (Section 3.6, Geology, Soils and.Seismicity) and flood hazards (Section 3.8, Hydrology and Water Quality). Alhambra Valley Estates Draft EIR 3-57 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following are areas of potential hazardous concern that may be associated with implementation of the proposed project: • Potential for harm to wildlife through the use of pesticides and herbicides • Potential to increase the risk of wildland fire • Potential to impair or interfere with emergency response or emergency evacuation plans • The potential to cause injury or harm to employees or the public from construction operations at the site, including operation of construction equipment, movement of soil, and public access to construction areas • The potential to cause injury or harm to employees, the public or the environment from construction activities that could release hazardous substances that may be already present in the soils at the project site Thresholds of Significance The following thresholds of significance are used to determine the level of impact for areasof potential environmental concern. The project would have a significant effect if it would: • Cause a significant increase in the likelihood of injury or harm to employees or the public from routine operations at the project site, including operation of construction equipment, movement of soil at the construction site, and public access to the site • Cause a significant increase in the likelihood of injury or harm to employees, the public or the environment from construction activities which may release hazardous substances that may be already present in the soils at the project site • Cause a significant increase in risk to wildlife through the use of pesticides and herbicides • Cause a significant increase in the risk of wildland fires Impacts and Mitigation Hazardous materials have not been identified in the project area, with the exception of soils beneath the location of the former fuel storage tank.Some hazardous materials from project- related development activities (i.e., fuels, oils) would be present on-site during development and construction activities. There is the potential risk of public and employee exposure to these hazardous or dangerous materials, whether through direct contact or through environmental means (e.g., water contamination from spills). impacts from and mitigation for hazards related to the site's hydrology are addressed in detail in Section 3.8, Hydrology and Water Quality. Potential Impact 3.7-1: Cause Injury or harm to employees or the public from construction operations at the site, including operation of construction equipment, movement of soil, and public access construction areas Construction employee safety is maintained through providing personal safety equipment on an as-needed basis, and holding periodic safety meetings to discuss issues dealing with site operations and existing construction activity safety plans. There would be no increased likelihood of injury or harm to employees involved in development activities. This safety impact to project- associated construction personnel would be less than significant. 3-58. Alhambra Valley Estates Draft EIR March 2004 ....................... - 3: ENVIRONMENTAL IMPACT ANALYSES Potential Impact 3.7.2: Cause injury or harm to employees, the public or the environment from construction activities that may release hazardous substances potentially present in the soils at the project site The Modified Phase i Environmental Site Assessment(ENGEO Inc 2000) revealed no evidence of recognized hazardous materials on the property that exceed established standards for exposure. The site's historic use for agricultural purposes presents the possibility that the site's soils may contain residual agricultural chemicals, which could pose a threat to humans. With implementation of the following mitigation measure, the risk of exposure of project personnel to construction-associated hazardous materials would be reduced to a less than significant level: Mitigation Measure 3.7-1.At least 30 days prior to issuance of a grading permit the applicant shall submit an agrichemical survey of the entire site to the Zoning Administrator for review and approval. The agrichemical survey shall be conducted in accordance with guidelines established by the Contra Costa County Environmental Health Department. The survey shall include the area beneath the floor of the former agrichemical storage area, located at the southeastern portion of the bam. If the survey reveals the presence of any agrichemicals in amounts that exceed accepted standards for exposure, no grading activities shall be commenced until a specific plan for mitigating the concentrations has been developed and approved by the Zoning Administrator. Such a plan shall include,but shall not be limited to,the following: * Identification of a method for the removal of contaminated soils • Identification of a disposal site for the soils Identification of a removal method that ensures that no contaminated soils are cast into the surrounding air shed or into adjacent waterways. Mitigation Measure 3.7-2.Prior to demolition of any existing structure on the project site, all such structures shall be surveyed by a qualified professional for the potential presence of asbestos. If the surveys reveal the presence of asbestos,the applicant shall first obtain a permit from the San Francisco Say Area Air Quality Management District for the safe removal of any asbestos contaminated material. Mitigation Measure 3.7-3. Prior to issuance of a grading permit the applicant shall contact the Contra Costa County Health Services Department, Hazardous Materials program or the San Francisco Regional water Quality Control Board,whichever is determined to have jurisdiction,to obtain a Clean Closure Letter for the former fuel storage tank site. Mitigation Measure 3.7-4. During site demolition and pre-grading activities the applicant shall retain an environmental professional, acceptable by the Zoning Administrator,to view areas of the property obscured from access and review during the Modified Phase I Site Assessment, and to evaluate the nature of the fill material observed along the western property boundary.The applicant shall submit a report to the Zoning Administrator describing the results of the study.The applicant shall follow all recommendations in the report prior to property transfer. Mitigation Measure 3.7-5. Prier to issuance of a grading permit the applicant shall decommission any on-site septic systems in accordance with state and County requirements and provide evidence of decommissioning to the Zoning Administrator. Mitigation Measure 3.7-6. Prior to issuance of a grading permit the applicant shall submit a construction safety plan to the Director of Community Development for review and approval. The purpose of the plan will be to minimize the exposure of the public to potentially hazardous materials during all phases of project construction through: Alhambra Valley Estates Draft EIR 3.59 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES • Implementing appropriate control methods(e.g., Best Management Practices)and approved containment and spill-control practices(e.g.,spill control plan)for construction chemical and materials on-site • Installing temporary safety fencing to restrict or prevent public access to active on- site construction materials or chemicals 3.8 Hydrology and Water Quality ENVIRONMENTAL SETTING Climate and Topography The 16-acre project site is found in the Coast Range geomorphic province, on the northern tip of the Diablo Mountain Range, at the confluence of the Carquinez Straight and San Pablo Bay. The region's climate is heavily influenced by marine winds blowing through the Carquinez Straight and is characterized by coal summers and mild winters. The region's rainy season extends from November to March with average annual precipitation of approximately 19.6 inches per year. Average temperatures range from a low of 48 degrees Fahrenheit in the winter, to 73 degrees Fahrenheit in the summer(Western Regional Climate Center, 2003). The project site is situated in the Alhambra Valley.While the site is relatively flat(slopes gently towards the northeast), it is surrounded by the steep slopes of the Briones Hills to the south and the steep slopes of the Franklin Ridge to the north. Elevations in the proposeddevelopment area range from approximately 253 feet Mean Sea Level (MSL) along the western boundary of the property to approximately 236 feet MSL near the intersection of Alhambra Valley Road and Hill Girt Ranch Road. Geology and Site Solis The project site is located on the northern slopes of the Diablo Mountain Range, part of the Coast Range geomorphic province. The Diablo Mountain Range is generally composed of northwest- trending mountain ranges and valleys. The site is underlain by undifferentiated Quaternary surficial deposits (Graymer et al. 1994). The characteristics of on-site soils influence drainage patterns;at a project site and are particularly important when storm water infiltration is proposed as part of the project drainage system, as is the case for this project. infiltration is the process where water enters the ground and moves downward through the unsaturated soil'zone. Infiltration is ideal for management and conservation of runoff because it filters pollutants through the soil and restores natural flows to groundwater and downstream water bodies. The characteristics of subsurface soils were described in the Geotechnical Study for the proposed development. Subsurface soils at the project site generally consist of firm to very stiff silty clay, which sometimes grades to clayey slit(Purcell, Rhoades &Associates, 2002). According to the Soil Conservation Service Soil Survey of Contra Costa County, two different types of soil occur on the project site: Botella clay loam (0 to 2 percent,slopes) and Clear Lake clay(0 to 2 percent slopes) (USDA, 1977). Botella clay foams, found throughout much of the project site, are generally characterized as well-drained soils with slaw runoff, a slight hazard of erosion, and moderate infiltration rates. Clear Lake clay foams, found in the southeastern corner of the subject site, are characterized as having very slow runoff, no hazard of erosion, very slow infiltration rates, and subject to flooding every 7 to 10 years unless adequate drainage is provided. Clear Lake clay loams are not generally suitable for infiltration. 3-60• Alhambra Valley Estates Draft EIR March 2004 _.... -. 3: ENVIRONMENTAL IMPACT ANALYSES Hydrology Regional Hydrology. The project site is located in the greater Alhambra Creek watershed. The Alhambra Creek watershed drains approximately 16.5 square miles from the Briones Hills, through the City of Martinez, to the Carquinez Strait. Alhambra Creek is joined from the west by Vaca Creek, which drains roughly 2.5 square miles of upper Vaca Canyon and Alhambra Valley. The project site is located within the Vaca Creek subwatershed. Vaca Creek forms the northern boundary of the project site, converging with Alhambra Creek approximately 2,250 feet to the north. Site Hydrology. The majority of the project site is on relatively flat to gently sloping land. Under existing conditions, runoff moves northeast as sheet flow and concentrated shallow flow across the project site, within earthen drainage ditches along Alhambra Valley Road, ultimately discharging to Alhambra Creek downstream of the project site. There is no existing drainage infrastructure on the project site. Flooding Regional Flooding. The Alhambra Creek watershed has a history of flooding problems. In 1996, large storms caused heavy damage to the downtown area of Martinez and severe erosion, flooding, and silting in the upper watershed. In May 1998, a cooperative project between the City of Martinez, state, and federal governments was granted $1.2 million to implement cost-effective measures aimed at reducing flood hazards along Alhambra Creek in downtown Martinez. Channel improvements that were implemented as part of the project have increased the capacity of the creek channel to convey the 10-year storm event between Ward Street and Marina Vista and the 100-year storm event north of Marina Vista Localized Flood Issues. A water surface profile analysis for Vaca Creek adjacent to Alhambra Valley Estates was prepared by P/A design Resources, Inc. using the U.S. Army Corps of Engineers` HEC-RAS computer modeling program. The model was used to calculate the water surface profile from the 100-year 12-hour storm along Vaca Creek adjacent to the project site. According to the 100-year base flood elevations (BFEs) presented in the model, some areas of proposed development would be susceptible to 100-year flood hazards. This issue is further discussed in the impacts discussion of this section. The 100-year floodplain of Vaca Creek adjacent to the project site is presented in Figure 3.8-2. Groundwater The California Department of Water Resources (DWR) defines state groundwater basins based on geologic and hydrogeologic conditions. The project site is not located within a groundwater basin (DWR 1975). The geotechnical investigation for the proposed project involved five exploratory borings to a maximum depth of approximately 15 feet below existing grade (Borings B-1 through B-5) and a single exploratory boring to a depth of approximately 30 feet below existing grade (Boring B-6). The borings were dug and sampled in December 2001, when seasonal groundwater levels are generally high. In Boring B-6, initial static groundwater was encountered ata depth of approximately 20 feet below existing grade. Groundwater was not encountered in the other five borings. Groundwater levels can be expected to fluctuate due to variations in rainfall and site conditions (Graymer et al. 1994). 3 Personal telephone communication with Tim Tucker,City Engineer in Martinez.July 7,2003, Alhambra Valley Estates Draft EIR 3-61 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES REGULATORY SETTING NPIDES General Construction Activities Storm Water Permit Requirements The CWA defines regulations for the discharge of pollutants to waters of the United States from any point source since 1972. In 1987, amendments to the CWA added section 402(p), which established a framework for regulating nonpoint source (NPS)storm water discharges under the National Pollutant Discharge Elimination System (NPDES). The Phase I NPDES storm water program regulates storm water discharges from major industrial facilities, large and medium-sized municipal separate storm sewer systems (those serving more than 100,000 persons), and construction sites that disturb 5 or more acres of land. The California State Water Resources Control Board (SWRCB)was last issued a statewide General Storm Water Permit for Construction Activities in 1999. The five-year permit requires all land disturbances of 5 acres or more to implement Best Management Practices (BMPs) to prevent the discharge of silt and sediment off site. BMPs are implemented through a site specific plan called the Storm Water Pollution Prevention Plan (SWPPP). It is the responsibility of the project applicant to prepare a project SWPPP prior to the commencement of construction activities. Section 1603 of the State Fish and Game Code Section 1603 of the State Fish and Game Code requires any person, governmental agency, or public utility proposing any activity that will divert or obstruct the natural flow or change the bed, channel or bank of any river, stream, or lake or proposing to use any material from a streambed, to first notify the CDFG of such activity. Based on information contained in the notification form and a possible filed inspection, the Department may propose reasonable modifications in the proposed construction as would allow for the protection of fish and wildlife resources. The notification requirement generally applies to any work undertaken within the annual high water mark of a wash, stream, or lake that contains or once contained fish and wildlife or supports riparian vegetation. A 1603 will need to be obtained by the project applicant for any creek bank work. Contra Costa Clean Water Program To comply with NPDES regulations set forth by the Clean Water Act, Contra Costa County,-19 of its incorporated cities, and the Contra Costa County Flood Control and Conservation Program formed the Contra Costa Clean Water Program. The program has Joint Municipal NPDES permits from the SF Bay RWQCB and the Central Valley RWQCB. The permits contain a comprehensive plan to reduce the discharge of pollutants to the"maximum extent practicable (MEP)." In February 2003, the San Francisco Bay RWQCB amended the Contra Costa Countywide NPDES municipal storm water permit for the Contra Costa Clean Water Program. The revised permit requires additional treatment controls to limit storm water pollutant discharges associated with certain new development and significant redevelopment projects after February 15, 2005. Alhambra Creek Watershed Management Plan The Alhambra Creek Watershed Planning Group was formed in March of 1997. The purpose of the group is to encourage a cooperative action between a wide array of stakeholders to recommend solutions to watershed problems that would benefit residents, property owners, business owners, and environmental health. In April 2001, the first edition of the Alhambra Creek Watershed Management Plan was completed. The voluntary plan includes several goals and recommendations associated with reducing flood damage; preventing excessive erosion; and protecting and improving water quality. 3-62. Alhambra Valley Estates Draft EIR March 2004 ....................................................................................................... 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.8-9: Project Area drainage Subbasins n a � 3 r 5 6� h a �Ea 4 � „ a4 x 'da' aa 'xs�n r, ,. E t "`F P 24 r SOURCE:Questa Engineering Corporation, Inc.2003 Alhambra Valley Estates Draft EIR 3-63 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3:$-2: 100-Year Floodplain of Vaca Creek Adjacent to the Project Site LJ eat a�zr t '"Ye o yrs o ndary za6 f p ✓ arx -� Nom..."` -N . � a'da rgje�i t �Y q �i 9 O 1` t ° *34 } : k � t rKey d�:fri1i3R ^y carr %,, i x SOURCE:PtA Design Resources, Inc.2003 3-54. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Alhambra Valley Specific Plan The Alhambra Valley Specific Plan, adopted by the Board of Supervisors in 1992, provides several goals and policies that apply to both private and public development projects in the area. Relevant goals and policies are described below. A.The Environment Goal 2,Policy 1: Avoid conventional development in flood inundation zones; prohibit development in FEMA 100-year flood zones. Goal 3,Policy 1: Require a creek setback for any development proposal along a creek or natural waterway.The creek setback width shall be a minimum of 50 feet, but may be expanded to protect the creek or its adjacent riparian habitat. Goat 3, Policy 2: Require a Creek Preservation Plan to restore and enhance this resource. S. New Development Goal 2, Policy 1: Require new development to provide on-site storm water and drainage facilities which accommodates full build out and considers a range of design alternatives. Goal 2,Policy 2:Control erosion in natural watercourses where creek capacity and bank stability necessitate,while maintaining consistency with the Creek Preservation Plan for that development. Minor structural improvements, e.g. drop structures, may be allowed if consistent with the concepts of the Creek Preservation Plan. Contra Costa County Cade The Contra Costa County Code includes several regulations that apply to new development within unincorporated areas of the County. Relevant portions of the County Code are summarized below. Chapter 914-14 Rights-of-Ways and Setbacks For unimproved earth channels within a subdivision,the structure setback line is determined by the height of the top of bank above the channel invert and is drawn horizontally from the top of bank. Because structure setback requirements vary depending on the height of the top of bank, structure setback requirements vary along Vaca Creek adjacent to the project site.The development rights for that portion of the creek on the creek side of the setback line,which is defined as the"structure setback area,"shall be offered for dedication to Contra Costa County. Chapter 914.2 Minimum [Drainage] Requirements Minor drainage facilities(i.e. those serving a watershed area less than one square mile) shall have adequate capacity to contain with sufficient freeboard a 10-year frequency of average recurrence interval runoff. ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following areas of potential environmental concern may be associated with implementation of the proposed project: The potential to violate water quality standards or waste discharge requirements Alhambra Valley Estates Draft EIR 3-65 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES + The potential to substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level(e.g.,the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or panned uses for which permits have been granted) • The potential to substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on-or off-site • The potential to substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff in a manner which would result in flooding on-or off-site • The potential to create or contribute runoff water which would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff • The potential to otherwise substantially degrade water quality • The potential to place housing within a 100-year flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map • The potential to plane within a 100-year flood hazard area structures which would impede or redirect flood flaws • The potential to expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam • The potential for inundation by seiche, tsunami, or mudflow Thresholds of Significance According to the State CEQA guidelines and procedures, and professional practices, the project would result in a significant hydrologic or water quality impact if it: • Substantially altered the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff,in a manner which would result in flooding cin-or off-site • Created or contribute runoff water which would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff • Violated SWRCB or RWQCB water quality standards • Substantially altered the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on-or off-site • Substantially depleted groundwater supplies or interfered with groundwater recharge such that there would be a net deficit in aquifer storage or a lowering of the local groundwater table Relevant Project Characteristics Vaca Creek forms the western boundary of the project site. No alterations to Vaca Creek have been proposed as part of the project. There would be no encroachment of work, structures, or 3-66. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES project development activity within the Vaca Creek corridor. The project would comply with the 50- foot creek setback required under the Alhambra Valley Specific Plan, as well as the structure setbacks required under Chapter 914-14 of tate County Subdivision ordinance. Both setback requirements are shown in Figure 3.8-3. Runoff that would be affected by project development has been divided into two separate subbasns: Subbasin 1 is on the 15.02-acre proposed project site and includes all runoff from the project site; and Subbasin 2 is on the area south of the project site, which extends across Reliez Valley Road. Run-off from Subbasin 2 travels north into Subbasin 1. Proposed drainage infrastructure Is depicted in Figures 3.8-3 and 3.8-4. Runoff from Subbasin 1 would be intercepted by a proposed 48-inch diameter pipe located at the southern end of the project site, between Lots 8 and 11. This pipe would convey all runoff from the upper portion of the watershed through the project site, and discharge it to a 48-inch storm drain proposed within the Alhambra Valley Road right-of-way. Runoff from Subbasin 1 consists of runoff that would be generated on the project site and from Subbasin 2. This runoff would be captured by a 48-inch storm drainpipe located on the proposed roadway that runs in a generally east-west direction across the project site (roadway has not yet been named). Outflows from the 48-'inch storm drainpipe would be constricted and would also serve as an in-line detention structure. This detention structure would be designed to reduce post project peak discharge to or below existing, undeveloped conditions. The detention capacity of the in-line detention structure is based on the 10-year/3-hour storm event. Onsite drainage structures would ultimately discharge to the 48-inch storm drain proposed within the Alhambra Valley Road right-of-way. Immediately beneath drop inlets, the 48-inch storm drain pipe would be underlain by approximately 2 feet of drain rock wrapped in filter fabric. This is herein referred to as the low-flow infiltration structures. The low-flow infiltration structures would serve to help filter pollutants from site runoff. Refer to Figures 3.8-3 for an illustration of the proposed onsite drainage system and Figure 3.8-4 for off-site drainage systems. Refer to Figure 3.8-5 for an illustration of the proposed low-flow infiltration structures for the project site. The 48-inch storm drain proposed within the Alhambra Valley Road right-of-way would commence at the eastern edge of the project site, between Lots 3 and 4 and continue north along Alhambra Valley Road to the intersection of Alhambra Valley Road and Wanda Way. Flows from the storm drain would discharge from a headwall at Alhambra Creek near the confluence of Vaca Creek. The bank opposite the existing 8-foot steel culvert under Wanda Way has experienced severe erosion. A discharge headwall and energy dissipation aprons would be constructed where the 48-inch storm drain discharges into Alhambra Creek at Wanda Way. The opposing creek bank would be enforced to prevent erosion. This work would be completed in accordance with engineering design that would be approved by the Contra Costa County Public Works Department, the SF Bay RWQCB, and the State Department of Fish and Game and will require a 16033 agreement in accordance with the Fish and Game Code. The proposed outfall is considered an enhancement plan for Alhambra Creek and would fulfill the Alhambra Valley Specific Plan requirement that some farm of creek enhancement be incorporated into the project(Gosset 20£2). PotentialImpacts and Mitigation The following potential impact was found to be a less than significant impact: Alhambra Valley Estates Draft EIR 3-67 Mauch 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.8-3; Proposed On-Site Drainage System / 4it M+9y Tda� j s Q # `ikj$ 3 P ;l i5 y . • S L NI) ��tsy.YYXY...• I t i^ � i • � lY ..ei. T `Sdr i ' E i� {k'F •�wt��p. �8' s .1 �� „. � 4r. �4 g� y N a 1 ���}kE*-• � % �'� r. FM ��i x.. '" .'�%� 'sS" � � b �,-fi �� � 'k.�Y�f"'�•fNy"�-';�r�A •t�">r� # ' x act a.Xf .1 6• - �`! 