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HomeMy WebLinkAboutMINUTES - 10222002 - C1 TO: BOARD OF SUPERVISORS FROM: MAURICE M. SHIU, PUBLIC WORDS DIRECTOR DATE: October 22, 2002 SUBJECT: ADOPT the Strentzel Lane Sediment Reduction project Negative Declaration in compliance with.the California Environmental Quality Act;APPROVE the project; and AUTHORIZE the Public Works Director to advertise the project, Martinez area. [CDD-CP#02-67] (District II) Project No. 7505- 6F8476 Specific Request(s) or Recommendation(s) & Background &Justification L RECOMMENDED ACTION: FIND, on the basis of the initial study and all comments received,that there is no substantial evidence that the project will have a significant effect on the environment, and ADOPT the Negative Declaration in compliance with the California Environmental Quality Act, (the custodian of which is the Public Works Director who is located at 255 Glacier Drive,Martinez), and APPROVE the Strentzel Lane Sediment Reduction Project, and Con 'nued on Attachment. X SIGNATURE: � � � � � L4, COMMENDATION OF COUNTY ADMINISTRATOR RXCOMMENDATTON OF BOARD COMMITTEE __ PROVE �--� .OTHER SIGNATURES) `~. .tom: ACTION OF BOAkD CIN £ 0$E 9 APPROVED AS RECOMMENDED_xOTHER r�r VOTE OF SUPERVISORS x x UNANIMOUS(ABSENT ) AYES: NOES: ABSENT: ABSTAIN: I hereby certify that this is a true and correct copy of an CS:sr action taken and entered on the minutes of the Board of G:\GrlsData\En�Svc1�:NVIR01BC3\2{?02\{10-22-02)CEQA-Strentzel T n.doc Supervisors on the date shown. Orig.Div:Public Works(Environmental) Contact: Cece Sellgren,Phone(925)313-2296 ATTESTED: OCTOBER 2 22002 cc: Administrator-Atte: E.Kuevor Auditor-Controller JOHN'SWEETEN,Clerk of the Board of Supervisors Cornniunity Development—K.Piona and County Administrator Public Works: Accounting Construction-R.Bruno K2 Design-B.Fernandez By f' r w ,Deputy Flood Control—K.Etnigh Engineering services -T.Torres,Enviro SUBJECT: ADOPT the Strentzel Lane Sediment Reduction project Negative Declaration in compliance with the California Environmental Quality Act;APPROVE the project, and AUTHORIZE the Public Works Director to advertise the project, Martinez area. [CDD-CP#02`67] (District II)Project No. 7505- 6F8476 DATE. October 22, 2002 PAGE. 2 RECOMMENDED ACTION(continued). AUTHORIZE the Public Works Director to ADVERTISE the project at his discretion, and DIRECT the Director of Community Development to file a Notice of Determination, and AUTHORIZE the Public Works Director to arrange for payment of a$25 fee to Community Development for processing, a $25 fee to the County Clerk for filing the Notice of Determination, and a $1,250 for California Department of Fish and Game fees. II. FINANCIAL IMPACT. The estimated project cost is$360,000 funded by State Water Resources Control Board(47%),County Road funds (33%),National Park Service (20%). III. REASONS FOR RECOMMENDATIONMA+CKGROUND: The project proposes to restore the tributary channel, construct grassy swales for sediment deposition, enhance existing and construct new drainage facilities, and restore a channel connection with the Creek to alleviate flooding and sediment deposition. It is needed in order to reduce sediment loads from an unnamed, ephemeral tributary and convey tributary flows safely through the Strentzel Lane neighborhood to Alhambra Creek. The prof ect has been determined to be in compliance with the County General Plan and the City ofMartinez General Plan. A Negative Declaration of environmental significance pertaining to this project was published on September 5, 2002. The Board has considered the Negative Declaration together with all comments received during the public review period. IV. CONSEOUENCES OF NEGATIVE ACTION: Delay in approving the project will result in a delay of design and construction and may j eopardize funding. .. E:cEn , C AUG 2 12002 Environmental Checklist Form NVIROi>I L!v L 1. Project Title: Strentzel Lane Erosion and Sediment Reduction Project 2. Lead Agency Name and Address: Contra Costa County Community Development Department 651 Pine Street,North Wing- 4th Floor Martinez, CA 94553 3. Contact Person and Phone Number: Cece Sellgren(925) 313-2296 4. Project Location: The Strentzel Lane project is on National Park Service (NPS), Contra Costa County (County) and private lands in central Contra Costa County near the City of Martinez 5> Project Sponsor's Name/Address: Contra Costa County Public Works Department 6. General Plan Designation: Public and Residential 7. Zoning: Public/Open space and Residential 8. Description of Project: Project Goals The goals of the Strentzel Lane Project are to reduce sediment loads from an unnamed, ephemeral tributary and convey tributary flows safely through the Strentzel Lane neighborhood to Alhambra Creek. Over the past three decades, this tributary, despite its relatively small size, has periodically flooded and/or deposited significant sediment loads into this neighborhood. Flooding and sediment deposition are at least partially the result of past agricultural practices in the area that have modified the tributaries sediment carrying capacity and eliminated the historic connection with Alhambra Creek. The project proposes to restore the tributary channel, construct grassy swales for sediment deposition,enhance existing and construct new drainage facilities,and restore a channel connection with the Creek to alleviate flooding and sediment deposition.. This project is sponsored by the Friends of Alhambra Creep,a local non-profit group,and will be undertaken in cooperation with the QTS National Park Service(NPS),which owns much of the tributary watershed,and the Contra Costa County Public Works Department(PWD), which will design; construct and maintain the project. Location The Strentzel Lane project is located on National Parr Service(NPS),Contra Costa County(County) and private lands in central Contra Costa County near the City of Martinez (Figures 1 fir, 2). The project site, which is a relatively narrow corridor alongside the tributary, is bisected by Alhambra Valley Road,and runs from the upper reach near the Strain Ranch on NPS land about 1500 ft east to Alhambra Creek adjacent to John. Muir's grave-site (Figure 3). The site is approximately three- quarters of a mile south of Highway 4 and is located in Township 2 north, Range 3 west on the Eriones Malley and Walnut Creek USGS 7.5 minute Quadrangles. No section number is given as the site is within Valle de San Tose, a Mission period land grant. Site Description The project site is the area alongside the tributary from its upstream end at the Strain Ranch to a proposed terminus at Alhambra Creek,a distance of about 1500 feet and a total area of about S acres. At the upstream(western) end of the project site,the unnamed tributary leaves the hills associated with Mt.Wanda and enters an eroded ditch,which marks the western edge of the project site. This ditch appears to have been constructed by the local ranchers;the ditch and the adjacent area of fill(a large and broad, levee-like berm)protect the Strain Ranch, a cluster of farm and outbuildings,from flooding. The Strain Ranch and environs are owned by the NPS while the watershed is subject to Moth NPS and private ownership. The ditch then drops into a moderately sloped, formerly grazed pasture where the flow alternately spreads across the pasture or is captured by actively eroding channels on either side of the pasture. Once the flow reaches Alhambra Valley Road,it is captured within a roadside drainage ditch on the west side of the Road and then flows into an existing culvert where it crosses underneath the Road. The culvert underneath the Road leads into a cement-lined ditch,which empties into an earthen ditch from Strentzel Lane lined with broken concrete and other debris.This ditch is then joined by another small earthen ditch as they both curve north towards Sheridan Lane.The combined ditch then ends, which forces flood flows and sediment loads onto Sheridan Lane. The project site continues to the east onto another NPS parcel that contains both an historic pear orchard of John Muir's father in-law as well as the grave of John Muir and his family,which sits adjacent to Alhambra Creek. Project Description The proposed project will restore the tributary's channel,reduce erosion and sedimentation,enhance existing and construct additional drainage facilities, and restore a connection to Alhambra Creek. Work will occur on both public right of way and private property;the property owners are donating easements over the private property to the county. Beginning at the upstream(western) end of the site,west of Alhambra Valley Road, a meandering channel will be restored in the pasture on NPS property that will reflect naturally occurring stream channels in the region. It will be approximately 250 feet long and designed to transport sediment efficiently through the pasture,thereby reducing the sediment eroded from this area and deposited in the neighborhood.The channel and adjacent pasture will be revegetated with native grassland and/or riparian species.The channel will terminate in a grassy swale constructed adjacent to, and just west of, Alhambra Valley Road. The swale will be approximately 100 feet long and will act to capture sediment flowing from the watershed. Approximately 200 to 300 cubic yards (CY) of soil will be generated from the construction of meandering channel and the swale. Much of this soil will be used on-site