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HomeMy WebLinkAboutMINUTES - 12201994 - 1.6 TO: BOARD OF SUPERVISORS FROM: J. MICHAEL WALFORD, PUBLIC WORKS DIRECTOR DATE: December 20, 1994 SUBJECT: Approve Camino Tassajara Realignment at Finely Road project and Addendum to the Final Environmental Impact Report for Sub. 5736 Project No.: 0662-6R4163-90, CDD-CP #94-72 SPECIFIC REQUEST(S)OR RECOMMENDATION(S)&BACKGROUND AND JUSTIFICATION I. Recommended Action: APPROVE project and the Addendum to the Final Environmental Impact Report (FEIR), for Sub 5736 and FIND that a portion of Assessor's Parcel No. (APN) 206-030-017 is needed for the realignment of Camino Tassajara per the FEIR's mitigation measure and the conditions of approval. DIRECT the Public Works Director to begin right of way acquisition and to prepare contract plan and specifications for construction. 11. Financial Impact: The estimated project cost is $1,010,000 funded by SB 300 (20%) and Tassajara Area of Benefit (80%). Ill. Reasons for Recommendations and Background: The project includes realignment and widening of about 2100 feet at the intersection of Camino Tassajara and Finley Road. It is needed to improve the geometrics of the roadway. The FEIR pertaining to this project was originally included in Subdivision 5736. Continued on Attachment: X SIGNATURE7Z,. ��5 —RECOMMENDATION OF COUNTY ADMINISTRATOR _RECOMMENDATION OF BOARD COMMITTEE APPROVE OTHER SIGNATURE(S): ACTION OF BOARD ON ULL APPROVED AS RECOMMENDED OTHER_ VOTE OF SUPERVISORS UNANIMOUS (ABSENT ) AYES: NOES: ABSENT: ABSTAIN: JY.jlg c\BO:bo20b.tl 2 Contact: Joe Yee, (313-2323) 1 hereby certify that this Is a true and correct copy of Orig. Div: Public Works(Design Division) an action taken and entered on the minutes of the Board of Sup 14n he shown. cc: County Administrator Attn: E. Kuevor PHIL BATCHELOR,Clerk of the Board Auditor Controller of Supervisors and County Administrator PW Accounting Construction �' � ' �'D�' ..Deputy Community Development V. Germany-Design Approve Camino Tassajara Realignment at Finely Road project and Addendum to the Final Environmental Impact Report for Sub. 5736 Page 2 December 20, 1994 The Addendum to the FEIR for Subdivision 5736 will provide for the acquisition of a portion of APN 206-030-017 to provide for right of way for the realignment of Camino Tassajara at the Finley Road intersection. The Addendum is consistent with County policies and does not lead directly or indirectly to significant physical changes in the project, nor does it alter the adequacy or the completeness of the environmental impacts and mitigation measures identified in the FEIR. Therefore, an Addendum to the FEIR is appropriate to address the minor technical changes in the project description. Upon Board approval, the Addendum would be attached to the FEIR for the Sub. 5736 project. IV. Consequences of Negative Action: Delay in approving the project and Addendum to the FEIR will result in delay of design and construction of the project. ADDENDUM to the FINAL ENVIRONMENTAL IMPACT REPORT (FEIR) for SUBDIVISION # 5736 CP#94-72 Prepared by: Maureen Toms, Planner Contra Costa County Public Works Department 255 Glacier Drive Martinez, CA 94553-4897 November 1994 Environmental Planner (Chief Planning Official) Public Works Department Title: Lead Agency: Cou n ty of Contra Costa Date: I ADDENDUM to the FINAL ENVIRONMENTAL IMPACT REPORT (FEIR) for SUBDIVISION # 5736 CP #94-72 Prepared by: Maureen Toms, Planner Contra Costa County Public Works Department 255 Glacier Drive Martinez, CA 94553-4897 November 1994 ADDENDUM to the FINAL ENVIRONMENTAL IMPACT REPORT (FEIR) for SUBDIVISION # 5736 PREFACE A Draft Environmental Impact Report (DEIR) was prepared in April of 1980 for Subdivision #5736 and discussed a traffic mitigation measure to improve the Camino Tassajara/Finley Road intersection. Condition #17(D) of the Conditions of Approval requires the reconstruction of the Camino Tassajara/Finley Road intersection to improve the alignment and sight distance. This document serves as the Addendum to the Final Environmental Impact Resort (FEIR) for Subdivision #5736 and evaluates the change of the project location. Consequently, the FEIR for the project consists of the DEIR, comments received on the DEIR, a list of all commenters on the DEIR, responses to the comments raised, and the Addendum. The Contra Costa Community Development Department (CDD) is the lead agency for the project, and on March 17, 1981, the Board of Supervisors (Board) approved the project and filed a Notice of Determination with the County Clerk. The Board acknowledged that the project would have certain environmental effects and adopted findings. In addition, the Board recognized future land use and hydrology; traffic and circulation; water quality; wildlife and vegetation; geology and soils; natural resources; noise; air quality; cultural resources; and growth inducement; and cumulative impacts would be reduced if proposed and recommended mitigation measures were followed. CEQA PROCESS. The California Environmental Quality Act (CEQA) prescribes that an Addendum (CEQA Guidelines Section 15164) to an environmental impact report (EIR) shall be prepared by either the lead agency or the responsible agency if: 1. None of the conditions described in CEQA Guidelines Section 15162 have occurred. These conditions are: a. No substantial changes have occurred which will introduce new or significant changes or environmental impacts not previously considered; 1 b. No significant changes to the conditions or circumstances in the area affected by the project have occurred, such as substantial deterioration in air quality; c. No new information has become available which shows that significant impacts previously examined will be substantially more severe than shown in the EIR or the project will have one or more significant effects not previously discussed. 2. Only minor technical changes or additions are necessary to make the EIR under consideration adequate under CEQA; and, 3. The changes to the EIR made by the Addendum do not raise important new issues about the significant effects on the environment. In accordance with CEQA Guidelines Section 15164(c), the Board must consider the Addendum along with the FEIR prior to making a decision on the project. According to CEQA Guidelines Section 15164(b) an Addendum does not require circulation for public review but can be included in or attached to the FEIR. As noted in the Preface, the Addendum is attached to the FEIR for Subdivision #5736. EXPLANATION OF ADDENDUM The Addendum to the FEIR for Subdivision 5736 identifies the need for the acquisition of approximately three acres of a 23 acre parcel (Assessor's Parcel Number 206 030 017), west of the existing Camino Tassajara roadway, for the realignment of Camino Tassajara per the FEIR'S mitigation measure and the Conditions of Approval (March 17, 1981). The property will be acquired in order to realign the roadway and provide the needed slope (2.5:1). This is a minor technical change to the FEIR, which does not raise important new issues about significant effects on the environment. The Addendum is consistent with County policies and does not lead directly or indirectly to significant physical changes in the project, nor does it alter the adequacy or the completeness of the environmental impacts identified in the FEIR. Therefore, the Addendum to the FEIR is appropriate. ADDITION TO THE FINAL ENVIRONMENTAL IMPACT REPORT This section identifies the language which is added or changed (bold-face type) or deleted (seeut) to the text and figures of the FEIR. p. 1, Project Location, add: Approximately three acres of Assessor's Parcel Number 206 2 030 017 will be acquired in order to realign Camino Tassajara. p. 3, After Figure 2, add: Figure 2A p. 27, add: Figure 17 p. 28, 5. Traffic, 1st paragraph, 1st sentence,add: (see Figure 17). p. 28, 5. Traffic, 1st paragraph, 2nd sentence, change: Also, off-site road improvements may be necessary such as at the intersection of Johnston Road and Camino Tassajara. and the Finley Read, Gamine T-assajaFa 3 BOARD OF SUPERVISORS OF CONTRA COSTA COUNTY, STATE OF CALIFORNIA, INCORPORATING FINDINGS OF FACT PERTAINING to the ENVIRONMENTAL IMPACT REPORT for SUBDIVISION 5736 The Findings for the Subdivision 5736 Project were adopted by the Board of Supervisors to comply with Section 15091 of the CEQA Guidelines and are incorporated herein by reference. 4 CONTRA COSTA COUNTY ADDENDUM FINDINGS for the FINAL ENVIRONMENTAL IMPACT REPORT for SUBDMSION 5736 The following information is presented to comply with Section 15091 of the CEQA Guidelines for FEIR for Subdivision 5736. 1. Environmental Effect: The project will result in the acquisition of approximately three acres of land for the purpose of realigning Camino Tassajara at the Finley Road intersection. Findings: There are no significant environmental impacts associated with this site for which the Addendum was prepared. The acquisition of property is not considered a significant impact. Minor technical changes to the project limits do not cause a significant impact that was not previously identified in the FEIR for Subdivision 5736. STATEMENT OF FACTS: a. The project to be developed pursuant to the Addendum to the FEIR for Subdivision 5736 is identical, or substantially similar, to the project analyzed in the FEIR. b. The FEIR for Subdivision 5736 consists of the DEIR, comments received on the DEIR, a list of all commenters on the DEIR, responses to the comments raised, and the Addendum. The FEIR was completed in compliance with CEQA. c. There are no subsequent changes, pursuant to CEQA Guidelines Section 15162 (a) (1) in the project which require important revisions of the FEIR because the project is identical, or substantially similar, to the project analyzed in the FEIR. d. There are no substantial changes in the circumstances, pursuant to CEQA Guidelines Section 15162 (a) (2), under which Subdivision 5736 is undertaken. Those circumstances remain identical or substantially similar to the circumstances analyzed in the FEIR. e. There is no new information of substantial importance, pursuant to CEQA Guidelines Section 15162 (a)(3), to the Subdivision 5736 project which could not have been known when the FEIR was originally certified by the Board of Supervisors March 17, 1981, and which shows that the project will have one or more significant effects not discussed in the FEIR, or which shows that significant effects previously analyzed will be substantially more severe. 5 f. None of the conditions calling for the preparation of a subsequent or supplemental EIR have occurred (see items 1 c - e above). Therefore, it is appropriate to adopt the Addendum to the FOR to make a minor technical change or addition by specifying that a portion of assessor's parcel number 206 030 017 be purchased (CEQA Guidelines 15164). The changes to the FEIR made by the proposed Addendum do not raise important new issues about significant effects on the environment. The Addendum shall be considered along with the FEIR prior to the Board making a decision on the purchase of the parcel, and in considering the parcel purchase the Board is considering the identical underlying project. The findings are supported by substantial evidence in the administrative record and are based on the FEIR for Subdivision 5736 which was subject to public review. Mt clinley\addendum.fin 6 29 30 24 25 28 Phase 8 31 26 .27 23 32 Phase 7 ,N` 21 APN# 37 40 41 206 030 017 Phan3 22 33 36 :19._ 34� 15 35 38 39 18- Phase 6 42 43 16 14 5 1' / '50- 17 Phase 1 52 11 12 49 13 48 44 10 9 1 47 2 46 Phase 4 8 45 7 Phase 2 Phase $ 5 4 3 Q Scale: 1" = 780' Source: Tentative Map Sub. 5736 and Contra Costa County Public Works Department Figure 2A. Proposed Subdivision .�.w.rr-.�;�..�.w•n„w�+4.w9waw.�wrNt4'PI4"%roR}}:n a.. yaw::+R Co.7R•'M+ar.'�'- .'h ••r,.••ff J P::W�Y:k4 „�Y1'.Y.4Y{ 1{)p�.`n'f!!ti'-f -.i''Fjii.�Yr�S9Vht^'4'll:S'1Mk!•5.'pNMI+.�<WAM.VMD53tM1yf .)1PAyMq/p/+.�yh . O O O J sJ O C7 ,.7 O 7 cl i TiI(A, Sli� is 1f ! SSS^ own! = 1O 3 s£�££ i S € j1 S + ` i 5 j s _ � ♦ qy t oil. 1 JOE; ! .€to CL All 1111� fill sf..4fi j�s p€ ill 1 "NEI r`r i��)gxk£s�r rn i e�si r!•if j � ky fEx s 3F � t� ,5.�. j ik { ill€ k # � 3 ` • A[ £{ its ss "11v�;�ss £ £; N i J t {{ s }} €£ � d�}{ 's jftttp #55 .51 s� t r}{5. . 