3`. \. ;'i �"µ A, f F SOURCE: P/A Design Resources, Inc. 2003 3-66, Alhambra Valley Estates Draft EER March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.8-4: Proposed Off-Site Drainage System ,Y w 4 R i "'"ems ' ._. � � y "asasre rd dw»nfo aaa ,ygy JW •l v x� :*{ E Ux rkMa 1nS 4 _ t � of Bs F 4 10nsw #4= : »+ 1V c sW � ]S f, ,�` r w ) 4 , l � . j tk x IN t p�( � � -w #� s i NORTH a ' I SOURCE: PIA Design Resources, Inc.2003 Alhambra Valley Estates drat EIR 3-69 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.8-5: Proposed Storm Water Inlet and Low-Flow Infiltration Structure LU IvIn Q) NQ1SN3N1GnnkY1N1" SOURCE:P/A Design Resources, Inc.2003 � � 3-70Alhambra Valley Estates Draft EIR -- � March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Potential Impact 3.8-1: Development of Proposed Project Could Result in Interference with Groundwater Recharge. The proposed project would result in an increase in impervious surface area. Impervious surfaces prevent the infiltration of runoff into the underlying sail and can interfere with groundwater recharge. However, the proposed project is not located in a groundwater basin, as identified by the DWR. The project applicant has proposed low-flow infiltration structures to allow for the infiltration of storm water. For these reasons project impacts on groundwater recharge are considered to be less than significant. No mitigation is necessary. Potential Impact 3.8-2: Alterations in drainage patterns and grading during the construction period could result in construction-related erosion problems. Implementation of the proposed project would require grading to create the individual building pads, to construct the on-site roadways, and for the installation of utilities (including trench spoils for the tiff-site utility pipelines). The applicant has proposed an on-site balanced grading plan that would require the total movement of 12,500 cubic yards of earth material, including on-site and off- site trench spoils. Increased erosion could result in the sedimentation of receiving waters. Sedimentation can lead to a reduction of water quality because sediment can carry nitrogen, phosphorus, and trace metals. Sediment can also accumulate at downstream storm drain system inlets and reduce capacity. The implementation of Mitigation Measure 3.8-1 and Mitigation Measure 3.8-2 would reduce construction-related erosion impact to less than significant levels. Mitigation Merasure!3.8-1: Prior to issuance of a Grading Permit,the applicant shall submit to the Building Inspection Department, Grading Division,for review and approval a detailed erosion control plan (ECP).The ECP shall define measures that the applicant will implement to mitigate erosion and sedimentation impacts during the construction period. Mitigation Measure 3.8-2: Prior to issuance of a Grading Permit, the applicant shall submit evidence to the Director of Public Works that coverage under the statewide General Construction Activities Storm water Permit(General Permit) has been obtained. The applicant shall comply with NPDES General Construction Activities Storm Water Permit Requirements established by the CWA. The applicant can obtain coverage under the General Permit by ding a Notice of Intent (NQI)with the State Water Resource Control Board's(SWRCB)Division of water Quality. The filing shall describe erosion control and storm water treatment measures to be implemented during and following construction and provide a schedule for monitoring performance. These BMPs will serve to control paint and non-point source(NPS)pollutants in storm water and constitute the project's SWPPP"for construction activities.While the SWPPP will include several of the same components as the ECP, the SWPPP will also include BMPs for preventing the discharge of other NPS pollutants besides sediment(such as paint,concrete, etc)to downstream waters. Potential Impact 3.8-3: Development of the proposed project could result in an increase in peak discharge at downstream drainage facilities. Project development would result in an increase in impervious surface area. An increase in impervious surface area could result in an increase in peak runoff at downstream drainage facilities and could potentially exacerbate downstream drainage and erosion problems. The potential increase in pear discharge as a result of project development is shown in Table 3.8-1. It should be noted that Table 3.8-1 does not account for detention that would occur through use of the proposed in-line pipe detention structure. Alhambra Valley Estates Draft EIR 3-71 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES The drainage calculations completed by the Centra Costa County Flood Control and Water Conservation District indicate that without detention, the proposed project would result in,a 2.7 cfs, 2 cfs, and 3 cfs increase in peak discharge for 2-year, 10-year, and 100-year storm events, respectively. An in-line pipe detention structure is proposed for the project to mitigate the calculated increase in peak discharge for up to the 14-yearf3-hour storm event. This structure consists of lengths of 48-inch pipe with constricted outflow into'a 48-inch storm drain proposed along AlhambraValley Road. Plows greater than the 10-year/3-hour storm event would overflow the structure and generally be'conveyed via overland flow through the streets to the proposed 48- inch storm drain along Alhambra Halley Road. The proposed in-line detention structure could potentially increase thepeak discharge downstream of the project site at Alhambra Creek.The detention structure stores runoff volume and slowly releases the flow at a prescribed rate. The detention basin alters the natural timing of peak flows from the project site subbasin (Subbasin 2). This may cause the discharge from the project site to coincide more closely with the timing of the peak discharge from the upper subbasin(Subbasin 1), thus, inadvertently increasing the peak discharge in Alhambra Creek. The Contra Costa County Public Works Department requires that new development mitigate for any potential increase in peak discharge for 10-year storm events. While there are no specific requirements for mitigating the potential increase in 100=year peak discharge, the public Warks Department does require that the project applicant demonstrate that 140-year flows can be safely conveyed through the project site.The project applicant has not provided data that show the relationship between the post-development peak discharge from the project site and the peak discharge from the upper watershed for 10-year storm events and has not specifically demonstrated that 100-year flaws can be safely conveyed through the project site. Implementation of Mitigation Measures 3.8-3 and 3.8-4 would reduce impacts associated with the potential increase in peak discharge and conveyance of 100-year flows to less than significant levels. Mitigation Measure 3.8-3.The project applicant shall provide the Department of Public Works with information that shows the relationship between peak discharge from the project site and peak discharge from the upper watershed. If it is found in the hydrology model that, these two discharges occur at the same time downstream of the site,the detention structures shall be redesigned such that post-development discharge is equal to, or less than the peak discharge under existing conditions at the point of discharge into Alhambra Creek at Wanda Way. Mitigation Measure 3.8-4.The project applicant shall demonstrate to the satisfaction of the Contra Costa County Public Warks Department that I00-year flows can be safely conveyed through the project site. if it is found that the 100-year storm event cannot be safely conveyed through the project site,the drainage plan for the proposed project shall be revised such that this performance criteria can be met Potential Impact 3.8-4: Project development could result in an increase in Non-Paint Source Pollutants to receiving'waters. Non-point source (NPS) pollutants are washed by rainwater from residential areas, landscape areas, and streets and parking areas into the drainage network. Pollutants from the proposed project would likely be consistent with suburban low/medium density residential areas, parking lots, and roads, Increases in the levels of oil and grease, petroleum hydrocarbons, metals, and possibly nutrients on the project'site are likely. Development of the project site would'result in an increase in the levels of NPS urban pollutants and litter entering downstream drainage facilities, and eventually, Alhambra Creek. An increase in NPS pollutants in these creeks'could have adverse effects on wildlife,fauna, and human health. 3-72. Alhambra'Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL. IMPACT ANALYSES Table 3.8-1: Potential Increases in Peak Discharge Without Detention Location Conditions Area(sq mi) Peak Flow(cfs) 2-yr/3-hr 10-yr/3-hr I00-yrl3-hr Onsite Pre-Development 0.021 6.9 16 24 Onsite Post-Development 0.021 9.6 18 27 offsite Pre-Development 0.207 41 98 155 Offsite Post-Development 0.207 41 98 155 SOURCE Contra Costa County Flood Control and Water Conservation District, (Mar 2002).Vaca Creek-Alhambra Estates. Executed by Mal Weston Low-flow infiltration structures that are proposed as part of the project would serve to filter out some of the pollutants found in storm water. The effectiveness of the low-flow infiltration components is dependent upon site soil conditions. The feasibility of Infiltration at the project site can be determined by percolation tests. The project applicant has not demonstrated that infiltration is feasible at the project site. Regular maintenance of the low-flow infiltration structures is necessary to preserve infiltration capability. The maintenance of such structures, however, is not specified in any project plans provided by the applicant. Implementation of Mitigation Measures .8-5, 3.8-6, 3.8-7, and 3.8-8 would reduce impacts associated with the potential increase in NPS pollutants to less-than-significant levels. Mitigation Measure 3.8-5. Prior to issuance of a Grading Permit, the applicant shall submit to Public Works for review and approval the results of percolation tests for site sails.The tests shall be conducted at the project site to demonstrate that site soils are suitable for infiltration. If percolation tests have already been conducted,the results of these tests shall be presented, along with a brief summary, to the Contra Costa County Public Works Department to ensure that infiltration is feasible at the project site. if it is determined that site sails are suitable for infiltration, specific design criteria for the structures shall be prepared and submitted to the Director of Public Works for approval. If the soils are deemed unsuitable for infiltration,the applicant shall design a suitable system for filtering pollutants found in storm water to submit to the Department of Public Warks for approval. Mitigation Measure 3.8-6.A Homeowners Association shall be developed and shall be responsible for the maintenance of drainage structures on the project site.The Homeowners Association shall be responsible for the proper maintenance of the low-flow infiltration structures. Mitigation Measure 3.8-7. Prior to issuance of a Grading Permit, the applicant shall submit to Public works for review and approval a long-term storm water pollution prevention plan (SWPPP)to protect storm water quality after the construction period.The SWPPP shall include the following additional BMPs to protect storm water quality: a) Proper maintenance of paved areas can eliminate the majority of litter and debris washing into storm drains and thus, entering local waterways. Regular sweeping is a simple and effective BMP aimed at reducing the amount of€Itter in storm drain inlets(to prevent clogging) and public waterways(for water quality). The Homeowners Association shall enter into an agreement with Contra Crista County or other street sweeping contractor to ensure this maintenance is completed. b) Proper maintenance of low-flow infiltration structures is necessary to ensure their effectiveness. Improper maintenance of the structures could result in a reductions of storm water conveyance capacity to overlying drainage structures as well as Alhambra Valley Estates Draft EIR 3-73 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES interfere with the Infiltration capabilities of the structures.The maintenance of the low-flow infiltration structures will be the responsibility of the Homeowners Association. Necessary maintenance includes:regular inspection during the wet season for sediment buildup and dragging of inlets and outlets; and regular (approximately once a year)removal of sediment.A maintenance schedule shall be submitted to the Contra Costa Public Works Department prior to project approval. c) The applicant shall prepare informational literature and guidance on residential BMPs to minimize pollutant contributions from the proposed development.This information shall be distributed to all future residents at the project site by the Homeowners Association.At a minimum the information should cover: 1)General information on the low-flow infiltration structures for residents concerning their purpose and Importance of maintaining them;2)Proper disposal of household and commercial chemicals;3)Proper use of landscaping chemicals;4)Clean-up and appropriate disposal of yard cuttings and leaf litter;and 5)Prohibition of any washing and dumping of materials and chemicals into storm drains. Impact 3.8-5: Project development could expose proposed structures on Lots 15 and 16 to 100-year fled hazards. The Alhambra Valley Specific Plan prohibits development within flood inundation zones and FEMA 100-year flood zones. The water surface profile analysis for Vaca Greek adjacent to the project site indicates that proposed structures can Lets 15 and 16 are located within the 100-year flood plain and thus, would be susceptible to 100-year flood hazards. 100-year flood hazards include risks to structures, human health, and property. Implementation of Mitigation Measure 3.8-9 would reduce impacts associated with the 100-year flood hazards to less than significant levels. Mitigation Measure 3.8.8.Project design shall comply with the County Flood Plain Management Ordinance requirements. 3.9 Land Use and Planning ENVIRONMENTAL SETTING Local Setting The project site is bounded by Alhambra Valley Road on the east, an approximately 7-acre undeveloped parcel on the south, the Vaca Greek on the northwest, and Hill Girt Ranch Road on the north (Figure 2.0-1). The project site is relatively flat, with the exception of some topographic relief on proposed Lots 14-16, adjacent to the Vaca Creep. Current site vegetation includes non- native grasses, a limited amount of cultivated hay pasture, a variety of mature tree species, and blackberry bushes. REGULATORY SETTING Contra Costa County General Plan/Alhambra Valley Specific Plan Two land use plan and policy documents guide use and development within Alhambra Valley: • Contra Costa County General Plan • Alhambra Valle, Specific Plan Contra Costa County General Plan. "The,purpose of the Contra Costa General Plan is to express the broad goals and policies, and specific implementation measures,which will guide 3-74. Alhambra Valley Estates©raft FIR March 2004 3:ENVIRONMENTAL IMPACT ANALYSES decisions on future growth, development, and the conservation of resources through the year 201 0.,,4 The General Plan, last updated in 1996, consists of nine elements: • Land Use Element • Growth Management Element • Transportation and Circulation Element • dousing Element • Public Facilities/Services Element • Conservation Element • Open Space Element Safety Element Noise Element Taken as a whole, the General Plan elements, and the goals, policies, programs, and standards outlinedin each, serve as guide to achieve the Plan's stated purpose. Alhambra Valley Specific Plan. The Alhambra Valley Specific Flan is intended "...to provide additional guidance to implement existing County General Plan policies which may apply to the area."Where the County's General Plan is general, by virtue of its task to guide the County as a whole, the Specific Pian refines and focuses those broader goals and policies specifically for the Valley. Land use designations for the project site are derived from the Alhambra Valley Specific Plan, which designates the site for Single Family Residential—Low[Density] (Figure 3.9-1), which the Plan defines as: Single Family Residential, Low[Density] (SL).While the County General Plan allows a density range between 1.0-2.9 units per net acre,this Specific Plan restricts new parcel sizes to 20,000 square feet or larger. Unique environmental characteristics of a parcel may warrant larger minimum lot sizes.This designation has been applied to lands on the valley floor along Reliez Valley Road and along either side of the northern leg of Alhambra Valley Road. Compatible zoning designations for this General Plan lands use category are R-20(20,000 square feet minimum net parcel size), R-40, R-65, R-100, P-1 and all Agricultural districts. The Specific Plan outlines goals and policies aimed at guiding use, development, and preservation of land and resources within Alhambra Valley similar to the General Plan. Zoning Ordinance The project site's existing zoning designation is R-20 (10.52 acres) and A2 Districts (4.50 acres) (Figure'3.9-2). R-20 Single-Family Residential district.The R-20 District permits the development of single family detached residential units on lots 20,000 square feet, or larger, in size. Cather permitted uses include'crop and tree farming, horticulture, temporary stands for the sale of agricultural products °Excerpt from the Purpose statement of the Introduction to the County's General Flan. Alhambra Valley Estates Draft EIR 3-75 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.9-1., Alhambra Valley Specific Plan Land Use Plan 0a u u, z u @ c� z+vivic`ui < ? 6 wren an _, c� 65 u www u- <., HUE a E i IV t ,6`3 fey F k.,.,...... ....... S ^ : +f��f2C C"'�Y3�*f$�Cr. ✓.� �' t�GY�V��YY�'G"�,,'C y�°v�y'y. 1yam4Y .s- . A Kit 41, = N V'o' SOURCE:Alhambra Valley Specific Plan 3992 Alhambra Valley Estates Draft EIR 3-77 March 2GO4 \ \ENVIRONMENTAL IMPACT ANALYSES / gore9 2: ExistingZoning Districts �( . SOURCE aA Design Resources andM 200 . Alhambra V¢|!e Ekes Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES While the entire project site is designated for low density residential uses by the Specific Plan, the Plan states that compatible zoning designations for that land use designation include the R-20 District and all Agricultural Districts (which includes the A-2 District). As such, the specific rezoning is not mandated by the Plan, nor necessitated to achieve conformance between the Specific Plan and the Zoning Ordinance; the Rezoning as proposed would be compatible with the Plan's direction for use of the site. 3.10 Noise Section 3.10 of this EIR is based in part on the peer review of the following environmental noise assessment prepared on behalf of the applicant: INingworth&Rodkin, Inc. 2002. Plummer Property Subdivision, Alhambra Valley Road, Camra Costa County—Environmental Noise Assessment, 2002 This reference is available for review at the Contra Costa County Community Development Department, 651 Pine Street, North Wing, 2nd Floor, Martinez, California. ENVIRONMENTAL SETTING Technical Background Sound is a pressure wave transmitted through the air and is described in terms of loudness or amplitude (measured in decibels [dBA]), frequency of pitch (measured in Hertz[Hzj or cycles per second), and duration (measured in minutes or seconds). Typical human hearing can detect changes in sound levels of approximately 3 dBA under normal conditions: Changes as low as 1 dBA are discernible under quiet, controlled conditions. The human ear is not equally sensitive to all sound frequencies. Sound waves below 16 Hz are not heard at all but can be felt as vibrations. While people with extremely sensitive hearing can discern sounds with pitches as high as 20,000 Hz, most people cannot hear sound with a frequency above 5,000 Hz or below 200 Hz. A special frequency-dependent rating scale is used to relate noise to human sensitivity. The A-weighted decibel compensates by discriminating against frequencies in a manner approximating the sensitivity of the human ear. Noise is defined as unwanted or objectionable sound, and usually reflects changes from typical background noise levels and spectra. Airborne sound is described as a rapid fluctuation of air pressure above and below the atmospheric pressure. Magnitude, frequency and duration are the variables used to characterize noise. A difference of 6-10 dB is perceived as a doubling of loudness. Distance serves to attenuate noise levels and changes in frequencies. With every doubling of distance, there is a corresponding reduction in noise levels of approximately 5 to 6 d13. Noise levels from familiar sources are shown in Table 3.10-1. LOCAL SETTING Existing Noise Sources There are no existing manmade noise sources on the undeveloped project site other than that generated by farm equipment occasionally used for mowing. The most significant source of off-site noise originates from vehicular movements along Alhambra Valley Road. Alhambra Valley Estates Draft EIR 3-79 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Table 3.1+0-1: Typical Residential/Commercial Noise Sources and Levels Noise Source Noise Level (dBA) Rustle of leaves in the breeze 25 Whisper(at 6 feet) 36 Inside average residence 40 Refrigerator(in same room) 40 Average office 55 Normal female speech(at 3 feet) 60 Vacuum cleaner(at 10 feet) 70 Garbage disposal(at 3 feet) 80 Food blender(at 3 feet) 90 Auto horn (at 10 feet) 100 SOURCE:Van Houten,J,J. 1974 Sensitive Receptors Sensitive noise receptors are generally residential land uses and facilities such as hospitals, schools, or resticonvalescent homes. Sensitive receptors in the project site's vicinity are limited to inhabitants of the residences nearest to the project site along Alhambra Valley Road, Hill Girt Ranch Road, and Reliez Valley Road. REGULATORY SETTING Federal The US Environmental Protection Agency (EPA) suggests a noise level limit of 70 dBA for the protection of human health and welfare in farmland and on unpopulated land. State and Regional California has not established absolute standards for noise exposure for the general population. There are established noise exposure standards for the workplace that are administered by the state's Division of Occupational Safety and Health (CalOSHA). The California Office of Noise Control (ONC) adopted and published in 1976 Guidelines of the Preparation and Content of Noise Elements of the General Plan. The 1976 ONC Guidelines have been updated and replaced by the Noise Element Guidelines issued in 1998 by the Governor's Office of Planning and Research. (Governor's Office of Planning and Research 1998), Local The Contra Costa County's General Plan Noise Element outlines the following policies with regard to exterior and interior noise environments for residential development: Policy 11-2.The standard for outdoor noise levels in residential areas is a DNLS of 60 dB. However, a DNL of 60 dB or less may not be achievable in all residential areas due to DNL.is the day night noise level 3-80. _ Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES economic or aesthetic constraints. One example Is small balconies associated with multi- family housing. In this case, second-or third-story balconies may be difficult to control to the goal.A common outdoor use area that meets the goal can be provided as an alternative. Policy 11-4.Title 24, Part 2, of the California Code of Regulations requires that new multi- family housing projects, hotels,and motels exposed to a DNL of 60 dB or greater have a detailed acoustical analysis describing how the project will provide an interior DNL of 45 dB or less. The county also shall require new single-family housing projects to provide for an interior©NL of 45-dB or less. ENVIRONMENTAL. ANALYSIS Areas of Potential Environmental Concern The following is an area:of potential environmental concern that may be associated with implementation of the proposed project: • The potential to generate construction noise • The potential exposure of persons to or the generation of noise levels in excess of standards established by the General Plan Threshold of Significance There would be a significant noise impact if the project would expose people to noise levels in excess of applicable standards Potential Impacts and Mitigation Potential Impact 3.10-1: Generation of construction noise The operation of heavy equipment, and the use of tools powered by electricity, air pressure, and internal combustion engines would be the principal source of construction-generated noise at the project site. The equipment would be used during legit development activities for grading and access road construction, earthmoving, infrastructure placement, tree-removal, and construction of the residential units. Neighbors to the project site and area could be impacted by the project construction noise. Attenuation of equipment and tool sounds, at a rate of approximately 5-6 db for each doubling of distance from the source, local topography, and existing vegetation would reduce, but not eliminate, construction equipment noise exposure to non-project personnel, such as individuals in adjacent residential units or recreational trail users along Alhambra Valley or Reliez Valley Roads. The construction of subdivision improvements (site grading, roadways, on-site and off-site infrastructure) are not expected to require more than one year, and therefore would be considered short-term and temporary. The construction of the individual residential units could be concentrated over a relatively short time frame, or could extend over several years,depending on whether the units are constructed individually or as a tract. Either case would be regarded as a temporary, short-term condition, although noise effects could be significant. The following mitigation measures would reduce the temporary effects of construction related noise to a less than significant level. Mitigation Measure 3.10-1. Noise generation associated with grading construction activities shall be minimized by implementation of the following noise control measures: Alhambra Valley Estates Draft EIR 3-81 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES • All noise producing grading and construction activities shall be limited to the hours of 7:30 AM to 5:00 PM, Monday through Friday. • Feasible, appropriate noise-reducing technology shall be used on all on-site grading and construction equipment, and tools. • The delivery of construction materials and equipment shall occur only during the hours of 7:30 AM and 5:00 nM on construction days. Construction materials shall not be delivered on Saturdays, Sundays, or federal holidays. • All stationary construction equipment shall be sited as far as practical from Alhambra Valley Road and Hill Girt Ranch Road. Potential Impact 3.10-2: Exposure of persons to or the generation of noise levels in excess of standards established by the General Plan. Existing traffic noise levels were monitored at the project site on January 9— 11, 2002 (CCTA 2002). Noise levels were monitored continuously over an approximately 48-hour period at one location 50 feet from the centerline of Alhambra Valley Road. The hourly equivalent sound level (L..) measured during each hour is shown on Figure 3.10-1. The measured day/night average noise level was a DNL of approximately 64 dB. During the noise measurements, the sky ranged from clear to partly cloudy. Winds were light and temperatures were moderate and typical of winter in the area. Vehicular traffic on Alhambra Valley Road was the only significant source of noise. The traffic was light during the observed times when the meter was installed and removed. Vehicles were observed to travel at a high speed through the area most likely due to the country setting and light traffic volumes. The Contra Costa Public Works Department and the Community Development Department were contacted to determine any expected change in the roadway or traffic volumes in the area. No information was available to indicate a significant change. This was corroborated via the traffic analysis conducted for this EIR (Section 3.14, Transportation and Traffic). The measured noise level at Lot 1 (50 feet from the centerline of Alhambra Valley Road) was DNL 64 dB. Traffic noise levels would drop off at the rate of approximately 4.5 dB with the doubling of distance from the road. Based on this formula, the projected 60 dB noise contour would be- approximately 100 feet from the centerline of Alhambra Valley Road on Lot 1, as well as for all other lots immediately adjacent to Alhambra Valley Road. There are four approaches to achieving the County's exterior 60 dB noise goal: Approach 1 - If the defined outdoor space for each of the lots located adjacent to Alhambra Valley Road was to be located between the residential units and Alhambra Valley Road, construct a solid, 6-foot noise barrier along Alhambra Valley Road, with wall returns at each end (a wall would not protect the second story of any residential unit located adjacent to Alhambra Valley Road) Approach 2 - Redesign the subdivision to shift the rear lot lines of lots adjacent to Alhambra Valley Road (Lots 1, 3, 4, 5, 6, 22, and 23)westerly so that those lot lines are a minimum of 100 feet from the centerline of Alhambra Valley Road (Figure 3.10-3) Approach 3 - Orient all residential units along Alhambra Valley Road toward Alhambra Valley Road such that the houses would be developed along the perimeter, and exterior space would be inside the lot, making that space useable and protected from the noise of Alhambra Valley Road. 6 For purposes of this analysis,the defined outdoor space for each residential unit is presumed to be the backyard. 3-82• Alhambra Valley Estates Draft EIR March 2004 .................................... 