for the construction of berms protecting the adjacent property to the north and the corrals to the south;however,some portion will be trucked from the site.No native or non:-native trees will be impacted in this reach of the proposed project. At the downstream end of this Swale, flows will be channeled into a new 54"reinforced concrete pipe (RCP) which will convey flows bath east into the existing 24"pipe under Alhambra Valley Road and north into a new 48"RCP pipe running along the west side of the road. The existing 24"culvert underneath Alhambra Valley Road flows into a 3-foot wide concrete lined ditch approximately 250 long. Flows will continue to use this ditch but will then flow into an improved grassy Swale approximately 20 feet in width, 3.5 feet in depth,with a bed 6 feet in width (Line D on Figure 3). This Swale replaces the existing, debris-lined ditch and will run for 235 feet before entering into a 36" RCP pipe. Construction of these features will require the removal of approximately 500 cubic yards of soil but would not result in the removal of any trees. This soil would be removed from the project site. As noted above, at the downstream terminus of the grassy Swale in the l�'PS land, flows will be channeled into both the existing 24" pipe under Alhambra Valley Road (with results described above)and north into a new 48"RCP pipe running along the west side of the road.This culvert(Line C on Figure 3)runs along the west side of the road under the shoulder for approximately 190 feet. Approximately 600 cubic yards of material will be generated from the installation of this culvert. This material will be removed from the project site. At the intersection of Alhambra Valley Road and Strentzel Land,the 48"pipe will turn 90 degrees and run east under Alhambra Valley Road approximately 100 feet and into a grassy swale alongside Strentzel Lane. This grassy Swale will be approximately 20 feet wide,3.5 feet deep and run for 235 feet. Construction of the swale will require shifting the paved portion of Strentzel Lame south approximately 3 - 6 ft. The downstream end of this swale will enter into a 48" RCP pipe approximately 50 feet in length. Approximately 510 cubic yards of material will be generated from the excavation required in construction of the grassy swale and culvert along Strentzel Lane. This soil will be removed from the site. All disturbed areas will be treated with biotechnical slope protection and/or other erosion control measures. At the terminus of Strentzel Lane,the 36"pipe from the south(Line D) and the 48"pipe from the west(Line C)will join in a 60"pipe and flow north for about 225 feet(Line B on Figure 3). At the terminus of Line B,the pipe turns 90 degrees east and flows approximately 350 feet before outfalling via a hardened, energy dissipating structure into Alhambra Creek (Line A on Figure 3). The structure will include the culvert outfall and attendant bank stabilization features. The area around. the outfall will be hydroseeded and/or planted with native plants to control bank.erosion. The construction of the outfall into Alhambra Creek will require an Army Corps of Engineers Nationwide Permit (NWT's 7 and 33), Regional Water Quality Control Board Section 401 certification or Waiver of Certification,and a Department of Fish and Game Section 1601 Streambed Alteration Agreement. The County will apply for these permits and will comply with all the conditions negotiated for the permits. Ownership The project site is on NIPS land, county right-of—way, and private propertysteal property transactions will occur throughout the project area to acquire any needed rights of way or similar instruments in support of these activities. 9. Surrounding Land Uses and Setting: Land around the upper reach of the project site is open space owned by NPS and residential land owned private landowners.sands around the lower reach consist of existing residential neighborhood. 10. Other public agencies whose approval is required (e.g., permits, financing approval, or participation agreement). U.S. Army Corps of Engineers Nationwide 7 and 33 Permits, Regional Water Quality Control Board Porter-Cologne Section 401 Certification or Waiver of Water Quality Certification, and California Department of Fish and Game Streambed Alteration Agreement. ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED: The environmental factors checked below would be potentially affected by this project,involving at least one impact that is a "Potentially Significant Impact" as indicated by the checklist on the following pages. _ sand Use and Planning Transportation/ — Public Services Population&Housing Circulation — Utilities & Service Geological Problems — Biological Resources Systems Water — Energy & Mineral — Aesthetics Air Quality Resources Cultural Resources ® Mandatory Findings _ Hazards _ Recreation of Significance _ Noise X No Significant Impacts identified S DETERMINATION On the basis of this initial evaluation: I find that the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION will be prepared. I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because the mitigation measures described on an attached sheet have been added to the project. A MITIGATED NEGATIVE DECLARATION will be prepared. I find that the proposed project MAY have a significant effect on the environment, and an ENVIRON ENNTAL IMPACT REPORT is required. I find that the proposed project MAY have a significant effect(s)on the environment,but at least one effect (1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and(2)has been addressed by mitigation measures based on the earlier analysis as described on attached sheets, if the effect is a "potentially significant impact" or "potentially significant unless mitigated." An ENVIRONMENTAL IMPACT REPORT is required,but it must analyze only the effects that remain to be addressed. I find that although the proposed project could have a significant effect on the environment, there WILL NOT be a significant effect in this case because all potentially significant effects (a)have been analyzed adequately in an earlier EIR pursuant to applicable standards and(b) have been avoided or mitigated pursuant to that earlier EIR,including revisions or mitigation measures that are imposed upon the proposed project. 10<1a� r Signature Date 0401 6ass. CCC Community Development Department Printed Name For 6 SOURCES In the process of preparing the Checklist and conducting the evaluation, the following references (which are available for review at the Contra Costa County Community Development Department, 651 Pine Street 5th Floor-North Wing, 'Martinez)were consulted: 1. Contra Costa Resource Mapping System-Quad Sheet Panels for Briones Valley and Benicia Quadrangles, CA 2. The(Reconsolidated) County General Plan(July 1996) and Draft EIR on the General Plan (September 1990) 3. Contra.Costa County Important Farmland Map 1998,California Department of Conservation Division of Land Resources Protection, 1999 4. Field reviews and/or Project Description(including coordination with Design Engineer) 5. Soil Survey of Contra Costa County,USDA, Soil Conservation Service, 9/77 6. Contra Costa County Flood Insurance Rate Zone Information Map 7. National Parr Service,General Management Plan and Environmental Assessment,John Muir National Historic Site, 2/91. 8. National Park Service, Martinez Adobe Historic Structure Report, 8/92. 9. Northwest Information System, letter to Mr. Earl Crosby(CCCounty), 6/ 8/2000. 10. California Natural Diversity Data Base, source report for Briones Valley and Walnut Creek quadrangles, 2/2002. 11. US Fish and Wildlife Service, letter to Mr. Earl Crosby(CCCounty), 5/24/2000. 12. Zentner and Zentner, Strentzel Lane Section 404 Jurisdictional Delineation, 9/6/2001. 13. Urban Creeks Council, Draft report on Stain Ranch Channel Design., 12/01. 14, National Park Service,Watershed Condition Assessment of Sub-drainage Zone 1167,2000. EVALUATION' OF ENVIRONMENTAL IMPACTS: Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Tmact Inco oration impact impact I. AESTHETICS. Would the proposal: a. Have a substantial adverse effect on aX scenic vista? (Source#1,2,4) — — �_ — b. Substantially damage scenic resources, — — X — including,but not limited to,trees,rock outcroppings, and historic buildings within a state scenic highway?