4�z ii. t; + � !.-.!°3< � d:'. 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D �5 fie• `ff j _> f 10-11'1. tIN �-.Cf# F i Yi t#!gr } � /`i. / � .,✓ �.,e�.y .. � Q1 Q1 Ql O) J J 11.:•. J m1-0-O O U O O O Contra /- Costa ! County CRAFT ENVIRONMENTAL IMPACT REPORT SUBDIVISION 5736 BRUCE AND JOAN FLANAGAN TASSAJARA AREA CONTRA COSTA COUNTY APRIL 1980 TABLE OF CONTENTS Page SUMMARY L INTRODUCTORY DISCUSSION 1 A. Project Description 1 B. Environmental Inventory of Region 1 1. Physical Description 1 2. Existing Use and Surrounding Area 4 3. Utilities and Public Agencies 6 4. Circulation 6 5. Plans, Ordinances, and Policies 11 6. Soils and Geology - 13 7. Hydrology 14 8. Vegetation and Wildlife _ . 18 9. Socioeconomic Characteristics 18 10. Aesthetics - 19 11. Energy 20 12. Cultural Resources 20 EL ENVIRONMENTAL IMPACT ANALYSIS 21 A. Environmental Impact of the Proposed Action 21 1. Land Use 21 2. Hydrology 21 3. Fire Protection 23 4. Traffic 24 5. Soils and Geology 24 B. Any Adverse Environmental Effects Which Cannot Be Avoided If This Proposal Is Implemented 25 C. Mitigation Measures Proposed to Minimize The Impacts 26 1. Land Use 26 2. Hydrology 26 3. Water Quality - 27 4. Fire Protection 28 5. Traffic 28 6. Soils and Geology 29 7. Cultural Resources 29 D. Alternatives to the Proposed Action 29 I. No Project Alternative 29 2. A-40 Zoning Alternative 30 3. Agricultural/Residential Alternative 30 4. Residential/Commercial-Recreation Alternatives 30 r 5. Energy Alternative 30 E. Growth-Inducing Impact of the Proposed Action 31 F. Organizations and Persons Consulted; Bibliography 34 G. Qualifications of EIR Authors 35 i TABLE OF CONTENTS (continued) III. APPENDICES 36 A. Initial Study A-1 B. Water Quality Study B-1 C. Archaeological Reconnaissance C-1 D. Geological Report D-1 LIST OF FIGURES I. Project Location 2 2. Proposed Subdivision 3 3. Project Area Topography 4 4. Site Aerial Photograph 5 5. Typical Road Section 7 6. Internal Circulation 8 7. Traffic Counts 9 8. Peak Hour Traffic 10 9. Project Area Zoning - 12 10. Project Area Soil Types 13 11. Site Geology 15 12. Site Liquefaction Hazard 16 13. Flood Hazard Boundary Map 17 14. Site Erosion 23 15. Land Use Mitigation 26 16. Horse Trail Easement.Realignment 27 LIST OF.TABLES 1. Project Phases 2. Soil Characteristics 13 3. Population Distribution _ 18 4. occupational Status 18 5. Household Income 19 6. Tassajara Study Area Subdivisions 32 ii SUMMARY Under Subdivision Application 5736 the owner/developers, Bruce and Joan Flanagan, propose to re-subdivide 323.6 acres from four existing parcels into 52 single-family parcels. The project site is located northeast of the intersection of Camino Tassajara and Johnston Road, north to Finley Road. Parcels range in size from 5.00 to 9.75 acres, averaging 5.88 acres. Access to the development would be from either Camino Tassajara or Johnston Road. The western third of the property is level, prime agricultural land (class I and II soils) while the remaining:land is open hilly grassland. 7assalara�Creek and three—tributaries flow"$ through.;the`'site L Twenty-three lots contain level areas for home sites,`T2 contain hilltop sites, and 17 lots require hillside home sites. Significant impacts have been identified in this report. They are -summarized below with mitigation measures suggested to reduce the impacts.- 1. mpacts:1. The proposal represents a basic change in land use from agricultural and general open space to residential use, inconsistent with the intent of the General Plan. The County Board of Supervisors have questioned the viability of agriculture on five- acre parcels as allowed on A-2 zoned land and planned for this project. The project will adversely and unavoidably impact future agricultural viability in the area. Significant mitigation is not available for the project as proposed. Minor mitigation is available by requiring adequate fencing .on the eastern border to allow continued grazing on adjacent A-4 land. 2. Erection of structures within .a designated flood hazard area. The finished homesites must be above the Flood Hazard elevation. Capacity analyses must be submitted to the Public Works Department for all proposed culverts and crossings y$ nsrs#�oiIlfi''be''SeTeCti�ei "oleate .vfsfruc£ioizs� iostorriivvalow.=' Detentionasins :rovirh, iec ada'rriss�ould. e -uastalied Lsatio�-locations-�3o=lessen 'downstreamflooding. __..... .. 3. The project affects the potential use, extraction, conservation or depletion of a natural resource. The project represents an irreversible commitment of prime agricultural soils (class I and II) and agricultural grazing land to residential use. The project as proposed cannot be mitigated to eliminate this impact. Alternative three suggests keeping the prime soils in agriculture and developing the less desirable soil areas. 4. The project has significant growth-inducing action. Approval of this project will encourage similar development in the area, including future loss of agricultural preserves. Approval plus others contemplated or possible in the future will place'a high demand for commercial services which are not available in this area. There will'be pressure to convert some agricultural land to commercial uses, especially as gasoline gets more costly in the future. The growth-inducing impacts of the project as proposed cannot be substantially mitigated. Therefore a statement of overriding considerations may be required. Three alternatives are described with reduced growth . inducement. Minor mitigation is possible by realigning the Sharon Drive street end. iii 5. Additional traffic will be generated, increasing road congestion and accident potential. The County Ordinance Code will require that Johnston Road, Camino. Tassajara, and Finley Road be improved along the frontage of this subdivision. Also, off-site road improvements may be necessary such as at the intersection of Johnston Road and Camino Tassajara and the Finley Road, Camino Tassajara intersection. Easement for a future bus stop and shelter should be provided along Camino Tassajara in case public transportation is established in the area. 6. The development will significantly impact the volunteer :Tassajara Fire Protection District. The District Fire Chief has provided a list of required mitigation measures including: an emergency water system installed to the standards of the District; road grades below 17 percent; applicant should contribute to the aquisition of additional fire sup- pression equipment for the District; and clear assignment of responsiblity to the homeowners for weed abatement and firebreak construction. 7. Potentially hazardous geologic and soils conditions are on the project site. Past geologic maps (1971) have indicated a possible fault trace directly through the project site. A later geologic map (1978) does not show the fault but a syncline axis. The County's liquefaction map indicates nearly half of the project site is subject to liquefaction in response to earthquake movement. Four landslides are shown on the tentative map; eleven are shown on the County's liquefaction map. A detailed geotechnical report should be prepared for those parcels located within the County liquefaction zone. Mitigation is available through foundation design and structure placement. A similar report should be conducted for those parcels near landslides. Mitigation of the landslide hazard may require removal of the deposits, excavation and reconstruction of the slope, or by buttressing the landslide. 8. A horse-trail easement is proposed which may have potential dater gda'li�y4impa It is recommended the trail easement -be realigned to one side of the stream and that riders use the proposed road crossings to cross the stream not the channel itself. Fencing may be required to keep horseback riders (and motorcycle riders) out of the stream. 9. Adequate well water may not be available or may impact surrounding wells by lowering the water table. Applicant should submit a groundwater study indicating well yield and drawdown data. Study should indicate that sufficent water quantity and quality is available with minimum effect on surrounding wells. 10. The project will require approval or permits by other than a County Agency. Tassajara Creek and three tributaries on the project site are "designated streams and will..require a ' aea611 IN_.J ��`j} - ».•iKi6MfYI�,tijtLj-J4G; 'iJ.s.' �.�..A.• .a.K:ir' .+aR.rvSa.,`.n•..�Lm� 11. The project has impacts which are individually limited but cumulatively considerable. As the first major subdivision of this size in the area, the project is likely to establish a precedent for other sudivision proposals on adjoining or nearby lands. The cumulative effect of such development will be significant on air, water, area hydrology and wildlife, schools, and demand for more urban-type services in an agricultural area. iv L INTRODUCTORY DISCUSSION A. Project Description Application: Subdivision 5736. Applicant: Bryan and Murphy Associates, Inc., civil engineers. Owner/Developers: Bruce and Joan Flanagan. Project Location: The project site is located northeast of the junction of Camino Tassajara and Johnston Road (see Figure 1, Project Location). The subject property is identified as Assessor's Parcel Numbers 204-080-001, 204-090-001, _204-100-001, and 204-110-001. The project is in Census Tract 3551. Request Re-subdivide approximately 323.6 acres from the existing four parcels into 52 single-family- residential lots (see Figure 2,*Proposed Subdivision). Background: In 1974, the same land (owned at that time by Friden and Rossi) was subject to an EIR when the same applicant (Bryan and Murphy Associates) requested approval of variances from the subdivision ordinance to create four parcels of 74.5, 83, 83, and 90.7 acres and requested a land use permit to have two existing residences on Parcel B (minor subdivision 51-74). The EIR expressed concern over splitting large landholdings into smaller parcels initiating the subdivision process. This could continue until the area became urbanized beyond agricultural suitability. Also recognized was the additional adverse impacts of urbanization occuring before utilities and transportation facilities become available in the area. Additional Information: The land would be developed in eight phases. Individual lots would vary in size from 5.00 acres to 9.75 acres, averaging 5.88 acres and totalling 305.51 acres. An additional 18.09 acres will be right-of-way. TABLE I. PROJECT PHASES Phase 1 11 lots 67.51 acres. Phase 5 3 lots 23.89 acres Phase 2 7 lots 39.56 acres Phase 6 4 lots 20.91 acres Phase 3 5 lots 26.29 acres Phase 7 6 lots 35.63 acres Phase 4 8 lots 49.57 acres Phase 8 8 lots 42.15 acres B. Environmental Inventory of Region 1. Physical Description The site's major topographic features, as shown in Figure 3, are the nearly level flood terrace of Tassajara Creek and its tributary on the western third of the site and the steep, rolling topography of the eastern two-thirds. A second tributary more or less parallels Johnston Road along proposed lot 45 while a third tributary passes through the southeastern corner of the same lot. The site elevations range from about 660 feet to 860 feet. -1- •f �. .. A \\P 1 M'ITTSSUR4 - l AKTtOCN � /CONCORD s `1 PLEASANT MILL I �• CLAYTON J 7 t t WALNUT CREtx LAFAYZI'M t 1 Alamo Dialm . Morgan S ITE E OaawlMa � . ••--•sae Rawaa � - i l Figure i. Project Location -2 - 29 30 24 25• 28 Phase 8 31 27., 23 �6 32 - 21 Phase 7 33 36 37 40 41 Phase 3 22 34 35 38 3 15 . 9 Phase 6 42 L.....__ 16 14 51- / '-50 43 17 Phase 1 52 11 . 1Z 13 48 49 44 10 9 1 47 2 Phase 4 8 46 45 7 Phase 2 Phase 5 5 5- 4 3 Source: Tentative Map Sub. 5736 Scale: 1" = 78C' Figure 2. Proposed Subdivision -3- ' : 1�.-•\ i Tamajara 5ch « Baa 1•_�^ ���s ; ,w.�3G *10 S �Tnssajam 1 � .J M 713 16 WVi 669 . % l \. 1• ..es ,._ .•\ _ 1 \! 1. l�a ausaq�i. - ; 1 i�f�� ... i, �. .