3: ENVIRONMENTAL IMPACT ANALYSES Approach 4 - Develop some ether residential design that shields the outdoor living space from Alhambra Valley Road noise. The Alhambra Valley Specific plan specifically prohibits construction of any solid fencing alone Alhambra Valley Road, therefore rendering construction of a noise wall moot(Approach 1). Redesigning the subdivision to shift all Eats, so that no portion of any lot is any closer than 100 feet from the centerline of Alhambra Valley Road, would place all lots at or beyond the projected 60 dB contour(Approach 2). This approach could result in a reduction of lot yield due to other development standards, such as minimum lot size. Orienting all homes toward Alhambra Valley Road would in effect utilize the homes as a noise barrier for protecting and reducing the noise exposure within the units'exteriors (Approach 3). The fourth approach represents a variation on Approach 3, and defers specific design opportunities to reduce provide exterior areas for each residential unit consistent with County General flan policy to the designers of the individual units. To archive conformance with the County's goal, the following Mitigation Measure shall be implemented: Mitigation Measure 3.10-2. Prior to recordation of the final map the applicant shall submit CC&Rs to the Zoning Administrator for review and approval. The CC&Rs shall state that all residential units constructed on lots 1, 3,4, 5,6, 22, and 23 shall provide outdoor areas that are exposed to noise levels from Alhambra Valley Road at levels no greater than 60 dB.The outdoor areas must be: 1)a 100-feet minimum from the center of Alhambra Valley Road or; 2)enclosed within a courtyard that places the residential unit between the courtyard and Alhambra Valley Road or; 3)protected from Alhambra Valley Road noise levels by the use designs that shield exterior spaces to levels from Alhambra Valley Road no greater than 60 dB. Typical California construction provides approximately 15 dB of noise reduction when going from outside to inside with the windows open, and more than 20 dB of noise reduction with windows and doors closed. Mouses within 100 feet of the Alhambra Valley Road centerline would experience adequate attenuation as long as windows remained closed. If windows were opened, the attenuation would be not be adequate, and residents would be exposed to interior noise levels greater than allowed by the Contra Costa County General Plan Noise Element. Under this latter scenario, future residents would be exposed to a significant noise impact. Implementation of the following mitigation measure would reduce noise impacts to less-than-significant levels. Mitigation Measure 3.10-3.Any residential unit constructed less than 100 feet from the centerline of Alhambra Valley Read shall be constructed with forced air mechanical ventilation systems, or air conditioning,or as approved by the Zoning Administrator. Alhambra Valley Estates Graft EIR 3.63 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.10-1: Noise Levels 50 Feet from the Centerline of Alhambra Valley Read a 9 an d:7 u7. CPn at'r e'a .Pt's Ce := `y cta t•. r. ctxp an u7 (Vap) va'ta-j asf SOURCE: Illingworth&Rodkin, Inc.2002 3-84. Alhambra Valley Estates©raft EIR March 2004 ƒ ENVIRONMENTAL IMPACT ANALYSES Figure 1 Approximate Location of 60 dB Noise Contour from Alhambra Valley Road . � _ SOURCE:PIA DesignResources, Inc.and 9HA 2003 Alhambra Ve Estates Draft SR 3-85 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES 3.11 Population and Housing ENVIRONMENTAL SETTING Regional and Local Population. Data available from the California Department of Finance's (DOF) Economic Research Unit(California DOF 2003) indicate that population growth in the County from 1990 to 1999 reflected an average annual growth rate of 1.67°!x, with a net increase of 142,516 people during that period. The growth represents a 17.7% population increase over the 10-year period. Table 3.11-1 illustrates the County's population growth over that period. The County is projected to have an annual average growth rate of 1.2% between the years 2000 and 21305(DOF 2003). From the estimated January 1, 2003 papulation of 994,908, a 1.2% increase represents an additional 11,939 additional people in the County in one year. Housing. There was an estimated average of 2.76 people per household in Contra Costa County in January 2002, with a total of 361,748 housing units (California DOF 2003). REGULATORY SETTING Federal, State, and Regional No federal goals, objectives, or policies are considered relevant to the potential population and housing effects that may result from implementation of the proposed project. Local The Contra Costa County's General Pian Housing Element addresses issues associated with the need to ensure the adequate provision of housing for all economic segments of the community. California law, as administered by the Department of Housing and Community Development, strictly defines the content and process of a housing element. The County's Housing Element includes goals, policies, and action programs that if implemented, would assist the County in meeting its defined housing needs. The Housing Element states that for the 1988 to 1995 time frame, that there was an existing (unmet) and projected housing need (for that time period)within the unincorporated County of 6,447 residential units for all economic segments of the community. Development of housing within the unincorporated County is guided in part by the Housing Element's goals, policies, and programs. One of the key policies in the Element fellows: Policy 1.1: Fair Share Housing Production. On a Countywide basis, attempt to increase the number of housing units to meet the need for additional housing during the 1990-1995 period.Contra Costa County's unincorporated objective is based on ABAG's determination of Contra Costa County's fair share of housing by income groups as illustrated below: Unincorporated Contra Costa County Quantified Objective Based on Regional Needs: 1988-1995 Total New Very Low Low Income Moderate Above Moderate Construction Income Income Income ABAG's 6,447 1,289 903 1,289 2,966 Determination 1988-1995 Annual Share 921 184 129 184 424 3-86. Alhambra Valley Estates Draft EIR March 2004 ............................ _..........................._.................................. ....... .......... ... ........ . ........ . ..... ......... ......... ......... 3: ENVIRONMENTAL IMPACT ANALYSES Table 3!11-1: Historic Annual Population Growth/Decline for Centra Costa County Population(July 1) Annual Growth Annual Percentage Growth 1990 806,300 1991 823,700 17,400 2.16 1992 840,800 17,100 2.08 1993 856,400 15,600 1.86 1994 865,600 9,200 1.07 1995 872,800 7,200 0.83 1996 883,400 10,600 1.21 1997 901,900 18,500 2.09 1998 919,800 17,900 1.98 1999 937,200 17,400 1.89 2000 -948,816 14,500 1.60 July 1st 2000 data extrapolated from April 1,2000 census data. SOURCE:California Department of Finance 2003 ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following area of potential environmental concern that may be associated with implementation of the proposed project: • Potential for generating unplanned population growth Threshold of Significance The impacts of project actions would be considered significant if population is affected in the following way: • Induce substantial population growth In an area, either directly(for example, by proposing new homes and businesses)or indirectly(for example,through extension of roads or other infrastructure) • Displace substantial numbers of existing housing, necessitating the construction of replacement housing elsewhere • Displace substantial numbers of people, necessitating the construction of replacement housing elsewhere Potential Impacts and Mitigation The project site is designated within the Alhambra Valley Specific Plan for low density residential development, with a minimum lot size of 20,000 square feet. In theory, that would translate to a maximum project site lot yield of 32.7 lots, without consideration for roadways, Vaca Creek, or other site development constraints. The proposed creation of 23 lots is below the maximum yield of 32.7 lots. Alhambra Valley Estates Draft EIR 3-87 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Based on the current estimated per household population, the proposed project would be expected to generate a population increase of 63 people, which is within the projected Contra Costa County annual population increase of 11,939 people. The relatively minor increase to the County's housing stock and population of 0.4064%and 0.0063% respectively would have a less than significant impact on population and housing. Implementation of the proposed project would not induce substantial growth either through the construction of significant numbers of new residential units nor through the creation of large numbers of permanent jobs, and would neither displace existing housing units nor people. Installation of the temporary wastewater pipeline may resulted in an accelerated pace of development within the Alhambra Valley but would not be expected to induce un-planned growth. Therefore, a potential significant impact on population or housing is not expected. 3,12 Traffic and Transportation ENVIRONMENTAL SETTING Regional Access The project site is located about 1.7 miles south (via Alhambra Avenue and Alhambra Valley Road) off of State Route 4 (SR 4). SR 4 is a multi-lane freeway, which extends from Interstate 80 (1-80) east through Contra Costa County. Local Street Network Local streets that provide primary access within the study area include Alhambra Valley Road, Alhambra Avenue, and Reliez Valley Road (refer to Figure 3.12-1). All of these streets provide two travel lanes with varying pavement widths. In the project area, Alhambra Valley Road and Reliez _ Valley Road are described in the Alhambra Valley Specific flan. Alhambra Valley Road is proposed as the principal point of access for the proposed project. Lot 6, located at the corner of Alhambra Valley and Reliez Valley Roads, would take its access directly off of Alhambra Valley Road. North of Reliez Valley Road, Alhambra Valley Road is designated a two-lane collector street which serves local access as well as providing connections to Alhambra Avenue and Reliez Valley Road. Alhambra Valley Road is about 22 feet in width at the proposed project access. There are no frontage improvements (curb and gutter) in the project area. West of Reliez Valley Road, Alhambra Valley Road is designated as a two-lane arterial street and continues west to the El Sobrante area. Alhambra Avenue is a north-south arterial street that provides a through access route between Pleasant Hill Road and downtown Martinez. This road is designated a"Route of Regional Significance" in the Contra Costa Countywide Comprehensive Transportation Plan. Alhambra Avenue is 2-4 lanes in width, although the City of Martinez is conducting studies that consider widening Alhambra Avenue to a four-lane width throughout its length. The Alhambra Avenue/Alhambra Valley Road intersection is controlled by a traffic signal. Reliez Valley Road is designated a two-lane arterial street which extends from Pleasant Hill Road in Lafayette to Alhambra Valley Road at the project site. Pavement widths vary throughout the length of this road. 3-88_ Alhambra Valley Estates Graft EIR _ March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Study Intersections and LOS Concept Intersection operation is usually considered a critical factor in determining the traffic handling capacity of a roadway system. Based on discussions with Contra Costa County and City of Martinez staff, the following two intersections (referred to as the study intersections") were chosen for analyses in terms of AM and PM peak commute hour operation: • Alhambra Valley Road/Alhambra Avenue • Alhambra Valley Road/Reliez Valley Road As a part of this analysis,AM and PM peak period (7:00-9:£70 AM and 4:00-6:00 PM) intersection counts were obtained for the study intersections. From the peak period intersection counts, AM and PMpeak hour volumes were determined and are shown in Figure 3.12-1. At the signal controlled intersection of Alhambra Valley Road/Alhambra Avenue, Level of Service (LOS) reflects the overall operation of the intersection. The intersection's volume-capacity ratio (vfc) is determined by the volume of conflicting traffic movements per hour and the capacity designed to accommodate them. This ratio, in turn, is rated from LOS A to F. The range describes increasing traffic demand, delays, and deterioration of services. At the intersection of Alhambra Valley Road/Reliez Valley Road where all approaches are stop- sign controlled, the resulting LOS reflects similar overall delays described for signalized locations. However, if volumes are substantially"unbalanced"between the intersection legs, vehicles on the highest volume approach would experience disproportionate delays. REGULATORY SETTING The analysis process and the findings with regard to traffic impacts have been completed in a manner that is consistent with Contra Costa County and Contra Costa Transportation Authority (CCTA) guidelines. There are no specific adopted significance criteria for the operation of the study intersections. Alhambra Avenue is a CCTA designated "Route of Regional Significance,,'and as such, operational objectives along this route do not adhere to typical LOS objectives. it is expected that intersections along Alhambra Avenue should operate at no worse than LOS D, an accepted CCTA standard for intersections on non-significant routes. The Alhambra Valley/Reliez/Valley intersection is stop-sign controlled and there are no CCTA adopted standards for such intersections. This intersection would also typically be expected to operate at LOS D or better. Both Alhambra Valley Road and Rellez Valley Road are described in the Alhambra Valley Specific Plan.The Plan provides information regarding the roads'function, roadway widths, and pedestrian/bicycle and equestrian paths. Traffic Conditions with Approved development Approved Development Traffic and Planned Traffic improvements. The CCTA provides technical procedures for conducting traffic analyses. These guidelines outline the appropriate sequence of analyses for proposed development projects. As per these guidelines, traffic analyses should consider existing traffic plus traffic generated by approved development. The effects of the proposed project can then be measured against this future baseline scenario. The existing and approved development in the project area primarily consists of smaller residential infill projects in the County as well as in the cities of Martinez, Pleasant Hill, and Lafayette. As an example, the City of Martinez has identified three approved residential infill projects totaling 26 dwelling units. Because these smaller infill projects are located in three cities and the County, it is Alhambra Valley Estates Draft EIR 3-89 March 20014 3: ENVIRONMENTAL IMPACT ANALYSES Figure 12p ae:.a>lnn Volumes Ahiu i J� r,l e Ct Hii ua s e s Signalized alized Interse ti ^4a A " ' I r L S Stop Sign Controlled 21 ('523i d 4 _ �s g� p ; Y ✓ _g@gg S � i April 25, 2003 AM Peek—7.15 AM —0:15 AM PM Peak—4.45 PM —5,45 PM SOURCE: George Nickelson 2003 ._-------------_. _._._.._ 3.90. Alhambra Valley Estates Draft EIR March 2004 ................................ 3: ENVIRONMENTAL IMPACT ANALYSES not practical to identify every approved development's trips in terms of their effects on the study intersections. In lieu of identifying specific trip generation from a number of smaller developments, CCTA traffic projections available for Alhambra Avenue, Alhambra Valley Road, and Reliez Valley Road were used. used on 2020 projections, it was determined that traffic growth at the Alhambra Avenue/Alhambra Valley Road intersection would be about 1.5% per year. At the Alhambra Valley Road/Reliez Valley Road intersection, the identified growth rate is about 3% per year. To establish traffic growth reflecting approved development, these growth rates were applied over a 3-year period. It is anticipated that the 3-year period would coincide with completion of the proposed Alhambra Valley Estates project. Traffic Flow Conditions With Approved Development. The study intersections' LOS designations have been recalculated with the traffic growth associated with approved development. Both of the intersections would remain at very stable LCIS A conditions as outlined in Table 3.12-1. ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following are areas of potential environmental concern that may be associated with implementation of the proposed project. • The potential to substantially increase traffic on area roads beyond their existing or planned design and operating capacity • The potential to create traffic conditions that could be considered hazardous or .dangerous • The potential to conflict with established transportation policies Thresholds of Significance The following thresholds of significance are used to determine the level of impact for areas of potential environmental concern. The project would have a significant effect if it would: • Cause an increase in traffic which is substantial in relation to the existing traffic load and capacity of the street system • Exceed, either individually or cumulatively, a level of service standard established by the county congestion management agency for designated roads or highways • Substantially increase hazards due to a design feature • Result in inadequate emergency access • Result in inadequate parking capacity Potential impact 3.12-1: Substantially Increase traffic on area roads beyond their existing or planned design and operating capacity Traffic Flow Conditions. Peak hour intersection (AM Peak—7:15 AM to 8:15 AM; PM Peak—4:45 PM to 5:45 PM) LOS designations have been calculated. Both of the intersections' operations are at LOS A, as shown in Table 3.12-1, indicating very stable flows with minimal delays. Predicted traffic flow conditions, based on the expected 63 residents and projected 220 daily trips, would not represent a significantincrease beyond planned, designed, or operating capacity. Alhambra Valley Estates Craft EIR 3-91 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Table 3.12-1: Existing and Projected intersection Operation (LOS and Seconds of Delay) Existing Baseline Traffic Baseline+ 2020 Cumulative Traffic Project Traffic Traffic Intersection AM PM AM PM AM PM AM PM Alhambra A A A A A A B B Valley/Alhambrai'� 0.56 0.52 0.58 0.55 0.59 0.55 0.70 0.66 Alhambra A A A A A A B B Valley/Reliez Valley{�} 9 9 9 9 9 9 11 10 LOS and delay designations refer to overall operation of this signal-controlled intersection. (2)LOS designation refers to overall operation and delays for all traffic entering this all-way stop—sign-controlled intersection. SOURCE:Omni-Means,George Nickelson 2003 Traffic Signal Warrants. The Alhambra Valley Road/Reliez Valley Road intersection has also been evaluated for peak hour traffic signal warrants. The peak hour warrants are established by Caltrans for installation of a signal. When an intersection's peak hour volumes exceed the minimum thresholds, a traffic signal could be warranted. Intersections that qualify for signalization under the peak hour criteria, may require further analyses of accident history, proximity to other driveways/intersections, and potential volume increases. The existing peak hour volumes at the intersection of Alhambra Valley Road/Reliez Valley Road are well below the minimum thresholds at which signalization could be warranted (Appendix B). Project Trip Generation and Distribution. Daily and peak hour trip generation for the proposed project has been based on the Institute of Transportation Engineers (ITE) research for single- family, detached units. The project's expected trip generation is shown in Table 3.12-2. The project would generate 220 daily trips with 17 trips (4 inbound, 13 outbound) during the AM peak commute hour and 23 trips (15 inbound, 8 outbound) during the PM peak commute hour. The project's trip distribution has generally been based on access convenience and observations of existing traffic flow characteristics at the nearby Alhambra Valley/Millthwait intersection. Based on these factors, the proposed project's traffic distribution would be as follows: • 65%to/from the north on Alhambra Valley Road • 15%to/from the west on Alhambra Valley Road • 20%tolfrom the south on Reliez Valley Road The AM and PM peak hour project trips have been distributed onto the surrounding street network and are shown in Figure 3.12-2. The project would add less than I% to the peak hour volumes at Alhambra Avenue/Alhambra Valley Road and 1-2% to the peak hour volumes at Alhambra Valley Road/Reliez Valley Road. These increases would not be measurable within typical daily fluctuations in traffic flows. Intersection Operation With Future Baseline Plus Project Traffic. The study intersections' operation was recalculated with the project trips added to future baseline volumes.As indicated in Table 3.12-1, the intersection LOS would be unchanged, and project trips would have no measurable effect on operation. Both of the study intersections would continue to operate at very stable LCIS "A." The project would not be expected to cause significant impacts at the study intersections. The project would add less than I% to the peak hour volumes at Alhambra Avenue/Alhambra Valley 3-92. Alhambra Valley Estates Draft EIR March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Table 3.92-2: Project Trip Generation Trip Generation Rate Trip Generation 23 SINGLE FAMILY UNITS @ 9.57/UNIT 220 Daily Trips 23 Single Family Units @ 0.75/unit 17 AM Peak hour Trips; 4 inbound/13 outbound 23 Single Family Units @ 0.1.01/unit 23 PM Peak Hour Trips; 15 inbound/8 outbound SOURCE: ITE,Trip Generation 6th Edition 1997; OMNI-MEANS,George Nickelson 2003 Road and 1-2% to the peak hour volumes at Alhambra Valley Road/Reliez Valley Road. These increases would not be measurable within typical daily fluctuations in traffic flows. Although the cumulative growth in traffic volumes would be measurable, the study intersections' operation would continue to be at very stable LOS "B"conditions. A potentially significant impact is not expected with regard to a substantial increase of traffic on area roads beyond their existing or planned design and operating capacity. Potential Impact 3.12-2: Traffic conditions that could be considered hazardous or dangerous Vehicle Speeds and Sight distance on Alhambra Valley Road.Vehicle speeds have been measured on Alhambra Valley Road near the proposed project access point. The "critical speed" (85% of all measured vehicle speeds are at or below the critical speed) is about 41 mph. The sight distance (the distance at which a motorist can see an object in the roadway), was field measured on Alhambra Valley Road at the proposed primary project access point. The sight distance to the north is about 1,000 feet. The sight distance to the south extends to Reliez Valley Road, at a distance of about 850 feet. Based on Caltrans design standards, the prevailing vehicle speeds on Alhambra Valley Road (41 mph critical speed) would require about 450 feet of"corner sight distance."The Caltrans corner sight distance standards state that"a substantially clear line of sight should be maintained between the driver of a vehicle waiting at the cross road and the driver of an approaching vehicle in the right lane of the main highway."This comparison indicates that the available sight distance at the primary project access should be ample for the vehicle speeds on Alhambra Valley Road. The proposed access to Lot 6 directly off of Alhambra Valley Road would be expected to have similar sight distance conditions to that of the primary access point at Deer Creek Court. Vehicle speeds on Alhambra Valley Road near its intersection with Reliez Valley Read would be expected to be lower as vehicles would be braking for the stop sign at the intersection, or would be accelerating after a complete stop and having made the turn off of Alhambra Valley and Reliez Valley Roads. Project Access.The site's primary access on Alhambra Valley Road would operate satisfactorily with all of the turning movements operating at LOS"A". The peak hour through volumes on Alhambra Valley Road are relatively low (300-400 two-way vehicles),and the peak hour vehicles in/out of the project site would not result in significant traffic conflicts. Based on design guidelines, there would not be a need for left-turn or right-turn lanes on Alhambra Valley Road at the site access. It is noted that while the existing 22 foot width on Alhambra Valley Road would remain adequate for two-way traffic flows, the Alhambra Valley Specific Plan calls for a 32 foot width ( 2 12-foot travel lanes with 4-foot shoulders)on this roadway. No significant conflicts or delays would be expected at the project access on Alhambra Valley Road. Alhambra Valley Estates Draft EIR 3-93 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.12-2: Peak Hour Project Trips AM and (PM) (PROJECT TRIPS ONLY) . Signalized Intersection 1 €3 (2) (8) 2 __ s Stop Sign Controlled 1 (3) i 1 (2) 1 NORTHRELI z VALL-Ey RD. April 25, 2003 IWAP NOT TO SCALE AM Peak—7:15 AM--8:15 AM PM Peak—4:45 PM—5:45 PM SOURCE:Omni-Means,George Nickelson 2003 3-94. Alhambra Valley Estates Draft EiR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES The applicant has proposed that access to Lot 6 be taken directly off of Alhambra Valley Road. The Contra Costa Public Works Department has determined that this could represent a potentially hazardous condition with respect to site distance, turning movements, and general traffic safety. Implementation of Mitigation Measure 3.12-1 would reduce the potentially significant impact to less than significant levels. Mitigation Measure 3.12-1. Prior to recordation of the Final Map,the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that delineate a revised vehicular access for Lot 6 in a manner such that it takes its vehicular access of off the subdivision's internal roadway system and not off of Alhambra Valley Road. The applicant has proposed removal of three mature trees along the project site's Alhambra Valley Road frontage. The Contra Costa County Public Works Department has determined that widening Alhambra Valley Road in accordance with the Alhambra Valley Speck Plan's Circulation Element would place the Road's travel lanes too close to those trees and could result in a potentially significant traffic safety impact if not removed. The applicant has proposed development of a divided entryway off of Alhambra Valley Road. The Contra Costa Public Works Department has determined that this could represent a potentially hazardous condition with respect to site distance, turning movements, and general traffic safety. Implementation of Mitigation Measure 3.12-2 would reduce the potentially significant impact to less than significant levels. Mitigation Measure 3.12-2. Prior to recordation of the Final Map,the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that delineate a revised entry to the project site off of Alhambra Valley Road.The entryway shall delete the center island. Internal Circulation. The project's internal street design would consist of an 800-foot long primary access cul-de-sac street with two shorter connecting cul-de-sac streets. The streets would have 32-foot curb-to-curb widths. These widths could accommodate two-way traffic flows plus parking on one side of the street. The applicant also proposes to have a paved 20-foot wide emergency vehicle access road connecting the internal street network with Hili Girt Ranch Road. The proposed internal street widths would meet the Contra Costa Fire District (CCFD)standard for a two-lane street with parking on one side (to accommodate parking on both sides, CCFD would require'a 36 foot curb to curb width). The CCFD standard turnaround radius of 35 feet(allowed in hilly areas)would be met by the proposed project's cul-de-sac radii. The proposed internal streets would serve the circulation needs of the project and would meet Contra Costa Fire District standards. Thus, the project as designed would not create a potentially significant impact with regard to traffic conditions that could be considered hazardous or dangerous. Potential Impact 3.12-3: Conflict with established transportation policies Pedestrian/Bicycle and Equestrian Access.The proposed project would include pedestrian/bicycle and equestrian facilities on the west side of Alhambra Valley Road. The project would include construction of an 8-foot wide paved pedestrian/bicycle path and a 6-foot wide wood chip equestrian trail within a proposed dedication of 22 feet of additional right-of-way. The path and trail would extend along the entire project frontage of Alhambra Valley Road. The proposed facilities are consistent with provisions of the Alhambra Valley Specific Plan's vision for trails, as expressed in Figure 3.12-3. Alhambra Valley Estates Draft EIR 3-95 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.12-3: Alhambra Valley Specific Plan Trails " Q9 a, t� �,�� i�J� � � �a - 'wire-• � i �- �, ra�, � ...__ ...`.._ � h..