(Source#1,2,4) C. Substantially degrade the existing — — X — visual character or quality of the site and its surroundings? (Source#1,2,4) d. Create a new source of substantial.light — — __�_ X 7 or glare which would adversely affect day or nighttime views in the area? Source#4) SUMMARY; The project will impact aesthetics in three areas:construction of a restored channel in an existing horse pasture; removal of trees along Alhambra Valley Road and elsewhere; and construction of a stormwater outfall at Alhambra Creep. The project site west of Alhambra Valley Road consists of a horse pasture in a relatively flat valley with attendant corrals and buildings of the Strain Ranch on the south side of the pasture.The pasture is readily visible from the Road; local hills appear to surround the pasture and emphasize its open character,However,the pasture is crossed by erosion scars and often overrun with tall weeds,such as thistle,which are unattractive. The preferred project will restore a meandering channel through the pasture and revegetate the channel and the pasture with native riparian species. A low berm, also revegetated with grassland species,will be built on the south side of the pasture to protect the Ranch outbuildings. A grassy Swale will be built along the west edge of the road and this will result in the greatest aesthetic impact, as the Swale will be adjacent to the road and readily visible. Although excavation will result in open channel and swale construction,revegetation with grassland species will hide the earthwork relatively quickly.Given the relatively flat topography,only a portion of the excavated area would be visible tom the road.Similarly,the low mound built along the Ranch outbuildings will tend to blend into the adjacent grasslands.Accordingly,this portion of the project should have only minor and temporary aesthetic impact. The loss of mature trees along the Road will have an aesthetic impact.Construction of the culvert at Line C will result in the loss of up to 15 trees of heaven(Ailanthus altisima)with diameter at breast height(dbh)between 9"and 3". These are invasive exotic trees that are actively removed by NTS, however, and their removal will reduce the potential for further spread of this species. Cather trees that are within the potential work area and that may be affected through excavation within the root zone, partial loss of their canopy, or other factors include one walnut (Juglans californica; dbh 8"), two buckeyes (Aesculus californica; dbh 30", 24"), five bays (Umbellularia califbrnica; dbh 1"to 6") and four Osage oranges (Maclura pomifera; dbh 12"to 30"). Several of these are large and/or native trees and their loss would present an aesthetic impact. Construction will not necessarily remove these trees but potential impacts to the root systems are possible. Accordingly, the Contractor shall be instructed to ensure that all sheared roots are trimmed cleanly and that any roots over 6"in diameter that cannot be avoided shall be wrapped in wet burlap after trimming. Construction of the grassy swaie and culvert along Strentzel Lane(Line B,western reach)will result in the removal of approximately two trees ofheaven(dbh 3"and 4"). These are relatively small and, as noted above, invasive exotics that would be removed at some time. The construction of this Swale may also affect thirteen large redwood trees (Sequoia sempervirens; dbh 6" to 30") and one large spruce (Picea sp.; dbh 24") through excavation into the root zone, partial canopy loss or other factors once the work area is specifically defined. Accordingly, the Contractor shall be instructed to ensure that all sheared roots are trimmed cleanly and that any roots over 6" in diameter that cannot be avoided shall be wrapped in wet burlap after trimming. Approximately 25 redwoods(between 3' and 9' tall)have recently been planted in the downstream portion of this area;these are relatively small and could be transplanted several feet farther into the property and away from the construction zone,however. Construction of the eastern reach of Line B may impact up to eleven small trees including three coast live oak(Quercus agrifolia;dbh 4",.5", 3"), three valley oak (dbh 6", 6", 3"), two walnuts (dbh 3", 1.5"), one bay(dbh 1.5"), one exotic spruce (dbh 24"), and one interior live oak(dbh .5")through root sheering, partial canopy loss of other factors. It is always difficult to define the specific limits of tree impacts due to uncertainties with regards to the extent of the root systems and the character of the underlying soils. The project will definitely result in the loss of 7 trees of heaven of varying size. As noted above,these are non-native, weedy species that are a significant pest species throughout riparian areas of the County. The loss of the 15 trees of this species adjacent to Alhambra Valley Road will result in a minor aesthetic impact,as the adjoining fence adjacent to Alhambra Valley Road will then be unshielded from view. The loss of the other two trees of heaven will not have an impact as other trees in that location also offer shielding and tree views. Of the remaining trees that may be impacted, many are relatively small and could be transplanted away from construction activities on the same property; their loss would not result in an aesthetic impact,however,due to their small size(see below,however,for tree and wildlife impacts).For the larger trees,loss of all noted trees would be an impact,although not significant due to the number of large trees in the neighborhood that would not be affected.However,to reduce potential impacts,tree preservation measures during construction shall be included in the project as noted above. Additionally, construction activities will be conducted so as to impact the minimum amount of vegetation necessary. Every effort will be made to retain as many trees in place as feasible. In order to minimize damage to any additional trees that will not require removal,but may be impacted by construction,contract specifications will include protective measures such as clean trimming of roots and limbs. Accordingly,removal of trees will not significantly alter the visual quality of the project area. The proposed stormwater outfall location on Alhambra Creek has been heavily altered in the past; two abutments presently occupy the east and west banks as well as a great deal of non-native vegetation. Construction of the outfall will result in the removal of approximately 200 sq ft of mainly exotic,vegetation and several small(less than 3"dbh)native trees.All disturbed,areas will be treated with biotechnical slope protection to ensure rapid regrowth of the understory.However,this area is within eyesight of the Muir grave and a natural setting should be maintained or restored to the maximum extent practicable.Accordingly,to ensure the structure remains relatively well hidden,the 9 adjoining area should be planted with fast-growing plantings of native species,which will effectively shield this area. Construction equipment will be visible temporarily during construction of the retaining wall and relocation of the roadway,however this is a minor and short-term impact,ending upon completion of the prof ect. Building the project will not create a permanent source of significant new light or glare. Potentially Significant Potentially Unless Less than Significant Mitigation Significant leo lmpgct incorporation hn ac ht?pact II. AGRICULTURAL RESOURCES: In determining whether impacts to agricultural resources are significant environmental effects,lead agencies may refer to the California Agricultural Land Evaluation and Site Assessment Model(1990 prepared by the California Dept. Of Conservation as an optional model to use in assessing impacts on agricultural and farmland. Would the project: a. Convert Prime Farmland,Unique Farmland, _ X 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?(Source#1,3) b. Conflict with existing zoning for _ X agricultural use,or a Williamson Act contract?(Source#1,2) C. Involve other changes in the existing X environment which, due to their location or nature, could result in conversion of Farmland,to non-agricultural use?(source#1,2,3,4) SUNMMAR.Y> The project will not impact any locally or statewide important farmland. The horse pasture to the west of Alhambra Valley Road is used intermittently as a pasture. Following restoration of the channel and adjacent lands, this area will be grazed only periodically, if at all, according to NPS management.No agricultural preserves are located in the immediate vicinity of the prof ect. III. AIR QUALITY. Where available,the significance criteria established by the applicable air quality management or air pollution control district may be relied upon 10 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Impact IncMoration lmac impac to make the following determinations. Would the project: a. Conflict with or obstruct implementation — — X of the applicable air quality plan? (Source#2,4) b. Violate any air quality standard or — — X — contribute to an existing or projected air quality violation?(Source#2,4) C. Result in a cumulatively considerable _ — X 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 which exceed quantitative thresholds for ozone precursors)? (Source#2,4) d. Expose sensitive receptors to substantial — — X — pollutant concentrations?(Source#2,4) e. Create objectionable odors affecting a _ X — substantial number of people? (Source#2,4) SLNMARY: Grading and other work will necessitate the use of heavy construction equipment. County staff estimate that work will occur for approximately six weeks.Emissions from construction equipment and objectionable odors may be generated during this construction;however,they will be minor and temporary. In order to minimize impacts due to construction activities,contract specifications will stipulate the use of properly tuned and muffled equipment and the elimination of unnecessary idling of equipment when not in use. Implementation of dust control practices including general watering of exposed areas and/or use of chemical stabilizers will also minimize air quality impacts. The minor temporary deterioration of ambient air quality at the construction site will have no potentially adverse long-terixl impacts to air quality. No permanent air quality impacts due to vehicle traffic will be generated by the project since no additional trips will be generated by the project. ISI. BIOLOGICAL RESOURCES. Would the project: a. Have a substantial adverse effect, either _ X directly or through habitat modifications, — — Potentially Significant Potentially Unless Less than Significant Mitigation Significant No irnnact ing=oration Irmogt Lm act on any species identified as a candidate, sensitive,or special status species in local or regional plans,polices,or regulations, or by the California Department of Fish and Game or U.S.Fish and Wildlife Service? (Source#1,2,4,12) b. Have a substantial adverse effect on any — — x riparian habitat or other sensitive natural community identified in local or regional plans,policies,regulations or by the California Department of Fish and Game or DS Fish and Wildlife Service?