-yam 1 'i 1 •Ylat�•' Source: USGS Tassajara.Quad (1974) Scale: P' = 2000' Figure I Project Area Topography 2. Existing Use and Surrounding Area Existing Use: The site -currently comprises four parcels primarily used for cattle grazing. Two residences and related out-buildings are located in the northwest portion of the• site, on proposed lot 19. A new home, pool, and guest house are under construction on proposed lot 52. Surrounding Area: Areas contiguous- to the north contain a number of single family dwellings on lot sizes ranging from 1.04 to 4.41 acres (A-2 zoning). The western border of the site is Camino Tassajara. The southern project boundary is Johnston Road and an 8.16 triangular piece of land containing two single-family homes. The eastern border is two large parcels of undeveloped land, one zoned A-4, Agricultural Preserve and one zoned A-2, General Agriculture. (Zoning is discussed in Section 5 and shown in Figure 8 to follow). The surrounding area is shown in Figure 4, Site Aerial Photograph. The dominant character of the Tassajara Area is rural ranching, the closest communities being Danville (8 miles), Pleasanton (10 miles), San Ramon (12 miles), and Livermore (13 miles). -4- - lam! •,� �..r. .� K� �=J T K 'I y+ Fes:'• j 1. - -1. • •t-.��•......• -d _ _ .. .-sssTYYY .�► ...•i•• .. .r H. Source: USDA.-SCS, °ho-o Dare August 16, 19'9 �"_�. :" = S60' Figure 4. Site Aer.a1 °hotog-_;;n _5_ 3. Utilities and Public Agencies Water: Public water supplies are not available; surrounding residents depend on well water for domestic use. It has been reported that several homeowners on the northern site boundary experienced well failure during the recent drought (Bleecker 1980). The tentative map indicates the applicant wishes to retain the ability to create a community water supply system in the event commercial water supplies are not available. A community water supply, however, would be contrary to a recent Board of Supervisors policy that rural residential developments of fewer than 200 parcels should be served by individual wells on each parcel (Gerow 1980). Generally, the County Health Department requires a dry season domestic well yield of five gallons per minute over a four hour period, or an equivalent level of flow and storage capacity based on the specific well yield. Sewers: The applicant plans individual sewage disposal systems for each lot. Two percolation- tests were conducted by Engeo, Inc., in the southern portion of the site, one on Conejo clay loam and one on Diablo clay. Their report (Engeo 1979) indicated sufficient percolation to support septic systems in those locations and on those soils. The tentative map indicates that in the event of insufficient soil percolation in other areas, the applicant wishes to retain the ability to use common leaching fields or other approved methods of waste disposal. This will require the specific approval of the County Health Department. Individual sewage disposal systems for each lot are consistent with County policy which discourages community sewage treatment plants because of inadequate effluent treatment (Gerow 1980) unless- they are specifically recommended by the Health Department for this particular project.' Police Protection: Contra Costa County Sheriff's Department would provide police protection to the proposed development. The subdivision will be covered by officers on Beat 14, stationed out of Martinez approximately 30 miles to the northeast (Dispatcher 20, 1980). The project will increase the need for service to the area, requiring more time than urban areas due to the remote location of the site (Lt. Robinson 1979). Fire Protection: The project is within the volunteer Tassajara Fire Protection District, less than 0.5 mile from the nearest station (at 6100 Camino Tassajara Road). District Fire Chief Stephen Eppler has stated specific concerns regarding this project which will be discussed in the Impacts and Mitigations sections to follow. 4. Circulation Immediate Access: The primary access to the property will be via Bruce Drive off Camino Tassajara, located midway between the junctions of Tassajara/Finley Roads and Tassajara/Johnston Roads. Secondary access will be via Laurie Lane off of Johnston Road. -6- Internal Circulation: A typical road section as proposed on the tentative map is shown below in Figure 5, proposed to be a 20-ft. wide pavement within a 60-ft. right-of-way. If the streets within the subdivision are proposed to be County maintained streets, the typical section must conform to County standard street width requirements. The minimum pavement width must be 28 to 32 feet wide (Cline 1980).. 1 !00 21GHT-OF-WAY 1 20 2' 2 V4;2 I cc VA2ie5 PAT>+ 3t-IOULOEXZ \ NOTE Pw/`ME.NT, CiAee ANO 5U13. 1�45c SPAI-1. 13E D ETE aM I N EO err -114F- ' 9' 14F- R' VAL.Uc. MI='HOD. Source: Tentative Map Sub. 5736 No Scale Figure 5. Typical Road Section The project will be served by three cul-de-sacs and a through street network (see Figure 6). Road grades over*ten percent are also indicated on Figure 6. A railroad flat car bridge is proposed for the Bruce Drive crossing. Before the flat car can be used for the bridge, the Public Works Department must review and approve the specific flat cars for use as a road bridge (Cline 1980). Traffic Volumes: Contra Costa Public Works Department traffic counts.in November 1973 the latest available) indicated Camino Tassajara Road had an average daily traffic (ADT) count of 476 south of Highland Road and 741 east of Blackhawk Road. Johnston and Finley Roads had counts of 50 and 90 ADT, respectively (see Figure 7, Traffic Counts). -7- Slopes over 10% are indi- cated. They only occur over short portions of the road. (See Tentative Map for �Al more detail). v�► LAJ SAM'S PLACE �~~ 296 •15% GORDON WAY 20% SHARON 41 BRUCE ' yF cn Q r o LAURIE LANE v PENNY LANE 14% CORTE ELENA �� JOHNSTON -�- Source: Tentative Map Sub. 5736 Scale: 1" = 780' Figure 6. Internal Circulation _g_ 0 a 741 50 ca no Tassajara ¢ Ra. w S 01VII Highland P.d. v a Q Source: Public Works Department No.Scale Figure 7. Traffic Counts On March 25, 1980 (a Tuesday), the EIR consultants conducted a traffic count at the intersection of Camino Tassajara and Johnston Road from 3 p.m. to 6 p.m. The peak hour traffic (found to occur between 4 and 5 p.m.) are illustrated in Figure 8. Assuming the peak hour flow is 10 to 12 percent of the ADT (Caltrans 1975), the current traffic volume on the western end of Johnston Road is about 170 ADT. Five hundred feet north of Johnston Road, Camino Tassajara has a volume of 690 ADT while 500 feet south of Johnston Road the ADT is 770. Traffic generated by 36 parcels of Subdivision 5736 (representing 360 ADT) will enter Camino Tassajara via Bruce Drive, Penny Lane or directly from their parcel. Those 16 parcels in the southern portion of the development (parcels 1 through 6, 39, and 42 through 50, representing 160 ADT) will use Johnston Road to reach Camino Tassajara. Approximately three-quarters of the current traffic on Johston Road appear to use Camino Tassajara south of the project. Road Widths: amtno 'ansa arae -, .'o 102 v �i�ta �►. wide a .emen -� wt '�` _ on or amino Tassajeta �'.Johnston Road is current- t. wide pavement within a 40-ft. wide right-of-way. Planned expansion is to a 40-ft. pavement within a 60-ft. right-of-way. (Road width data obtained from Khanna 1980). Accidents: Public Works Department records indicate there have been no reported accidents (reported by the California Highway Patrol to the County) at either the Camino Tassajara/Johnston Road intersection or the Tassajara/Finley Road intersection from January 1979 to March 1980 (Vukad 1980). -9- till Q 42 3$ : V) CC 42 0 35 0 �O IO . ,}OKNSTON ROAD 42 5 35 IO No Scale Source: C.E.A., Ltd. Date: March 25,1980 Figure S. Peak Hour Traffic Count 10- 5. Plans, Ordinances, and Policies General Plan: San Ramon Valley (SRV) Area General Plan (1977) designates land in the Tassajara-Johnston Road area as general open space and states that much of the land so designated in the eastern portion of the Pian area is expected to remain in open space through the 1990 time frame of the Plan (SRV Area General Plan, page 37). Lands surrounding the Tassajara-Johnston Road area are planned as agricultural preserve. Plan policies affecting the proposed project include: "Discouraging premature or "skip" development which can constitute. an undue economic burden on the general public, require extension of facilities, and result in growth pressures in inappropriate areas. "Protect agriculture for a balance in land use, to meet the long-range needs of the County and for resource conservation. "Encourage urban expansion in areas where it will .minimize conflicts with the agricultural economy. (General Plan, page 10). The Plan projects a population increase from 41,000 (1975) to aproximately 80,000 (1990), most of this concentrated in the urban service areas along Route 680 within the San Ramon Valley Area. Open Space and Conservation Element: The Open Space and Conservation Element 1973 reinforces the policies of the General Plan, stating that in Major Open Space Areas, such as the area of this project, permitted development should be directly related to agricultural production, recreation, and use of natural and animal resources. Addi- tionally the Element states, "construct no growth-inducing highways or roads to serve areas outside the Urban Growth Areas" (page 36). Trails: The Trails Plan in the SRV Area General Plan (Map 12) indicates Camino Tassajara along the property's western border is planned as a bicycle, riding, and hiking trail which extends from the Tassajara/Johnston Road intersection northwest to the central county area. All of Johnston Road on the property's southern border and continued eastward is planned as a riding and hiking trail. The applicant proposes a horse trail easement along Tassajara Creek and tributary within the project boundaries. The easement will provide access to the county trail system. Zoning: The project site is currently zoned A-2 (General Agriculture) which allows a minimum five-acre parcel size. The proposed development will be consistent with the zoning classification. Area zoning, shown in Figure 9 on the following page, indicates there are extensive A-4 lands near the project site. Related Projects and Plans: Less than two miles northwest of Subdivision 5736 is the 2185-unit Blackhawk development. Although service capacities for this project have been designed to accommodate it alone, the project will add-traffic to Camino Tassajara and may encourage nearby property owners to develop their lands. Additionally, the County is now reviewing the proposed Sycamore Valley Specific Plan, which -recommends designing infrastructure for over 1800 new units within three miles of Subdivision 5736. The Blackhawk and Sycamore Valley pians could lead to an additional 13,000+ people immediately west of the project site and would necessitate widening Camino Tassajara to four lanes west of Dougherty-Blackhawk Roads. These road plans assume that residential development in the Tassajara area east of Dougherty Road is held to 200 units (Sycamore Valley Specific Plan EIR, page 67). -11- AA4 A 2 t� A2 A .00 A2 � . i i A4 raG„LanO A4 A2 --A 2) Source: County Zoning Atlas, Page W 19m. Scale: 1” = 2600' Figure.9. Project Area Zoning Tassajara Area Study: Concerned with the rate of minor subdivision activity in the Tassajara Area, the County undertook a .study of incremental residential .development, agricultural viability, and the effects of existing land use policies in the area. The resulting report (Tassajara Area Study 1978) suggested an increase in the permissible agricultural parcel size to stem development pressures on agricultural lands. In October 1979, the Board of Supervisors adopted Zoning Ordinance 79-108, providing for agricul- tural zoning districts with minimum parcels of 20, 40, and 80 acres. At.the present time, no recommendations have been made for application of these zones to specific areas. This matter will be coming before the Planning Commission and Board of Supervisors in the near future. However, nothing prevents an individual landowner from requesting a rezoning to any of these districts. Regional Plans: The Association of Bay Area Governments' Regional Plan (ABAG 1978) stated that new residential development should be encouraged only where public services can support the added population, or where there is a commitment to infrastructure improvements; scattered development should be avoided and dependence on the auto- mobile reduced. -12- 6. Soils and Geology' Soils: .The'*USDA Soil Conservation Service (1977) maps-four,soil types within the project site. These are the Brentwood, Conejo, and Cropley clay loams, and the Diablo clays. Soil type locations are shown in Figure 10 below. The following table lists the soil characteristics. _ - - TABLE 2: SOIL CHARACTERISTICS Soil Type Brentwood Conejo Cropley Diablo Symbol Bb CeA and ChA CkB DdE Soil Class I Ito II II IV Erosion Potential' ' Negligible; Negligible Slight - - Moderate - (bare). :. . _ Shrink/5we11 _ .. g - .Moderate`... <_ •. gh= High Potential Permeability===--- Moderate -="= Moderately Slow -: ; __Slow: ___. _.._ . Slow Slopes - _0 - 2 0 - 2 . - 2 - 5 15 - 30 (source: USDA 1977) Ta_ _ �� i t .