�. � I�•.t err ix�y t� ti i 4 � r - 3 F r � Y, 1rCrx eY � a `� k r r SOURCE:Alhambra Valley Specific Flan 3-96• Alhambra Valley Estates Draft EIR March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Existing and Proposed Transportation Facilities. An assessment of potential effects on existing facilities as well as potential effects on completing facilities in the project area was made. A separate path along Reliez Valley Road is in the planning process. An existing path is located along Reliez Valley Read from the Briones,Park access southeast to Grayson Road.Construction is also underway on a separate path from Withers south toward Pleasant Hill Road. Alhambra Valley Road has no other path/trail facilities between Reliez Valley Road and Alhambra Avenue. The proposed project would have no effects on the operation of any existing facilities or impede the completion of any in-process facilities. Alhambra Valley Specific Plan. The Alhambra Valley Specific Plan Circulation Element establishes a requirement that Alhambra Valley Road, be improved to a right-of-way width of 80 feet, including two 12-foot travel lanes with 4-foot shoulders. The applicant's preliminary plans for the proposed project do not include the widening of Alhambra Valley Road along the project site's frontage to the fully improved width,which represents a significant impact. The following mitigation measure will ensure that Alhambra Valley Road is improved in accordance with the Alhambra Valley Specific Plan. Mitigation Measure 3.12-3. Prior to recordation of the Final Map,the applicant shall submit Improvement Plans to the Contra Costa County Public Works Department that illustrate the widening of Alhambra Valley Road per the Alhambra Valley Specific Plan. 3.13 Utilities and Service Systems ENVIRONMENTAL SETTING Water Supply Water service to the project area, including an existing water main within Alhambra Valley Road, is provided by the City of Martinez(Alberto, personal comm. 2003). The City of Martinez Water System purchases both raw and treated water from the Contra Costa Water District. The water is sourced from the Sacramento Delta at Old River and Rock Slough and then stored in the Los Vaqueros Reservoir. Los Vaqueros provides storage and helps maintain a high quality water supply year round. Water is then delivered via the Contra Costa Canal to the Martinez Reservoir. The Martinez Water Treatment Plant takes raw water from the Martinez Reservoir, and treats it for potable uses. The plant processes consist of coagulation, sedimentation, filtration, and disinfection. The plant operates seven days a week, 365 days a year(City of Martinez 2003). Water storage capacities for the Los Vaqueros and Martinez reservoirs are 100,000 and 270 acre- feet, respectively (Contra Costa Water District 2003). The City of Martinez water distribution system serves approximately 9,700 services, with four pressure zones. The distribution system contains 10 storage reservoirs, 7 pumping stations, and approximately 100 miles of various sizes of pipe. A full time crew maintains the piping, repairs leaks, installs new services, and other tasks associated with the system's operation and maintenance (City of Martinez 2003). Current water use by the City of Martinez is approximately 5,400 acre-feet per year. The City's Urban Water Management Plan, dated December 2000, projects this usage to increase to 6,400 acre-feet per year by 2020. Future demand estimates for the City were developed by the Contra Costa Water District and were based on a consumption rate of 400 to 630 gallons per day per connection, depending on the type of land use (Contra Costa Water District 2003). Alhambra Valley estates Draft EIR 3-97 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Wastewater Existing residential units in the project area utilize septic tanks for wastewater disposal. The County has indicated that there have been numerous septic tank system failures in the Alhambra Valley over the past several years, due largely to the area's soils, which are not conducive to long- term wastewater leaching. The Central Contra Costa Sanitary District provides wastewater collection and treatment services to all the cities and unincorporated areas of the central County, excluding the eastern side of the City of Martinez and the southernmost portion of the City of San Ramon (Contra Costa County 2002). The project site, and much of the Alhambra Valley area, is not within the Sanitary District's boundaries, but is within the District's Sphere of Influence (Figure 3.13-1). The nearest.Sanitary District connection points are at the intersection of Alhambra Valley Road and Gilbert Lane, approximately 1 mile north of the project site, and near the intersection of Reliez Valley Road and Sage Drive, approximately 0.85 miles east of the project site (Contra Costa County 2002). The Sanitary District's wastewater treatment plant is located at the intersection of Route 4 and Interstate 680. The treated wastewater is piped north and discharged into Suisun Bay(Contra Costa County 2002). The plant has a current treatment capacity of 45 million gallons of wastewater per day(Central San 2003). This capacity is expected to serve approximately 450,000 customers (Contra Costa County 2002). Currently, the Sanitary District serves over 428,000 customers (Central Contra Costa Sanitary District 2003). The District published a report entitled "Facilities Plan for Wastewater Utility Service to Alhambra Valley in 2003 that details the District's incremental plans to extend wastewater collection service to the entire Valley. Solid Waste The Pleasant Hill Bayshore Disposal Company currently provides solid waste collection service to residents of Alhambra Valley. Waste is collected and taken to the Contra Costa Transfer and Recovery(CCTR), 3 miles east of Martinez at 951 Waterbird Way. Non-recyclable waste is taken from CCTR to the Keller Canyon Landfill in Pittsburg for disposal (Pleasant Hill Bayshore Disposal 2003a). As of June 6, 2001, the Keller Canyon Landfill had a remaining capacity of 68,279,670 cubic yards, and is scheduled for closure in the year 2030 (CIWMB 2003). The Keller Canyon Landfill covers 2,600 acres of land; 244 acres are permitted for disposal. The site currently handles 2,500 tons of waste per day, although the permit allows up to 3,500 tons of waste per day to be managed at the facility (Pleasant Hill Bayshore Disposal 2003b). Gas and Electricity The Pacific Gas and Electric Company supplies electricity and natural gas to consumers in the vicinity of the project site. Gas and electricity systems are currently in place along Alhambra Valley Road. Storm Drainage Storm water runoff and drainage facilities are discussed in Section 3.8, Hydrology and Water Quality. 3-98. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.13-1: Central Contra Cast Sanitary District Boundaries and Sphere of Influence DOWNTOWN _ Ac 7, . ._ STRENTZEL FAMILY 'GRAVEYARD~ / _IC WORKS DEFT.." VALIGNMENT Of L LANE SEDIMENT )SIOiN CONTROL PROJECT Ar 6pD� /rg. \ 1.. MILLICAN? •' VA""! CT LU �PL@1MthPk � H4fe Cr \. LE4 ! PPIb�` , ��xlJLTi/RAL UK ARY 1 2 I ti PCt81,IC WORKS DEPT::.. E ALFOFMENT XMLI FAMILY' .I ISTRiC`r BOUNDARY ., CCGBD SPHERE OF INFLItENCE AM= COLLECTION CREEKS F SOURCE:Central Camra Costa Sanitary district 2003 Alhambra Valley Estates Draft>EIR 3-99 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES REGULATORY SETTING Water The following goals and policies are identified in the Alhambra Valley Specific Plan under"C. Public Services and Facilities:" Goal 3: Ensure that adequate and a quality water supply is available to areas designated for new homes. Policy 2: Water service systems for new development shall be required to meet State and County regulatory standards for water delivery,water storage, and emergency water supplies. Policy 3: Prior to approval of development entitlements, new development shall obtain verification from the appropriate water service agency, be it the City of Martinez or the County Health Services Department, that an adequate and safe water supply can be provided to serve development.All new subdivisions created after adoption of Specific Plan within Urban Limit Line shall be connected to Martinez Water Department. Policy 5: The establishment of small community well water systems to serve proposed subdivisions shall be prohibited. The following Water Service goals and policies are identified in the Contra Costa County General Plan, Public Facilities/Services Element: Goal 7-F.To assure potable water availability in quantities sufficient to serve existing and future residents. Goal 7-G. To encourage the development of locally controlled supplies to meet the growth needs of the County. Gaal 7-H.To encourage the conservation of water resources available to the County and to the State. Goal 7-1.To protect and enhance the quality of water supplied to County residents. Goal 7-J.To ensure that new development pays the costs related to the need for increased water system capacity. Policy 7-19. Urban development shall be encouraged within the existing water Spheres of Influence adopted by the Local Agency Formation Commission; expansion into new areas within the Urban Limit Line beyond the Spheres should be restricted to those areas where urban development can meet all growth management standards included in this General Plan. Policy 7-21.At the project approval stage,the County shall require new development to demonstrate that adequate water quality and quantity can be provided. The County shall determine whether(1)capacity exists within the water system if a development project is built within a set period of time. or(2) capacity will be provided by a funded program or other mechanism. This finding will be based on information furnished or made available to the County from consultations with the appropriate water agency,the applicant, or other sources. Policy 7-26. The need for water system improvements shall be reduced by encouraging new development to incorporate water conservation measures to decrease peak water use. 3-100. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Wastewater The construction and installation of septic tank and leach field systems are governed by a variety of regulations, including those of the Uniform Plumbing Code and the Environmental Health Division of the County's Health Department. Sewer districts are required by State law to have adopted "Sphere of Influence" boundaries, which show the ultimate area that is expected to be served by the agency. The existing service is then expanded as necessary to included projected growth areas within the adopted Sphere of Influence boundary. The project site falls within the adopted Sphere of Influence boundary of the Central Contra Costa Sanitary District. The project site would be annexed to the District in accordance with all applicable provisions of the.Contra Costa County Local Agency Formation Commission (LAFCO). The following Sewer Service goals and policies were identified in the Contra Costa County General Plan's Public Facilities/Services Element: Goal 7-K.To provide sewer collection, treatment and disposal facilities adequate to meet the current and projected needs of existing and future residents. Goal 7-N.To assure that new development pays the costs related to the need for increased sewer system capacity. Policy 7-32.Development of rural residences, or other uses that will be served by septic tank and leach fields, shall be discouraged in areas with high groundwater levels or soils with poor percolation characteristics. Policy 7-33.At the project approval stage,the County shall require new development to demonstrate that wastewater treatment capacity can be provided.The County shall determine whether(1)capacity exists within the wastewater treatment system if a new development project is built within a set period of time,or(2)capacity will be provided by a funded program or other mechanism. This finding will be based on information furnished or made available to the County from consultations with the appropriate water agency,the applicant, or other sources. Policy 7-37. The need for sewer system improvements shall be reduced by requiring new development to incorporate water conservation measures,which reduce flows into the sanitary sewer system. The following policy is identified in the Alhambra Valley Specific Plan under"C. Public Services and Facilities": Policy 4. Require all new development to be served by a public sewer service or to provide an adequate and safe septic sy tem,�which meets the standards of the County Health Department. Solid Waste The following Solid Waste Management goals and policies were identified in the Contra Costa County General Plan's Public Facilities/Services Element: Goad 7-AE.To provide for the safe, efficient, and cost-effective removal of waste from residences, businesses, and Industry. Coal 7-AF.To provide adequate disposal capacity at landfills for the County's solid waste. Alhambra Valley Estates Draft EIR 3-101 March 2004 3: ENVIRONMENTAL IMPACT ANALYSES ENVIRONMENTAL ANALYSIS Areas of Potential Environmental Concern The following are areas of potential environmental concern that may be associated with implementation of the proposed project: • Potential to create water demand in excess of currently available supplies • Potential to increase demand for wastewater treatment services in excess of current capacity • Potential to increase demand for solid waste disposal in excess of current capacity • Potential to increase gas or electricity demands beyond current capacities and supplies of the existing system Thresholds of Significance The following thresholds of significance are used to determine the level of impact to areas of potential environmental concern. The impact would be considered significant if the project would: • Cause a cumulative water demand in excess of Safe Annual Yield • Cause a cumulative demand on wastewater treatment in excess of current capacity • Cause an increase in demand for solid waste disposal in excess of current capacity • Cause an increase in gas or electricity demands beyond current capacities and supplies of the existing system Potential Impacts and Mitigation Potential Impact 3.13-1: Water demand in excess of currently available supplies The 23 residential units that would be constructed as a result of implementation of the proposed project would require approximate 10.3 acre-feet of water annually. Annual water demand for the Martinez Water System is projected to increase by 1,000 acre-feet by the year 2020; the increase in water demand due to project implementation represents approximately 1% of this projected increase in demand. Impacts resulting from increased demand for water would be less than significant. Potential Impact 3.13-2: Demand for wastewater treatment services in excess of current capacity The applicant has proposed the installation of a force main from the project site to a CCCSD connection point at Reiiez Valley Road and Sage Drive (Figure 3.13-2). This would require annexation of the project site and the pipeline alignment to the District. Central Contra Costa Sanitary District's wastewater collection system has a capacity of 45 million gallons of wastewater per day, which can serve approximately 450,000 customers. Currently, the District serves 428,000 customers. The proposed development would add 0.012%to the existing customer population, and would accordingly add no more than approximately 0.012% to the wastewater stream. The addition of no more the 0.012% to the existing wastewater flows to the CCCSD system is not considered significant. If annexation of the project site and pipeline alignment is not approved, an alternative collection and disposal system would be required. The alternatives to the proposed force main would be on- site septic systems, a package on-site treatment facility, or a gravity flow connection to the 3-102. Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.13.2; Proposed Off-Site Wastewater Pipeline Alk fl. :a 't ' Alml 1 i if `l r l hx UfOM+UGC y-7 e3'9NYlar iw SOURCE:PIA Design Resources, Inc.2003 Alhambra Valley Estates Draft EIR 3-103 March 2004 3:ENVIRONMENTAL IMPACT ANALYSES CCCSD's system at Alhambra Valley Road and Gilbert Lane. The potential environmental effects of these alternatives are addressed in Section 5, Alternatives to the Project. Any alternative system would be required to adhere to all applicable federal, state, and local requirements, codes, and ordinances, which are designed to ensure efficient collection and disposal with concurrent minimization of environmental effects. To ensure the provision of adequate wastewater collection and disposal as proposed, the following mitigation measure shall be implemented: Mitigation Measure 3.13-1. Prior to recordation of the Final Map, the applicant shall apply to and receive approval from the Contra Costa County LAFCO for annexation of the project site and the alignment of the off-site wastewater pipeline to the Central Contra Costa Sanitary District. Potential Impact 3.13-3: Demand for solid waste disposal in excess of current capacity The projected additional 63 residents resulting from the proposed project would add approximately 290 pounds per day of solid waste to the County's solid waste stream. Solid waste from the project site would be collected by the Pleasant Hill Bayshore Disposal Company, and delivered to the Keller Canyon Landfill. Based on current disposal rates and a continuing trend of reduced disposal per capita, the Keller Canyon Landfill is not projected to reach its capacity until 2030. The increase in waste generation due to the proposed project would be considered insignificant compared to the average daily intake at Keller Canyon Landfill. Impacts resulting from increased demand for solid waste disposal would therefore be less than significant. Potential Impact 3.13-4: Electricity and natural gas demand beyond current capacities and supplies of the existing systems Pacific Gas and Electric would provide electrical and natural gas services to the project site. The proposed project would add to the overall demands placed on PG&E's systems, but at a rate that would be imperceptible when compared to the overall system's capacities. Impacts resulting from increased demand for gas and electrical supplies would be less than significant. 3-104• Alhambra Valley Estates Draft EIR March 2004 ........................................................... 415 CUMULATIVE Al GROWTH=INDUCING IMPACTS 4.1 Introduction This section discusses the potential cumulative and growth-inducing impacts associated with the proposed project, according to CEQA requirements. Cumulative impacts are defined as two or more individual;effects which, when considered together, are considerable, or which compound or increase other environmental effects. Section 15130(a) of the CEQA,Guidelines states that: An EIR shall discuss cumulative impacts of a project when the project's incremental effect is cumulatively considerable...Where a lead agency is examining a project with an incremental effect that is not'cumulatively considerable',a lead agency need not consider that effect significant, but shall briefly describe its basis for concluding that the incremental effect is not cumulatively considerable. This section provides descriptions of related projects near the proposed project that druid potentially contribute to cumulative environmental effects in the area. The potential for cumulative impacts associated with the proposed project are discussed for each resource section. Following the cumulative impact discussion, this section addresses the potential for growth-inducing impacts associated with the proposed project. 4.2 Related Projects The cumulative impact analysis considers impacts of the proposed project along with the potential impacts of ether projects that are reasonably foreseeable to take place near the proposed project. The potential vehicular trip generation by those projects, which represents the single, most discernable combining impact from those projects, together with the proposed project, has been includedin the traffic analysis prepared for this EIR (Section 3.12, Transportation and Traffic). Alhambra Valley Estates Draft EIR 4-1 March'2004 4:CUMULATIVE AND GROWTH-INDUCING IMPACTS Certain assumptions about the County's projected growth rate were used in the analyses for this EIR. There are no known plans that would suggest a change to the historic growth trends of the last decade. The absence of any known significant new development suggests that the papulation growth assumptions outlined in this EIR are reasonable. 4.3 Cumulative Impacts _ The following resource areas have the potential to be significantly impacted by the proposed project and are discussed in relation to their potential cumulative impacts. AESTHETICS The proposed project would change a portion of the site's current open space character to urban development via the addition of roadway and infrastructure improvements and built structures. Residential development has occurred alone Alhambra Valley Road and the vicinity in recent years. The County has specific development standards intended to preserve the rural character of the region. Because of the required adherence to applicable development ordinances and standards, this project is not expected to result in significant cumulative visual impacts to the community. AGRICULTURE The proposed project would result in the permanent, irreversible conversion of the project site to residential use. The project site is rated as Unique Farmland on the Contra Costa County Important Farmland 2002 map, by the Farmland Mapping and Monitoring Program, California Department of Conservation, Division of Land Resource Protection. Implementation of the proposed project would irreversibly convert the site to non-agricultural uses, and in so doing, would irreversibly convert 15.02 acres of Unique Farmland to non-agricultural uses, Mitigation would require dedication of a conservation easement over a similar acreage of agricultural land elsewhere in the County, and will assure conversion of the site to residential use would not contribute to a significant cumulative loss of agricultural lands within Contra Costa County and within the state. The County established an Urban Limit Line with the intent of protecting agricultural resources beyond the Line's limit, and allowing urban uses within its boundaries. The County has previously determined that the demarcation provided by the Urban Limit Line represents a balance of uses and needs, and adequately protects agricultural resources within the County. Implementation of the proposed project would not result in cumulatively considerable loss of agricultural resources because the project site is within the boundaries of the Line and on lands designated for urban use. AIR QUALITY The San Francisco Bay Area Air Basin has been designated as non-attainment for 03 and PMJo. The proposed project's contribution to local air emissions is not regarded as significant by the BAAQMD because of its relative size compared to other, larger development projects. Together with other projects in Contra Costa County and throughout the Bay Area, the proposed project would represent a cumulative contribution to the degradation of the regional air shed. The project air emissions are not regarded as potentially significant. Mitigation measures have been identified in Section 3.3, Air Quality, which would reduce the project's air emissions. Those measures would also reduce the proposed project's cumulative emissions contribution to the regional air shed. The proposed project contributes to the cumulative impact to the regional air 4_2 Alhambra Malley Estates Draft EIR March 2004 4. CUMULATIVE AND GROWTH-INDUCING IMPACTS shad. The project air quality impact is not considered cumulatively considerable because of the temporary nature of the construction phase of the project(ogle of the largest sources of project emissions), the small size of the project, and the mitigation measures that will reduce project emissions. BIOLOGICAL RESOURCES The proposed project would convert a majority of the project site to urban use, and most of the site would be irreversibly altered from its current condition. Analysis of the site's biological resources presented in Section 3.4, Biological Resources, shows that no protected species were found on the site at the time that surveys were conducted. There remains the potential that six species of concern could frequent the site and be affected by the proposed project. Implementation of the project would not have a significant effect on those resources with the application of mitigation measures outlined in Section 3.4. Implementation of the proposed project would potentially remove foraging habitat for protected and non-protectedspecies, which individually, is not regarded as significant due to the proximity of vast open spaces in the area. Cumulatively, in combination with other projects in the area, the proposed project would continue a trend of removing foraging habitat, which could ultimately have an impact on the future of a variety of protected species, and in particular, raptors. The impact at this time is not cumulatively considerable or significant. Construction of the proposed project has the potential to interfere with the movement of the protected California red-legged frog within Vaca Creek if construction were to occur in proximity to the Creek during periods of movement or if project development were to modify elements of the Creek. Mitigation Measures are identified in Section 3.3, Biological Resources, which would prevent a significant impact to CRLF. Implementation of the identified mitigation measures would ensure that the proposed project would not be a contributor to the loss of habitat for or specific individuals of the California red-legged frog. The proposed mitigation measures will allow for continued use of the creek by wildlife such that the proposed project does not have a significant cumulative effect on biological resources. CULTURAL RESOURCES The potential for encountering cultural resources during construction of the proposed project is considered minimal, as discussed In Section 3.4, Cultural Resources. Mitigation measures are outlined in this EIR that provide guidelines to address such resources should they be encountered during subsurface disturbance. The proposed project's lack of potential effect on cultural resources indicates that it would not result in a cumulatively considerable effect on cultural resources. GEOLOGY, SOILS, AMC} SEISMICITY The proposed project would expose people and buildings to potentially significant effects from a variety of geologic conditions. There is a significant unavoidable risk for every property in the San Francisco Bay region, and the implementation of mitigation measures identified in Section 3.6, Geology, Soils, and seismicity, would reduce the significance of such impacts on the project site to less than significant levels. Development of the proposed project would add to the existing population and structure count within Alhambra Valley, thereby increasing the number of people and structures in the local area susceptible to harm during a significant seismic event. No element of the proposed project would exacerbate any existing geologic, soil, and seismically related impact in the project area to cause a cumulatively considerable effect. Alhambra Valley Estates draft EIR 4-3 March 2004 4.CUMULATIVE AND GROWTH-INDUCING IMPACTS HAZARDS AND HAZARDOUS MATERIALS The proposed project's potential exposure to, and creation of hazards or hazardous materials is extremely low. Mitigation measures have been identified in Section 3.7, Hazards and Hazardous Materials, which would reduce any remote potential for exposure or creation of hazards, or to the release of hazardous materials, to less than significant levels. The types of impacts associated with hazards and hazardous materials are site specific and would not combine with projects on other sites in the area_ HYDROLOGY AND WATER QUALITY The proposed project includes plans for a storm water collection and drainage system that would collect and convey storm water flows to downstream systems. The proposed project's systems are designed to ensure that peak flows from the site are not increased, thereby ensuring that the project's contribution to downstream drainage systems will not overburden those systems during periods of peak flows. A cumulatively significant impact could occur as a result of project implementation because the project would add load to the drainage system, which would create less availability for other developments; however, the proposed project's incremental contribution is less than significant considering the overall capacity of the lines and the amount of other contributions. The proposed project would not have a cumulatively considerable effect on water quality, groundwater recharge, or erosion because mitigation measures were defined to reduce effects and there are no local project impacts that would combine to cause a significant cumulative effect. LAND USE AND PLANNING Analysis of the proposed project's conformance with applicable provisions of the Contra Costa County General Plan and with the Alhambra Valley Specific Plan shows that the proposed project is in conformance with.the direction provided by both plans. The proposed project can be regarded as furthering the Plans' implementation. The proposed project would not impede the Plans' implementation, or present condition that would impair their full realization. The proposed project would not cause a cumulatively considerable effect because it is in compliance with local plans. NOISE Construction of the proposed project could result in the generation of construction-related noise, and could expose the project's future residents to noise levels in excess of standards established by the County. Mitigation measures have been presented in Section 3.10, Noise, which would reduce those potential impacts to less than significant levels. The additional vehicular trips that would be generated by the proposed project would incrementally add to noise levels on area roads, with the most probable greatest contribution to noise levels along Alhambra Valley and Rel€ez Valley Roads. However, the relatively few additional vehicular trips that would be added by the proposed project would be relatively imperceptible to the human ear. The proposed project noise effects would be less than significant. There are no other local project with which the project effects would combine to cause a cumulatively considerable effect. POPULATION AND HOUSING The proposed project would add a projected 63 people to the County's population, which is well within the County's estimated annual growth rate of 1.2% (currently slightly less than 12,000 people per year). There are no known projects within the unincorporated County or with the County's incorporated cities that would, when combined with the proposed project's projected 4-4 Alhambra Valley Estates Draft EER March 2004 _............................................... 