(Source#1,2,4) C. Have a substantial adverse effect on _ x federally protected wetlands as defined —by section 444 of the Clean Water Act (including,but not limited to,marsh, vernal pool, coastal,etc.)through direct removal, filling,hydrological interruption,or other means?(Source#1,2,4) d. Interfere substantially with the movement X of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors,or impede the use of native wildlife nursery sites? Source#1,2,4,12) e, Conflict with any local policies or — — X — ordinances protecting biological resources, such as tree preservation policy or ordinance? Source#2) t: Conflict with the provisions of an — _ — X adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local,regional,or state habitat conservation plan? Source#2) SI RMMA RY: Special status species The complete listing of potential special status species for this region included 136 species of mammals,birds,herptiles(amphibians and reptiles)and plants.None of these species are considered likely to use or inhabit the site due to the lack of suitable habitat (grazed pasture and suburban 12 Potentially Significant Potentially Unless Less than. Significant Mitigation Significant No impact Irrcorooration Irn*�act bpa--t residential are generally not suitable habitat for these species): extent of disturbance (again, these species are rare in areas of intensive and extensive disturbance);and absence of sightings on-site or nearby for these species. Specific notes on several species of concern in the region are provided below. Contra Costa County staff reviewed the project site and Alhambra Creek with U.S Fish and Wildlife Service (FWS) staff for the potential presence of the California red-legged frog (Rana aurora draytonii),a Federally-and State-listed native frog.The FWS concluded that the site was unlikely to host this species. The California tiger salamander (Ambystoma calforniense) is likely absent for similar reasons (lack of suitable ponds and similar breeding habitat; absence of known locations nearby; and extent of local disturbance). Alhambra Creek has been investigated for the presence of steelhead trout(Onchorhynchus mykiss irideus)by several fisheries ecologists. Barriers to upstream migration in the City of Martinez and downstream from the project site are such that this anadromous species cannot reach the Creek at the project site(Alhambra Creek Watershed flan; May, 2001). The Alameda whipsnake(Masticophis lateralis euryxanthus)may occur in the hills above the project site; this area is included in the lands determined by the FWS to be critical habitat for this species. However,this snake occurs in scrub-shrub covered hillsides with occasional patches of grassland or woodland, conditions not occurring or,the project site. Finally,the Western pored turtle(Clemmys marmorata), a State and Federal Species ofConcern,is known from the region and although the CNI DDB records do not place it in Alhambra Creek, it is possible that it occurs there. The turtle is relatively wary of humans and will move away from the construction site of the outfall once work begins. Accordingly, no impacts to this species are expected. Riparian resources The project site includes a portion of Alhambra Creek, which is an important riparian resource. Construction of the outfall will result in the removal of approximately 200 sq ft of mainly exotic, vegetation. Periwinkle (Vinca major) an exotic ground cover, poison oak (Toxicodendrum diversiloba; native), creeping wild-rye (Leymus triticoides; native) and Himalayan berry (Rubes discolor; exotic) dominate this section of the creek bank. Also present are California blackberry (Rubus ursinus);California rose(Rosa californica),and stinging nettle(Urtica dioica ssp.gracilis). A small valley oak(Quercus lobata; dbh 2.5"),buckeye(Aesculus californica dbh 2.5"), and two willows(Salix sp.;dbh 1.0"and 1.5")may also need to be removed for the installation of the outfall, 13 Potentially Significant Potentially unless Less than Significant Mitigation Significant No naCt Incorporation. Lmp act depending on the extent of the final work area. Any native riparian trees greater than 6" dbh that require removal will be.replaced at a 3:1 ratio with like species up to one gallon in size. The replacement trees will be planted on the bank after construction and will be maintained for a period of three years and monitored annually for a period of five years. In order to minimize damage to any additional trees that may be impacted by construction, contract specifications will include protective measures such as clean trimming of roots and limbs.Change construction fencing will be installed to delineate the limits of construction impact at the retaining wall location, The fencing will serve to isolate environmentally sensitive areas(ESAs).from construction activities. The ESA fencing will be installed at the expected limits of construction impact as delineated on the construction plans. All disturbed areas will be treated with biotechnical slope protection and/or erosion control measures. Wetlands Wetlands on-site were assessed through a wetland delineation. Technical standards for delineating wetlands have been developed by the Corps in its Wetlands Delineation Manual (Army Corps of Engineers, Environmental Laboratory, Technical Report Y-87-1, U.S. Array Engineer Waterways Experiment Station,Vicksburg,Miss., 1987["Delineation Manual"])and adopted by the R.WQCB, and many local agencies. No wetlands or other Corps/R.WQCB jurisdictional areas were found on-site except Alhambra Creek, which is defined under the Corps methodology as an"Other water tributary to waters of the United States". These areas are not wetlands but the construction of the outfall into Alhambra Creek will require an Army Corps of Engineers Nationwide Permit(NWPs 7 and 33),Regional Water Quality Control Board Section 401 certification or Waiver of Certification, and a Department of Fish and Game Section 1601 Streambed Alteration Agreement.The County will apply for these permits and will comply with all the conditions negotiated for the permits. The construction of the outfall will result in a minor amount of"waters"loss that will be mitigated by native plantings,bank stabilization,and the restoration of riparian channel in the upstream horse pasture. Migratory corridors The project site,with the exception of Alhambra Creek, does not provide a migratory corridor for any wildlife. The ephemeral tributary now ends in the Strentzel Lane neighborhood,which would 14 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No act Incorporation Impact Ili act not an appropriate terminus for wildlife. In any case, the project will not interfere with movement of wildlife in this area but will provide a positive impact by providing a restored riparian channel in the pasture. The construction of the outfall in the Creek will create a temporary,permeable block to wildlife movement along the Creek for the two to three week construction period. Many of the wildlife that use the Creek for movement do so at night; construction will occur only during the daylight hours and it is likely that many of these species will continue to move through:the project area.. V. CULTURAL RESOURCES. Would the project; a. Cause a substantial adverse change in the — x — significance of a historical resource as defined in §15064.5?(Source#1,10) b. Cause a substantial adverse change in the e — X significance of an archaeological resource pursuant to §15064.5?(Source#1,10) C. Directly or indirectly destroy a unique X — paleontological resource or site or unique -- geologic feature?