- i \,�`��, ��trt! as`.4-+•. .i r �.'s�=�`: I• � .!r Ali V. T )am -.` DdEc CkB ,I -j- CeA` i Cha .4'. ; _ ,'1 ! i 1 ChA wail 76+ 669 r� I ! -• - .. ! Fes.✓�( �� 1: t. Source: USDA 1977. Scale! 1" = 2000' Figure 10. Project Area Soil Types -13- Faults: The Mount Diablo fault, considered potentially active, is located approximately four miles to the northwest of the project site. Eight miles west of the site is the active Calaveras fault. Located eight miles to the southwest is an active section of the Pleasanton fault. In 1971, Brabb et al. published a report indicating the approximate location of a fault crossing directly through the center of the site (see Figure 11, page 15). Wagner (1978) later mapped the area as part of his Ph.D. thesis and indicated.the site was crossed by the axis of a syncline but not a fault. Aerial photographic analysis and field reconnaissance by the developer's geologist indicated "that if faulting is present, there is no surficial indication that it is any longer active and thus not likely to affect site development" (Engen 1979). Liquefaction Potential: Contra Costa County's liquefaction map indicates nearly half of the project site is contained within a potentially unsafe liquefaction area (see Figure 12, page 16). Liquefaction of a wet soil can occur in response to movement from an earthquake and transforms an otherwise stable soil material into a liquid condition. Landslides: Four landslide are shown on the tentative map for Subdivision 5736, one each in lots 27, 28, and 38, and one extending over both lots 33 and 35. These four landslides were mapped by the developer's geologist and shown in that report (Engeo 1979). The report states the slides in the northeastern corner of the site (lots 27 and 28) are shallow (less than 10 feet deep). Figure 12, the County's liquefaction map, indicates eight landslides completely contained .within the site boundaries and two other landslides extending through the boundaries. The largest glide, extending through the site's southern boundary, has a home built on it outside the project site. Site-Specific Geology Report: "Preliminary Soil and Geologic Reconnaissance, Bruce Flanagan Property", prepared by Engeo, Inc., October 5, 1979. The report (provided in Appendix D) concludes: "1. Site subdivision into large site single family 10 acre—"' lots appears geotechnically feasible." (the developers propose 5 acre lots, however) 112. The percolation capacities of the soils are adequate to support septic systems. Site specific percolation tests should be undertaken when building placement has been decided." - 113. Attention will need to be given to ground water supply and its relation to septic systems. A number of existing wells have already been drilled." 114. A detailed soil investigation should be undertaken prior to any site development, and should address problems,.such as soil shrink-swell potential. No further geologic work is necessary for the proposed use." 7. Hydrology Drainage: The project site is situated in the upper portion of the Tassajara'Creek-,-drain-, age basin, a tributary of the Alameda Creek watershed. Western portion of the proposed development is on a nearly level flood terrace. The Safety Element of the County General Plan indicates the Flood Control District has not.formed a watershed flood zone for this area of the county. U.S.XIeological:Survey (1974) indicates the sit_-d&.!justingrth of._act.tiarea..subject�to `f00=year' f1oo The FederatAIns�e: cjmini ation.flood hazard.boundary.mapIocAhe-area (shown in Figure 13, page 17) ft i+cates-ant reas adjace to:.T.ss jars.,Creek-and-;tributariesa�bjecvtmtlood nrbyea4OO-year-flood: -14- �•`I �,/'n�i .1�.'` .a.a �lI !• i�-�'�}' yrY✓ /, —�.. I :l ``•.':''•• ••�.C� i 7.5 al -_• �,;;;. i +� �'" j T- ljarn Sch r\ \ . .�000 ;� + N. 3.� 35 L• ^•/ ` if Tomajand t• 'ten"..`i I 8 S • `��. / \ BM 71 r ` i-tom \ _� / 27 Well is �yNI:`� .s '663 �• I!,,1� u .1 I •l r•` •; :` 'Un�'v JM— •��.,4lt�i-• \ ` r� BM 616 - r ArendmAl o I: \ ---� -�1�.. '1 _(� �� irr� rl�rj.�'96B- ���_ ``! •`��1 i.' it �," J .- Ir- - �• / � - � .,_ �, !�. , % •„5 .� . 'coy:• �—J \ Qal: Quaternary alluvial deposits To: Tertiary Orinda Formation Source: Brabb et al. 1971 Scale: P' = 2000' Figure 11. Site Geology -15- as �s44 a 4 .}• �trll4 N�-: I � � �. �/:9R -�, A ��, i�! �` (1' `S, 1t, �war,iy `rr.+. jfJ'J"/�)/\ r �� (\ � ;".,-'r '/-�all,� �.')l'�• r�\ �1irT �;!_. �J'l�„i• T r 11�'a'M' =LAY ` '�> :'�.►J '\ ',,/ $0'• :, f , ,' .rn, ;r. •♦ NJ Ok ©c�ch,. -�•;r/L. �✓^i y�`+..BQ�J, ��y�4-`,i,.'t'g='' "�. ' ., ..v'�, gales �L,�111vsi; {tCY 1 a'ai Q''!� �' d• \"^�,:�i 1 �„�. _�':.� aha• {{--`.'��� '' t �"���./` � .fit •_ �S.Y .��.?�+,` ....T,a�!'r!_..-.�' , � y t.�l^`•�_ �, � ` t •+�, -Schp 1 11' Ll �Jl�y- - _ i � ! ,"._��•�..�,;5'' ala Ip�'�; -:.s,'rr,,:;��j o � '/,- ,.','.••L �• ..+/' • Lam/^ _t �"a y't ' 4��:..-� �`+�','!"atp: ���.��••� I Vie' :�' r � "17.;T►Y.iS d 1 k.:"_al,�. �.r. :�,►'.'. - :� , J 14,. r % ,/'�. t/ ti ...+w�iif� ,•+.•y.n. ',.�r�'+ �,. V wLl1t}ft!•,i" J i: ��� V I (7 S ry. i�"I`• -���- '+i�w :t:':'42' `{ems'-., t � ;t nn ~� ` — rl ' •:i%.."t`?!t/ '.•'. w,1d,t t_:. .+.1,. -'S'r ••, t � ,! rFt'r• !MF f� � •� R•� '\�'� j4• >> t a r'�It7ft, � I 11 ��� r r• r:'\ t ?,. -r'�d�X � �y� t„ `Q ty t r`_•�' ~�„�t�"'�:ts•r �•t ° ""�{1ny r.� ` •, 2 ;o,!.� ', '9 all- 7$i�r.I� �.�i1 ,:•`�``� � r�iii YJ� •-�' r fi ..i .\ lam-��. W I 6B9i+s:4u.+';r, �,y•��- x r. t_ , M r `4' /�( "� 'I,•SOI /.��� a ••� N :.,::,�,,.,s:�,a�;]}i �.y,q• t J/ Y •f jt '• (.\•r� -•✓�' i� ,,�. 4!x:3:: ''� 'i ► '!=� ' ` - _ f —41 Wei ��""-'_'" •r� .._.�G� Mx t � `" `�\G t�f,�,fiV!r r `t�J 11��1 ~� ,fes ��.�.. R tI (tV tI�` \ ..-\CYT a i•T. �I l-' j K;. r:e.a('n�.,:�:. YStI� �\ ^o' G , )��=..- ti=•ice•'` e -,�, _ -•' �!'w+ ' .. fir. �\..t!' ....� �'.`. ...7j i � � i r!_ Utd'%l\.i -,S1 I 'wt�. � ,,��..+�•�'v `V // t ,� - �_� ��� !, '.\ J `•' ,..-� '.l � ! _. t 1 X31 }•'•ice"-.ITi�.t�' 1 �-.a".a v''r 't' .•-•.i1.a. � - !`-' ,•f� 1. r•\_ .-� �' •�a-��'�/'� `) . •.'t7 .+� ,S',,..[(•^"��O tT +�. !..� ,'! V CGr J` .... i J F1`'} `, Q•- - ;/,; �\\lel`/\,1�j� l��•y�j:: �_ -r. -}I ,? � - ���. �.��'�' ,,f,,,�! t '7- ,. Scale: 1 = 2000 Source: Contra Costa County Figure 12. Site Liquefaction Hazard -16- Tassajara-_Cxeek and three unnamed-�tributaries pass through the site (see Figure 13 below). The existbign5channelabanks"are-v—iie-ff'ep in ureas, fr=-ggdd r eZcee"dingrl f- slope. Nurer�,ouas�bstrear}, ank. aginto- hecl"anneY'were'ob"served. Sam_ Drainage Improvements: The tentative map indicates the need for severalt-.stream -crossings indditior� o"tfie existingcrossing at'.lot_:19�. These are between lots 12 and 17 across Bruce Drive, between lots 14 and 34 across Sharon Drive, and between lots 23 and 34 across Gordon Way, and between lots 45 and 46 on Laurie Lane. A crossing may be necessary to reach lot 13 or an easement could be provided through lot 14. A pair of culverts have already been placed in the stream between lots 14 and 34. A second culvert has been installed on the north side of an old concrete bridge between lots 12 and 13. Crossing of Tassajara Creek on Bruce Drive is proposed to be a railroad flatcar bridge (the flatcars are onsite). - A sto eij00*feetdeia�edo. e ceaxered:!along Tassajara.:,;Creel ,_ ndther.maim ributargnxhrough-"thelzpropez . A �t��oot`fiorsa: traif easement:-issindite-tbeme'ryi,a-'P'"t� e'" Teff ovi3fiin!4� iitiage-easement~. Stad I u Q34 / f ISrr / --� _ l A. TASS I -- it :.�.: 2 ZONE A 71 Source: HUD Federal Insurance Admin. Scale: P' = 2000' Figure 13. Flood Hazard Boundary Map -17- Water Quality: An examination of the macroinvertebrates in Tassajara Creek was conducted as part of this report. The number and diversity of organisms, as listed in Appendix B., indicated that the e=vmng-levet--ot'-'water quality-is-good, supporting a healthy:aquatic-biology communitya. 8.. Yegetation and Wildlife /egetation: Open grassland (60%), under cultivation (25%), riparian woodland (10%), and -nak woodland (5%). The channei..-of-Tassajara:Creelo4is lined with a number of large, mature-oak, willow, and cottonwoods;trees and other-riparianu vegetation. While the riparian vegetation is important.-to; the area's. wildlife; it is not a.significantly-.unique- aggregation--to-warrant complete preservations (The riparian vegetation was not significant enough to have included in the riparian vegetation map (Map 10) in the SRV Area General Pian). Proposed krr*19h-has a numbemof-nonLnativeRtrees used in landscaping and for a small orchard. Along the southern border of lot 45 is a double row of large eucalyptus trees. The flat western portion of the site has been under cultivation and is in agricultural crops. The remainder of the. site is covered with native and introduced grasses with several large oak trees. Those large oak trees within lots 1, 2, 13, 14, 24, 25, 28, and 29 are of significant landscape value to preserve. Given the large parcel sizes within the project, the majority of these trees should be able to be saved without restricting development. Wildlife: A sighting of the Northermbrown:.skink, Eumeces gilberti placerencis, was made to the sodtifaf'-the-sitebas recorded in Planning Department files_ The skink (a slim-bodied, olive or brown lizard with shiny scales) is a tocaftdepfeted species found in grassiandgmaodtand, or torestrare By re i zgwthe=proposed hdri&-frail tomoR�t-de:*esu.eaaxchanneLawproposeaWtte47ffdgatiov*amasures, the proFject-ur-not expeczed,�to depreciate;,the--?slue ePthe!fcreekwa3F. The6entirL--stte-iwprobabi3r:used-.by numerous species for hunting (such as Mawks, taxes,_and-cayctes) and foraging (such as raicep-rabbits, and-deer?: TrackqR0Prra=an and"deerlwere-.observed:ardnr---the-,stream b&tlfby the EIR consultants. _ 9. Socioeconomic Characteristics` (data from Social Profile 1978) Population:" In Census Tract 3551: 1975 = 2,139;L980 (est. ..- 3,500, 1985 (est) = 7,000. Project will add approximately 173 additional residents to the area (based on 3.33 per unit and 52 units). Table 3: Census Tract 3551 Pooulation Distribution (1975) Total 0-9 years 10-24 years 25-49 years 50-64 years 65+ years Males 1159 157 394 404 . 132 72 Females 980 147 244 370 107 112 Total 2139 451 638 774 239 184 Table 4: Census Tract 3551 Occupational Status (1970) Total Professional and Clerical, Sales Skilled and 16+ years Managerial and Related Semi-skilled Unskilled Number Percent Number Percent Number Percent Number Percent 389 114 29.3 81 20.8 134 34.4 40 15.4 -18- Table 5: Census Tract 3551 Household Income (1974) Total Less $6,000 $12,000 $20,000 $30,000 Households Than To To To Or $5,999 511,999 $19,999 $29,999- More 577 69 139 184 114 71 Workplace of Wage Earners: The 1975 Special Census indicated people living in Census Tract 3551 had the following distribution of workplaces: City of residence: 17.7 percent Eastern Contra Costa County: 2.8 percent Central Contra Costa County: 13.9 percent Northern Contra Costa County: 12.1 percent Western Contra Costa County:_ I.I. percent Alameda County: 10.9 percent San Francisco County: 2.0 percent Other Areas: 3.3 percent Unemployed or.not in.the labor force: .36.2 percent_ Housing Counts: In 1975, the Contra Costa Special Census indicated Census Tract 3551 had 470 single family homes, 127 mobilehomes, and no multiple-unit buildings. Schools: The project lies within the San Ramon Valley Unified School District: Grade School Distance from Site Capacity Status K-6 Green Valley 10.5 miles Beyond capacity 7-8 Los Cerros 11.0 miles Reaching capacity* 9-12 Monte Vista 11.5 miles Below capacity *To relieve crowding at Green Valley Elementary, sixth grade students are using space at Los Cerros. Students per single family unit in Census Tract 3551: elementary = .69, high school = .44. The project will thus generate approximately 36 elementary school students and 23 high school students. The project may have an adverse impact on the school district as crowding currently exists_in the lower grade levels. Partial mitigation could be achieved through the application of the School District's $330. bedroom tax (chargeable on the second and third bedrooms per unit). If the- project homes averaged three bedrooms, a total of $34,320. would be available to the District. 