4:CUMULATIVE AND GROWTH-INDUCING IMPACTS population contribution, result in annual population increases in excess of those projected. The proposed project is not projected to result in the addition of any permanent employment opportunities, and therefore, would not be a contributor to the additional demand for housing. TRANSPORTATION AND TRAFFIC The proposed project would result in the generation of additional vehicular trips during both construction (short-term) and post construction (long-term) phases of the project. The analyses presented in Section 3.12, Transportation and Traffic, show that the project's contribution to area traffic would be less than significant. There are no other approved or planned projects in the project area that would cumulatively contribute to traffic volumes in the area. UTILITIES AND SERVICE SYSTEMS Section 3.13, Utilities and Service Systems, presented the conclusion that implementation of the proposed project would not result in the generation of impacts to utility or service systems. The project by itself would not stretch existing utility delivery systems beyond their current capacities. Development throughout the County would continue through the life of the project. Based on the current knowledge about the County's development pace, it is not expected that the combination of the proposed project and known future development projects would negatively impact utilities or their delivery systems, or cause a cumulatively considerable effect on the systems. 4.4 Growth-inducing Impacts Section 15126.2(d)of the CEQA Guidelines requires preparers of an EIR to consider the growth- inducing impacts of a proposed project. Section 15126.2(d) states that the EIR should: Discuss the ways in which the proposed project could foster economic or population growth, or the construction of additional housing, either directly or indirectly, in the surrounding environment. Included in this are projects that would remove obstacles to population growth. The proposed project would add housing to the County's existing stock, but would not add permanent jabs to the existing employment base. The construction labor force required during subdivision improvement and residential unit construction is expected to come from the local labor farce, thereby not resulting in increased demands for additional housing for construction labor or increased demands on community services and facilities. The addition of 23 new homes to the County's housing supply would incrementally add to the Countywide demand for services and facilities. The projected annual growth rate of 1.2% or approximately 11,939 people, provides for an annual residential unit construction rate well in excessof the proposed project's 23 residential units, and would therefore not produce unplanned growth'impacts. Construction of the proposed force main may allow connections to that system in addition to the 23 proposed lots. If that occurs, the pace of development within Alhambra Valley may accelerate, but would not exceed the maximum development potential outlined in the Alhambra Valley Specific Plan. That Pian does not include a limitation on the pace of development; only on the total number of units as expressed on the Plan's Land Use Map. Alhambra Valley Estates Draft EIR 4-5 March 2004 5 : ALTERNATIVES TO THE PROJECT 5.1 Introduction Section 15126.6 of CEQA requires that an EIR describe a range of reasonable alternatives to the project that would feasibly attain the basic project objectives and avoid or substantially lessen any significant effects of the project. Alternatives may be eliminated from detailed analysis in the EIR if they fail to"meet the most basic of project objectives, are determined to be infeasible, or cannot be demonstrated to avoid or lessen significant environmental impacts. PROJECT PURPOSE Section 2.1 of this EIR identifies the purpose of the proposed project as the creation of-"residential building lots for the subsequent development of single family detached residential units." This broad objective provides a wide range of possible alternative projects, including those with greater or fewer residential units.The following alternatives analysis presents a discussion of potential impacts associated with alternative project plans. This section contains discussion of the following alternatives: • Alternative sites where the project might be developed • Reduced density alternative • No project alternative • Wastewater disposal alternatives Alhambra Valley Estates Draft EIR 5`1 March2004 5:ALTERNATIVES 5.2 Alternative Sees The subdivision of land for the subsequent development of residential units can occur on any of the lands designated for residential development within the Alhambra Valley Specific Plan.' Residential development is not site specific, and is only guided by the County's General Plan, specific plans, Zoning Ordinance, and other land use regulatory documents. The potential list of alternative sites is extensive within the county. The applicant has proposed a specific project on a particular parcel of land. There are other undeveloped parcels of land within Alhambra Valley that could be subdivided and developed with residential units in a manner consistent with the General and Specific Plans. It should be noted that these other undeveloped lands might not have current owners interested in selling or sponsoring development. A specific inventory of potential alternative sites has not been made. The range of parcel size,the underlying Specific Plan Land Use designation, and the sites' existing zoning designation would guide the development of all undeveloped lands. Development of a similar project on an alternative site would generally be expected to generate similar impacts as identified for the proposed project site. Possible exceptions to this general conclusion would be the generation of traffic(which would increase or decrease depending on the number of units and the adjacent roadway system conditions), and biological or cultural resource impacts, depending on alternative and localized area conditions. Any alternative site could have a different localized traffic condition that could conceivably result in a significant impact upon localized traffic with the addition of 23 single-family homes. Alternative sites may not possess the same types of biological and cultural resources as the project site; other areas may have equally important or more biological and/or cultural resources to be evaluated and protected. The Alhambra Valley has limited undeveloped land left for major subdivisions that possess similar characteristics as the project site. The property identified as Assessor Parcel Number 365!060-002 is 73.2 acres in size, yet only approximately 13 acres is within the Urban Limit Line. The parcel is designated by the Alhambra Valley Specific Plan for Single Family Residential—Very Low uses, and is within the R-40 Zoning District(43,560 square foot minimum lot size). While the parcel could be developed under the Specific Plan, the parcel's R-40 zoning designation would allow a maximum yield of approximately 9 lots. Further, there is no access from the site to public sewer, so it does not meet the objectives of the developer. Additionally, oak trees would likely be removed as part of the parcel's development process. Assessor Parcel Number 367-160-010, a 10.4 acre site that is also within the R-40 zoning District is a hillside site, and Assessor Parcel Number 365-1401-005, a 65-acre site, is depicted in the Alhambra Valley Specific Plan for agricultural use and as a potential parkland acquisition. 5.3 Reduced Density A similar, but reduced density project on the site would provide a relatively reduced level of overall impact as compared to the proposed project. While yielding fewer residential units, most, if not all of the potential impacts identified in Section 3, Environmental Impact Analyses, would remain; only the order of magnitude or the reach of the impact would be correspondingly reduced (e.g.,fewer vehicular trips would be generated, lesser air borne emissions of criteria pollutants, lesser grading depending on reduced density site design, etc.). Other types of potential impacts, such as those that might affect biological resources, may not be substantially reduced by a reduced density 'The discussion of alternative sites has been limited to the Alhambra Valley because of the vastness of undeveloped lands within Contra Costa County. 5-2 � Alhambra Valley Instates Draft EIR March 2004 5:ALTERNATIVES alternative. The stated project objective could largely be met by a reduced density alternative, with the principal exception of the objective of the applicant's desired lot/unit yield. The project site is designated within the Alhambra Valley Specific Plan for low-density residential development, with a minimum lot size of 20,000 square feet. In theory, that would translate to a maximum project site lot yield of 32.7 lots, without consideration for roadways, Vaca Creek, or other site development constraints. The proposed creation of 23 lots is below the maximum yield of 32.7 lots. The Specific Plan does not establish a minimum number of lots for the project site or for the Alhambra Valley as a whole. 5.4 No Project CEQA requires consideration of the environmental consequences if the project is not constructed. The No Project alternative would maintain the project site in its present state and current land use (an undeveloped parcel within the R-20 and A-2 Zoning Districts). The No Project alternative avoids any direct impacts associated with the proposed project. Although this alternative avoids potentially significant and mitigatable environmental impacts identified in Section 3, Environmental Impact Analyses, it would not accomplish the objectives of the County's General Plan and the Alhambra Valley Specific Plan as expressed by the site's designation for urban development. The selection of the No Project alternative would prevent or at least delay the current applicant from developing the property, but would not prevent further or similar development in the future. Such future development could result in greater or lesser environmental impacts than these associated with the currently proposed project. 5.5 wastewater disposal Alternatives The applicant has proposed that wastewater generated by the proposed project be conveyed off- site via an underground pressurized pipe to a connection with the CCCSD system for treatment and disposal. The CCCSD has tentatively expressed reservation about permitting a pressurized system as proposed.Two other options to that proposal are possible: • On-site wastewater disposal • Gravity flow to the CCCSD's system at Alhambra Valley road and Gilbert Lane ON-SITE DISPOSAL One option for disposal of the project's wastewater would be to treat and dispose of it on-site, via a number of possible means. Among the possible alternatives are: • Individual septic tanks and leach fields on each lot • Individual treatment and disposal in a community leach field • Community treatment and disposal Individual Septic Tanks and leach Fields Linder the individual septic tank scenario, each lot would have a septic tank installed in which wastewater would be biologically treated. The treated wastewater would then flow out of the tank through a series of pipelines and flow into the soil (leach field), where the soil would act as a filter Alhambra Valley Estates Draft EIR 5-3 March 2004 5:ALTERNATIVES prior to the wastewater entering the ground water system. These types systems have been used successfully in many areas of the County. The one critical attribute that is required for a viable leach field is soil with properties that allow the wastewater to move freely through the soil (percolation). The project site's soils, like much of the soil on the floor of the Valley, has characteristics that do not necessarily lend themselves to suitable percolation. Some portions of the site may include soils suitable for the installation of leach fig �s, while some areas do not possess such soils. The net effect of using conventional septic tanks and leach fields would be a probable reduction in total lot yield. The use of unconventional individual systems, such as raised mound systems, could conceivably increase the lot yield. Beyond the site's poor soils for leaching of wastewater, is the site's proximity to the Vaca Creek. Regulations established by the state and the County would require leach field setbacks from the creek to ensure its protection and the protection of its water quality. This could further reduce the site's potential lot yield. Overall, installation of individual leach fields would not be expected to result in the generation of any specific environmental impacts, inasmuch as established regulations would require their installation in a manner designed to avoid any impacts. Individual Treatment and Disposal in a Community Leach Field A variation on the individual system method of wastewater disposal is the individual collection and treatment within a septic tank, and the disposal of the wastewater in a community leach field. The site's soil conditions and characteristics, as discussed above, would continue to be a limiting factor, and the need for community maintenance of the field would be an added administrative issue. Effects would be similar to those of the individual septic systems. Community Treatment and Disposal A third on-site alternative would be the installation of a community treatment and disposal system. Sometimes referred to as a "package plant," a community system would function in much the same way as the CCCSD's facilities. Wastewater would be piped from the individual lots to a central treatment and disposal system. Unlike the individual septic tanks and leach fields, which are to a degree, maintenance free, a community system requires operation and maintenance. The effects of a package plant can't be evaluated at this point because not enough is knovJn about what kind of plant or where the plant would be located. This alternative may have greater environmental effects than the proposed project because of the noise, dust, and traffic related to construction of the plant, and because the plant might generate odors. GRAVITY FLOW CONNECTION TO THE CCCSD Another alternative method of wastewater disposal would be construction of a gravity flow pipeline from the project site to Gilbert Lane, approximately t mile north along Alhambra Valley Road. Once constructed, this alternative would virtually be maintenance free when compared to the proposed force main to Sage Road, or several of the on-site alternatives. Construction of such a gravity flow line is beyond the scope of this environmental document and would normally be a project undertaken by the District, after annexation of Alhambra Valley to the District. Annexation to the District has been an issue with significant apposition in past years. The CCCSD issued a report dated October 2, 2003, entitled Facilities Plant for Wastewater Utility Service to Alhambra Valley. That report summarizes the wastewater disposal issues in the Valley and also delineates a plan for the eventual expansion of the district's services to the area. Among the options outlined in that report are a force main from the Alhambra Valley Estates project site to a connection point at Reliez Valley Road and Sage Drive, followed by the ultimate construction of a gravity flow system to the Alhambra Valley Road/Gilbert Lane intersection. This parallels the 5-4 Alhambra Valley Estates Draft ElR March 2004 5:ALTERNATIVES applicant's proposed method of wastewater collection and disposal and would have similar environmental effects. 5.6 Environmentally Superior Alternative The No Project alternative would maintain the project site in its present state and use and essentially avoid or eliminate any direct environmental impacts associated with the project. However, the no project Alternative would not further implementation of the County's General Plan or the Alhambra Valley Specific Plan. The No Project alternative would also not preclude a development proposal for the project site being submitted for consideration in the future. The proposed project would generate only one significant and unavoidable impact (impact 3.2-1. Conversion of Prime Farmland, Unique Farmland, or Farmland of Statewide importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use). All other potentially significant impacts are mitigatable to less-than-significant levels with implementation of mitigation measures outlined in this EIR. Potential impacts associated with project alternatives, including the Alternative Sites, and Reduced Density alternatives would meet the project's objective, and would retain (or transfer in the case of the alternative sites alternative) most if not all of the proposed project's potentially significant impacts at the same or similar levels to other similar sites designated for residential use. There remains the potential that a method of wastewater collection and disposal other than that proposed by the applicant may be required. Any of the potential alternatives would be required to adhere to defined regulations,which have as their purpose the avoidance of impact. With the presumption that it is the County's intent to facilitate the use and development of lands in accordance with the General Plan and the Alhambra Valley Specific Plan, then development of the project i site and other similarly situated, General Plan and Specific Plan designated lands would be accordingly developed. There is no substantial body of evidence at this time that points to one of the alternatives being environmentally superior to the proposed project on the project site. With most of the alternatives, the number and significance of the potential impacts would remain at levels similar to that of the proposed project. Alhambra Valley Estates Draft EIR 5.5 March 2004 C : ■ REPORT PREPARATION & DISTRIBUTION 6.0 List of Preparers This section lists those individuals who either prepared or participated in the preparation of this EIR. LEAD AGENCY Contra Costa County Community Development Department Catherine Kutsurls Deputy Director Rase Marie Pietras Senior Planner Christine Gregory Planner CONSULTANT TEAM This EIR was prepared for and under the direction of the Contra Costa County Community Development Department by MHA Environmental Consulting, Inc. of San Mateo, California. The following staff contributed to this report: Dain Anderson MHA Project Director Laurie McClenahan MHA Project Supervisor Tania Treis MHA Environmental Scientist Ted Slowik MHA Biologist Andrew Gentile MHA Environmental Analyst Alhambra Valley Estates Draft EIR 6-1 March 2004 6. REPORT PREPARATION Robert Carr Visual Roscurces Specialist Eric Wohlgemuth Archaeologist and Archaeobotani=st, Far Western Anthr€ po ogica Research Croup, Inc. Will Hopkins, PhD Senior Engineering Geologist, Questa Engineering Corporation Sydney Temple Senior Engineering Hydrologist, Questa Engineering Corporation Kelly White Environmental Scientist, Questa Engineering Corporation George Nickelson r raffic Engineer 6.1 AgenciesrContacted The Community Development Department submitted a copy of this Draft EIR to the fallowing agencies and organizations: Alhambra Valley Improvement Association Say Area Air Quality Management District California Air Resources Board California Department of Conservation California Department of Fish and Game Region .3 California Historical Resources Information. System, California State Clearinghouse Central Contra Costa Sanitary District City of Martinez Contra Costa County Biologist Contra Costa County Building Inspection Contra Costa County Geologist Contra Costa County Community Development Director Contra Costa County Flood Control District Contra Costa County Health Services Department, Environmental Health Division Contra Costa County Health Services Department, Hazardous Material Division Contra Costa County LAFCD3 Contra Costa County Public Works Department, Engineering and Traffic Division Contra Costa County Public Forks–Special Districts Contra Costa County Sheriff Office,Administration and Community Services Delta Protection Commission Department of Food and Agriculture Department of Toxic and Substances Control -.._...._....._..----..._.. - 6-2 Alhambra Valley Estates Draft EIR March 2004 6: REPORT PREPARATION John Swett, Unified School District Martinez library Native American Heritage Commission Regional Water Quality Control Board-San Francisco Bay Region Ban Francisco Bay Conservation&Development Commission State Lands Commission, Executive Office State Water Resources Control Board(SWRGB) State Water Resources Control Board, Department of Water Quality US Fish and Wildlife Service Alhambra Valley Estates draft E€R 6-3 March 2004 7 ■ REFERENCES The following references were consulted during the preparation of this EIR. Those references . preceded by an asterisk are available for review at the Community Development Department, 651 Pine Street, North Wind, 2nd Floor, Martinez, California. *PA Design Resources, Inc. 2002. Alhambra Valley Estates Vesting Tentative Map- Subdivision 8634, Plan Sheets 1-10. *Contra Costa County. 1992.Alhambra Valley Specific Plan. *Contra Costa County. 1996. Contra Costa County General Plan. BAAQVID 2003. Bay Area Air Quality Management District website www.baaamd.00v. CAF2B. 2002. California Air Resources Board Ambient Air Quality Standards. www.arb.ca.gov/aqs/ags.htm. [Accessed July 22, 2002]. EPA. 2001. United States Environmental Protection Agency website. www.epa.gov/fedrgstr/EPA-AIR/2001/0ctober/Day-19/a26419.htm [Accessed July 22, 2002). World Climate.2003. Average Rainfall, Average Minimum Temperature, Average Maximum Temperature', Data for Walnut Creek and Antioch, Contra Costa County, California LISA. www.worldclimate.com[Accessed April 21, 2002]. California Natural Diversity Data Base (CNDDB). 2003. Database overlay for the Briones Valley USES 7.5-minute quadrangle. California Department of Fish and Game. Sacramento, California. April 2003. *LSA Associates, Inc. 2003. California Red-legged Frog Habitat Assessment for the Alhambra Valley Estates Project near Martinez, Contra Costa County. May 2003. *Moore Biological Consultants. 2000. Biological Resources Inventory at the 16 f/-Acre Plummer Property('Assessor's parcel No. 367-134-33), Martinez, CA. December 2001. *Traverso Tree Service. 2002.Alhambra Valley Estates Subdivision 8634. June 2002. *Traverso Tree Service. 2002. Tree Survey At the Plummer Property on Alhambra Valley Read. February 2002. Alhambra Valley Estates Draft EIR 7-1 March 2004 7: REFERENCES Baldrica, M. J. 1980. Archaeological Survey of the La Forte Property, Contra Costa County, California. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Chavez, D. 1981. Archaeological Survey of Minor Subdivision. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Fredrickson, D. A. 1966. CCO-308: The Archaeology of a Middle Horizon Site in Interior Contra Costa County, California. Unpublished M.A. Thesis, Department of Anthropology, University of California, Davis. Gudde, E. G. 1969. California Place Names: The Origin and Etymology of Current Geographical Place Names. Berkeley: University of California Press. Third Edition Heady, H. F. 1977. "Valley Grassland,"it) Terrestrial Vegetation of California, edited by Michael Barbour and Jack Major, pp. 491-514. California Native Plant Society Special Publication Number 9. Helley, E. J., and R. W. Graymer. 1997. Quaternary Geology Map of Contra Costa County, California. U.S. Department of the interior, U.S. Geological Survey. *Holman, Miley. 2001. Archaeological Field Inspection of the Plummer Property, Alhambra Valley, Contra Costa County, California. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Kroeber, A. L. 1925. Handbook of the Indians of California. Bureau of American Ethnology Bulletin 78. Washington. Kuchler, A. W. 1977. Map of the Terrestrial Vegetation of California. in Terrestrial Vegetation of California, edited by Michael Barbour and Jack Major, pp. 491-514. California Native Plant Society Special Publication Number 9. Levy, R. S. 1977.Costanoan. in Handbook of North American Indians Volume 8: California, R. F. Heizer, ed., pp. 485-495. Washington, Smithsonian Institution. Lightfoot, K. G., and E. M. Luby. 2003. Late Holocene in the San Francisco Bay Area: Temporal Trends in the Use and Abandonment of Shell Mounds in the East Bay. In The Archaeology of the California Coast During the Late Holocene, J. Erlandson and T. Jones (eds.), UCLA Institute of Archaeology Perspectives in California Archaeology, Margolin, M. 1978.The Ohlone Way., Indian Life in the San Francisco and Monterey Bay Areas. Heyday Books, Berkeley. Meyer, J., and J. Rosenthal. 1997. Archaeological and Geoarchaeological Investigations at Eight Prehistoric Sites in the Los Vaqueros Reservoir Area, Contra Costa County, California. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Milliken, R. 1995.A Time of Little Choice: The Disintegration of Tribal Culture in the San Francisco Bay Area 1769-1810. Ballena Press Anthropological Papers 43. Rosenthal, J. 2001. Archaeological Survey and Extended Phase I/Phase €i Excavations at CA- ALA-485 and -486 in the Baumberg Ecological Mitigation Tract, Alameda County, California. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. 7-2 Alhambra Valley Estates Draft EIR March 2004 7: REFERENCES Self, William. 1999. Archaeological Survey and Assessment of Parcel 367-130-016, Alhambra Valley, Contra Costa County, California. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Shoup, L., M. Smith, and S. Baker. 1991.Archaeological Reconnaissance of Gas Line 191 Replacement Project, Alternative 2, Briones Regional Park, Contra Costa County. Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Werner, R. H., and K. Zahniser. 1991. An Archaeological Study of the Santos Property, near Martinez, Contra Costa County, California (APN 365-150-033). Report on file at Northwest Information Center, California Historical Resources Information System, Sonoma State University. Wohlgemuth, E. 2003. Charred Plant Remains from CCO-235. Report submitted to Archeo-tec, Oakland, California, Association of Bay Area Governments. 2003. http/Jcuake.abag.ca.govl California Division of Mines and Geology(CDMG). 1995. Landslide Hazards in the Martinez- Orinda-Walnut Creek Area, Contra Costa County, California, Landslide Hazard Identification Map No. 32, DMG Open-file Report 95-12, *Darwin Myers Associates. 2002. Review Letter for Geotechnical Study Proposed for Single Family Humes. Graymer, R.W., Jones, D.L., and Brabb, E.E. 1994, Preliminary geologic map emphasizing bedrock formations in Contra Costa County, California: A Digital Database, U.S. Geological Survey Open-File Report 94-522. Halley, E.J., and Graymer, R.W. 1997. Quaternary Geologic Map of Contra Costa County,A Digital Database, U.S. Geological Survey Open-file Report 97-98.Home Subdivision Plummer Property. May 2002. *Purcell, Rhoades &Associates. 2003. Review letter for Supplemental Geotechnical Study for Proposed Single Family Home Subdivision Plummer Property. July 21, 2003. *Purcell, Rhoades and Associates. 2002. Geotechnical Study Proposed for Single Family Home Subdivision Plummer Property. January 2002. US Department of Agriculture(USDA).1977. The Soil Survey of Contra Costa County. US Geological Survey(USGS). 1980. Preliminary Geologic Map of the Briones Valley Quadrangle, Contra Costa County, California, Open File Report 80-539, City of Moraga. 