(Source#1,10) d. Disturb any human remains,including _ X _ those interred outside of formal cemeteries? (Source#1,10) StuMMARY: The project area is near or adjacent to historic and cultural resources centered on the family and person of John Muir, the noted conservationist. This includes a pear orchard., possibly planted by Muir,adjacent to Alhambra Creek and near the downstream end ofthe prof ect site(Figure 3). NPS staff consider the pear orchard an historically significant landscape and an important component of the National Historic Site. A records search conducted by the Northwest Information Center ('STC) at Sonoma State University found no recorded Native American or historic cultural resources listed with the System but noted that there was a high potential for identifying resources in the area..Further work has been done in this area by the NIPS as part of the General Management Plan for the National Historic Site (see sources above). Known or potential resources in the project area include the Strain Ranch,the Muir gravesite, and the pear orchard adjacent to and north and west of the gravesite. NPS staff determined that the preferred project would not affect the pear orchard or gravesite.NPS staff then 15 Potentially Significant Potentially Unless Less than significant Mitigation Significant No L*npact Incorporation lin act impact evaluated the Strain Ranch and determined that it was not eligible for listing to the National Register of Historic Places.The State Office of Historic Preservation provided written concurrence with this finding. Although the Strain Ranch is not eligible for listing and the project will not apparently affect the Muir gravesite or adjacent pear orchard,additional cultural or historic resources maybe found during excavation.Therefore,contract specifications for the project will require that the contractor stop all activities within 85 ft of any cultural or archaeological resources discovered on the project site. Additionally,the Resident Engineer for the project will receive instruction regarding identification of archaeological and historical resources in the field. VI. GEOLOGY ATNID SOILS -Would the project? a. Expose people or structures to potential substantial adverse effects,including the risk of loss,injury,or death involving: 1. Rupture of a known earthquake fault, — — X as delineated on the most recent Alquist- Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. (Source#1,2,5,8) 2. Strong seismic ground shaking? — — X 3. Seismic-related ground failure, including — — � X liquefaction? (Source#1,2,5,8) 4. Landslides?(Source#1,2,5,8) b. Result in substantial soil erosion or the loss X of topsoil?(Source#1,5,8) — m C. Be located on a geologic unit or soil that is — — _ X unstable, or that would become unstable as a result of the project, and potentially result in on-or off-site landslide, lateral spreading, subsidence, liquefaction or collapse? (Source#1,2,5,8) d. Be located on expansive soil, as defined in X 15 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No pct Ing=ora i t lit b,'P—ac t Table 18-1-B of the Uniform Building Code (1994),creating substantial risks to life or property?(Source#1,2,8) e. Have soils incapable of adequately supporting _ � _ X the use of septic tanks or alternative waste disposal systems where sewers are not available for the disposal of waste water?(Source#N/A) SUMMARY The closest fault is the Franklin Fault,which is,located approximately l mile from the project site. There are no active earthquake fault zones at or in the immediately vicinity of the project site. According to the Contra Costa County Soil Survey,soils in the vicinity of the project consist almost entirely of Botella clay loam. These are moderately well-drained soils on alluvial fans and floodplains. Permeability of relatively slow and runoff can be rapid. The hazard of erosion is moderate to high where the soil is bare depending on the slope. This soil type is primarily used for homes, dryland grain or grain hay. Presently,sediment from the watershed is either deposited on the horse pasture or is carried by major storms over the pasture and.Alhambra Valley Road and into the neighborhood.. The horse pasture itself is also a major sediment source. As it does not have a defined channel, flows tend to cut channels into the pasture(several are visible on the pasture edges) and carry this sediment directly into the neighborhood with every storm. Stabilization of the pasture through construction of the restored channel will provide for significant, annual sediment relief to the neighborhood. Grading and excavation associated with the project will result in minor changes in topography and temporarily increase the exposure of soils to stream erosion. To address the exposure ofbare soils to stream flows, contract specifications will require the installation of erosion control measures (seeding,soil stabilization, and revegetation)to prevent soil from leaving the restored creek channel. These measures will be incorporated into the construction contract. Because the disturbed area will exceed S acres,the County PWD will obtain a General Stormwater Construction Permit from the State Water Resources Control Board. The Contractor shall prepare and implement, after County approval, a Strom Water Pollution Prevention Program(SWPPP). Superficial grading of the project area is not expected to result in unstable earth conditions or change geographical substructures. Exposure of people or property to geologic hazards is not expected to increase as a result of the project. All areas left exposed due to construction will be seeded with a 17 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No IWact Lncorporation- im Lmtsact Ur:gact mix including native grasses and wildflowers upon completion of the project in order to stabilize exposed soil. VII. HAZARDS AND HAZARDOUS MATERIALS Would the project: a. Create a significant hazard to the public — — X or the environment through the routine transport,use,or disposal of hazardous materials?(Source#1,2,4,7,8,9) b. Create a significant hazard to the public — — X or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? (Source#1,2,4,7,8,9) C. Emit hazardous emissions or handle X hazardous or acutely hazardous materials, — — — substances, or waste within one-quarter mile of an existing or proposed school? (Source#1,2) d. Be located on a site which is included on aX list of hazardous materials sites compiled — — — pursuant to Government Code Section 65862.5 and, as a result,would it create a significant hazard to the public or the environment? (Source#1,2,7) e. For a project located within an airport land — — X use plan or,where such a plan has not been adopted, within two miles of a public airport or public use airport,would the project result in a safety hazard for people residing or working in the project area. (Source#2) f. For a project within the vicinity of a private — _ — X airstrip,would the project result in a safety hazard for people residing or working in the project area? (Source#2) g. Impair implementation of or physically — — — X interfere with an adopted emergency response plan or emergency evacuation plan? (Source#1,2) h. Expose people or structures to a significant — — — X risk of loss,injury or death involving wildland 18 Potentially Significant Potentially Unless I.,ess than Significant Mitigation Significant No Imna—t Incargoratim fact Irrs act fires, including where wildlands are adjacent to urbanized areas or where residences are intermixed with wildlands? (Source#1,2) S�,'MMAR'Y: The project has the potential, although minor,to release hazardous substances, such as accidental petroleum spills from equipment, during construction. Per the contract specifications, standard construction safety practices will be followed during construction to ensure no accidental release of hazardous substances or increase in the potential for exposure to these substances. No interference with an emergency evacuation or response is expected to result from the project. The majority of the work will occur within the project area. Alhambra Valley Road in this area is semi-rural and has relatively low traffic levels. Traffic control measures around the work area will minimize the potential for accidents. Standard specifications for the project will require installation of sufficient warning signs regarding the construction and associated work hours. VIII, HYDROLOGY AND WATER.QUALITY- Would the project: a. Violate any water quality standards or _ _ X waste discharge requirements? (Source#2,4,6,9) b. Substantially deplete groundwater supplies X 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 planned uses for which permits have been granted)? (Source#1,2,4,6) C. Substantially alter the existing drainage _ X 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? (Source#4,6) d. Substantially alter the existing drainage m X 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? (Source#1,4,6) e. Create or contribute runoff water which X 19 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Impact lacorPor ration b!a= Impact would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff?(Source#1,4,6) f. Otherwise substantially degrade water � _ � X quality?(Source#4,6,9) g. Place housing within a 100-year flood — — X hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map? (Source#1,2,6) h. Place within a 100-year flood hazard area — — — X structures which would impede or redirect flood flows?