10. Aesthetics A scenic route, as defined in the County Scenic Routes Element, is a road, street, or freeway which traverses .a scenic corridor of relatively high visual or cultural 'value. Camino=:Tass4jara_:is-desigrm"md,,!W�'-Cod' ty•Sceriie-?horoughfare.% The proje�IIrea and much--of--rural Contra°Costat.were also included in the RidgeI& ds:=dydRidgelands 1977) concerned with development on scenic ridgetops. -19- 11. Energy Electricity: Electrical power will be supplied to the project by Pacific Gas'and Electric Company. Service lines supply the surrounding area and can be extended to the project site with little impact. Natural Gas: PG&E does not have gas lines available in the area. Surrounding residents use propane gas from individual tanks at their residences when gas is desired. Energy Conservation: The inland coastal valley area in which the proposed development is located has both a moderate heating (2750 degree days) and cooling (550 degree days) requirement. The large parcel size (averaging 5.88 acres) and the rolling topography of the eastern two-thirds of the development allows a number of good southern orientation opportunities for solar energy use. Solar energy will be especially important in space heating; since natural gas is not available the other major alternative will be electricity. In the early years of the project, added energy for cooling will be required until landscaping matures to provide shade in the summer. Energy for transportation will be relied upon heavily by the project's residents. The nearest major shopping facilities are in Danville (8 miles away), Pleasanton (10 miles), and San Ramon (12 miles). The Special Census 'has"indicated about 18 percent of the area's residents worked near their home while 26 percent worked in central and northern Contra Costa. Another 11 percent worked in nearby- Alameda County. The traffic survey conducted for this EIR indicated the majority of project residents will travel south to the Dublin-Pleasanton-Livermore areas to 10 to 14 miles away. 12. Cultural Resources Historic Sites: y a mjxvagishoat house. on Finley- Road,. approximately 0.5 mile north of project site. .the building is now used as a community center.. Sitft-c&the*'Tassar -OtUc�. Building established as a post office in 1896 on Finley Road, the lurF Archaeology: An R and -p over the proposed-development by.California Archaeological.Consuitants, Inca (see Appendix C) to determine if the project area.-contained. features-of potentiai archaeologic or historic significance. TheCULW (Tctiges3i wer"e�°re'vie " Al ecoid' though several areas of significance exist in the general vicinity. Thep y was conducted by qualified archaeologists at the standards of a "mixer -strategy-14 investi- gation as recommended by Sonoma State. No-features:off--archaeologic; historic, or cult wa.L significance-twere:robserved. There is a remote possibility a historic structure was located near the border of proposed lots 18 and 19 by the presence of several old palm trees. No evidence of a foundation was observed, however. Based on these findings, it is expected that gn iear aduersewwttaeafcgmsmpa&e_Z tIJroecE=as&a result of development of the proposed project. -20- IL ENVIRONMENTAL IMPACT ANALYSIS A. Environmental Impact of the Proposed Action The following discussion deals only with those environmental impacts .considered significant in the Initial Study or considered to be significant by the EIR consultants. Impacts which are considered to be cumulative or negligible were reviewed in the Initial Study (attached to the back of this report as Appendix A), verified by the EIR consultants, and further discussion does not appear to be warranted. 1. Land Use The project conflicts with the San Ramon Valley Area General Plan insofar as the primary- intent of the designation for the area, General Open Space, is primarily intended to the protection of natural resources and rural, agricultural land uses. The thrust of the Plan is to direct additional development into areas where urban services exist or are planned (such as in Danville, San Ramon, and the Sycamore Valley), and then to further contiguous development once serviced areas have been filled in. Other lands should retain their open space and agricultural status during this period. Whether the A-2 zoning (five-acre minimum lot) adequately fulfills open space purposes is now being reassessed by the County, as indicated by the Tassajara Area Study and subsequent adoption of A-20, A-40, and A-80 agricultural zoning districts (Ordinance 79-108). Grazing in the area is extensive, as it is the sole source of livelihood for many residents or at least affords some supplemental income (Tassajara Study questionnaire, October 1978). Increased residential development near agricultural uses such as grazing can have both direct use conflicts and indirect impacts on land values, tax assessment, and development potential. With added population and traffic near livestock, there is greater need to guard against trespass, vandalism to property and animals, and intrusion of pets. Since the proposed project has nearly 2,500 feet of common boundary with A-4 property used for grazing to the east, these impacts are probable to some degree. The proposed project is likely to have indirect impacts on the land market in the area and on the long term viability of agricultural use. Conversion of the agricultural land in question to residential use may induce increases in the market value of nearby agricultural lands if these lands are perceived as having similar development potential. In the immediate future, this impact would be mitigated where land is subject to agricultural preserve contracts under the Williamson Act. In the long run, however, expectations of developing land or increased conflicts with non-rural uses in an agricultural area could lead to cancellations or non-renewals of Williamson_ Act con- tracts. 2. Hydrology Surface Water: Erection of structures adjacent to Tassajara Creek and its tributaries in designated Flood Zone A (as shown in Figure 13) presents .a flood hazard from the 100- year flood. Inspection of the stream channel at those locations indicated =adequate r.capacity to contain the flow from at least the 50-year flood (based upon the hydraulic geometry method of Leopold, et al 1964)..if.=the channels--were-clear..of..debris: Along -21- most of the stream banks, however, are large trees. At two locations trees were found to have fallen across the stream. During storm conditions, the trees_ may trap debris and cause minor, local flooding. irja�ent-tattte�stream c•� incrrase� - _ res=downTll -" asz ess =chanebaat, erosien. as for the area rrw...�... �r7.. - �.._.._.,.�.._.. - ° .` a�..bein+p°rt to the area s_ -----encs. The proposed project will require a number of.. stream crossings, each having the potential to cause localized flooding if they are not engineered with sufficient hydraulic capacity to pass the design flood flow. The area upstream of the crossings would be flooded as water flow through the culvert is restricted and begins to back up. As part of the Drainage Permit process, the applicant is required to submit hydrologic and hydraulic calculations__fdr—all proposed culverts indicating proper design. The Flood Control District/is particulart)`eoncerged about the proposed-crossing_of :•Tassajara'Creek on Bruce:.,Dr.Lve (Agnew 1980). . The creek banks at the proposed bridge site are on a 1:1 slope which the District feels is unstable and subject to- further-slippage and erosion: The District believes the existing,creek.alignment_approactt.to the bridge.is.poor;.and will cause-problems,to the bridge and the general vicinity. The possibility also.exists for minor soil-slides into i e creek causing flooding. Areas of bank slippage into the streams were observed. Soil slides into the stream are particularly possible along lots 2 and 3, and to a lesser extent, lots 13 and 14. NewA.road:_surfaces4.and,structures-w�ouldn add.additionar discharge •to6'Taisajara:Creek:via increased-=impermeable:surfaces. The increased'ninoff-would be offsessomewhat by the igpreasedbevapetranspiratiorr�deniand"from-new landscaping. This is not anticipated to be a significant adverse impact on five-acre parcels but a cumulative impact. Groundwater: The project is located in an area where domestic and agricultural water is primarily obtained from wells. Since the site is located at the junction of a perennial stream and an intermittent tributary, groundwater may be more readily obtained on the flat Quaternary alluvial deposits. The higher elevations ori.Tertiary materials may have more. difficulty obtaining adequate, well water. . A synclinal formation below the site (Engeo 1979) indicates the possible presence of an aquifer. .Geologic strata dip toward the site from both the north and south. The s f& 'impacdtwrr=mrditt w s a ted<AKLtltouspedic' opese�teilCieids and dcawdown� If the consumption was 1,000 gallons per parcel per day (domestic; irrigation, and livestock use), the development would require about 52,000 gallons per day (58.3 ac, ft. per year or 36 gallons per minute, continuously). The Fire District requires 60,000 gallons also available to meet emergency needs (see following section on fire protection). Available groundwater may be a significant constraint to the development as proposed. The tentative map indicates the applicant wishes to retain the ability to create a community water supply system. Several large water tanks have been constructed on the upper elevations of lot 52. Most small community water sources experience greater difficulty with maintenance than with failure of the source to supply the necessary quantity and quality (Dunne and Leopold 1978). A method of financing emergency and routine maintenance of a community water system should be available. -22- uh UZI ifa .. �: - A+S,. .�*•+� ,;.�.... '�. �!_ � r` -, n, 2E- - ..•e..��-, .. �. ♦r� i.r...y� - �' �,�_t __�_^'.s> 'SS. rya^`•�a' .- ,y�f_ ..- -_ �r�+,. a �- �.`�..-'`•1 T _♦SS'L-2"-.:'� '4- � .int •'•/ .i �..�le,.•.�.-3A `�'G•:i a��,sem �- �__��s.�- •"''Z' tw. .. �• •~t ""::`=Ce'♦r`T =:4 � ~.Z.. 1'C"•'f„ya., i'�F,�aZ, a•��7.. .,_ , '.�~ 'b�iy �'�s .a^: ' y<. �`�o'�l'`� <t•S� •.� �r`I.f��` �'iC � � ^R: 71.. ��_� r��-. ate. \ �—� f• �- • ���'t`.�' y' i '�T -'R:«t��E+•-a`hc. -.r'a �e.',� :jam'�'- e ".c. _ „�T2r�����.._ - ,'y•':�-t�'..�•�'.i.�Jli'c,S��- r-►iv::•�'!. ��a'�.�•.l�ar°,�;::�.• - _ .�� �_. - -�•g w:� ~'�4�.: b. Road System: "the need for roads to provide adequate access for emergency vehicles"; c. Fire Equipment: "the need for substantially increased inventory of fire suppression apparatus by the Tassajara Fire District; and d. Weed Abatement: "the need for clear assignment of responsibility for weed abate- ment_and firebreak construction. Unless substantially mitigated as described in the Mitigation section, all four concerns have the potential to produce significant adverse impacts on the Fire District. 4. Traffic The proposed subdivision will generate aproximately 520 average daily trips (ADT) based on 10 ADT per residence. Most of this traffic will head south to Highway 580 and the Livermore or Pleasanton areas while a quarter to a third will head west on Camino Tassajara to Highway 680 at Danville. Danville is approximately el ht miles away while Pleasanton is.10 and Livermore is 13 miles away. EarElinaass ascurcesttiy _qder- ,.. stud? rea ig tea betweertmSycamore»-,_, 1W an e'Sa� oa y e "cealignrrrent y...0 �.: may a7tec the non-commute"travel'patterrro the-new-residemaking the road more efficient to travel. The project is expected to add:I3Q'_ADT (one fourth of 520) to-Caminor.