2000. General Flan (Update EIR. Radbruch, D.H., 1969, Areal and Engineering Geology of the Oakland East Quadrangle, California, Map GQ-769, U.S. Geological Survey, Washington D.C. Wagner, J. Ross, 1978, Late Cenozoic History of the Coast Ranges East of San Francisco Bay: University of California, 'Berkeley: Ph.D. dissertation, Department of Geology and Geophysics. ©ibblee, Jr., T.W., 1980. Preliminary Geologic Map of the Briones Valley Quadrangle, Contra Costa County, California: USGS Open File Report 80-539. Borcherdt, R. D., Gibbs,J. F., and Lajoie, K. R., 1975, Prediction of maximum earthquake intensity in the San Francisco Bay region, California, for large earthquakes on the San Andreas Alhambra Valley Estates Craft EIR 7-3 March 2004 7: REFERENCES and Hayward faults: Report to accompany Miscellaneous Field Studies, United States Geological Survey, Map MF-709, 3 maps, 11 p. Greensfelder, R.W., 1974. Maximum Credible Rock Accelerations from Earthquakes in California. California Division of Mines and Geology, Map Sheet 23. California Department of Forestry. 2000. Contra Costa County, Natural Hazard Disclosure (Fire). [www.fire.ca.gov]. Accessed June 16, 2003. Bay Area Stormwater Management Agencies Association (BASMAA). 1999. Start at the Source, Design Guidance Manual for Stormwater Quality Protection. Department of Water Resources (DWR). 1975. California's Groundwater-Bulletin 118. Updated 2002. *Gosset, Lawrence. 2002. Permit SD 02-8634, Creek Outfall Detail. Dated 817/02. [better to Rose Marie Pietras, Project Planner]. Graymer, R.W., Jones, D.L., and Brabb, E.E. 1994. Preliminary Geologic Map Emphasizing Bedrock Formations in Contra Costa County, California:A Digital Database: U.S. Geological Survey Open-File Report 94-0622. *P/A Design Resources, Inc. 2002. Alhambra Valley Estates, Arroyo del Hambre Creek Water Surface Profile Analysis, Contra Costa County, California, November 2002. United States Department of Agriculture (USDA). 1977. Soil Survey of Contra Costa County. Western Regional Climate Center. 2003. Period of Record Monthly Climate Summary for the Martinez Water Plant,California (045378). Period of Record: 2/1/1970 to 12/31/2001. Online. 18 April 2003. http://www.wrcc.dri.edulcgi-binIcliRECtM=pl?camart. *Illingworth & Rodkin, Inc 2002. Plummer Property Subdivision, Alhambra Valley Road Contra Costa County--Environmental Noise Assessment Van Houten, J.J. 1974. Technical Background Study for the Noise Element of the City of Montebello. Anaheim: J.J. Houten Associates. California Department of Finance. 2003. E-1 Report City/County Population Estimates with Annual Percent Change, January 2003. Caltrans. 1995. Highway Design Manual, July 1, 1995. Contra Costa County Fire Department(CCFD). 2002. Design Guidelines for Fire Vehicle Access. December 5, 2002. Contra Costa Transportation Authority(CCTA). 1995, Contra Costa Countywide Comprehensive Transportation Plan, July 19, 1995. *Omni-Means. 2003. George W. Nickelson, P.E., traffic counts in April 2003. ITE. 1997. Trip Generation. 6th Edition. Transportation Research Board (TRB). 1985. National Cooperative Highway Research Program Report 279 - Intersection Channelization Design Guide, November 1985. Contra Costa County Water District. 2003. Contra Costa County Water District website http://www.ccwater.com. Central Contra Costa County Sanitary District. Facilities Plan for Wastewater Utility Service to Alhambra Valley, October 2, 2003 7-4 Alhambra Valley Estates Draft EIR March 2004 ................_........................................- 7: REFERENCES Central Centra Costa County Sanitary District. 2003. Contra Costa County Sanitary District website http://www.centralsan.org. Pleasant Hill Bayshore Disposal 2003. Pleasant Hill Bayshore Disposal website http:]/www.pleasanthillbayshoredisposal.com. Alhambra Valley Estates Draft EIR 7-5 March 2004 APPENDIX A NOTICE OF PREPARATION Com m n IContra Dennisits. krry.Alf Development Costa Department Coon' County Administration Sui ding 651 Pme.Street 411)Floor,North Wing, MarIinez.California 94553-0095 (0-25) 335-1216 n March 6, gg',", NOTICE OF PREPARATION NOTICE 3F SCOPING SESSION ENVIRONMENTAL ENTAL IMPA ` REPORT FOR A REZONING AMC} SUBDIVISION OF 23 RESIDENTIAL LOTS, IN THE A I AMBRA VALLEY AREA OF MARTINEZ, CALIFORNIA This letter constitutes a Notice of Preparation for an Environmental Impact Report, as required by Section 1 03 (a) of California Environmental Quality Act ( EQA) Guidelines, for the proposed Alhambra /alley Estates of 23 residential bats, Pm'ettfan/ ttcar$ The project site is located on Alhambra Dalley at Reliez Valley Roar. The triangular shaped site is vacant, undeveloped property SUrrounded by rural residential parcels to the east, south and west. The northwestern tag+!- feet of the property is the centerline of Arroyo Del Hamhre Creek, ars ephemeral stream. Access to the site is by gray of Alhambra Valley Road on to Deer geek Court, proposed private road. This access wilt be utilized for ingress and egress to the site. The applie n4,Serlt}r Owner,s is proposing to subdivide 15,02 acres into twenty-three parcels, A rezoning is also requested for 4.5 acres from A— (General Agricultural,5 acre rninim urrn) to R-20 (Residential 20,000 square foot minimum lot size). The project includes two off site improvements: (1)installation of a 48"storm drain within the Alhambra galley Road right of way with a discharge headwall into Alhambra Creek at Wanda Flay: and(2)installation of 5,400 linearf e?of a temporary sewer-lige from t a pump station at the project site, aping Reliez Dalley Road to Sage Street, .Environmenta. Impact Report: The Community Development Department has determined that an Environmental Irnpact.Report ( IR) is required for this project, An initial study prepared by the S.rornrEnunity Development' Department is attached and has identified the following issues that need to be analyzed in the EIR . Aesthetics Agricultural Resources Office Hours Monday Friday. :00 a.m. - .5:00 p.m. Office is closed the 1 St, 3rd & 5th Fridays of each month Biological Resources cultfJ"ai Resources • Geology and Soils,} Quality Hydrokxly and er Land Use an Planning Noise g Population and l-fOUSin' Transportation and Traffic • Utilities and Sevices Systems Growth inducefyneW c in Session: A scoping session will be held 3y the County Zoning Adm inistrator (ire accordance with Section '(F)0,83 oa the CEOA Guidelines)on March 24,2003 in Roam 107 of the Board Chambers at 3:30 P.M. Interested agencies and individuals may submit rural and written comments, which address environmental concerns resulting from the proposed project, Res rinses to the otf e saf l!re, rstJon4 es onses to this Notice of Preparation rust be received no later than 5;003 p.m,on April 7,2003, t the Contra Caste County Community Development Dep rt ent,651 Fine Street,4tb Floor- North Wing, Martinez, CA 94553, Attention: Rose Marie Pietras. If you have any qUestions reg6rding this project or the process, please call Rose Marie Pietras at (925) 335-121& Environmental Checklist Forn, Alh,1111bra Valley .Estates Lead Agency ttrt�e anal Address. �":;c�ntra �;casta(:;c�trnt� C;orrtrrttrtait�°I�c�,el�apr�aer.t Dep,trtr:nent 651 :bine Street. North Wln#,� - 4tli .l-`loor ,Pvlartinez. CA 94551 Costas t'l'erson and.phone Number: .loose 11,10arie; 'ietras: 4, Pr-oJect Location. Al:lianibra V allcy Road at.Reliez Valley'Road Alharnbra Valley Specific Plan Applicant'!; Narne and Address: Security Owners Corporation ration 555 Escobar Street 11. 0Box 430 t4ail,inez, CA 9455'-l 105 Contact: Scott Busby 6. General Plan Desi ptttticarr: SL, Single-F arnily Residential. Low Density (1,0-2. DL ' et acre) 6bi Alltwnbra Valley Specific Plan Designation: ST_ Single-Family Residential rain A; R-20. Residential 0,000 square feet minimum lit: size;, A-2, Agriculture - ntir7irnuni lot size— 5 acres Description ofProject-. `rhe Applicant requests approval to subdivide 15.02 acres into twenty--three parcels, A rezoning is also requested 15or 4.5 acres torn 'k-2, Agricultural. 5_ acre rninimurrs to -20, single-far ily residential ininirnum 20,000 square foot lot size, Tlat project irschides two off site i pro enlents: (1 installation tai' a 48", storm drain within ilio A.1harnbra alley Road rilght of way with a discharge headwall into Alharrrbna Creek at Wanda Way,and('2) installation of 5,400 linear feet of a.temporary se er line fronn a purnp station at the project site, along Rehez k all.eY Road, to Saga:, Street.. 9, Surrounding Lind teand Setting: the 15.02'-acre si£L is <' `y iC; na IX7tvelo 1LC property Surnoun led by rural resideentiF�z parcels to the easL south anti west, T'ht northvvest,,'�rn 700, let ol`the PT"(g?�x;[.�'i: i,,,, the ceriP.�;r ine of s"�IIC�`ao I )ci _ 1"l;..mbre (leek, an eplaerTaual suc°ani. Mer Tatalilic, agenciesvvhose U.S Army Coto s of Engineers (`;x,, ion 40-4). approval is regtaired (c.s.,, perrntits, (.'4alifibrrai:a :c)ep at'nment ofFish and Ganfic finat7cing, :4n°)prtyv aL cw panictadNi (stm arnbal Altemdon Dean ) SF Eby W oonal Utgred:rnent}. Vk ter Quality Control Board (S'kVPPI',1 Sec!.ioin (annexation), {:;at' ofl% arrtinez. (, at dine Construction). FACTORS POTENTIALLY LLY AFF C:TI D. Ile environmental factors checked below N-vo altl he potentially affected i)y this project,t.in 3 olvi : at least one inquact th a is a "Pot.er:atially Significant Impact" as i-ndicated by the chcckli5t can the Mowing pages. tai trran iti cases ragatiotit t e astwes are provided wh'-ic h reduce these, impacts to less yyatl ansignificant- Ae thetics Hazards � Recreatbil grrcultu-tal Hazardous waste Transportation,' Resources urces X ,.aspd 1 sc aatt.cl Traffic affic .`fir Quality Planning w� l;tilities & ser"ict, Biological Wscaurces � Mineral resources sy.MS C"'ultural and Sails Noise � No Sir ficant Geological I'roblenis 4\-', Population&Housing h-apacts ldientib'ied I~Iycli-Olo&y & Public ServicesMan�lat.a:ry Fjndira,s ,. kk'ater Quality _ _w.. of Sigaaaiic anc -- Oil flk basis cif°dais initial evaluation: I find that the,proposed project CO1.."t.D NOT have a significant effigy:t on the envit•ont'lle'ra, and as NEGATIVE I`IVE DE(,1 \,,R,A.?I(.) will be prepared. _.... I fired that although the proposed project could have a significant effect oil the env-ironnnie nt, thea:wiII not he a sigraffica nt effect in this case because the mitigation measures described care an attached sheet have been added to the project, A MITIGATED NEGATIVE DEK-LAILkTION will he prepared. x is find that the proposed project MAY have a sip,)i cant effect on the environment, arid an, ENVIRONMENTAL IMPACT REPORT is required. l fund that:the proposed project MAY have a significant effect(s)oil the ennvironnme nt,but at. least one effect (l) has been adequately analyzed in an earlier d€acaxrtnem purstaannt to a i)plicai[Ae legal standards, and (2)has leen addressed by zniiti at on measures based on gine earlier analysis as described on attached she ts, if the effect i. a. "potentially sign icant impact" or "potentially si;TIficannt unless mitigated." An I NNVIRONNI-1ENTA[:, IMPACT R `T'OR]"is required, but it must arialyzc only the effects that remain to be addressed. I find that although the.pr paased prcnjec;t could have a significant effect conn the enx iron rnennt; there WILL NOT has a sianificant effect in this case because and ptatentially{signi f carat effects (a,)have been analyzed adequately in ars earlier EER pursuant to appf cab e standards and(h) have been avoided or mitigated pursuant to that earlier E ,including revisions or a itigation measures that are imposed upon. the proposed project. Signature Date; Pn-inted Name t. omr-tnuriity Develop-ment Department y 4 In To process of Im-e ?aii' ng We Checklist xid C'j)t'3Cl Ming the f'valuat:io.n tl'Rf: foil.?: dray ie,e.. Ils,-'C's (witch i3i'e available W't't"*'4f;w tlt ixl:,.Anfa C(?sm�_1?1aI11y("0111munity De'" di.._p,11C fi Dpsl, nic€>L; 651 Pine tre£et 5th 1Mloor-Ni Orth Wing, lartinez) were consultod, Cony, f..€>:tx '"S("U 'e ": yster, a Qt 3ti 7 a( � 31a firjo y,, �all i". ..A "Me( ec.onsol ate )Aunt=General Plan(Iui E11Z or) I!i e ncnal 111an i,J an Ll a ry { General Plan and Zoning mal:)s , Security Owens C on)oralEla.n, Alhani�ra Valley, Specific F'Ian, (10ci€;til)cr 6, 0112) and N€ s.',rt'4,v De,claration (1992) 5. Site Vi: it t 0ct(7ber 1 r3. &22, 20t,t_), t). Arrnoyo Al Flambra Preservation. and j7niiarcement:£Tarr € ui `). 20021. 7. Public Works lepartx'nnt Contra Costa County mc,mi,u (September 12, May 13,, 21)02). pity ol'Martinez latter(N-lay 1,2002), ri C;ontsm Coma Cowuy bite Protection District, letter(April 24, 2002)• ifl, I A1-t.01 letter(ftp-ril 22-24002), 1, (,`_i:1 ts'it ."C�=rt.I`ii ;ti 3 iui?zt�iS"?"l.)i'�tnct, lettt7, (Nt3'�crnber 16, 2001). 11 Rewwng Exhibit Alhambra Valley f,�tates Subdi-aision 131134,fait 1;)emjpi R(.`o,aac4 s,inc;.,r r€,•date°r::i), 11 AM% Valley Estates AsIg Tentative Map-Subdivision 8034 RA D � gn Resou ce,, (Aphl 11, 2002). aril revised (Janie 27, 2002 14 ,.l,rc'.iv rso"1twl. Sf',rv3ce, letter(,Zuni: 1c&+, 200,2 and- February 1.2002), 15. Mono S& Associates Llk • letter,(N-Jay 20 2002). x, 35n. Mr31,k & .1sst'rt:irite4 I..:I.,C,. 1>tir=rlFlr€rttar�'7, 2003 , 16, Moore Biological C.:'cansultants, letter,(Decernb,er,20, 20(11), I7ai. Security C)�wnen-,(or €ra tion, It tier(June 26, 2002), 1,7b. Security{..):vners S, <:srpora2iion„ letter Ottly 3;, 2,100 j., is. E)t3S"%'an Nlrm; Assso ates 11eWr(May 13, 2002), 19, 11r £r ren >er :tat;1, lettere��7�e €;lie 3f}, 2i:)f)1). 20, fiiinp orth& Rodkinletter tl•e"biva?'y, 20()21 21. SO! t..<)z3:,c`rvation `'tC.Mea`, `x€it SUrvey of f.;G)i'm (:osta(,*oL1D't , H 9 75';), 22. Contra ("star CAoijnty sal,«:icultural Ctpi"S1Ilu5s'1o1`er, CC)r'nmitT'1ication, E'itti B'..;£" i;3,4Ys, t t)4t; 1l)t',r o. 2ff12), 23, BAA0114D Guidiclincs, (.Decerrrbor 1999). ' =1. Puavc,11, Whoads& Associates,(i .utcchnical Study, (July 23, 002), 25, Cleary C'omr Wtan6�. Cleary; (.Noveinber 1, 2002), 2(i. .17Viro,rsa�eiitzi (7ollalx)ran #, ccrrr�srr urni� €t on with �rr�i�€€i ar°in f0 tob.e 2$l 'rax)'}. 2' Untra C't`sta(,`.f3urity Fire Protection District, a:liFY11T€unicanon.. Rtc1xard Ryan. CN41Yenit e 4, 20,02). u.,eT1traf (..01111-A t.,O;iW Sanitary District. communication With cuftt s aan€ x Yi &- Russ 1"C t"at., (November 4,2002), 29, i)lunen;>!€ns 4 1..:1"3{.:lnce'ring,s:t"ruinnu€#icat.ion vvith Doug.1D•i:ri'€IYIan, tx','^�E)`,:ernbe 21002, ,4i v i'1 4 .irt7ll�7('T t°IE',t a t#tT 1.) 1.ai-It-1 11#,C(5i`:1TfJLI ic<iT.ion.'4'iffi l im"?ii , °et`;t'"�£;`:"'c'7tl?f'.P' 6. 2002). Si, grliI5,4m ii?izz:C t1 t,t,(rYi% ,T 1. ALBA°til,a if. . Would the proposal- Have ro osal-Have a substantial adverse effect orf a scenic: vista" (Source�i 1, 2, 3. 4, 5 & 13) buhstant ally Barna e scenic resources, x including, hitt not limited to, trees'. rock outcroppin,gp, and historic buildings within a state scenic highway? (Source 1. 2 3, 4 S & 13) C. Substantially degrade the existing x_ visual character or quality of the site and its surroundings': (Source#~1, 2; 3, : 5131 d. Create a neer source of substantial light or glare which would adversely al"ll ct day or nighttime views in the arca': Source 4 1, 2 3, 4, 5 & 13) a. -- d.. The Applicant proposes to establish one sirtl lt-fa.xtily residence on each of the proposed twenty-three parcels. The prvjcct site is -visible from the two adjacent roadways. The roads, Alh nihra Valley load and Relie z Valley load,are both designate l scenic routes in the Alhambra Valley Sl ecitic flan(AP)and in the oanty's General Plan(CCCGP). The intersection ol"thesc lwo roadways is designated as a "gateway" in the Alhwnbra Valley Specific :flan . There are l goals and Policies* which relate to the presem-ation and enhancement of the aesthetic character of Alhanib.ra Valley' These goals andpolicies generallyrelaw to meed for new develo meat to integTat into the natural setting, reserve areas of high scenicvalue and preserve the, rural residential characters, A, Goal t i;"s he.Envjro.,j, ajjta3 Pollicics I, 2 and 4 Trzf'ac, C irc.uiation&Scenic Routes, Gua+;rl;Policic s, 7.4 fi,F� Scenic Re.,; vrc:es&Community Design,Casal I n Goal#IL policiti#!,�, 7 8,&9, 6 'file iWer >ec;li mn of :Oiambraz `4'"aallcY Road and l .c°1lez Valley Road d aas ca.cValrl the Alhambra Valle-, Spocific:Man, "1`iac linten t:oftllc; ]harn""Ira V aIIey Speei f`°c; flan rs,.lo pre, r,w' the eh l,tlrt v;evs trt raa these .l!a l�rcal��ss cl project rt�elta�l�:a 6 s7 rircel that will b planted' with 3 crepe nia,rtles and drought tolerant grz-owi cover shrubs. 'In front will be the mors;. trail arca pedestr:iaarrfbik:e path, The existing oliVe tr"ec gill be prc st rvecl. Views`w t'rt 1Tm ti'YrStr3ag liorn.es tsaarr"i}t7Iiding the }1tjoc ) to areas o, 6-lrt : Wt " l � �i- ) slopes to the south ofth �>, C, %x"hi'ch are: desigaaated as potential darkd� anra in the Alhai-nbra V aikv Specific: Plan(Figur 33), mai. be€ bstructed by the proposed proJee.t. Tficre ar-c aestlietic l)rotectz(:)ra po.licios in thf:Alhambra Valley,Specific Phm Haat should be addressed In the Environmental halpa ct Rcpoi-t. 1. YAC I IC,,.LT!JF�. l R.ES I..':l�t.l, Io zoto;rtaintrt whetl':r" 1.nnpacts to i•1:�'rict.,ftt cal i'C'.`Sf3t�rc � ar sr.gn,l.trcaant c:tm�-zxcarxn.ental effects, lead '�T�aarrorc�s may relfert"Yto))tpthe QCaliftsmiiar*q'11�gricqulltturrll]lr<3(�n } Evaluall ent lodell pr-;naar dl by the C" liform a l:?cl*t. 01'C onset ation as apt )ptjonal model to use: ira assessing Impacts un :ag cralturaal and fu.-mland. Would tlaC Project: a. t"a.t c rt F'rime Faama and, Unique Farrralaan , or. Fa rmland of State�ide Importance (Farmland), ars shown on the rnarlrs prepamd pursuant to the. Farmland Mapping gridM- onitoring Pr os�,rarrm of the Caalifomla Resource-, gencv. to non-agricultural use'? (Sourc;e Wil, 2 ; 4, 5 la, 2-1 & 22) b. Conflict Nvith existing-, Zoning for ar<4�rl rltazrtat use. oras ; slliaarrtsc r� Act contract?t`' (Source #1, ' 3, 4r t . 13) C. fiwolve other changes in the existirrg _...._ eiiviro.lznent which. due to their liocation ............................._..........................._.. .. or nature, c.oruldresult of ConYer'si n of Farrida.nd., to rion-rafgr€cultural ttse? (Source .rel. ' 3, 4. 5, & l 3;) a. The project site is underlain b-::3otella Clay loans, rated as prirtae agricultural .roil: by the Soil Conservation Service (St€ rie :Ended of 81), and as Prime Farmland on the l':trrydarid N'a,ppin & Monitoring Program. either the Alharnbra, Valley Specific Ilan, nor its accompanying en- iromnental docutraety addresses the conversion of°prime agricultural to non—a ricultural eases, l"Ior�-e-ver.the Alhambra Valley Specific Plan designates areas for a& cultural preservation ll"i urt 41). Hie pr()Ject site;is not desigrtated for protection. The C ounty"s General Plan addresses this issue. through Policy -l? which encourages conservation ofprirne ttgric;ulttaral lands outside ilia L rlr�an Lima :Line. This project is within the Urban Limit Line; and the conversion is not considered a s gtai acant impact. b. & c, The site is not zoned agric ult-ural preserve: nor will the project frivol.'e other changes (beyond thofit„'disczrssed in above). III. AIR QUALITY, Where available, the si', ni icanc e criteria established by the apl ltc>ablt air quality management or Lair po lOotx control district may be relied upon. to make the; following,determinations. Wortld the protect: a. lict�.�srith or obstruct implementGatiota C°omf � _... of Clic:applicable air quality plarO Source# 2, 13. & 23) b. Violate any ,air duality standard or _.._ �. ..w...... , contribute to an existing or projected air quality violation's (Source� 13 & 23) C. Result in a cumulatively considerable ......... net Increase of4any criteria pollutant for ,vhich the project=`ct re ion is non-attainment under an applicable federal or state ambient pair chirality standard (including releasitly ernis dons which exceed quantitativ Y n, thresholds fior ozollt;precur'+ors,' (i, 1,:Xpose sensitive receptors to substantial pollutarit concentf"a1:1{ ns"'(Sol 7-ce ft 13 & t,rCate objectionable odors affecting as X substantial number of peopWl (Source X13 & `?3) r no antic gated potentially significant inipacts w ai.€-qu btv,sas ti c proiec t doce�,-,=.scat gene!ate the miTurnurn resbold ti`s ffic generation sit by taw 13,E �t Nlr,) at :'2 ta1� �ay, c',. As this is a residential project. no 3rnpacts associated with odor are aailaad,",%p aied, d "File r)r€iecl will have slaoil-g'ril'l c(,mstru tion related lwllicll :`�#I� OC Ted�tlE:;�;"d b condi€ioniing the project.apprf)Val to irac!cI (, the C unity's standard construction measures, TV. 1 fC l 11w I- F t.��,"t CES. Wo Uid ti;a Pl,(.)'t. J, Have a substantial aclvime ef•foc:t, eil.he d-Imetly or ffirongh habitat rnodificatio is'. � __ _ _ n.•_... on any species ideriti ed as a candidate. scns,ti�,c, or special status speciein local or regional plans;, polices, or rega*lation , car by the Callfornia-a lD partment of'Fi h and C arse or U.S. Fish and WildIffe Service'! b Have a substantial advc;rse o f cit on araeF r ip •iar;.,aabitat:or other sensitive nal-Ural _•__. � community identified. in local or rc ional plans, policim, regulations or by the C'aalillori i a Department(if"Fish and Ciamo or US Fish and wildlificService'? ( Source &1.1, ', 4 5, 6 14, 15 16) C, Have 4a 4 ubs1 tantial adverse efj'�d on fedc rally rotected wetlands as defined by Section 404 of the Cleaai %N`at z°Act including, but not limited to, marsh, venial pool, coastal, etc.) throu lla direct removal, filling, hydrological interruption,or other me:ans".•'(Soaarce; 1, 2,4, 5, 6, 14, 15 & 16) cl. Interfere substantially vvit.h the movement of;any native resident or migratory, fish or wildlife species or with established native resident or migratory wildlife corridors, or unpede the use:of native wildlife nursery ;sites`,' (Source 41, 14. 51 6, 14, 15 & 1&) C: Conflict with any local policies or ordinances protecting biological resources, such as tree preservation policy or ordinance'' (Source #1, 2, 4, 5, 6, 14, 15 & 1 ti) f. Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan'? (Source 41, 2. 4, 5', 6, 14, 15 & 1 7) ta. —d. The project site is within two miles of known California red-legged trOg habitat. Additionaliv =Arroyo Del Harnbre is hvdre logically connected with e:reeksin.Brione:s Regional:bark to the south, Briones bark supports several populations of California red-legged frogs, Hence, : rrovo Del i-larnabre may serve as a migration corridor for this federally listed frog species, A Bloloerical Resources Assessment,prepared by Moore l3iological (Dec ember 210,`'Utt1. ), a evic wed a.ra earlier version of the tentative map. Subsequently a ne�v,map has been submitted. The pro'ject's associated offsite sanitary sewer axed star in drainage improvements may result in the disturbance e of biotic.resources. A biological reconnaissance of the areas affected by the proposed sewer and storm drainage Bali€crunent M)r potential construction-related imp Acts) is required. required for the constructittrt =:)f the outfall tassociated with Alhaanibra Creek). It 1s l.ikeiv the Applicant witl need to apply for t permit fi-r',m the 1_'.SArrny Corps of Engineers (pursu,nt to Section 404 oftlae Clean Water Act). aI certification of'Eh ester quality from the California R€a;gionlal AN"ater Quality C::owrol Board ( urswwt to Section 401 of the Clean Water Act), and a st l-anibe alteration sag-eernent fx,)m C Bali!ornla ep irtraaent offish and Ga me t taa,sttaaat fres��,c.tions 1 0 t-16'0 from the California Fish and Game C ode)} The Arborist's Repon :and the tentative reap identify a)urteen trees Haat wotald be impacted by the proposed project. lh native species f ta se tres are Qtaercus Kellog €Califoraaia lack Oak Quercus, lobata (Valley Wllte Oak), Quercus Agrifolia ("Llre Oak). Other o-n-native trees to ^tc.' rLnwved include,camphor, ofv ,cedarand eucalyptus. I.3tyc}syci*eesG=S4oct`1Lcepw3LS)tl3wi.)utf'alI will need to he addressed. The t3I"C)il t Stte iS not located in an area covered by i? .l-la haft Cori sery"ati on flan. Natt:iral Community( C3nser,allo i Plan, or..sirnllar local plan and as a I-eS R M iRD:D3C:tS 10 �,UICIDa plan will t:=i;Ctir, Would the project: VCUT a.: C attsi3 a stibstanta:a.l adverse1✓har Lc; 1.n the x sS,..tit 1.a'.2Ccdnce of a hi toncal r Vgoarce as defined in l 5(-')64.5'N Source 13& 19) b, Cause a substantial adverse €°harige In the x si&znif£cance of an archaaeolo6catl resourCe __.. faursuaatat to, 15064 '(Source #4l3& 19) C' Directh,or indirectly destroy a tinique palcontolog cel resource or site or unique gcologic: ft atetre`? isourcc "1.3&: 19 d. Distttrb any lauxnan remains, including those interred outside off-formaal ce:-neterrie-s' (xSo arse 4 13 & 19) <S�;3tF�.C2fii Si4 S 1,"ai M7tina!or; `1?wii f1c. a.—c, I he project was surVey Cil by the Applicant`As archaaeologicaal i;;on suit an and was fOuiidl to liaa 'e TIO r"Corded historical orp rehistaarical sites inside its borders. } ttiar�st rcca�tcl cicaaltaarxal test atr�°c: is Ait mirano Adobe,localed ust to the northwest ofthe current proJect area. No surface indicalo s of abonginal use a nd.'Or Presence inside the E roliect area were rioted at eaTIV poiilt: n<)ne of the visual indicators t:jncaa.l of this portion of Contra Closta County were seen. '.Mere was no evidence of fire altered rock or sails(evidence of cooking fires),no concentrations of either freshw—atter or salt-water shellfish, no concentrations of stone or bone, and no artifacts of these ntaaterials. Given the, recent cfiscing band the fact that this parcel has been utilized for itgnicultural purposes(it shows no signs o containing imported fill'),evidence sof aboriginal habitation sites andior temporarycamps should have been evident on the surfaace, 'I'lac location of this parcel near a creek(the Arro o Del I-faambre)and at the confluence of what must have served as an aboriginal trail system should make this area a arehaaeoloalcally sensit ve;yet thea is no trace ofprehistoric settlerraents anywhere inside the parcel. -rhe Environmental hratpact. eport w'ill evaluate any cultural resources in the areas of'trenching aalnd the outftall, d. Future construction tura activities Ior a st+rin clrainatize and sanitary sewer development could haa-ve a potentially significant =.rtapaact on prehistoric or historic cultural resource as the areas ofsewer arid water drainage 1111provenle nits have yet to be suneyed. There is always a possibility that deep trenching and grassing associated with building a.:ouid Will tat) archaeological resources, perhaps buried by the historic deposition of silts from the n", -by creek. clearing flo-oiling episodes— VI, GEOI..OGY AND SOILS - Would the project'? a. Expose people or structures to potential substantial adverse -effects, including the tisk: ref"loss, injury, or death involving- .1. nvolving-I. Rupture of as known earthquake ake fault, _. � . X as delineated on the most recant AICILaist- priolof:arthquakcFaaultZoning Map issued by the State Geologist for tl"e area or based can ether substantial evidence of as kazoos fault? Refer to Division of Mines and Geology y peciaal Publication 42. f otarcc 1, 2, 3,4, 18. & 22 3 12 2. Strong,seisnuc griJftild sh akiniz? i, Scis,ini -related 2"ouml faiiure, including 1igttef ct On`? (Source M. 1i tie i'��iction? tSource awl, 2, :�, 4; 18 "22 i IS, & 2) Result in substantial.soil erosion or the lass of topsoil`' (Source N I. 2, 3. 1 18, S_ 2:' C. Be bocatcd on a geologic unit or soil that is unstable, or drat would old bec;ome unstable its a result cif the project, and potentially result in tart-or off-site lauds ide, la twt'tal spreading. Stlbside°t ce; 1_iclue acJon Or collapsc? d. Be to ated or, expansive soil, as defined in `I`Lablc 18-14B of the U#�„�iforttt Building Code(1.;}94�, creating substantial disks to lite or l)roperty" (Source Q 2, 3, 41 18, & 22) e. Have sails incapable €f aide u asely _._ XX supporting the use ofseptiG tanks or alternative �A aste disl)os al systems More senors are not a ah abb for the disposal of write w- tL;;r? (Source#.1, 2, 3, 4, 1 1., 18� & 22) Yy --ei The t'�l�pjjl35cyant 1�i�4zs submitted a geotechnical b stttaYdy'ytof�tl�i�r; project sgyi9te�Sr.ful�:t>23, 20fat2gy), {'14`.he nearest acti e'aul-t is tl`i�;C oncorcl-Gre..en. �<zi ley Mill. ST'F�1:Wh �.�Gi:Sses" '"4.5 miles northeast L�f,st i.��7. the site, An trending Walt traverses the site but this has been,determined to be arl inactive fault("Personal communication N>1i_l;e C leai-yi (.,icary Consultants). __._......_..._...... _...................................................... Si ;til Can ST !'1C air N! Cha tx ".1can r "A. a.". (i. Scismcall y-in aced ground shaldrig with minor structural darnage rnay occur within the economic lite of the development. The sewer and storm drain routes have not leen studied. A. s>cyoloinc re�,onn i ssar ce cit the sewer lines and storm drainaoc routes wil i need to be perforl-ned and rnitiL ions developed. 4r. 1, F�cc€girding t€�the; =��pplicant's geologist. the site is in aan area thx is rated ``rr�oder°ate to low"' lique!