(Source#1,4) i. Expose people or structures to a significant — — X risk of loss,injury or death involving flooding, including flooding as a result of the failure of a levee or dam? (Source#1,2,4,6) Inundation by seiche,tsunami, or mudflow? — — — X (Source#1,4) STUNL 1ARYe The primary purpose of this project is to reduce sediment loads and flooding into the Strentzel sane neighborhood through the restoration of natural channel functions and the provision of additional flood and sediment control facilities. According to the Contra Costa County Flood Control District Flood Insurance Rate Zone Information Map and the Resource Mapping System,the neighborhood and project site are located in a floodplain. This floodplain is the,area flooded by the ephemeral tributary contained within the 264-acre watershed of Sub-drainage Zone 1167,which also encompasses 117 acres of?VI'S land, on the south sides of Mts. Wanda and Helen. Rick Inglis, hydrologist with the'INPS,has completed an assessment of the watershed and flood hydrology(see Sources for reference). His work found that the neighborhood will flood in even relatively small storms of 20 to 50 cfs, which is the 2-yr storm also described as the mean annual flood. The proposed project will provide for protection from up to the 10-year storm,which is 182 to 190 efs. The proposed project's reconstructed channel and grassy swale in the horse pasture will have a relatively small capacity and is not designed to provide significant flood retention. These features will, however, help to slow flood flows which increases total capacity in the system and will help reduce downstream. flooding. The impacts of these features are, accordingly, beneficial. Similarly, downstream improvements through the neighborhood will expand flood capacity, which will alleviate these hazards in the 20 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No immt ineWoration mac: neighborhood. The potential impacts of the outfall into Alhambra Creep have been addressed in several ways. Because the channel capacity of the system upstream of the outfall will be increased,additional flow from the project watershed will slightly increase Alhambra Creek flows.For the mean annual storm, for example, (which controls the size of the tankful channel and is, therefore, responsible for channel stability) creek flows would be increased by 10%, according to County flood. analyses. However,the peak flows for any storm level from the project watershed will have entered Alhambra Creek via the outfall and moved well downstream before peak flows from the Alhambra Creek watershed reach the outfall.Therefore,the total increase in flows to Alhambra Creek is likely to be insignificant relative to Alhambra Creek flows and not appreciably increase the bankfull flow or channel of Alhambra Creek. The outfall has been designed as a cast in place concrete structure,designed to minimize turbulence or other shifts in velocity. Accordingly, the outfall structure is not expected to result in significant impacts to the stream system.. In addition,building the project will not adversely affect the quantity or quality of ground water or public water supply. Measures will be undertaken in the design and construction of the project to avoid adverse impacts to water quality. Contract specifications will require the installation of silt fencing or other effective sediment barrier to prevent soil from entering the creep due to construction activities. Contract specifications will require the storage, servicing and fueling of construction equipment on the road rather than in the slide area. Standard construction safety practices will be incorporated into the project to reduce the possibility of a spill of gasoline,oil,or other pollutant that could have a significant impact on water quality. In addition,stockpiled materials will be located far enough from the banks of the channel to prevent construction materials from entering the creek.At the completion of the project,all disturbed areas will be stabilized through the use of hydroseeding with a mix including native grasses and wildflowers and/or erosion control blanketing, as appropriate. The construction of the outfall into Alhambra Creek will require an Army Corps of Engineers ?nationwide Permit (N- Ps 7 and 33), Regional Water Quality Control Board Section 401 certification or Waiver of Certification,and a Department of Fish and Gaspe Section 16101 Streambed Alteration Agreement. The County will apply for these permits and will comply with all the conditions negotiated for the permits. 21 Potentially Significant potentially Unless Less than Significant Mitigation Significant No JW.pact InorpQration hipgagb2wt IX. LAND USE AND PLANN LNG-Would the project: a. Physically divide an established community? — — x (Source#2,4) b. Conflict with any applicable land use plan, — — — X policy, or regulation of an agency with jurisdiction over the project(including,but not limited to the general plan,specific plan, local coastal program, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental effect? (Source#1,2,4) c. Conflict with any applicable habitat — — — X conservation plan or natural community conservation plan? (Source#1,2,4) SUMMARY: The project will not result in an increase in population, displacement of people, or create a demand for additional housing. X. MINERAL RESOURCES -Would the project: a. Result in the loss of availability of a known — — _ X mineral resource that would be of value to the region and the residents of the state? (Source#1,2) b. Result in the loss of availability of a locally- — — X important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan? (Source#1,2) SUMMARY: During construction,the project will use concrete,wood products,and other materials derived from natural resources; however, the project will not significantly impact these resources. The use of oil and gasoline to operate the machinery for construction purposes is negligible and of a short-terra,temporary nature. In order to minimize impacts due to construction activities, contract specifications will stipulate the elimination of unnecessary idling of equipment when not in use. 22 potentially Significant Potentially Unless Less than Significant Mitigation Significant No Impact IngMoration Impact ham et NOISE-Would the project result in: a. Exposure of persons to or generation of — — X — noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? (Source#2,4) b. Exposure of persons to or generation of — X — excessive ground borne vibration or ground borne noise levels?(Source#4) C. A substantial permanent increase inX ambient noise levels in the project vicinity — — — above levels existing without the project? (Source#2,4) d. A substantial temporary or periodic increase — — X in ambient noise levels in the project vicinity above levels existing without the project? (Source#2,4) e. For a project located within an airport land _ _ — X use plan or,where such a plan has not been adopted,within two miles of a public airport or public use airport,would the project expose people residing or working in the project area to excessive noise levels? (Source#N-1/A) For a project within the vicinity of a private — — _ X airstrip, would the project expose people residing or working in the project area to excessive noise levels?(Source#N/A) SUMMARY: The dominant source of noise in the project area is the vehicles currently using Alhambra Valley Road as well as trains on the adjacent railroad. Construction of the project will not increase the capacity of the Road. The existing road is the only access to the homes beyond the project area, therefore the ambient noise levels associated with routine use of the road will remain the same. Construction of the project will increase the noise level temporarily;however,there are no sensitive receptors in the vicinity of the project. In general,construction activities produce noise levels of 86 dBA at 50 feet,which is well below the threshold of pain of 120-140 dBA. Contract specifications will require the use of properly tuned and muffled equipment to minimize other noise due to construction.Working hours will be limited to 7:30 a.m.to 7:00 p.m.Monday through Friday,unless modified upon written approval by the resident engineer,to reduce construction noise levels. These working hours will be incorporated as part of the construction contract. 23 Potentially significant Potentially finless Less than significant Mitigation Significant No h-VaQt Inemoration hipact tmnw XII. POPULATION ANL M HOUSING Mould the project; a. Induce substantial population growth in an — — X area,either directly(for example,by proposing new homes and businesses)or indirectly(for example,through extension of roads or other infrastructure)?(Source#2,4) b. Displace substantial numbers of existing _ — _ X housing,necessitating the construction of replacement housing elsewhere? (Source#2,4) C. Displace substantial numbers of people, — — — X necessitating the construction of replacement housing elsewhere? (Source#2,4) SUMMARY:The proposed project is located along an existing roadway. Installation of the project will not affect available capacity of the Road and will,therefore,not induce population growth. The project will not result in the displacement of any homes or residents. The project will not result in a change in the location, distribution, density or growth rate of human population in the area. The project will not affect existing housing,or create a demand for additional houses. The project will not require the removal of any homes or the displacement of any people. XIII. PUBLIC SERVICES a. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities,need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts,in order to maintain acceptable service ratios,response times or other performance objectives for any of the public services(Source#2,6): 1. Fire Protection? X 2. Police Protection? — —_ X _— 1 Schools? — X 4. Parks? X 5. Other Public facilities? — X 24 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Trntract Inco oration hnect lin fact SUMMARY: The project is located within the Contra Costa Consolidated Eire District and the Martinez Unified School District. The project will be installed adjacent to an existing roadway but will not increase the capacity of Alhambra Valley Road. Once constructed, the project will not increase the need for fire or police protection, schools, parks or other governmental services. In addition,it will not increase the capacity of Alhambra'Valley Road,nor will it increase the need for public services. During construction, access will be maintained to the homes off the Road at all times. The majority of the work will be conducted alongside smaller roads; therefore, heavy equipment will not block the entire roadway. Residents and emergency service vehicles will be able to drive around the construction areas at all times. Due to the relatively small volume of dirt being moved from the project site, construction-related traffic would have a negligible impact on traffic flows associated with drop-of and pickup of students at John Swett Elementary. The County currently maintains .Alhambra Valley Road and periodic maintenance of road improvements will continue to be performed by the County. XIV. RECREATION- a. Would the project increase the use of _ X existing neighborhood and regional parrs or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? (Source#11,2,4) b. Does the project include recreational X facilities or rewire the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? (Source#1,2,4) SU-N-IMARY> The County Resource Mapping System and the field reviews did not identify any recreational opportunities in the immediate project area. There is a combination trail (hiring and riding) identified by the Resource Mapping System that wanders through the upper watershed; however,the project will not impact recreational activities on the trail. Surrounding land uses in the immediate vicinity of the project consist of undeveloped land and existing neighborhood. 25 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No h4mt Inc==iion Imp hnpact XV. TRANSPORTATION/TRAF'F'IC-Would the project: a. Ouse an increase in traffic which is _ X substantial in relation to the existing traffic — — load and capacity of the street system (i.e., result in a substantial increase in either the number of vehicle trips,the volume to capacity ratio on roads,or congestion at intersections)? (Source#1,2,4) b. Exceed, either individually or cumulatively, — — — X a level of service standard established by the county congestion management agency for designated roads or highways? (Source#1,2,4) C. Result in a change in air traffic patterns, — — X including either an increase in traffic levels or a change in location that results in substantial safety risks?(Source#N/A) d. Substantially increase hazards due to a design — — — X feature(e.g.,sharp curves or dangerous inter- sections)or incompatible uses (e.g., farm equipment)?(Source#1,2,4) e. Result in inadequate emergency access? — — — X (Source#1,2,4) f. Result in inadequate parking capacity? — — — X (Source#N/A) g. Conflict with adopted policies,plans,or — — _ X programs supporting alternative transportation (e.g.,bus turnouts,bicycle racks)? (Source#2) SUMMARY: The Urban Creeks Council estimates that construction of the channel on the Strain Ranch will result in the excavation of approximately 193 cubic yards of rnaterial, About 60 cubic yards of this will be used on-site for filling the eroded gullies. An additional 750 cubic yards of material will be generated by excavation of the swales; about 63 true loads will be required to remove this material. The material will be exported over a period of approximately six weeks (30 days);therefore,truck trips generated along Alhambra Valley Road are expected to be approximately 2 trips a day over the 30day period. Based on the relatively small number of truck trips generated and the limited number of days over which the trips will occur,the impact due to the transportation of fill is less than significant, 26 Potentially Significant Potentially Unless Less than Significant Mitigation Significant NT O Irnbact lncarporationfii act impact The project will not alter waterborne,rail or air traffic as no water or air transportation facilities are located in the immediate vicinity of the project area, and the project will not impact the railroad, .XVI. UTILITIES AND SERVICE SYSTEMS - Would the project: a. Exceed wastewater treatment requirements _ X of the applicable Regional Water Quality Control Beard? (Source b. Require or result in the construction of new _ X water or wastewater treatment facilities or expansion of existing facilities,the construction or which could cause significant environmental effects?(Source#�'vT/A) C. Require or result in the construction of new _ X storm water drainage facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? (Source#N/A) d. Have sufficient water supplies available to _ _V X serve the project from existing entitlement and resources, or are new or expanded entitlement needed?(Source#N/A) e. Result in a determination by the wastewater _ _ Y treatment provider which serves or may serve the project that it has adequate capacity to serve the project's projected demand in addition to the provider's existing commitments? (Source#N/A) f. Be served by a landfill with sufficient _ X permitted capacity to accommodate the project's solid waste disposal needs? (Source#N/A) g. Comply with federal, state and local statutes _ X and regulations related to solid waste? (Source#N/A) SUMMARY: The project will not affect utilizes and service systems with the exception of the expansion in the stormdrain system described above. 27 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Impact Inco?poration LmMct _ XVII. MANDATORY FINDINGS OF SIGNIFICANCE- a. Does the project have the potential to degrade — X the quality of the environment,substantially reduce the habitat of a fish and wildlife species, cause a fish or wildlife population to drop below self--sustaining levels,threaten to eliminate a plant or animal community,reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? b. Does the project have impacts that are indiv- — — X — idually limited,but cumulatively considerable? ("Cumulatively considerable' means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects,the effects of other current projects, and the effects of probable future projects)? C. Roes the project have environmental effects _ X which will cause substantial adverse effects on — — human beings, either directly or indirectly? SUMMARY; The project does have the potential to temporarily degrade the environment during the construction phase. This potential will be reduced considerably by the implementation of Best Management Practices during the course of construction. A representative of Contra Costa County will be onsite to ensure compliance with all environmental conditions imposed by either the regulatory agencies or County policies. Potential aesthetic impacts,primarily through the potential lass of trees, have been addressed through avoidance and minimization of impacts to tree root systems. Potential biological impacts are limited and have been mitigated through replanting of native trees at a 3:1 ratio(planted to lost).The project will have geologic(sediment production)and hydrologic impacts but these are beneficial as the project is designed to increase flood capacity and reduce flooding and sedimentation in the Strentzel Lane neighborhood.Potential erosion and related impacts have been minimized by the restoration of the NPS horse pasture and the design of the Creep outfall. Finally, as discussed in Sections II (Agricultural Resources), III (Air Quality), VI (Geology and Soils), IX (band Use and Planning), X (Mineral Resources), XI (Noise), XII (Population and Housing), XIII (Public Services), XIV (Recreation), and XVI(Utilities and Service Systems), the proposed project will not result in substantial adverse effects on human beings, either directly or indirectly. E Figure 1 a, It ID a � k ys ' m C'1 1 W-1 alum 00 r ne Iwo �t- P � I e `! i ''�7"' 333 �, ' y� � �•tt ,Pub, ger •,,t 52r t J07 MIS fit \ t 1 tra AIW tltlay�t 9pLa� VF.a .+.,� .Wt 1 1 F} S a 1+ F ' r ti ti ...ate -- '^'_':_ I < y do r ! y .r / `� \ ,� y �✓ , Ito 10, $• iM .,. .. °°fig o, •a �S.y aPig ,;. '� !� J�jA � ' as .�„r�,� ".�p . �°`f t ,� � t � 4`' _ "+1 �•` • e>v ,.°L y r< d ra //J ffJfflJ(/ J/ w k • �"' ` � h !, k 10 VP.-- ujCtf cn LLJ Li 1yo N I NbG712� HS au ' d _� • +' :' 1 _,' ,. ti r r' t 1 �, t v C Q - co Lu W LL LJ Fw- W c tt �� t ...•,� 1 �' 1 � � 1 � c i w goyLi + co •i U,) to cec z o. 2 ¢ rX •fry >.. W"... 1 ��\Jy \ _ �� ! Ito 10 �� +• �i I ', �C, ` \�\ r... . .....•''-"" .-....,,,,�4J�,...r �.\•-._.