=:Tassajar-&headed .west toward Sycamore_Valley Road or Diablo Road and Highway 680. This will be a 19' percefmwincreaser over the existing 690 ADT at the project site. Added to Camino Tassajara southbound toward Highway 580 will be 390 ADT, a 51 percent increase over the existing 770 ADT. Sixteen lots (1 through 6, 39, and 42 through 50) could be expected to use Johnston Road to reach Camino Tassajara. This will add approximately 160 ADT to Johnston Road, an increase of 94percent over the existing 170 ADT. Another proposed development to the east (MS 81-79, S. Moore, Applicant) is expected to add 48 ADT to Johnston Road, bringing the total to 378 ADT. Johnston Road is currently in need of repair and resurfacing, a portion having fallen into the creek east of lot 45.- The tentative map was revised to eliminate Gordon Way west of Sharon Drive in response to comments from the Country Lane Homeowners Association. With the installation of a standard traffic barricade: at the end of Gordon Way as proposed, no direct. traffic impact is expected on.Country Lane or Finley Road_ 5. Soils and Geology Soils: The soils over the project site are characterized by a moderate-.to high. shrink- swell potential-(as listed in Table 2). This produces soil expansion during therainy---winter months and contraction during. the dry summer months. The repeated change in volume can be particularly damaging to shallow building foundations or concrete slab foundations which have not been designed to withstand this effect. The soils also are characterized by sfo,�?"to"moderate7perrieability. • The engineering geologist's percolation tests indicated there should be adequate percolation capacity for individual septic units (Engeo 1979). Large lot sizes planned for this subdivision should allow sufficient room to provide adequate septic drainfields. A site-specific drainage test, however, will be required to insure adequate percolation capacity. -24- Landslides: Four landslides are shown on the tentative map while several others are shown on U.S. Geological Survey reports (as described in Section I.6 on page 14). Of particular concern are the landslides mapped on lots 27, 28, and 35. The upper elevation of lot 27 is covered by a landslide. If a home is constructed on the lower elevation near Elizabeth Way, the danger of the slide moving against the structure exists. Lot 28 has a slide mapped between an upper elevation home site and the road. Thus a driveway would need to traverse the slide. The slide currently has a surface slope of over 40 percent. The western half of lot 35 is covered by a slide. Placement of the septic drainfield will need to be carefully considered to prevent the liquid from lubricating the slide. Licuefaction: Areas within the project site along,Tassajara Creek..and tributaries are rated as having a high.liquefaction potentiat�by the,Countya. The transformlatidhi-of the wess-;aihndaNrnateri;Wto"a;Iiquid`state;=can 4:reate"ty 'potentiaL.bazard3. The'Tir-'t is the sudde atmd'settld nenrbeneath`;they"r*K"d " The,Rh&4is the possibility of-4a=vztmgwlandslidesxinrsteepMrea9a Damage can result"to homes, septic systems, roads-, and utility lines and pipes. Faults: Subdivision 5736 is four to eight miles east of three active or potentially active faults. There is some professional disagreement on whether or not the project. site itself is crossed by a fault. Although significant earthquake damage can occur to homes or roads constructed directly on a fault, the greatest amount of damage is caused by the ground shaking and related ground failure during an earthquake. Level of damage from an earthquake is a function of the size of the quake, its distance from the site, and the characteristics of the ground. Homes constructed on the project's hilly regions may be subject to earthquake-induced landsliding while those on the level areas near the streams may be subject to earthquake-induced liquefaction damage. B. Any Adverse Environmental Effects WNch Cannot Be Avoided If This Proposal Is Implemented 1. Irreversible loss of prime agricultural land to residential uses. 2. Conflict with adjacent A-4 agricultural uses. 3. Urbanization would occur before utilities and transportation facilities become available in the area. 4. The project has the potential of inducing further residential growth in a predom- inantly agricultural area by setting a precedent which similarly situated property owners might reasonably expect to follow. 5. Increased demand on the• area's aquifer for well water and increased potential for groundwater pollution through the installation of septic tanks. 6. Increased demand.on the volunteer Tassajara Fire District. 7. Increased-,-traffirflow`onto`'Camiho:Tassajara*and the western portion of Johnston Road. 8. a meat -25- 9. Increased enrollment in a school district currently reaching or beyond capacity. 10. Placement of structures on ridgetops adjacent to a County Scenic Thoroughfare and within the Ridgelands study area. 11. Significant commitment of renewable and nonrenewable resources. The remote- ness on the project site creates an adversely large demand for energy. C. Mitigation Measures Pr000sed to Minimize the Impacts 1. Land Use * The eastern end of Sharon Drive could be 42 43 eliminated, instead turning south into Laurie Lane (see Figure 15). Land to the east is SyAR currently zoned A-4. The presence of a ON DRIVE street end at its boundary may increase the probability of rezoning to similar A-2 resi- dential. 49 LAURIE . LANE * The applicant should adequately fence the As Proposed eastern border of the proposed development to allow continued grazing on the adjacent property with a minimum of impact. 42 43 2. Hydrology SygRON , - 44 49 s tori 1oa slti �- m eteminatioc�o€ ctiiiaff iv i s As Mitigated arid " 'tyaciatyes must be reviewed and- approved. ndapproved. by the County Public Works Department. Figure 15_ Land Use Mitigation 11 oil W n This is especiaffy"e "- - ve `assajara L.ee - * Flood control installations should be designed to the requirements of the County Flood Control District.. Existin culverts or bridges which are found to be inade ate should be replaced or removed. b-d d be"` * A detention:-basin could be created4irwarkexpandedmWr& dry-iNWeasemenr-upstream- of the Sharon Drive crossing through minor grading. Used in conjunction with a crossing of specific hydraulic capacity, the basin could .itti cfewnstxea flooding through detention storage. -26- * An area could be excavated on lot 12 at the Tassajara Creek and tributary junction to also function as a temporary storage area with the installation of a flow restriction. weir (check dam) or baffle downstream. * A site-specific groundwater investigation must be conducted to confirm the existence of adequate well yield for domestic and fire-fighting use. prior to approval of the Tentative Map. * A site-specific percolation study must be conducted to confirm the ability of each parcel's soil to function for septic tank and drain field uses. * If the applicant proposes one major well for a community water supply system, it must be specifically reviewed and approved by the Environmental. Health Division of the County Health Department. The well should be located within the- center of the development so that-the drawdown has minimum effect.on neighboring wells. * Adequate funding for routine and: emergency maintenance: of community well and water supply equipment should be included in homeowner- agreements if a community water supply system is developed. 3. Water Quality * To reducerthe. mpact�pf>horse-trave --hrthetstrearw.bed:, the hd&41! d'7easemerrt should be placed on thewestern�'�'assajaraoCreelzj6 This would allow sufflci dtn.ITO ride°-on the"3evel'a .eas, aVdId_-'gefation, and restricrmtre=iutrossings. Trail easement on the east side of lot 12 should be transfered to the north side along Bruce Drive to let riders cross the streams on the Bruce Drive and Sharon Drive bridges (see Figure 16, Horse Trail Easement Realignment). Move horse-trail easement to the east side of tributary north of ; Sharon Drive crossing. ; ► ► Move horse-trail easement to parallel Bruce Drive and allow -; .stream crossings only on bridges. ► Move horse-trail easement to west side of Tassajara Creep t Source: Tentative Map Sub. 5736 Scale: P = 780' Figure 16. Horse Trail Easement Realignment -27- I In addition to -eing essential h i ar w die, it provides a natural streamside filter-of horse and cattle organic contaminants as well as any deleterious substances such as pesticides. * A fence may be necessary to prevent. motorcycle or horse riders and cattle from continuous access to the stream channel, causing erosion as well as contributing organic contaminants and enrichment to the stream. 4. Fire Protection (taken from Eppler 1980) * All roads and private driveways shall have grades not to exceed 17 percent. Roads shall be of all-weather construction with a minimum width of 16 feet. * The developer shall be responsible for meeting State requirements for weed abatement. The developer-shall be responsible f or-the design and construction of a water system to conform to minimum standards for fire suppression in a major subdivision in a rural district, including: a. capability for a minimum fire flow of 500 gallons per minute, b. a. minimum pressure of 20 p.s.i_available at any hydrant at such flow, c. capacity for duration of two hours for such flow, d. hydrants to.. be. of standard EBMUD type with one 2Y2-inch and one 4Y2-inch discharge,- e. fire hydrants to be placed along roads so as to supply fire flow to all residences; details-of such placement subject to approval of Tassajara Fire District, and f.. water storage required to supply above requirements to 60,000.gallons in excess of any domestic water supply. - - * The developer shall make 'appropriate financial arrangements for the provision to the Tassajara Fire District of an apparatus. for . structural fire suppression_ Detailed specifications.for such-a-unit shall beset b)o,the Fire District -- '� To assure adequate fire protection for the proposed. subdivision, the Tassajara Fire ~~District recommends that a Special. Assessment District be established by the owner to finance and maintain the facilities-described in these mitigation.measures. 5.. Traffic- Also, off site roao ' cnvements--_t = is MAJI'l 4­Aldo LIN= -in -Road and * Easement for a future bus stop and shelter could be provided along. Camino Tawajara Road. Although there is no-commercial bus service available in the area, the demand for mass transit services_ will increase if the area continues to be converted to five acre residential lots. -28- 6. Soils and Geology * Home foundations should be designed to have minimal contact with the soil zone of maximum seasonal expansion. An example of a foundation meeting this requirement would be drilled piers obtaining their support below the expansion zone. * Garage slab foundations should be supported on a layer of non-expansive fill, designed to free float, with appropriate reinforcing. * Roads and other pavements should be designed to minimize the impact from expansion pressures. * A detailed geotechnical report should be conducted prior to parcel development and the report's recommendations incorporated into site design. This may require landslide deposits on or adjacent to home sites be mitigated by removal of the deposits, excavation and reconstruction on the slope, or by buttressing the landslide. Recon- struction or buttressing should be engineered and construction supervised by a registered engineering geologist. * Roads and utility easements should be located away from landslide areas wherever possible. Slide zone stabilization, such as where Sharon Drive crosses a landslide, should be accomplished by overexcavation and engineered reconstruction. * A detailed geotechnical report should be prepared for those parcels located within the County liquefaction hazard zone. The report should address the liquefaction hazards and recommend site-specific mitigation measures to incorporate into parcel design. 