`ac tion potential. This is based or soil and groundwater conditions encountered in their boning and penetration tots performed daring drilling. Potential impacts will be evaluated as part of the Environmental ental :lam pact Report, Additional geologic investigation may law warranted. a. 4, The site: is flat, there is no evidence to suggest any potential impact. b. The potential for soil erasion occurs,with,all development. The Environmental Irnpaact Report will assess erosion,potential or control measures for the pipe inc route,or the:outfall into A lharnbra CreeK. c. l.,aboratorY testing=and field observations indicate:that the near-surface soil possesses amoderate to high in expansion potential. Potential impacts will be evaluated as part of the Envirorin-le atal Impact Report. e, The project proposes to connect to public sawter. Annexation to Central Contra Costa Sanitary District will he required {see XVI,Utility Services Systems. below), Would the project: a. Create a significant hazard to the public _ x or the environment throuzglr the routine transport, use, or disposal of hazardous inaterials? (Source l ?, 3, 4, & 5 ) K Create a significant hazard to the public x or the environment thrmlgh reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the enviroruiie nt`' (Source# 1, ?, 3, 4 & 5) snit hazardous emissions or handle x hazardous or acutely hazardous nataterials, } substances, or 1vastl- wi[hm t}s`tw.quarler !i" is of an cxisting or proposed school? cl. Be Jocatwtl on a site xhich is included on a list cif zwpard sits materials sites compiled nursoant to C:rovernmen t.":ode Section 658615, and, tas a result, would it create; a significant hazard to the public Or tile et'i0'ir01MI rat`:' (Source #Q. 22, 3, 4. 5, & 20) F4.Jk S, projectlocated within A.an At.dillo..L tali4S _,........ `....,._. ..,.....,.., !� iise plan or, where such a platy has not been adopted, within two rail les of a public a iprt or public use: ai.;p+:irt, =.`Ould the proiec;t result 'in tt safetl hazard for veopkl residing or vvor.kino trt ttic project area. (Source =r1. .' s3. 4, & 5) A; Fora project within tiie vicinity of tr _._... _..._ private tiirsbip,would the prOlect re:sciit in ;a s of ty hazard for people rsi inti- ryci`l iri irr theprcc c; iiei: Irrrpair arilpienientation ofoi-phys c ail: nterfere with all adopted ernci ganc'yr response plan or emergency evacuation plaTV (source =r'l, , 3' 4& 5,) I.. Expos :people or strLwttlres to xi _ N, si ;i ilicant ride of loss, inju.n,or death involvin -vilclland fires, i:nciciding where vvildlands are adjacent to urbanized areas or w!'Wre residences are intermixed with ii. w}a. The,Contna Costa County Fire Protection District does not have conce.rtis w4b either w ildiand liras cri i?ic site or development impeding ctrarenc Ian S. _.................................................... _.........................................................................................................................................................._.__..................................._... ""'Incan't ;rel=t �.i.fi .':ant 1I zpUct The :site has uppoi-tcd a tree farm and a,•in;yard although it is currer►tl y not cultivated and l ous-es aao structures. It is riot liswed zas<a lea ardous materials site and the pnte.ritiaal ibr exps7 cure to hex a 'dous ra,aateri als'is, therefore, "I"hc site is neither within `,,. rtrile ofa school ncrr within 2 miles of ail airpml. The likelihood of residential pesticides(lz•om the tme farniJng,or 'ineyand operation) al:ter this period oll time is remote. VIII. M'DROl.OGY AND WATER t;,)UJALl FY w Would the lirgject: a. Violate any water quality standards or (w ante dischargey� requirer�ents' (Source#1. 2, 3.4, -5, `17. 8, 1„) & I a, 1`7b , '29) I~, Substantlafly deplete grssundmvater supplies or interfere substantially voth groundw a€er recharge such that there would be to net deficit in aquifer volume or a lowering )fthe local -rouradwater table level (e.g., the production rate sofpre-existin"zae�arbg�. wells would drab to a level which would not support existing land rases or-planned uses for which perrraits have been gr-anted)? (Source 1, L, 3; 4, 5, 717, 8, I 17a, ,17 b &219) C. Substantially alter the existing drainage pattern ofthe site or area, including through the raIteration of the course of ra stream serrivor, in a rrminer which would resent in substantial erosion or siltation ura- or off-srte" (Source tl. 1, 3,4, 5, 7. Vii, 13 & I?a. d' Substantially alter the existing dram age pattern sof the site or tarea, including through the alteration of the course of stro txa or river, or substantially increase the vats: or aariount of surface r€znsrff iri a manner which F' ,i a Is (%vot€lel I'i stilt in tit`�odit�..�ern.- (--?r Off-site? - 17b &29) Would exceed the czap:zdy of eximing or planned storm drainage systems or prwtitle substantial additional sources of pol ltaed r<rrasa f`f~% (Source e#1, :n 3, 4. 5 x.11) f. t::3 hen iso; substandaDy degade water quaal ly? (Source 41, 2. 3, 4, 5 & 1 l ) 1 Place housing <a 100-yeaar flood hazard area as mapped on a l.ederaal Flood Hazard Boundary or Flood insurance Rate Map or other flood hazard delineation map? (Source >1, 2, *, 4, 5 & H) h, Place within as 100-year flood Era 7 trd area _. structures #-1tich ouId impede or redirect i. Expose people or structures to ;s significant cant r sk of loss, injury or death involving flooding. including flooding as as resuIt olf the failure of as levee ordam? Source :,,� I, 2, '3, 4t w & 1 1) ;. Inundation by seiche, tsunami, or anudt?caw" tSourca 41, 2, 3, 4, 5 & l 1 t a. ik f. TH Applicant has provided a conceptual plan that, includes al eomnbitiaticn of 01 -sill,` collection. filaratisrrr asitia grassy s wales, an of site 48'' storm drain line Witlt aara Outfaill into Alh an,brta Creek-, There is conc rn that these rne:asures Nvill :tact produce The required water qu of tz results. Potential layclrolog atacl-,s'ater aluaality iara acts will e t- aWaatedl. �; lk6 y%aiii. h. e. The proposal includes a system of on site collection and off site disposal (imiudin construction) of stoma dra.ina-e. A recharge component is included. Fire 1"nvirc3nmental .l xapac,t: R port will evaluate the s�.rstern to identify any environmental itnpac t's. fe,la.K, i. 'Proposed structures are outside the food plain,therefore t=ill not impede cis•redirect flood flows. , Site no(,adjacent to ocean,sea or lake therefore there is no risk cif"seiches.tstrra uni,or rrrudflo w-s. IX. LAND USE AND PLAININING - Would the prplect: xa. Physically divide an established c;ommunitv":' (Source#l, 2, 3, 4e 12 & l ) b� Conflict with any applic;ablc hued use x Plant, policy, or regulation sof ata agency with iurisdic;t:i€tn over the:project (including,but not litmited to the general plata, specific plan, local coastal program, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental effect? (Source 01, 2, 3, 4. 5,12 & 1.3) C. Conflict with any applicable habitat _.. conservation blare or natural ec}mmunit conse ation playa'.' (Source �1, 2 3, 4, 7,12) & 13) <a. The project will continue with rural :residential development in an area designated for such development, theret:bre,no division of cot-fit unity,v rind oc-cur. 1). J he property has (i neral flan designation of Single: Family Residential (SI:-,). °:l"lae propert current zoning designation is Agmicultvral (A-2) and Residential (R-20). The ti1lhr unbr-a V alleNl, Specific Plan designates the site as Single Family Residential Low Density(1.0-2.9 d.u.bet acre). '.Fhe current zoning would allow for T9tats. The proposed project would create 23 tats on the 15.02_ aches aflce rezoning the. 4.5+/_ acres, from A-2 Agricultural 5 ac.-minimum lost: raze; to R-10. Residential 20,000,,;f ininir urn lot size. £(1 ? tr 1"::t<1'losurc Ofpe.T-sor'ls to or gen-crattiol7 o .�� borne noise levels? (Source . 1. �, � 4, 5 & 'f) C, A substantial pem anent increase In _._.. an ?, at r,e iso levels in (lie pro'mt vicinity above. 1eavels existing without the project;' dl. A. substantial temporary or periodic _.w.. _._._ mcre3se its ambient nolIse lev,;is in the project, vicinity above levels existing w it; out the project'? (Source 41, �, 3, -4. uk 20� a 13rti iect located within an all-port iand ease' plan or. where such a plan has not beer, adopted, within tNvo miles of a Public airport or pubhe use airport, would the pro).-t eNvose people res.ding or l,"ominl it) the project area to excessive f, For i projcet rvitbin the vicinity ol'a priv ate airstrip. would the protject expose people residing or working in the pro ic.c;t area to excessive noise leveis'-'r f`outce 1, 2 31 ,, 5 : 20"1 a_ JhQ Applicant's molse Co sultant7s repot, st.om:,, that portions of residential lots IIt"tmediatelyv` acljac ent to Alliambra Valley Road are exposed to e xistin and future note levels e=xe,,ceding the tit dB DNi:_: threshold scat forth ixr, the County (Jenenil Plan. The proposal showsan Open wire fct7ce~ aalon- Ml,onflgra Vatlley Road (along the:l.ad lyarels of lots whic ti,back onto Alb tt"l bray Valley Road). ,FhC noie consultant report recommends: Noise barrier ;fences 6 fleet high, located along the Alhambra Valley Road .fionta.ge, would reduce noise levels in backyards to �vithln County Oliidelinus. hits TeCOMIllti'.rlded mit.ication t'Tle--sure. (of' soild J5en es) 3s in conflict v ith the Alhambra Vallcy Specific Plain goals and policies. The Environmental linpae.i Repoil will evalualc _. .................................................................................................................................. ......... ......... _. _ .�a tr:ial i:.is35 i than t LTMAS isj"t? noise impacts and propose mitigation n casures. h'- [mironrnental impact Report v,,111 evaluate; whether interior rrOisc leVela could excl—ed dic General Plan Policy 11-4 cit a DNL of 45dB or less, lr.,c,e. f. The proposed projedct,.ill riot expose;a nevvv population to ground bounce vibrations a no st:iurce:for such activities exist:within the arca.. The project will not result in increases in ambient noise 11-vels. The prclpect is not Nvithin ? milers of a public; or private airs<'rip. l.l. PORT A,TION AND .T101.'S1NC:1 Would the project: a. Induce substantial population growth in an X area, eit1her directly Obr example, by Proposing neve° homes and businesses,) or ind rec,tI (for-example throe D, extension of roads or other infiasirticture) (Source A 1.; 2, 3, =l. & 5) 11. Displace; substantial numbers ofexistin lrcusini . necessitating the construction of replacement housing elsewhere? (Source 91, 2, 3, 4& 5) C, Displace substantial numbers of people ........ .necessitating the:construction of"replacenient �. housingelsewhere" (Source e #1, 2, -3), 45) at The project proposes to construct both a sewer lire and a storm chairs litre. both of which will have:capacity in excess of the pr{.�lect's needs. Discussions with public works indicate that the >ton.ii. drainage litre will provide a public benefit in that it will replace existing deficient;storm drains, The e ver line %Fill extend for over 5400' and pass by numerous undeveloped parcels, These are considered potentially significarit trrravoldable and potentially growth inducin impacts. b. & u. The Applicants are proposing housing on a vacant parcel that is ratted for residential development. therefore, there will be no diSpl4teeMCnt OfPcspulation. :._ E'x�s r� X111. M."BLIC SERVICES el. Li 0111€1 the proiect result M substantial adverse physical al finpacts associated with tkie provision ofnew o,:physically altered loo�°ertirriental tacil.rtles,need f4:)r new or ;gib -sically a terecl govemmental facilities, the construction of -which could cause sikzlif CLJJJjt environmental fmpacts, in order to n aintaiza acceptable service ratios,response times or other performance objectives for any,of'the pubii€. services ;Source; 1, 2, 3. 4, �;J: 1, t ire I'rc>tctic; f, ._. `'. I ofic e, Protection'? I Schools'.,' x w_.. :irks:' Other Public facilities? ., I t ill inc°realentallY, although not cumulatively considerably,considerably, itt mac all The ter€l ase cf 13r s public service,.,,, a. Would the project increase the use cifX € existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the hicility would occur or be accelerated) (.Source ' I. 1 3, 4, 5 & 30) b, Does the project. include recreational facilities or require the construction or ex an.;ion of rec;re ti,"m l facil tics which trtight have qui adverse physical effect on 41. & b� There are no potenti.ally significant impacts stemming {r€ern the proposed rezoning. ars subdivision. ........................ ...... ......... ...................................................................... ............................... .._.... ......... ............ ............................. ... ................................... ..._ the prowct. aa. Cause an increase in traffic which is substantial in relation to the existing traffic load and capacity ofalae stfeet syst.c;rn O,e.,, result in za substantial increase in either the number of vehicle trips; the wAume to capacity ratio on roads, or congestion at intersections)? (Source #1., 2 3, 4. 5, S & 13) b. Exceed, either individually or cumulatively, as level of service standard established by the c-ounty,congestion management agency for designated roads or hi hw ays'' (Source*1, ", 3, 4, 3, 8, 13) , 30) C. Result in a change In air traffic patterns, including Either an increase in traffic levels __.. _»... or a change in location that results in substantial safety risks'." (Source =1, 2, 3. 4.1 5, 8 & 1.3) d. Substantially increase hazards clue to a � _._.... design x feature: (e. ., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)) (Source # 1, 2, 3, 4. 5, 8 & 13) el Result in inadequate emergency acc;ess'? (Source;='I., 21, 3; 4, 5x 8,1.3 & f: Result in inadequate parking capacity" � _... _. , (Source #'1, 2, 3,4, 5., & 13) 9. Conflict with adopted policies. l pins; or m faros:ranns supporting alternative trans sortation (e. ., bus turnouts,hicvt le racks)'-' (Source-01, 2. 3, 47 5, '13 & 30) gitior :a. £i l3. l Crt°v -sIIT w'iic%v 11oi.is:'s mmadd add 230 additional car tnps;'dray or 23 l.t<:ak lWLW trip! The 1't"!.?7ml prop scs a rim project entrance C? t:%oshe QtlAl Mlow c. - '` The project vvill -not af'fe'ct arae-traffic routes; will not increase hal ards dLic to &Si�4n t:� rttrrc , amt will not affect Onlery-elley access. The prof c;t will provide de off`strect parking, g> A itltin a 22' ri,,hi o %v ay, the:project proposes an S' xvide bicycle a..rad pedestrian trail and a Vii' 1'F idehorse arafl. carr thca west side. of Alhambra Valley :Road, T lie Alharrbra V<rll y Specific Plan slao�ws these; unproverx Brits on the east side;of tliz Alhambra V,-lley Road, }'rind the prg,icc.t: T Exceed ;mstewater treatment requirements, �M of the applicable Regional Water Quality ality Control 13t ruxl`' (Source oil. 13, 4& 5) ta, Requiro or result in the construction of new or expansion f existing factlitics, the: construct,ton or svhicb could cause sigtaificant euvir- rat ental effects:"(Source 1, 2, 3. 4, C, Require or result in the construction fit new, storrat waWr dt'abm e Militks or empansitarr of existing facilities, Ohe construction ol'which could cause significant e,_,virca€tame tal :11"ects' {Scrartc.c , 1, 1 3 4, 5 13 & 8) ci. Have insufficient wziter supplic: &av ailabie to sea 4-e the project ftom existing enfitlernent and resources, or are or expanded entiticz'ner;at. S2#'ttf?s.°i':i Result M za determination by the w. _._. Wastewater tre(atrz ent prcivi& r vvbicli sen,e< or may sere the pr(aject di at it n as adequate capacity to serve the project's projected demand in Addition to die provider's existing ct3rim--ltti'itnts"? (,Source i 1. 2, >, 4. -, U, 248, & 30) f Be ser(A by a laridfili with sufficient p rrtaattecl capacity to acc omriodate the proJect's solid waste disposal' needs'? (Source k t. 2, 3.4, 5 &- l ) 4. Comply with fiederal, state andlocal _._.. ,,,atutes and regulations relak,d to solid waste" (.Source 1, 2, 14 & 5) 1). Water servl�e will be provided by the :ity.)f°NI artiz ez, Tile City has identified everal conditions, cif a pro al to their letter of May 1, 2t 04- a. & b. l 1 c° )r(, eCt Proposes the construction of a 54001' temporary sewer line (along Alhambra Valley Road and Rel ez V alley.Ro acl),includ:,ng a pump station. CC-,CSD 1 policies t -,,,,or gravity flaw systems(see discussion of VI Geology&Sails and IV Biological Resources,;above). "I"his sewer live will extend ley"«rid the boundaries of'the Alhambra ambra V alley Specific 1 lxl planning area and into tfae jurisdiction of they City of Martinez. c. The prc.#��ct proposes 900 li: ear feet of a 43"nee x storni drain lin alongAthajuibrra.`�'al.ley I . with an outfall into Alhambra Creek (at s parclra rive), Uaal~:tiown potentially significant impacts could he associated with the outfall location.and construction. a. Does the project tiave the potcaatiaal tri degrade the quality of the envirc unient, substtantially reduce tile.habitat,c,f a fish and wildlife species, cause a :fish or Wildli:tc population to cheap below self-sustaining levels, threaten to eliniiiirate a fla t or anianal conarrit ity. reduce the number or restrict the raanve of a rare or crad angr'cal plant or unimaal or eliminate imponant ex.ample's of the aaaAlor periods of Caaliforniaa history 01' relaistury' b_ l:tcses the project have impacts that are _..__. iatdivicltaally 1amited, but cumulatively ccarzsi era ble'> (Cumulatively considerable means haat the incremental effects of"aa prgject are c on.si€lc rable when viewed in connection with the effects of,Past Pr0-jects, the effects of other current pr jects, and the effects of probable future lngjects)? C, Does the lea°"ect haavenviroaamenta i effects, rshIcla will cause substantial adverse effects on hurnaan beings, either directly or indirectly" ........................ �.,p! ,. Q �/ / C��'•� y.'', 4 'FK" ° t i k^W y '„j($Yr.-�«-.yi' w, p. `n4*.f°�(�+�." � f F S IIIA AIT! x ti ;:,syn♦ � "`�f.: i F z i"f "'Y F� �"rl�{4:,.� ��E 'w,,.H'l.�°��•r,�� { �a $ t {-I,^.,'.,` psj f is r � /� e �{ i; .... \� � 'kms'`'+ "{1��\X g#`� \ y�!� `� ✓ i'�`S�`\ ( � �. .. `', �` '# \y �,% ��.✓� yam,. "�-,�, �„ � � �s,�.,� w � �4 i Y / .y r ,.. � C� Lis .- .- .. ♦ ♦, , n s£ ✓'� �}. ti �(r s '0". } too cq all' 1111 ,! 1 , v : b N ' x S A 1. Ff 1*001 : � x• � P� ki Sa.w '.of a t '4S, a Z ..a &ti's: � r :s } p ea"T, M ' �x a 's 4� , a�r r a 3Y 1 h !— \�±iJ d 3 ^tri ++'", }. ,i , `t• '�SIVA "a UAV J � ��'"'" 7 a# �.:� -� L.� �Sr=`•:." Shu ;tiP� �� ,�(,., .x.. .A»,"x C"S �,+, � `^~� { •�i � v vim, O h S ✓' v 7 � \ z \ §X s MU it atP a z, its r' i t r g` J iN f 51 ti i • Y 5. n. C2 x �g sy 5� du � A• n a°te t i n k< if } y✓✓ d T x \� ✓iFLYT�`)� F SAY}" t `s A" CIO f � a+ f 1 ` � t � r p •.e IN, IT_ mow ,yR ate, � rl sy 4✓ 7 $ moi Ml g i .k4I s� ?" v� j x, 1� ....................................................................... _............................................................................................................................................ f IV f I No £3F PREPARA'T ION LIST ,..)14 A Elft T O S-'H? Yes or No I I DRAFT EIR DrS°TRI'BUTION LIST TO : 1?Yoa, ......... or Nes_. ... i I NOTICE OF INTENT TO ADOPf A NEGATIVE DECLARATION TO SCH? es--- or No Fila No. Project srtfea AIk fa' �� ListFy._...... .m.._ __.,._ .w.,.._..._ Mailed By: ,.., _...__._.. . ._ _...a., .., ,,_. Date: . M.........., __....... Cler. Send No, cler. Send aft;. Applicant. Eflg�nefw Lao / r 4 t l 10 Stale Cie aringfinuse(Mail with Original State Clearinghouse (Via Certifle4 Wall I C ] 2 Main Library, Pletasa t Hi l(interroffic�e) 4< arena labrane � _..._...............�.._..... } 3 public Works c/orr , F+ariineeringi Sevvices aDiviskg .i�s.r°vlcrc,r_t t t I f`I 1 Health Department(Interoffice) 1 USDA Soil Conservation Service, WCIO ¢Larry'ScscratO I ? Contr+,a��9Resource 4st�ns'a,lw�Y.a ior{ 13i that } i i t LAF',-t.,la (interoffice) T ASAG hail vAth€opy of stata Clearincghouse N C; Font?', { I I 1 t C ontr r Cresta Mo sgtiitu.Abatement District, UO chwrIes Bee"6e 3, t)isvit;t fvl a,aq' r FAAQPAD, Aura: Envirorarrarrrial Review Section, 939 Eflis >tro€t, Isar =ranfisu) 9,1109 I 1 ( 3 ta'oiw O stril than Plastrsinq Division, ESMUD Mailstop 701< 3 75 11 rl, £ Oakland 9.007 I I Iv l School D'strtc 2 I 9 I r I ar aler DiWtaa ao anitary District. . C/o Ears 0,astract: 't ( Nearby tarty. 't_._ „_ ...._.,. ilea I 4 ( l I Water tOistribution Plann;n�) Division, ESNIUD Mailstop 701. '375 11th 51. Oakland 94607 E I [ 3 Local iviisdictions Adjoining Contra Costa County (Notice of Corso tkw ••«•If-riptti'D Oroje t generates rnorr than 100 peak hr trips: fradodu these t`a'rp Cuzrzrxri#r��s.',««« Please designaxto del CEa u'_ of NO ,.. 1 WCC-TAC (West Col 3.`i"FtAfdw;G t AN fEsst Co) 4. SWAT (Scuth-west Co) S, T VTC (Tri VitIley Tei,,linic i i:ft ym mt:-Pei Special Agencies of l"ie.uer� i<, ioc to img € ewsmedii': I I [ Jtm._ Hors e;c>wnw's r'ssu iiafiiowt', Special Inwrest Gtoupa ' A`'l Hoc C-ur;o Y e : £1,i44G3( . ��tZ.... _. . .._ _n Furan A Notice of Completion & Environmental Document Transmittal PO C:x 0444 '`.Saxe CA � ;S A�.. ,v3:4 9,�.,���� £��13 r � Project Title: .��� � _.� L.n,,J '+gC..1 y; „f&. .. Project Location. ! ,`i)ag y .. �eA4 _ .. a�'`�r'`•.., ` ,_>7.M) d d "`1.1 .'Su..�:.br?. Twp, .. ...........w_.__ `"?" ....___._ .x`4 ...,.._.,.._. ...._.. Document Type: .D,,x=-i,._--:. Early 0,,;iS t("HN''' Local action Type: i,.,.?..,.. °u'F i"It- , and',D .STS?': Development Type: f T1e" ia,.:°.1�.<... ,i..er �-;e s E ' s ski°'' 7 1�wtr fozib-,d .>: w _, ` i ( ;`r ....�......._,......., � �`�...........___,_..-. P:PAik�a,?3>z;t "_.,..,..�.,...__. F�'1.s�LY+h`Fi,�; '�r��3P�'"CSS._..............._... .,..�,.,............. ., .,,.....,�..,..,.....e,_ ._._.._._. ?E.'t'E'sfl:; S.e. ._... Ix..»...s.,3.,aa.�.a.' ,.a....._.._...,._._.._. ......._.._. ..,.,._....�............,__._..._.,.��..�......»,..,...,.„..,_ ?�'.�k,,.�..sIi?�.�s�?cu> i.( #dd4E11C#G Project issues Discussed in Document: '� 0kIi, l3 C 'f `+... ,71..0 'yE21s" c i 71, Present Land UsefZoning/General Plan Designation- Prosect Description: _ In LA _. ........................................................................................................................ ...._......". KEY —Resources genc}r Boatim,&�� at:J�,?#'f#}'S D{cla a !a4 a <.';.1 b f. h`r Suggested �.s'if r ----Coastal t:'onam sslorl Environmental Protection Agency Resources Board �ichk­ Gomm ore ti .i`73' TCSC '.':>I'S ..._.,........''W P'CD: (.:1aal3 wa a.. rant, i_14 at o 11;Sto'i" f TIt ti,,i?'vs ,reit r. —SVVRCIF4Delta ,._Parks L4:RwCX"eaIIC3C1SWR ,, Board _ _S%"_ C'B:tea€l r Riglit'S" Via„'C:€;werg'"s dovi&DEr''t.l(3pT trt C£2i v ais aAc 11 R#gional WQCB Youth& Adult Corrections Business,Trans porta Lion & Housing _C 0.1mclions Independent Commissions& Offices aae C' LlTS31I't5 l}ta 1 #t &C..f3z;7 Z uni s' �evtlopniiei?i tAfsit Utilities L1321I#lS E.Cn &A+sri talture _S1111L Lands Corzaza=_issi€an Health&Welfare _.._.._.»i r l>'Regio.a3's Planning A ucr State&Consumer Services Public Review Pernod fto be f" i.c t, ,, 1,­ac ageaI:.vi �' <..�� .v .............._.......:..�.................:..�....4...+.........,.,..._....M.....,..... fi`s fY»pD�a,.l eit.v .�;�.�.....�.....,. .w�y^y ....._.._,,.............._,.._....,.,._._nd"."._.._W_..._,�...___ ........ i t Lead Agency (Cornple e if appl'ivabie): iii For Sl id Use Drag€. I ' DatW Re .._Ac€? at Soo Dattc f' ie%v S r , D att.v)Ag '."i . __.. n._..... " M....., `Ssr,..., I ......_.......W......,..�,...M,.......� 4 Glfwoxac€;Date i . . w� ....._ W _......_ ,._._, .__ _. _. .._w. _. Applicant. 'ektIAX-1 £ d r#,.wz 1'4d K '5' if'�✓a o- y,�. `'tne" .yam. f LsSG#le+ «i9 f l,. r ' j APPENDIX B LEVEL OF SERVICE CALCULATIONS /SIGNAL WARRANT GRAPHS APPENDIMS Level of Service Definitions Level of Service Calculations Signal Warrant Graphs 13 LEVEL OF SERVICE DEFINITIONS LEVEL OF UNSIGNALIZED SERVICE SIGNALIZED INTERSECTIONS CTIONIN E'ERSEC;TIO "A" Uincongested`operations. all. queues clear in at Little or no delay. single-signal cycle. {Average stopped delay less (Average delay of than 10 seconds per vehicle, V/C less than or = .10 seconds) 0,60). "B" L`sas;€ingested operations, all queues clear ina Short traffic €clays. single cycle, (Average delay of 10- U secon€ls: (Average delay of ti fC=£3.61-0.710. > 10 and 15 secsa) C 0 Light €on estion, €ccasional backups on critical Average traffic delay. approaches. (Average delay of 0-35 seconds (Average Idelay of V/ = .71 .80 , > 15 :and <2 5 seas.) D" Significant congestion n of critical approaches but Lona tniffic delays for inter,,action functional. Cars required to wait s€one approaches. through more than one cycle during shirt leaks. (Average delay of. No long queues formed. (Average delay of 35- X25 arid X35 secs.) 55 seconds; V/C=0.81-.{3.30), "E" Severe wn estioh with s€)ane long standing Very long traffic queues €n acritical approaches. Blockage of delays fi)r s€me intersection may occur if trafficc signal does not approaches. (Average provide for protected turning, movements. delay of >:35 and Traffic queue may block.nearbytintersection(s) upstream of critical approach(es). (Average €clay ol'55-8U seconds, VIC=O.91-1.00). ".1"" Total breakdown. stop-and-go operation. l"Atr€rne traffic delays (Averaa e deIlay in excess € f 80 seconds-, WC of for some approaches 1,01 or greater). (intersection may be blocked by external. causes--delays >5 Level of Service; refers to delays encountered by certain stop sign :ontrolled approaches. C3tier approaches may operate with little delay: Source: Transportation Research E3oard, Hi iii° C;r °ci =ra ail, 2000. CCTAILOS So ,ware ver'. 2.35 by TJKM Transportation Cnnsu tantr; C,ondition, A4 EXISTING CONOFT'IONS 04/25/03 INTERSECTION 1 ALHAM9RAVA EYRiJr'AL RAMI RA AVE. CCC County, Martine rou ., Date 4/22/03 , me AM PEAK Peak Hour AST •CCtA METHOD RIGH1 THRU LEFT 4-PHASE 11Hs 1AL r � t f { (( t! cc,. p� SP ti t.�? N LE . i'' _w_ .0 1.1 1 . . 1.1 w_. ?IGHi STREET NAME:: THRU '23», µ 1.0 (NO. 05 LANES) 1.1 --- 39? THRU AL.HAMBPA AVE. R au;-T 299 1,0 1>0 0.0 1.0 .,... 61' LEF I i v N 1 i SIG WARPANT,» W + E 320 0 59 ur1>-Y; Rur-y 5 'EFT THRU RIGHT 'Sol it? N STREET NAME: ALHAMBRAVAL11Y;RG ....�.,,...x:��.»:_,............,......:x...:z�.x.:.�ss ...,�ttrresw•:���.:x.:sx.�,,...,.........sw,.W:.:.:.,:.W:» ^:.;nw.:.,:.:.:...«..........,�:�x�.::..aox ORiG!NAL ADJUSTED Vic CRITICAL MOVEMEW VOLUME Y{)`c..ME'° C-APACi_TY RATIO Vic NR FlGi"T iR; 59 " 1650 0.0000 LEFT 'L) 320 3i0 1650 0.1939 0.1939 S8 RiGHT (R, 0 0 1650 0.0000 0.0000 T Hrill i I-i 0 (:7 1650 0.0000 L E1"T (L'l* 0 c 1650 0.0000 + R ! '?6:,7T 0.0000 r .r. L 0 '1650 0. 00 0 0.0000 EF� RzG11T (Re 2" c * 1c O 0.0000 THRU 534 534 0..323b 0.3236 LEk..3 (L) ? 0 s653 0.0000 W R:C'11T R) 0 0 1650 0.0000 THRJ (T) 391 391 1650 0.2370 wEF' (L) 67 67 x650 0.0406 0.0406 i650 0.2370 TOTAL V°OWME-i`O--CAPAC.T T Y RATIO* 0.56 1N'ERSECTION LEVEL OR SERVICE* A a:��•::.::�;-.;�:.:sw,-::::::.zw::r axw �a -.:�acc:•: �-:.:-.m y.ca-_:.-.::ar•��--ams:wtmca::eex .�:z.�ser.,':���>.: ADJUSTED FOR RTCiiT TURN ON RED Cr�P- .,UAI. S 4of, are ver. x.'5 "'„ ,, iia iY a;: t cl CCI?st.i S.i.(artU s t 3i. fISTING L,1ND firs N/2909 WERSECTION : A f?Emir'A'4'xLL YRKliAF!iAmi,�.RA AVE, r-c l...u�,'';;:', mw3. .tmez ..!3mt one =.si3 TWe RM PaK Peak Hm . s;i.....�K5 pff i FT � F STREET NAME: Ri GFE 302 ..i .L` er0 ..c 1.0 •«", 4,, LES - (........_ > 1 f � SIG usTRANTS, ....._......._..�,..._....-,�., ,.�ncxc.w mmiuv =..... __... __.x...M.�rnx......w:..w... ...........__ _u.,.,.,w„.y Yrs 0 6510 0.0W301. .1.WOO - 1650 00000 3 1650 0.0000 0 1650 0,0000 EB `lf-,H 1 (R) 302 BL) Y 650 0.0485 TfM T) 535 tat 4650 0.302 0n..'',:u ,`0.'..00.:,� TRU _T) 640 640 1650 0.3879 03879 .. F 44 44 1650 0.U267 640 165" 0,3879 TOTAL i:) SMC.'-TO-CAPFCI TY ',Al'io: 0.52 jNTERSECT:0N LEVEL Or SERVICE: k A0jU'S G,) FOR RIGHT 'JRX )SN- PH _ 'si�l,,-..:X.iNT,4`.^t!"mak Ph`.'`s:L,res=,. .................... CCTALJS Software ver. 2,.5 by �JKM ';"2J1sp>.7rtat'lCw Crt1°suLtants Condition: AM PEAK FASELIN . J5�3"�r03 ,»-.::c�. ...��-..W�.,:-:a.::.,,:.�.c:-:: xru.-.-:xcx -.:v.�.:::_ca.:r.:;,� -�::...«-„aw:a:...:.w•�.m�.�...�.-::�.:.���.�v.��:; N: t?5 u”ION ? f 3•FeP 3i2PVA i..EY TIAL;i#I P.h AVE. CCS County, Martinez k toi rn; Date 4/22!03 TimAM PEAK Peak Hour 7%15-8:15 Am ccTA,, METHOD RIG Tot` U LEFT 4 PHASE SIGNAL g STREET NAME, THRe,3 558 1.90 tNO. 0r LANES) %1<—, 409 THPR.3 AL4AMBP,A AVE. t1i s1. 312 1.0 1,0 10 1X LO ...._... 70 LEFT 1 j v N SIG WNRAN TS.. u + E 334 0 62 Uri-Y, R r-Y STREET NAME: ALHAMEWWALLEYTYO ..:..:...: .......,.....�:.�=r»....z,,.y.'^..qx�.h.�...�a '::.:.3�:.��::�'�w.GL"CG vG'�'.aC................::«.� ......:u:..,. ryry.......».:,.,....,:.....:....:,r:. MCNEME VOLUME. VOLUME* CAPACITY RATIO VIC LEFT •'.:.3 334 334 1650 0.2024 0.2024 5:: P.s.OT €) 0 0 1650 0.0000 0.10000 ThRu (T,= n 0 i650 0>0000 LEFT ;L) 0 0 1650 0.0OW w .,. R 0 1650 0.0000 + L i 16550 0.(0ry000 R L ti.i 1650 0.0000 „3 P:Cr3; (R) 31,2 16i0 0.0030 THRU 'T) 558 558 1550 ru,3382 G,3182 :E—FT tt.} r n50 0.0'u .0 'O0 RI?GHi DRi v1, 0 1650 0,0000 i4gu tT` 419 409 1650 0.2479 LIFT 'L) TO 70 1650 00424 O} 0424 P, 409 1650 0,2479 TY,,'A' 'VOLUME-- O-CA#AC? TY RATIO,* SS INTEi?5r"Tii:N €.F' EL OF CC(Z! ,E A * A)3.iv�TED FOR RIGHT TURN Mi REC, "CAL05 S ?f"'=.:barn -, vr.r.. 2.35 Cir TJK c nd tion: PM PEAK SASFLINU 4P r . S ui'xJ iLHAMSRa kALLE'iRD Ai',HAi`PsPA AVE. £=~C county, Martine-, wt Due W503 T me MSM PEAK Pwk Hwr 445055 PM 'C€A MFIH01'? R I G HT lf4Z :EFT 4-PHASE SIGNAL STREET NAME: THRli 55Q _w_ 1.0 NO. i:i" LANE'S i. , -- 669 THRU ALHAMBM AVE. I ci. x((, v f ? . S 1,0 46 LEFT v `t ( SIG 11RKI'ANTS. w + E 232 r 27 ilrbwY. R=WI- .STREET NAME: A,�HAM.8--,AVAIA..EYRC- {)RIGINAIL AWUST ST ED V/c CRIWAL LEFT 0 3... 