��.1,..,..,(1_... a,- r,� rrt I�� IjJj�i t d 1 t 1 1 E S CALIFORNIA ENVIRONMENTAL QUALITY ACT NOTICE OF DETERMINATION CONTRA COSTA COUNTY COMMUNITY DEVELOPMENT DEPARTMENT 651 PINE STREET 4TH FLOOR NORTH WING MARTINEZ,CALIFORNIA 94553-0095 Telephone: (925)313-2296 Contact Person: Cece Sellgren, Environmental Planner l Proiect Description, Common Name (if any)and Location: Strentzel Lane Sediment Reduction Project(CP 02-67), Martinez area. The goals of the Strentzel Lane Project are to reduce sediment loads from an unnamed, ephemeral tributary and convey tributary flows safely through the Strentzel Lane neighborhood to Alhambra Creek. Over the past three decades, this tributary, despite its relatively small size, has periodically flooded and/or deposited significant sediment loads into this neighborhood. Flooding and sediment deposition are at least partially the result of past agricultural practices in the area that have modified the tributaries sediment carrying capacity and eliminated the historic connection with Alhambra Creek. The project proposes to restore the tributary channel, construct grassy swales for sediment deposition, enhance existing and construct new drainage facilities, and restore a channel connector with the Creek to alleviate flooding and sediment deposition. This project is sponsored by the Friends of Alhambra Creek, a local non-profit group, and will be undertaken in cooperation with the US National Park Service (NPS),which owns much of the tributary watershed, and the Contra Costa County Public Works Department (PWD),which will design, construct and maintain the project. The project was approved on October 22, 2002. Pursuant to the provisions of the California Environmental Quality Act: ( } An Environmental Impact Report was prepared and certified (SCH # } { ) The Project was encompassed by an Environmental Impact Report previously prepared for (SCH# }. (X) A Negative Declaration was prepared (SCH#2002032017) Copies of the record of project approval and the Negative Declaration may be examined at the office of the Contra Costa County Public Works Department. (X) The Project will not have a significant environmental effect. ( } The Project will have a significant environmental effect. ( ) Mitigation measures were made a condition of approval of the project. { } A statement of overriding considerations was adopted. ( ) Findings were adopted pursuant to Section 15091 of the State CEQA Guidelines. Date: By: Community Development Department Representative AFFIDAVIT OF FILING AND POSTING I declare that on I received and posted this notice as required by California Public Resources Code Section 21152(c). Said notice will remain posted for 30 days from the filing date. 1 l Signature Title i Receipt# Applicant: Department of Fish and Game Fees Due Public Works Department EIR-$850 Total Due: $$1,300_ 255 Glacier Drive _X Neg.Dec.-$1,250 T otal Paid $ Martinez,CA 94553 DeMinimis Findings-$0 Attn:Cece Sellgrer. _X_ County Clerk-$50 Receipt#: :sd G:\GrpData\EngSvc\ENV1R0\2001 projects\Stentzel Ln Improvements\CEOA\Strentzel NOD.doc CALIFORNIA ENVIRONMENTAL QUALITY ACT I NOTICE OF DETERMINATION CONTRA COSTA COUNTY COMMUNITY DEVELOPMENT DEPARTMENT 651 FINE STREET 4TH FLOOR NORTH WING MARTINEZ,CALIFORNIA 94553-0095 Telephone: (925) 313-2296 Contact Person: Cece Sellgren, Environmental Planner Project Description. Common Name (if any) and Location: Strentzel Lane Sediment Reduction Project(CP 02-67), Martinez area. The goals of the Strentzel Lane Project are to reduce sediment loads from an unnamed, ephemeral tributary and convey tributary flows safely through the Strentzel Lane neighborhood to Alhambra Creek. Over the past three decades, this tributary, despite its relatively small size, has periodically flooded and/or deposited significant sediment loads into this neighborhood. Flooding and sediment deposition are at least partially the result of past agricultural practices in the area that have modified the tributaries sediment carrying capacity and eliminated the historic connection, with Alhambra Creek. The project proposes to restore the tributary channel, construct grassy swales for sediment deposition, entrance existing and construct new drainage facilities, and restore a channel connection with the Creek to alleviate flooding and sediment deposition. This project is sponsored by the Friends of Alhambra Creek, a local non-profit group, and will be undertaken in cooperation with the US National Park Service (NPS),which owns much of the tributary watershed, and the Contra Costa County Public Works Department(PWD), which will design, construct and maintain the project. The project was approved on October 22, 2002. Pursuant to the provisions of the California Environmental Quality Act: { } An Environmental Impact Report was prepared and certified (SCH # ) { } The Project was encompassed by an Environmental Impact Report previously prepared for (SCH# }. (X) A Negative Declaration was prepared (SCH #2002032017) Copies of the record of project approval and the Negative Declaration may be examined at the office of the Contra Costa County Public Works Department. X The Project will not have a significant environmental effect. { } The Project will have a significant environmental effect. ( } Mitigation measures were made a condition of approval of the project. { ) A statement of overriding considerations was adopted. { ) Findings were adopted pursuant to Section 15091 of the State CEQA Guidelines. Date: By: Community Development Department Representative AFFIDAVIT OF FILING AND POSTING E I declare that on I received and posted this notice as required by California Public Resources Code Section 21152(c). Said notice will remain posted for 30 days from the filing date. Signature Title Receipt# Ai:)Ocant: Department of Fish and Game Fees Due Public Works Department EIR-$850 Total Due: c$1;300_ 255 Gacier Drive _X_ Neg.Dec.-$1,250 Total Paid $ Martinez,CA 945533 DeMmimis Findings-$0 Attn:Cece Sellgren _X_ County Clerk-$50 Receipt#: :sd G:\GrpDat2\Eng8vc\ENVIR0\2001 projects\Stentzel Ln Improvements\C_4A\Strentze1 NOD.doc PROOF OF PUBLICATION (2015.5 C.C.P.) STATE OF CALIFORNIA County of Contra Costa lei I am a citizen of the United States and a resident of the County aforesaid; i am over the age of eighteen years, and not a pay to or interested in the above-entitled matter. I am the Principal Legal Clerk of the Contra Costa Times, a newspaper of general circulation, printed and published at 2640 Shadelands Drive in the City of Walnut Creek, County of Contra Costs, 94598. And which newspaper has been adjudged a newspaper of general circulation by the Superior Court of the County of Contra Costa, State of California, under the date of October 22, 1934. Case Number 19764, The notice, of which the annexed is a printed copy (set in type not smailer than nonpareil), has been published in each regular and entire issue of said newspaper and not in any supplement thereof on the following dates,to-wit: June 6, 13 ail in the year of 2003 f certify (or declare) under penally of perjury that the foregoing is true and correct. Executida at W l, t C a , Califo 'rvlla�nut U ee �,Olifo — , C 3 On this da nuJ . 200i C' .............................................. Signatur at Contra C sta Times P 0 Box 4147 Walnut Creek, CA 94596 (925) 935-2525 Proof of Publication of: (attached is a copy of the legal advertisement that published) NOTICE TO CONTRACTORS The Public Works Director wile receive seated bids at the Public Works Depart- ment, C.C. Rich Bulldlnq, 255 Glacier Drive. Marti. nez California 94553-4897, until 2 o'clock p.m,,on Ju- 1 Yy 1, 2003 at which time tPsey w'1{ be publicly ap���ned and read, for: STRENTZEL i..ANEE RO51 N AND SEDIMENT REDUC- TiON PROJECT. General work descrlption: The pproject consists of in- staling drainage pipe, and constructing manhole structures, a rock pipe outfaii, excavation and embankment, grassy swales, asphalt concrete Cavement and aggregate base driveway replace- ments,and re-str€ping. Engsneer's cast estimate: $31000 A Fre-bid meeting will be held on Monday,June 16, 2003 at 20:00 am, at the Public Works Department to cover the County's Bad- der Outreach Program. Prospective bidders at- tendance is recommend- ed but not mandatory. Contract Documents, In- ciuding plans and sppec€f cations, may be viewed and/or obtained at the Public Works Depparimer,* C.C. Rich Bull Ing, 259 Glacier Drive, Martinez, California 54553.4897 Monday - Thursday (7:0i� a.m. - 12 Noon and 1:00 pp m. - 5:00 p.m.) (closed Fridays).To obtain plans and specifications a serv- ice charge Is requlred In the amount of $25.98 ((sales tax Included). PLANS AND SPECIFICA- TIONS MAY BE ORDERED BY MAIL FOR AN ADDI- T,'ONAL SHIPPING AND NANDUNG FEE OF $3=. Checks shall be :Wade ayable to'The County of ontra Costa' and be mailed to the above ad- dress. The Public Works Department does not guarantee the arrival of t m plans and speciftca- tions In time for bidding, Plans and specifications will not be sent overnight mall. This project is to be ad- vertised pursuant to Pub- lic Contract Code 20125. This contract Is subject to state contract nondiscrl- mination and compliance requirements pursuant to Government Code,Section 12990. The Contractor shall pos- sess a Class A License or Class C-34 at the time the Contract Is awarded. Bid*must cover the entire pro}ect,and neither artl- at nor contingent bids will be conswered The successful bidder shall furnish aayment bond and a performance bond. The Board has ascer- tained the general prevail- Ing rate of wades applica- ble to this work The pre- vatting rateqt per diem wages Is on ftie with the Cleric of the Board of Su- pervisors,and Is Incorpo- rated herein by reference thereto,the same as If set forth In full herein. For any classification not 'n- oladed In the its%the min- !mum wage shall be the �enerairprevalling rate for ontra..ossa bountty� The bid opening date may be extended oY adden- dum issued by the Public Works Department no tat- er than JUNE 27 2003, In which case any rIds sub- mitted for the original bid opening wiii be returned unopened and sea', bid proposals for the extend- ed bid opening shall be submltto on or before JULY iS 2003,at 2:00 p.m. and will be * ned, maa and recorded at t' same place specified above. Ail proposals received fate wilt be returned uno- pened. .he said Board reserves the right to reject any and all bis or any portion of any bid and/or watve any Irregularity In any bld received, For questions regarding the project contact Wes Cooley at(925)323-2304 or Prank Navarro at (92S) 313.2264,both of the De- sign Division. By order of the Board of Supervisors of Contra Costa County John Sweeten Clerk of the Board of Supervisors and County Administrator By:/s/Emy L Sharp, Deputy Dated:June 03,2003 Letga!CCT 7790 Pubitsh June 6,13,2003