7. Cultural Resources * If, during site excavation, grading, or development, features such as bone, shell, obsidian, or charcoal are unearthed, work in the vicinity should immediately be halted within a 30 meter radius and a qualified archaeologist be contacted to evaluate the find. D. Alternatives to the Proposed Action 1. No Project Alternative This alternative emphasizes that appropriate site uses are primarily agricultural. Presently the site comprises four parcels of 74.5, 83, 83, and 90.7 acres. Under present zoning one housing unit may be built on each legal lot. Given two existing homes on parcel B, there is potential for three additional units. To clarify land use policy in this alternative, A-2 zoning should be changed to Exclusive Agricultural District A-80, with a variance granted for construction on the 74.5 acre parcel. A minor change in parcel boundaries would be required to accommodate the house Under construction which straddles the parcel boundaries. This alternative would' minimize adverse impacts on groundwater supply and growth inducement. Conflicts with existing grazing uses, particularly agricultural preserve lands, would be avoided. -29- 2_ A-40 Zoning Alternative: At one unit per 40 acres as many as eight residences could be developed. Considering the topography of the site, there are advantages to clustering units on two to five acre sites on flatter lands close to Camino Tassajara and leaving the steeper hill lands to the east open for grazing. Contra Costa Agricultural District zoning allows such flexibility for single family dwellings, provided development. rights, grants and/or open space and conservation easements are conveyed to the County for those lands not- occupied by housing. The conveyance "shall be valid for the period of time specified by the planning agency but not to- exceed twenty-five years" (County Ordinance 79-108, Article 84-80.1204(3)). Clustered siting would result in savings for some community services costs (e.g. roads) but, depending on density and location, might require installation of a community water system. The effects of this alternative include stabilizing development potential of the site, securing up to 85 percent of the site exclusively grazing. 3. Agricultural/Residential Alternative This alternative recognizes that the western third of the site is prime agricultural land, Class I and II soils, an "endangered" resource in both California and the Nation. Prime farm lands are the most energy-efficient acres, producing the most food, feed, fiber, and forage with the least amount of fuel, fertilizer, and labor (NALS 1979). Prime farm lands, unfortunately, are also the easiest and least costly to build upon. The western portion of the development could be. divided into two parcels. Parcel A (lots 4 through 12) would cover 50.2acres. Parcel B (lots 15 through 22 and lot 34) would cover 47 acres. These two parcels could be put in an Exclusive Agricultural District A-40 classification. The remaining 34 parcels would then be developed as proposed. This alternative would eliminate the loss of some prime agricultural land as well as minimize the flood hazard by restricting uses in the flood-prone low. areas. 4. Residential/Commercial-Recreation Alternatives: These alternatives are based.on the premise that economically viable uses complementary to agriculture and limited residential development could be accommodated on the. site. It could be accomplished through either agricultural (A-20) or Planned Unit (P-1) zoning. The difference between.the two is gross residential.density..allowed: one.unit per 20 acres under A=ZTversus'one unit per five acres under. P=I zoning: Combining various provisions of A-20 zoning,- project design could include up to' 15 dwellings (clustered as in the A-40 Alternative), a small commercial horse stable, and dedicated open area in the hills which could be devoted to equestrian trails or grazing. As with the A-40 Alternative, total number and siting of units would be contingent on arrangements for water supply and other facilities as well as site capabilities. With P-1 zoning a higher unit density would be possible; depending on residential site suitability and the total acreage not devoted to residences and open space. Appropriate residential density in the P-1 zone is determined by the General Plan designation - in this case "general open space", allowing a maximum of one unit per five acres under conforming A-2 zoning. "In establishing residential densities using the general plan as a guide, those areas set aside for churches, schools, streets, commercial use (such as. a horse stable) or -30- other nonresidential use shall not be included in the net development area for purposes of computing residential densities. . The areas set aside for common open space, outdoor recreation use (such as equestrian trails) or parks shall be included in the net development area for purposes of computing residential densities" (County zoning code, section 84- 66.026). The project's 323 acres could be divided into 23 acres of roads and a 10 acre horse stable. The remaining 290 acres could contain 58 single family units clustered in several areas with open space and horse trailssurrounding them. The increased density would, however, increase all of the impacts identified with the proposed project. 5. Energx Alternative It is recommended the developer take advantage of state and federal tax incentives to incorporate energy efficient systems and materials in new home construction. Such measures would result in considerable savings in the cost of residential heating and cooling. Landscaping with deciduous trees to the south and west of structures and efficient structural ventilation and orientationwould minimize energy requirements for space cooling. Such measures should mitigate the higher energy use patterns of the proposed detached single-family dwellings. E. Growth-inducing Impact of the Proposed Action The project as proposed is growth-inducing. While not the first major subdivision (division into five or more parcels) proposed in the Tassajara Area, this 52-lot project is significantly larger than any predecessor (see Table 6: Tassajara Study Area Subdivisions, on the following page). It is reasonable to anticipate that further approvals of both major and minor subdivisions in the area will enhance the development expectations of similarly situated property owners. For an order-of-magnitude estimate of development potential (disre- garding for the moment constraints such as topography, access, and water supply, which can be partially overcome by site design), the Tassajara Area includes over 6,500 acres of.land zoned A-2 exclusively (that is, lands with the same zoning as the project site). If developed at one dwelling unit per five acres, these lands ,would generate 1,300 additional residences and a population increase of over 4,000. Even assuming that such development were accomplished on an incremental basis, with individual domestic wells and sewage disposal rather than community facilities that might have growth-inducing capacity, the impact on shared services and facilities such as police, fire, schools, and roads would be substantial. Reliance on a water supply policy that recommends individual wells rather than community service systems has several potentially divergent growth impacts. On the one hand, contrasted with extension of a water district or community system, individual wells assure that excess capacity is not developed; indeed, overall capacity to provide water to both new sites and existing developments drawing on the same aquifer is depleted. Furthermore, such a policy may reduce total development potential on a site because some parcels may not have adequate water. On the other hand, the policy permits development scattered according to water availability, which is inefficient for providing other services and in reinforcing dependence cin automoUes. The approval of this project plus others contemplated or possible in the future will place a high demand for commercial services which are not available in this are. Any residents will need to travel to the Livermore-Pleasanton area (12 miles away) or the Danville area (8 miles away). There will be pressure to convert some agricultural land to commercial uses, especially as gasoline gets more costly in the future. -31- TABLE 6: TASSAJARA STUDY AREA SUBDIVISIONS (data from County Subdivision Log to February 10, 1980) Subdivision Total Acres Parcels Parcel Size 1977 Approved Subdivisions (Two minor subdivisions were denied) 76-77 11 2 5.5 acres 81-77 26 4 6.5 86-77 26 4 6.5 95-77 10 4 2.5 147-77 440 4 110.0 170-77 12 2 6.0 188-77 10 2 5.0 189-77- 11 2 5.5 190-77 46 4 11.5 226-77 160 4 40.0 229-77 35 4 8.8 265-77 853 4 213.2 278-77 149 4 37.2 290-77 98 4 24.5 317-77 10 2 5.0 320-77 15 3 5.0 331-77 11 2 5.5 341-77 10 2 5.0 342-77 143 3 47.7 5247 360 7 51.4 20 subdivisions 2,436 acres 67 parcels Subtotal 1978 Approved Subdivisions (Four minor subdivisions-were denied), 23-78 52 4 13.0 57-78 TQ: Z '5.0 58-78 45 4 3.8 70-78 547' 4 136.8 100-78 84 4 21.0 124-78 19 3 6.3 135-78 235 4 58.8 207-78 133 2 66.5 213-78 77 4 19.2 10 subdivisions 1,183 acres 33 parcels Subtotal -32- TABLE 6: TASSAJARA STUDY AREA SUBDIVISIONS (continued) 1979-1980 Subdivisions (none denied) Subdivision Total Acres Parcels Parcel Size Status 32-79 60 3 20.0 Approved 54-79 146 2 73.0 Approved 61-79 111 4 27.8 Pending . 62-79 97 4 24.2 Pending 63-79 107 4 26.8 Pending 64-79 110 4- 22.5 Pending 81-79 50 4 12.5 Pending 4-80 15 2 7.5 Pending 14-80 55 4 13.8 Pending 2391 145 22 6.6 Pending 5638/5384 48 8 6.0 ' Pending 5686 225 6 37.5 Pending 5736 323 52 6.2 Pending 13 subdivisions 1,492 acres 119 parcels 1977 through February 1980 Total 43 subdivisions 5,111 acres 219 parcels 23.3 acres average parcel size 119 acres average subdivision size; average of 5 parcels per subdivision -33- F. Organizations and Persons Consulted; Bibliography During the preparation of Environmental Impact Reports, written and oral communications take place between the consultants and the Planning Department, Public Works Department, and other county departments. -The General Plan and its various elements are also scrutinized regarding the proposed action. Additional Consultations and Communications: Agnew, Robert.' Contra Costa County Flood Control District. Personal communication. February 11, 1980. Bleecker, Dr. Michael D. Letter from the Country Lane Homeowners Association to Arnold Jonas, Contra Costa County Planning Department. January 23, 1980. Cline, V.L. Letter to A.A. Dehaesus, Director of Planning from Public Works Director. March 12, 1980. Dasher, Harry. Contra Costa County Farm Adviser. Personal communication. February 14, 1980. Dispatcher 20, Contra Costa Sheriff's Department. Personal communication. January 29, 1980. Eppler, Chief Stephen P. Tassajara Fire Protection District. Personal communication. February 21, 1980. Gerow, T. Contra Costa Health Department. Personal communication. February 13, 1980. Khanna, T. Contra Costa Public Works Department, Transporation Division. Personal communication. March 28, 1980. Robinson, Lt. J. Letter to AEP Associates regarding nearby project. December 26, 1979. Vukad, L. Contra Costa Public Works Department, Traffic Division. Personal communi- cation. March 28, 1980. Bibliography: (ABAG) Association of Bay Area Governments. 1978. Regional Plan. Berkeley, Calif. Brabb, E.E., H.S. Sonneman, and J.R. Switzer. 1971. Preliminary Geologic Map of the Mount Diablo-Byron Area. U.S. Geological Survey. Basic Data Contribution 28. Caltrans. 1975. 10th Progress Report on Trip Ends Generation Research Counts. District 4, San Francisco.- Contra Costa County. 1978. Social Profile: Part U. Dunne, T. and L. B. Leopold. 1978. Water in Environmental Planning. Freeman and Co. Engeo, Inc. 1979. Preliminary Soil and Geologic Reconnaissance, Bruce Flanagan Property. -34- Leopold, L.B., M.G. Wolman, and J.P. Miller. 1964. Fluvial Processes in Geomorphology. Freeman and Co. (NALS) National Agricultural Lands Study. 1979. Where Have The Farms Gone? Wash- ington, D.C. Ridgelands Administrative Board. 1977. Ridgelands: A Multijurisdictional Open Space Study. USDA Soil Conservation Service. 1977. Contra Costa County Soil Survey. US Geological Survey. 