2:32 2 3650 0.1406 0.1406, 53 �'IG H i f'11 C, 0.171300 r., T P, A 1650 0.0000 0 1650 0.0000 r L. 0 1650 5.0000 000 IHR' i7, 559 550 1650 0.3388 LEFT M 1 1 1650 0.0006 0.0006 WS, i':I H (p) 0 0 1640 0.0000 Btu :E /669 669 1650.4055 0,4055 INIERSEXTION LEVEL DF SCRVIrCk Al INT-X,!.NT,VOL=PM6A3E,CAP- CTALCS Software Vii', 2,35 by IJKM ranspx3rtvtlon Cansui.tant,a �snC?t,iai.' AM MASE + PROJECTT51O9d03 1NTERS E"TION , AL,-iA BRA tAL.i.EYRu3RLHAM.BRA AVE.. ccc :;tUv.1"Y. 'Martinez blunt, Date 4/22/03 Time AM PEAK Peak 1-to r 7:15-8:15 AM --------------------------- CCTA ME'NOD RIGHT THRU l.W°.F 4-PHASE MNAL j v N LEFT C .._... 1A %I 1.1 1 T., - 0 RIGHT STREET NAME-. TNRii 558 _ 1.0 tNW OF LANES) 1.1<--- 409 THRID ALHAMBRA TWE. UcHT 314 1,0 1.0 0.0 1.i) 1,0 --- 70 LEFT N LTG it&RANTY W .- E 341 v 63 purl" ``; Ru- S 1.EFT THRU RIGS+T ."split'' N �TREEr CAME. ALHAM3PIWALLEYRw M��,._w•�. __:__�,m�.. ...._...._w�:�_�w��:�:���-..���:x�_�..:��� .��,�-.�..`��-..:mow: -.::����: €"iRI"GINA. ADJUSTED v11C CRITICAL MOVEMENT' "I11u mE VOt.L€ME' CAPA,,,ITY PATIO SIC Ns PIG€a-; (R) 63 0 1650 O.Gt300 LEFT '(..; 341 341 1650 0..2067 0.2067 $6 RIGHT OR) xa 0 1650 0.0000 0.0000 THRU T; 0 0 1650 0.0000 EFT t i} 30 0 1650 W DOOO T R 0 1650 0.0000 L 0 1650 0.0000 P + i,. 0 1650 0.00,00 EH RIGHT (R) 314 0 1650 0.0000 THRU (T) 5.8 358 1650 0.3382 13382 LEFT 's L7 t 0 1610 G'.Ilf1N WB RlChT" OR! 0 0 1650 0,0000 THRU CT 405 409 1650 0.2479 LEFT (i` 70 70 1650 10,0424 0.0424 3 y. R 409 1650 4.2479 TOTAL VO tiME ?O €-APA'CITY TIO: 0.59' INTEPSECT1O>, LEVEL OF SEWICE: A AWUSTE4 F4R RlGriT TURN ON RED _CT Al,08 Scif tw re ver, 45 by IJKM Transport aon :,C3n.S,.,.`:.7 C'ind i t}cn: PM BASE - K10,iECT t NT ERSEC I CN I filer';P''aaSPAV L.E_F.YrZi:it`AL_i.A,!•€BRA +iVj . CCC ,r.',ount.r`, Pls",T't"ie2 i� it r L EFF , --- x 41 L 1 i h 1 0 €I GGT 5`BEET NAME,. THRU 559 .._... �j I NO. OF LAN-.1,S)Si 1,l/--- V)9 1 H.RU Eli<Hji°✓RA AVE. R3GH, ._ l i.i! r , 0, 48,, LEPT V' N SIC, WARPANTS, w + E` 2M 0 28 IWWY, Rur=Y S LEFi THRUI RI',.—HT Spkit? N N�kMt: ALHAMEVVALLEY01 "P,lG"si3I, ANUSTED V% ' CRI 7 1 CA L EB (R) 324 88 1650 0.0533 M1.l bPU, sµ, .. 559 650 :7 :7388 LEFT W 1 , 1650 0.5006 0.000 ivu $Y L u 16 0.000 THMi (T! 669 W 1650 0,4055 044055 LEFT ILI 48 48 1650 0,0291 669 1650 MOP TOTA�. VOLUME—TO—CAPACITY RA1,10: 0.55 TNTERSC.2,1111 ON LEVEL 0, SERVICE* A * A0,JUSTEu FOR RIGHT 'TURN ON RED "CTALOS Soflware ve—, 2.35 by TJKM 'r'ansportation C-onsuLtan.a Condition: N'20 AM CUMULATIVE 05/09/03 ...�.t".xC�....'.."':'�'S^o...".��.x:!H'C12S".�5�*.CC.SY2�SS�IG'.2.k...A_.:T........ .......»...,.•�'tr�."^�^.YtYIC(E�T..S.S'CR^,.t.0 ...:.'t0.�tlC....»�'....'.w.`%T.: INTrRSECIION a .A HAMBRAVALLEYItC/AlLHAMBRA AVE. Cot County, Martmez I sten: Date* 4.122/03 T'mw AM PEAK Peak Hour 7,15•-8:15 /ado CCTA METHrD RIGHT THRU LEFT 4-PHASE SIGkAL I 0, RIGHT, f STREET NAME, THRU 670 > 1.0 iNC. OF LANES) 4„1z -- 491 THRU ALHAMBPA AVE. RlGwi 375, .... ?.0 1.0 C. I.0 1.0 Eos LEFT 4 V "3 j € SIG WAfPPAAIS: W r 402 C '74 Ur~ Y, Rur=Y LEFT `r€ft RIC34T Split? N ;STREE' NAME: AL'iAMBRAVAI. EYRD Cq�IG!Nk ADJUSTED Vic CRITICAL MOVEMENT VOLUME VziL ME* CAPACITY RATIO WC €'YB :RIGH11 IR) ,rip 16,50 0.0000 SE !NICHT (R) v v €£50 0.0'0i;0 i}.vf:uU THRU it 0 1,, 165 . 0.0000 E,"T €t_; 0? U 1650 0.0000 i + R u1650 0.0000 C 16 G 0.0000 + L 1650 0.0000 i.a 1<TGHT gR; 3'"s 165E 0.0 000 THRU €T,= f,70 1670; 1650, 0.4061 0.4061 L ;FT iL' C u 1650 010000 -------------------------------------------- WB PfGHT iR? C 0 1450 0.0000 `HKU (T) 491 49-1 16:0 IV.2976 i.F"F` L'. i$4 8; 1650 0.0 509 I,0509 + R 491 16,50 0.2976 "GTA€ VOLUME-TO-CAPACITY RATIO. I TcRSECTION UVEL 09 SERVICE; � I AIDIJUSTED FOR RIGHT TURN ON RED NT-:k,INT,VOl.=AMCUv.,CAP= CCTALO�, Software ver. 2.35 bv !JKM Transportation Cwd�d tion: 2020 PM C0 I A 3?`:. 1K!"Er5EcTi ON }3LHfaR#Fte.A AixEYR,,.nl..giAMBRA AVEE .r,;, 'fit nr''ir , _�,.. split? N LEFT E --- 1A 41 R ,. . 1.1 STREET NAME, y 803 d rA � HvR , . i _ RIHAiT 379 '__ .w l.e? `_../ I.cl 1.0 .. LEFT_ V SIG IWIARRANIS: STREEET NAME:: AHAMBRA AU EYRG N9 R <'?3 55 to G7v 0.0 100 LEFT (A 279 M 1650 C.1691 0.1691 s; RICH (tit D c I651D 010001 04.G-000 omo (C 1 0.L i L 16 50 0,ONIO 7 r 1655 0.Cie s of ES RIGHT :?; 3?,9 lco 1650 0.0606 THmi (7) 671 671 1650 0.4067 LEFT M 1 1 1650 0.0006 D.0006 W8 RIGH7 (R) C 0 1650 0.00011 TIM (T) 803 803 1650 0.4857 0,4867 LEE! QLQ 55 55 1650 0.0333 TOTAL VOLUPIE-10—CAPACITY 'h..,£C`„ Ener. T .,i LEVEL E c� SER,VICF. B IRT.. ac.0 Ivy€ � t ',"r: ,� A,JI,:tu FCOR RIGHT T1IRN CtsE..{; CHAPTER 17-AWSC-9. N IGNALIZED INTERSECTIONS WORKSHEET ET Analysis Summary E General Info tip Site Information Analyst (MIN _._.... . _ ��. Jurisdiction/Date CCC CO., Agency or company Cs`t N _�.._ _ . EB-wB street IFL_IEZ VALLEY RD. Analysis PerlodtYear PM EXISTING _. N8-S8 Street AIwlIA1BRA VAI-1-1`Y ISI'). Comment PM EXISTING C ON:I:)TIONS EB WB NB z8 Lune 1 Lase 2 Lar 1 Lame 2 Lane 1 Lane 2 Lane t Lane 2 _ .__ , w_.._._... .... _ Lane costa(Lane 1 is cuffs lase) I:,1, FR LR ............ ..i....._ 3, Leh-hsrrs '7Q 9(1 Voltsstse flartatagh J`f 3 (veWh) Right-tors! 98 74 Peak-hour factor '1 .9 ...-. ..._. %Heavy vehicles 3 1 ; , Outputs EB V4B NB S8 Lane 1 Law 2 i Lane 1 i Lane 2 Lam 1 Lane 2Lame 1 Lane 2 `IWI lame flour rate(YeWh) 141 I6R 182 __.. _.... ..._.._ _...._ ......... Departure headway,hd(s) Degree of utiilzatlsrs,x I4 3 I9 227 _w....m. ._...... ..... M Move-up time,In(s) 2 Service time,t () 2.fi:, 2.18 2.49 Capacity(vehlh) ?3' 82,5 i.. Delay(s)(Equation 17-55) B 8,2 �8 .t� r ��_� � } 2`A w Level of service(Exhibit 17 22) _ ;. _.. _..._.. ._v w.,. .. _., _ ..... ....� . �_..._ Delay(s),approach 8.7 21.2 _ 8.8 Level of service,approach A A Delay(s),intersection &6 Levet of service,intersection A _..__._ _........ ... .. ...... __ . ........ . .. . .. .. .... _..... _....,._. ------ .................... Hi AP 2000 TM 1 of 1 C1-at,lin a Engineering,lr..c- CHAPTER 17-AWS _UNSIGNALIZED INTERSECTIONS WORKSHEET Analysis Summary General Information Stte Rrstssr atlorr Analyst (AVN _ _ _. Tcarksrlick rt/I to t L M I Agency of CompanyCacti_�._._._ ........._.............w�.�.__.._w. ._... EB-WBSlteet FRELI ZVALL<1""� RD tinalysisPerkodiYear AM BASE- NO-S8Str�t I L�$�M8RA Al t E Y RD, Comment ......... ...... - r_.. ,._ ... _ ....,..,,.. _._. ..m...._ Input Data EB WB f SB Lane 1 Lane 2 , Lane 1 Lane 2Lane 1 Lane a Lane 1 Lane 2 Lime code(Lane 1 is curb tate) � � T L m _.. F m.. �. .. ., Left turn 125 100 _.� ._._ _..__ W;._ _._ volume _.:_- __.. ,__ (veh#h) Through 66 2� . . ._.___ ._..- F..... . Right-turn 111 80 Peak-hour Factor 9 <? Navy vehicles , , Output rB W8 F S41 Lane 1 Lane 2 Lane 1 Fane 2 ! Lane t Lane 2 Lane 1 Lane 2 To€al lane flava rake(vehlh) 212 1,56 2€0 Departure head"y,ha(S) 4.76 424 4,65 dlegreo of utilixati 28l -183 .251 _..,, _ _ ._._.... ... :..... .. 2 Move-up time,m(s) 2 1 _2 -, setvicetime.tv,(s) . �. 2.� G _._.._ ___._._ _.._.__._ _.. .. _.. Capacity{uektih) 727 805 ._.. ..._.......... w _ _.._... . ..... Delay(s)(Equation 17-65) 9,6 8") 93 Level of service(Exhibit 17-22) A r� A Delay{s),approach . 9,6 Level of service,approach A A .1 Delay(s),interwelivn9. Level of service,intersection A ......... ...... ............................................................................................................................................................................................................................................................................................................................ Analysis Summary General Inf+ i ticart Site Information _ .,.... ..... _. _,. _..._. __. .M . Aiaatyst G . ... 3tarlsdle r aitFate ((.,C. �,f), , I x _ !"9r 47 x.. _ _ _ __. _ Argency or Company GWS _._ �� _ _ E8.W8 Street ii.ELIEZ VA11EY Rl)3 Analysis PariodNear PM. SSE .... X1#3-SB Street AI..HAMBI£A VALL Y D. Comment Input Data LB W6 NS Six Lane 1 Lane 2 Lane 1 Line 2 Lame 1 Lane 2 ! Lane 1 '; Lane 2 Lane coda(Lane'1 is curb lane) I.,7 I R IA Left-turn 76 98 Volumeflir h 628 Right-turn .. 117 , . . x .... .: Peak-hour tactor '9 %Heavy vehicles .y i Outputs [a wu X113 S Lane 1 Lane 2 Lane 1 Lam 2 Lane I i Lane 2 Lane 1 Lane 2 Total lam flow rate(Vehfh) 1:5:3 183 199 Departure he eparttrete $yi h �(s) AA F1 4.215 A.....«........,...«.......y,.......,...P,....,.F....7.,...,,...-x�. � Degree of Wliaataon„x -------_._____._ Move-up time,m(s) ' _._ . __......_.............. ._..... Seruieetirne t (s) 2"r 1 2 2-57 capaciq OWN .,244 810 5 _ Delay ts)(Equation 37-55) `t `I 9A Level of service(Exhibit 17-22) A+ A A _ __.... ......_ �._ ..., Ww . . _.... . .. _... . __ _......... Delay 4s3,approach 9x.:1 Delay(s),intersect€on8•R Level of service,into section , _.._ _...._._..._._... _.__,._ _ _...._m....... ... IGAP 2000 EI3 ;'<,' E ,pneebrt< Inc,_ Analysis Summa Gesterol Information Site Information Analyst OWN � _ Jarlsdictia�r�TC?ate C:'C C (C) Ml AWcy or Company <1L N Cli_W8 s#reK 1 E L It'I VA.L.LEY RD. _._.._ ...._ .. Analysis periodlyear ANA.BASE I?ROJ N8-5B Street A HAML3RA VALLEY Y RD Comment _ __ ._..._w____.. ._.� _ _ ._. __.._ W_.._..._.,,__..._...._._. Input Data EB W8 No , { Lane 1 lame 2 Lane 1 Lane 2 Lane 3 - Lane 2 Lane 3 Lane Lana:rtmde(Larne 1 is curb lane) LT TR L. ... . ...:.. Lei#-1t�rra 3 E> 103 _._. . .._ . ... _..._ ... e#UsnQ 1lsrough k+ 29 (vets1h) .....M. _..__..... Right-turn 1 f 2 82 teak-botir factor %Heavy vehicles t Outputs EB WB NB Sly Lane 1 Lane 2 Lane 1 Lane 2Lane 1 lane 2 Lane t Lane 2 .............._....... __ __. .. natal tare flow rate(vehlh) _S 4 I": "06 ........................... Departure headway,hd(s) �. � �. S> 4aaC� DegrM Ot u61060",X Move-up time,ur(s} 2 _ __ Service Lane t (s) 2 2C' 2,6o Capacity(vehih) Delay(s)(Equation 17-55) ca " Level of service(Exhibit 17-22) f A A _. ._ . ._ ... ...... _ _.... ._.._. ._ Delay(s) approach Level of service,approach A ,� A _. _........ .. Deiav(s),intersection `) " Level of service,interseclior A HICAP 200 ¢0 IV ?of't CHAPTER 17»AWSC-UNSIGNALIZED INTERSECTIONS WORKSHEET i Analysis Summary Y General Information Site information _. ._ r _.. . ._.. .. __ ._._........... . ... ... Analyst GV durisdictsortlt}ata C {" ?. i�il� Agency or Comp GWN EO_W3 Street RELIEZ V A€]_E h1? Analysis Petiodlftw P s1 BASE r PROD _ � NEI-SB Sued ALHAN41 RA Vr1 C; EY RD.� Comment Input Nta _....._ _.. ... ___ ,_..._.w.:_............_,.._........_ ... _. :. W_ .. .. ..._. .... ................__. EO WS NO SO Lary 1 Larne 2 Lana 1 Lona 2 Lane 1 Lane 2 Lana 1 Larne 2 .. _ ............. _ _ m_ .._ s .......... .................. Larne code(Larva 1 is crura lane) LT TR 1,R ._...w Lett turn ......._. ...............;.- _._, -............................ _.......... Is l(}t) volume Through 62 58 Right-tum 1 I 82 Peak-hour factor 4 Q ..........._......._ .. . __..__ ..m„_ _ . .....,.... _ ,... .. . ..... ...... w.... Heavy vehicles 3 1 Output __.._....._ _...__.,_ _....: y _.:..:: .__ ..: ___.w_ :, w.._ Ii 1ff3 S8 Lane 1 Dane 2 Lana 1 Lana 2 Lime 1 Lam 2 Lane 1 j Lana 2 _.__ .. _ . .... ._._.� ..... ..., ............... Total large flow to fyWh) 156 187 202 ... ..... .. .. .... Departure headway,ha{sl 4d 8 4.26 41 3� ._. ..__w _...._.... . , w Degree of natninxatnor�x 2$16 221 25 __........._....,_ _ .._.._... ... _: _..__._ _..._. __. ._. _____.._..........._..._..___.r ........._ .. ..._._. Mova up tittle m(s) 2 1 ' Service fime,1,(s) 2.78 i 2'6 ? 8 ....... .. .....«.............:,.-- ...-......_ ..................................a ................. ...�.......,.,,.._.....,._..,.y... ......//��....: F........ _..........i .. - .-.... ....^Jq.. . ...... ...... ,p 721. 8VJ 1 3 ' £ 21 ,... capacity(vehfh) - ... ,_................d.... ..._ .... I ........_ ?..... _.......... ..................... . ...... x.,.. Delay(s) 17 55)(Equation 17-55) 8,S 9 2 .__. .............. __ ........ - .-... ...... .. Laval of service(Exhibit 17-22) A AA _ ...._� O,approach. ... . ... .. .... _........................._.......... ..._..... Delay s 9 8.5 9,2 ,r ............... .._ Leval of car ica.appta w._ A A A ;. .w_ ._ ....... _............... Belay(s),intersection8.9 Level of service,intersection ........ _,_. __.............................._..:..........._....._.............. ._ _.,_ .. ................._................_................__......_......._---------._._. Hi AP 2000 M 1 tat 1 +�irrtrllitlzl�f'lyir?C?F2{'tt€�,Iliz:;. ------ CHAPTER 17-AWSC-UNSIGNALIZED INTERSECTIONS WORKSHEET T analysist#mmary ....... _..,.... _. ... _._ _._.... .._ General information Site Infortstation rsatYstG `.._.__ _. iur{5ttrci#onf#3ate C .C. t ')., i T _ __..l r{ E, Agency or Company �L " EB_W Street lt1JFZ V�E I.]:., 141 Analysis Period/Year AM CUM _ NB-SB Stmt Al I I�'�BR� �A I. Y Ili) _ w.._ . ._ Comment 2020 MN11 input beat EB WB N8 SB Lane 1 Lane Lan 1 Lame tangy 1 L» Lane 7 Lase ti _..__.._. . ...................... _ Lane code(Laine'1 is curb lanae) [.,'#° "[R i.,I3 _._a___._.................. Left-turn t i' 139 _... Volume ' (veta#is) ,. Through.,..,.. 4 st # Right-turn 154 # c) ._.__.__._..._.,_.._.m,...._ ............ _ ._... ------------ Peak-hour .._._..__peak-hour Maw � 9 9 %Heavy vehicles , 3 Outputs ER W3NO a#i Lane 1 Lwe 2 Lane 1 Lane 2 tarsi l Lane Lane? Lzar 2 Total lane flow sate fvehlh) 296 Departure headway.hj(s) .#et .66 S.(a Degree Of wlitanon,z 42139 1 Move-up time,Tyr(a) ?. '2 Sof Vice time,k'(s) 3.13 �,.fifa � 0 M......._.............._.........._._._._ w.... .�. w, _:_�. p__. ........ Capacity(vehth) (i „' fes' X66 �,..._,..,.._ ...._...._..w_.,.._,............._. ._. .. .... .. !......_... _................ ...,.,..,._,_.. ....,_.r.,.. _.._.._ __.. _.. Delay(s)(Equation 17-55) i 1.n 9,; t(. ........_ ._ ._..,_... .. _.__... . . . Level of seruir ( x13Ebit 17-22j 13 A _......._ _ ..... Delay(s),approach 1 I. _.M .., #1. ...... - Level of service,approach BA 13 [Delay(s),Inter".Don t 1 Level of service,intersection la ............ ___........... ______ _._.___ _ ._.._.-. ....... ....... ......_._.. .... _._. _._ ___._. .: HICAP 2000 "'n s r ring"Inc _........................................................................................................................................................................................................................................................................................... ............................................................................................................................................................................................................................................................................................................................ CHAPTER 17-AWS -UNSIGNAMED INTERSECTIONS WORKSHEET Analysis Summary General fnf rmat(att Site,Information Analyst Cris N � Jurisdictionl0ale CCC CO, NM 12/03 Amy or Company E %,Es-%,B sntg RELIEZ.VAUEY C2t3. Analysis Perirs€31Year PM {`t Ne-SB Street AUTAIMBRA 4`< 1 t 1 ,1 . Comment' 21120 PM Input Data EN wa Ne SB Lane 1 taste 2 Lane 1 Lane 2 lanae 1 Lane 2 Lane I Lang*2 ........ _. ..,... ........... ............... .......... .. ................ .. .......... ...:......: ... .. ..q... ....... ... .. .. .......... Lane code(Lame t is curb larw) T Lx Lets=#arra 106 136 ............ ...... _ _............_.... Volume B Through— - . 80 Right-turn 148 117 teak-hour factor .9 9 9 _w_. __......, .. ,.........a.. .. . ...._...; ..... [ ..y,, _ %Heavy vehicift ....- ..,. ,m Outputs ED IND NES S Lana'l Lane 2 Lane 1 Lane 2 Lane 1 Larne 2 Lane 1 Lane 2 Tow[lane flow sate(vehltt) 213 253 T16 Departure headway-1 ha(s) 5,1} i _ 6 4.93 a Degree of attttatatatln x 304 X24 .373 _ ........ Move-up tittle,ass(s) ? 2 Sevic.. ._.. __ _... -.,_._ ...... ... Capacity(vehth) 6677 747 687 Way(s)(Equation 17-55) 10.4 9.8 10.9 ...:._. .. Levet of service(Exhihit 17-22 f31 13 May(s),approach ... £ 100 9.8 1€k9 _,..._... _.............._.__.� ... ... __........_. _ _..�._1__,............._.,.. __.................._.....__ Lent of servim approach ! 13 A 13 Delay(s),intersection 1 D.4 _ ........... _._. ....................__...a_,._..., _w_ Level of service mtersecttaors f1 HICAP 2000.rt,' i of 1 ,DC atr iini,,s.nciinle:;ring Inc, CHAPTER 17»TWSC r UNSIGNALIZED INTERSECTIONS itYORKSHEET Analysis Summary .. _ e General Information Site Information Analyst txWltarrsdictiantllatc L t 1 f_— _._....._. al Agency or Company OWN � Major'weet .1I$dAMB A.VAI 3_EY ROAD Analysis Analysis Fa±rSodlYear ANI_SITE ACCESS ... ..... IVliaror Street 5IT A( ESS Comment AM,Sl l t?r�C`� (s`i`p ._.�.w...._.___�_......_. ___._...._..�..__._ ...._.. ..., Input Data Lane Configuration (3 SB WB E13 _._ _....._. ._. .............. __ .... Lade 1(curbs L:l TR �_._.. .. _. . ___.� . :_._-.._ .... .....� Lane 2 e 3 _.._ ..;_ ..... __ X13 SB `T Ell _ _ Movement 1 (U) : 2(RI) 3(RT) 4(U) 5(TH) `:6(RT) ;(La) 8(TW 8(R1') 10(L-f)i 11(TH)=12(RI3 Volume(veh;h) 2 237 180 2 8a _ . _ __. Proportion of heavy vehicles.Har 3 3 � � . .. Fla*rate 2 2fi3 . :00 9 6 �.... _�__...,.. .... _----- Flan storage(4 of vehs) i> 0 Mian storage(0 of vehs) it Signal upstrearn of Movement t _ - - P: Movement 5 Length of study period(h) Output Data ...... .. �..... Lane'.Movement Flow Rate Capacity vtc Queue Length Control Delay ; LOS Approact=, ._. (vehth) w ,...._(velvh) .. . NOW ... ts) . .>.. ...._ €3 ya Loi i , W 2 ,.._.... ..... 3 1 l,it. fi _ f307 <I c,3' .3 A 1364 JAU 1 T6 Of I HICAP 2000 ;4t lEr Ft 3t ,.ri ..t inn, _ _. .. Analysis Summary General Information Site Information ..........._............ _......._ Analyst "�' lurisdis lonlF►i CCC,CC'). NITZ `l a _ . Agenic or Company GWN Major Street Al iJAM RA V AI CESS lei.) D ......_.. ._ .._.. Analysis PetiodlYear PNI S IT A CCF. s W Minter Street ;"317'E ACCESS Comment PM BASE.?-PRO1 lriput tate Lane Configuration NBsI W, EB iane`!(curia) l,�' 7"Ry�IWEi _ _ . _................... Leve 2 Lane 3 NB .� W.8 _ ..� _ _.EB. ......, Movement 1(U) z rg) 3(RT) 4(U) 16(TH) s ( t) 8(TH) 10 SLA (a ) 2( w w» ( Volurne(t atitil) S 1 i 8) 1,19 to 3 is PHF ,9 1 .9 9 9 .9 1 ,9 Proportion of heavy'±ehicles,HV ' 3 3 t a � 3 3 Flat ate 6 1403 199 1I t fi 3 W._._.- ..... ... .., _,.,... _. .... Flare sage( of velis fJ Median storage(4 Of hs) ; () i Signal upstmant of Movement 2 �_it Msiverri ret S Lenp of study prod } _ Ctttip+ot Det;k, Lane'Movement Flowl?ate Capacity Vic I Queue Length Control Clay , LOS Approach (Vwh (V `h) 5veh1 _._...,__......_.... ._._..._ _ ..mwOe y and LOS.,! _._w _. ..... ........_. i w B 2 _ » _.._...... _... ........ .._,..-_... ........, . I LR 3 834 .t?isgi9.3 �3 3 I '� .... .. Iwo _m T' a 13.E Qty t s .A 4, :...,.....« r.�,.........w....... .......,.....,_......::........ ... .........„....n...........,«... ....,..,............................,,....., ..,.......,......._u.w.«.,..i....,�»�»., - �............._.............. ....,..........i FlICAP 2000 rv: I of 1 9-14 TRAFFIC SIGNALS AND LIGHTING TtSfffc Manuw Fits ' PEAK HOUR VOLUME WARRANT (Urban Areas) 0 2 OR MORE LAN ( OR)& 2 OR MolqE 2 OR MORE LAN '500 OR 1,LANE &20RMo LANES( NOR s 400 � cr 300 200 x 1091 , LANE(MAJOR) I LANE(MINOR) 500 600 7 1100 1240 1300 1400 1500 1600 1700 1800 0MAJOR STREET-TOTAL OF BOTH APPROACHES-Vpm 150 VPH APPUES AS T14E LOWER THRESHOLD VOWME FOR A MINOR STREET APPROA i R MORE LAN ANO 100 AP AS THE LOWER TNR,,,,L VOLUMEFOR A MfNOR .STREET ............................................................................................................................................................................................................................................................................................................................ CHAPTER 17-AidlfSC-UNSIGNALIZED INTERSECTIONS WORK HEFT !Analysis Summary taerai lrrt rtn tlaara Site fnfonnatix _. .... _..__. _ ,.... ,_.. w. _ „ . ... Analyst trWN Jurisdictiont#1ate 4i".903 Agency cir Company OWN _. Ec3-VS8 Sited RELIEZ VALLEY RD. _ .Analysis PetiodlYear kI'EX113T°I 0 t4B.S8 Street A1J-LAM,B t,'%VALLEY RD, comment Ali. .XISTIN ��JI DITIONS .. _. Input data M::.�. .::.:.. _....:. ... . E8Wa ? NBS8 r Lane 1H µf:ane 2 ane 1 .Lame 2 ! Lame 12 Lana 2 Lane 1 Lane 1 Latae core(Lanae 1 is cairn lane) LT 1 It Lit . LeA taros 1 l S 92 61 Throu h 27 w....._ ..........:.:.. _... Kiat-turas s 102 73 _ _ _,._._... . ._ ... .... . ......_. _ _._.... Peak-hour factor 9 d1 _.......... ............ . Heavy vehicles j Output .............. ...., _» ,,r_ m.._ E gN8 S8 Lane 1 Lane 2 lane 1 Lane 2 I Lane 2 Lana 1 Lane 2 ....................... . w _. Totaf lana flue rate vWh 1 T X143 i � 183 ., Departure headway,lad(s) 4,77 1 4 7 _. . :... ........ _. .. .._. _ b Degree €utilization,x ZS3 (o5ta ? .23s _._g_ee �ulnas i , Move-up tune,In(s) 2 1 2 f ' Service time t (5) 2.7 2.l r 21,59 Capacity(Vewh) 71-9 74' .. _..�.. 1. 1L _ Delay(s)(Equation 17.Sa) c3 s 3 .... Level of servim(Exhibit 17»22) A A .: 93 . ...Delay r Level of service,approar�a A A � � A ........... ... ..._.. Delay(s),intersections . Level of service,intersection A HICAP 2000 10l 1 :...... :RC1 h. As stated in tl3a. Al}launbraa Valley Specific Plan Q `91 all d vc1opprie:.,l t aappl c ants uau . comply, itJl the provisions and peyheie s comatled in Cl1?1"• er 8 of the Amy General X l 14mi 1 i'It3 1i1; that "All development :applicado s wt ich imiudlc a portion o a L`;iveali. Whin the sic, shall he rc;eltaared to provicle, as part of"the clevelopinei'a application s€brni.taj. a C'r-6, Preservation and Enhancement Plan,' This Specific Plaa3 does not allow the creek setback arca. U) he Nc luded A any c;:arh:,d at:;; n. *406 de~te":rr3 hes a ,°fia't's net 'parcel size. or for rT ee'l.ing, 1I31.r11IT?um lot sJze ,sta.ridlc` rds for rang im�i c aii allr>' plal:rairtcd ela signation, The.Applic;ant has provided cross sections&A-roji)Dol l ariabre i.,re ek:und lavas stated that tzl.,y�;vi l not encroach into the creek(they will enter only to remo e;debris). (. rcok cn.c:roaac hn'lent is pi<<pose d 15'.°i Alha;,lrKa.Y... eek at the storm drainage outfall, ?. Result in the; loss of availability ol'al kz3own.113ineral resoarme tlla3t would be o'v{llue to the region and the residents of the stat.&?(Soum.W 1, `?, 3, 4 & 5) b. Result in the loss of availability of h.,acaally-lnrpor-tarit mineral resource recovery site: delineated on to local general Maar, specific plan or other land use plan? (Source w 1, "' 3, 4 & 5) a, & h, 1\laeT'e are no impacts to mineral S'esot,lrces sternI'Y ing fTd:3:rn the -proposed sed Baal divis#on ,`;2'id Xl. NOISE - Would the proj ct result in: 11. Exposure of persons to or generation of X _ .. noise levels in excess of standards established in the local geinerai plan or noise ordinance, or applicable: standards of other as{J,„encic;s' (Source 4 1. ' w, 4 & 5) 6:REPORT PREPARATION Robert Carr Visual Resources Specialist Eric Wohlgemuth Archaeologist and Archaeobotanist, Far Western Anthropological Research Group, Inc. Will Hopkins, PhD Senior Engineering Geologist, Questa Engineering Corporation Sydney Temple Senior Engineering Hydrologist, Questa Engineering Corporation Kelly White Environmental Scientist, Questa Engineering Corporation George Nickelson Traffic Engineer 6.1 Agencies and Persons Contacted The Community Development Department submitted a copy of this Draft EIR to the following agencies and organizations: Alhambra Valley Improvement Association Say Area Air Quality Management District California Air Resources Board California Department of Conservation California Department of Fish and Game Region 3 California Historical Resources Information System California State Clearinghouse Central Contra Costa Sanitary District City of Martinez Contra Costa County Biologist Contra Costa County Building Inspection Contra Costa County Geologist Contra Costa County Community Development Director Contra Costa County Flood Control District Contra Costa County Health Services Department, Environmental Health Division Contra Costa County Health Services Department, Hazardous Material Division Contra Costa County LAFCO Contra Costa County Public Works Department, Engineering and Traffic Division Contra Costa County Public Works®Special Districts Contra Costa County Sheriff Office,Administration and Community Services Delta Protection Commission Department of Food and Agriculture Department of Toxic and Substances Control 6-2 Alhambra Valley Estates Draft EIR March 2004 3: ENVIRONMENTAL IMPACT ANALYSES Figure 3.12-1: Existing Volumes AM and (PM) Peak Hour AL kfaRA Ave Signalized Intersection 0 (0) 6 cs 0 0 •a 391 (040) 57 (44) (535) 534 , > (302) 299 1 Stop Sign Controlled 2 c7 4 102 (9 ) i (53) (70) 115 ( 7) 1 REL,IEZ V LES' RD, MAP NOT TO SCALE April 25, 2003 AM Peak—7:15 AM —8:15 AM PM Peak--4:45 PM —5:45 PM SOURCE:George Nickelson 2003 3-90. Alhambra Valley Estates©raft EIR March 2004 3: ENVIRONMENTAL IMPACT"ANALYSES Thresholds of Significance The CEQA Guidelines state that the exposure of people or structures to major geological hazards is considered a significant adverse impact. The potential geologic, soils, and seismic effects of the proposed project can be considered from two points of view: (1) construction impacts; and, (2) geologic hazards to people or structures. The basic criterion applied to the analysis of construction impacts is whether construction of the project would create unstable geologic conditions that would last beyond the short-term construction period. The analysis of geological hazards is based on the degree to which the site geology could produce hazards to people or structures from earthquakes, ground shaking, ground movement,fault rupture, or other geologic hazards, features or events. The following thresholds of significance are used to determine the level of impact to areas of potential environmental concern. The project wouldhave a significant effect if it would: • Expose people or structures to potential substantial adverse effects, including risk of loss, injury,or death involving rupture of a known earthquake fault,strong seismic ground shaking, seismic-related ground failure, including liquefaction,or landslides i Result in substantial soil erosion or the loss of topsoil • Expose people or structures to a geologic unit or soil that is unstable, or would become unstable as a result of the project, and would result in on-or off-site landslide, lateral spreading, subsidence,liquefaction,or collapse • Expose people or structures to soils characterized by high shrink-swell potential and which would have the potential for expansion and/or settlement Impacts and Mitigation Although projects can have impacts on the local geologic environment through induced slope instability and soil erosion, most projects do not affect the regional geologic environment. However, projects can be affected by regional and area wide geologic conditions. Many seismic events, particularly large magnitude earthquakes, are felt regionally. Injury; damages and property loss tend to occur along and near linear earthquake fault zones of regional extent and in areas of soil and geologic conditions susceptible to high amplitude ground motion, settlement, or instability. Most seismic experts agree that for planning and project evaluation purposes, a large, damaging earthquake event should be anticipated to occur within the design life of all projects in the San Francisco Bay Area. Regional and local geologic impacts that could significantly impact the project will primarily be damages to the infrastructure (utilities, roads, etc.). Potential Impact 3.6-1: Surface fault rupture There are no faults zoned as active by the State of California Geological Survey that cross the project site. An unnamed fault has been mapped crossing the project site, but is shown on regional geologic maps as concealed by Quaternary sediments that blanket the site. The Southampton fault, as mapped by Dibblee (1980), crosses 200 feet west of the site. The State of California Geological Survey has not zoned either fault as active (CDMG, 21300). An investigation of a possible fault on the subject property was performed by Purcell Rhoades and Associates (PRA 2003). After that investigation PRA concluded that a continuous sequence of sediments in the near surface show no evidence of having been cut by surface fault rupture. However, borehole data suggest the possibility of a fault beneath the surface sediments. PRA interprets the subsurface data as a possible bedrock fault or contact between geologic units. In a peer review of the PRA report, Darwin Myers Associates recommends additional study to verify the 3-54. Alhambra Valley Estates Draft E1R March 2004 3:ENVIRONMENTAL IMPACT ANALYSES Figure 3.1-8: Alhambra Valley Estates—Proposed Gateway Treatment Detail as * 3 I L-i a ?YAC} G°+ v7' .""!n: As..n Hf" wl ETMA SOURCE: P/A Design Resources, Inc.2003 Figure 3.1-9: Proposed Landscape Design at Alhambra Valley Read I w_ � . SOURCE:P/A Design Resources, Inc. 3-24. Alhambra Valley Estates Draft EIR March 2004