1974. Interpretive Report 4. Wagner, J.R. 1978. Late Cenozoic History of the Coast Ranges East of San Francisco Bay. PhD thesis, University of California, Berkeley. G. Qualifications of the EIR Authors Consultants for Environmental Assessment, Ltd., of Albany, California, prepared this envir- onmental impact report under contract to the Contra Costa County Planning Department. Key personnel of CEA included: Michael C. McMillan, B.S. Geology and Geophysics, M.S. Wildland Resource Science Carolyn Yale, B.A. Anthropology, M.C.P. Master of City and Regional Planning Thomas Flynn, B.S. Zoology, M.S. Aquatic Ecology -35- APPENDICES Appendix A. Initial Study Appendix B. Water Quality Study Appendix C. Archaeological Study Appendix D. Geological Report -36- CONTRA COSTA COUNTY PLANNING DEPARTMENT INITIAL STUDY OF ENVIRONMENTAL SIGNIFICANCE File I X-Ref. Prepared by Date /Z- Z 7 7 _ Reviewed by Datemom / RECOMMENDATION: � . ( } Categorical Exemption ( } Negative Declaration (Environmental Impact Report Required Class of Exemption ( ) Conditional Neg. Declaration (Must Include Mitigation Measures) The Project (May)�(.;Li�-1Have A Significant Effect On The Environment The recommendation is based on the following: _ �- .T�+►%Gi>., _r J��.�,t�OthC ra fob cSS�f'G�7Gi/_� G /iL.- �Lc;�lr/�-1l'l /IV • 51A- l /',�?.:,w, 771E 7%J C Ccs /r1 G/ r!� ,r•�c iM,D/�G 75 TOkiD49 A?)ene:r,, -Awi, .S�.�.•�'Co4 /�r�rJ /71/�-� G�L.L'7 /ila,► /n-J/�Gi J G��Dyt�!)�clrc`,F� �i��j�-r., , 7LL . o e P Sect ee �mpa-cts? tY�?�sx1�%1>G C��,7id��s�sJrS 11 n•�>a�C Gf<JiJfc:G /A_1 U,Scr .�NQ�c Y�� r�L."�( rylT�.0 /f?L: /R,76'yt7 c� j7�,:- �,i►_-�1�'i�C, ,y L/J i', , Project Location: USGS Quad Sheet Geographic Lat: _° Coordinates Lona: ° GENERAL CONSIDERATIONS: 1 . General Plan Considerations (Land Use Designation, Area Plan Name and Date, specify. any conflicts): �rl/ l�'/iL 2. Zoning District (Specify Current and Proposed and any Conflidts) : 3. Site Description and Existing Land Use: ,>41 �.- �-r; 4. Nature of Request or Proposed Land Use:ekMl ol(i"/yJC G�.i5. , iti•c- 5. Characteristics of Surrounding Area: 6. Related Applications:. (list any EIR`: prepared for nearby projects) a i _ Coes it appear that any feature of the project, including aesthe- ,. -tics, will generate significant public concern? (Nature of Concern): YES NO MAYBE �O47<_l'� Will the project require approval or permits by other then a County Agency (Consider spheres of influence, and City Pians)? YES NO Agency Names) - ENVIRONMENTAL IMPACTS: - S--Significant N_Negligible C=Cumulative No=None U=Unknown 1. Water. Will the project result in: S N C NO U a) Erection of structures within a designated flood hazard area? — b) Reduction of surface or ground water quality or quantity? — c) increased runoff or alteration to drainage patterns and streams? 2. Earth. (Consi.der the Seismic Safety Element) Will the proposal ' S N C NO .U result in or be subject to: a) Erection of structures within on Alquist.-Priolo Act Special Studies Zone? --- --- — — — b) Potentially hazardous geologic or soils_ conditions on .or im- - - mediately adjoining the site? (slides, springs, erosion, liqui- faction, earthquake faults;.consider.prime soils, slope, septic v tank limitations). Cite any geologic or engineering reports. c)-. Grading (consider height, steepness and visibility of proposed slopes;consider-effect of grading on trees, creels channels and ridge tops). /�l�l.rJ�rvr - 3: Plant/Animal Life: N C NO' U -"a) -Wilt there be--a-reduction of-habitat.for plants and•animals? — b) Wiil the project affect the habitat of any rare, endangered or unique species located on or near the site?. c) Will new species be introduced or expanded into the area? (dogs, cats, pests)? ,G�`�r,✓Sc.-�i✓:�LO 4 ("le,-WA("'C% ---`=�— — ---- �i �•!.1 �i�r�rtw•G•��- .mit 2.;uG- of9c;72���v�,S _ d) What vegetation (habitat) types-exist an the site.(gi4e relative % or-proportions if significant)?'List habitat types. Discussion: ©p:=: . A-2. 4. Energy/Natural Resources/Hazards (Consider Safety and Seismic S N C NO U afety lements). Will the project result in: a) Any additional consumption of energy? b) Affect the potential use, extraction, conservation or depletion of a natural resource? Cajrvxi,779f/ulr l%M c) Increase risk of explosion, release of hazardous substances or other dangers to public health and safety? _ _ L_ S. Utilities and Public Service ..Will the project: S N C NO U a) Require alteration to- or the need. for new utility systems (including sphere of influence or listrict' boundary change;. water, sewer, solid waste)? b)- Result in the need for new- or expansion of the foliowing ~ services: fire and police protection, schools; parks- and recreation,.roads, flood control or other public works facili- ties, public transit or governmental services (include changes to sphere of influence)? c) Affect recreational opportunities (consider . Recreation Element-Trails Plans)? 6. Transportation/Circulation. (Consider the Major Roads Plan)Will. S N C. NO U the project result in: a) Additional .traffic generation or increase in circulation prob- lems (consider road design, access, congestion, parking and v accident potential)? ?4aa-L .e,,,,4 5 r. 4� 4e.S, !V -��.� ,rte s.r��,,i.•3 L .t«�; /c'�•hsf.'T:'��:c , - b) Special transportation considerations (waterborne, rail, air or public transportation systems and parking facilities)? 7. Housing and Community Development.(Consider Housing Ele- ment).* Is the. project: YES NO = . a) Within a-low and moderate income housing site? v b) Located in a Neighborhood Preservation Area? C� c) A growth-inducing action (encourage additional requests fora similar uses)or set a precedent in the area? _ 8. Aesthetics. (Consider.the Scenic Routes Element) Will the project S N C NO obstruct any public scenic vista or view, create an aesthetically offensive site open to public view, or produce new light or glare? Discussion: �yJJ�.G...,vn� � ��?v G:_l flf/j.f L- y<_•%t':'/-��<;� • S •tire G��>> Ocv-4.� u"'J�< i JOSS� e';G�: ftt x�.//1 L. des'�3 ci= � i.::•A'/ <<i«it.'.:{1'G �1,���,1•:'�i , * A yes answer should be referred to t a 1':.)mrnunity Development Section., 9. -Cultural Resources. a) Has a resource review been done by the Regional Clearing YES_NO_DATE._,. . house? (their recommendation)? bl Nearest County Historic Sites (consider Historical Resources Inventory) -57 il4gW A 1 -�' c't��c' 1-11 449�. , -- 10.. Noise Will the project result in: S N C NO a) Structures within the 1990 60- dBA noise contour (check.the General Plan Noise Element)? — b) Increases from existing noise levels? 11. Air. Will the project result in deterioration of existing air quality, S N C NO. U including creation of objectionable odors, or will future project residents be subjected to significant pollution levels? - 12. Mandatory Findings of Significance. (A"yes" check on any of the YES NO C of owing questions requires preparation of an.EIR) '- a) , Does the- project- have the potential to degrade-the quality of the environment, or curtail the diversity in the environment? — • b) Does the project have the potential to achieve short-term, to the disadvantage of long-term, environmental goals? - c) Does the project have impacts which are individually limited, but cumulatively considerable? "/tG -- Ise /94z,4 ale'a-l-AJ ;5dc .SGML//CGS /./ d)_ Does the project have environmental impacts which will. cause substantial adverse effects on human beings,..either directly;or. indirectly ? _ Discussion--. /0.S rc�2S� ti/dc%2 v�� �3���'S�v�-t afC Tl1sS - fa CS/20*4,-6 Al./>/ ,tJ�4u-s,7 .e `cam=f.�� �igO��s�•c• f.1�o Sa L5 ou ao�Ja/•vic.� oit //G1�,�,6'� G,o�,o S:. - '. rl Gfa.r»a Gv7�LL' �f'CZ 7 af" ►� Ac: Lrii�C �i,► , Si�v+liG.,rjt7 �'1 .oi�z Grr�-7�,;-ki i1.(.%c.�� - S`3-�uc ci S AV 4A./ ,&4:7V,GxyG A-4. CALIFORNIA A13CHAEOLOGICAL CONSULTANTS, INC. Q ROBERT ORLINS • 39 FIRST ST. « WOODLAND, CA 95695 • (916) 662-0979 M PETER BANKS 5916 DOVER ST. OAKL-AND, CA 94609 . (415) 658-6560 v ARCS. ozo�-0 INVESTIGATION OF SU3z rTS ION 5 7;0 , TA+SSAJAR4 r CONTRA C OSTA C OnLIT I, CALZORNI3 Prepared for Consultants for E=viror-ental Assessment , Ltd. bq 'Teter U. Banks March 1950 C-1. CALIFORNIA ARCHAEOLOGICAL CONSULTANTS, INC. 0 ROBERT ORLINS • 39 FIRST ST. WOODLAND, CA 95696 • (916) 662-0979 . M PETER BANKS • 5916 DOVER ST. • OAKLAND, CA 94609 (415) 658-6550 A= -krchaeologlcal Investigation of Subdivision 5736 , T3ssajara, Contra Costa County, California Peter M. Banks March, 1 , 1980 Introduction On February 14, 1980 the author and three experienced arch- _ geological technicians conducted an. archaeological investigation of Subdivision 5736 , a 323 .5 acre aprcel located near the com- munity of. Tassajara, in southeastern Contra Costa County, California (see Map- 1) . The investigation was requested by Consultants for Environmental assessment , Ltd.. acting. for the owner/developer of the property, Bruce Flanagan. Proposed development of time subjecW parcel would include construction of approximately 52 low-density residential units . The purposes of the investigation were : (I to determine whether any archaeological resources were present within the subject parcel; (2) to evaluate the significance of any such resources ; C3) to estimate the effect that residential devel- opment might have upon such resources ; and (" ) to recommend procedures to mitigate any adverse impacts that residential development might have upon such resources . Following - an intensive examination of the ground surface and of all exposed soil profiles , it can be reasonably con- cluded that no sigai I* cant- archaeological, resources-:.were present. within Subdivision 5736. However-, because ma�.�pre- hist otic._,sites;.yin-eastern-�o ntraz-Costa-County�:rhave-:•be e�puri end by-alluvium, there is a slight:uposs'fbi'li'trthat there ma�:ba burie(i-sites within tae subject parcel . It is recommended C-2. that- J any archaeological materials are encountered during construction, the worm is the imaediate area be halted until an. archaeologist evaluates the finds and a representative from the American Indian Council, San Pablo is notified. The nature of the materials that might be encountered. is discussed below. Envir omental Setti ^= Subdivision 5736 was located just south of the cam--Unity of Tassajara , in southeastern Contra Costa County, California. _ It is depicted on the USGS Tassajara quadrangle , 7W series (1974) within the southwest � of Section 341 m 1 S , R 1- E ; and within tae northwest '�L of Sections 3 and the northeast part-Jon of Section 4-, T 2 S , R 1 E. The project was centered. at appro=+mately 6 01 000 m R; and 41 83 250 m N —IIT.U, as measured from the Ut .' Diablo meridian (see- Map 1) . Subdivision 5735 was immediately southeast of. the later- sections of Tassajara and Finley Roads . It was bordered to the . west by Tassajara Road; to the east. by a. fence-line marking the half-section lines of Sections 34 and 3 ; to the south by Johnson Road; and to the north by residential properties 'Located on Country Lane. and- on Old School. Road . The subject_ .parcel was situated.. in. and_ along. the valley floor and slopes. of the middle reaches ;of Tassaj.ar3 Creek, and. _Lm as area ._where. the.. steepening _of: slope marked. the trasition from.-broad, flat-- valleys:. and.. -law., r-ouad.ed "hills to the foothills on the south_ side. of Mt_ Diablo. The elevations within- Subdivision. 5730' ranged. from 660 ft on tae valley floor to 850 ft on the hilltops is the northern portion of the parcel. Most of the area. within Subdivision 5730 was within the Walley floor of Tassajara. Creek. and its seasonal tributaries . The valleys forced by these drainages were flat and fairly extensive ,. measuringup to 600 meters in width. Within the subject parcel , and separating one intermittent tributar.7 C-3. from another , were low minor ridges that rose about 200 ft above the valley floor. To the east and north of Subdivision 5736 were major ridges that were part of the foothills of Mt. Diablo , and were 400 - 500 ft above tae valley. The ridges and hills within and surrol=ding the subject parcel presented a rolling, rounded appearance; the result of the underl.7ing bedrock, i.e . , the shales and sandstones. of the Great Palley sequence , being easily weathered. 3s a result , Caere were few bedrock exposures within the parcel , and none that would have been utilized by the prehistoric peoples . The soil within Subdivision 5736 was generally a dark brown loamy silt that frequent exposures along Tassajara . Creek- revealed was uniform up to depths of 3 meters . Soil on the ridges and hillto:s tended to- be� less loamy-' in texture ,. lighter in color, and much more shallow. Tsaja �es ��picte� ab th`ems° agrs -Barl.= }) L' e $SLZ3g ;Z' e IIE� WlIIGma22ita ZIIS- 7 a: pear-rouac "vfl_ owever tjzet� _ beecaa�eg-,uer _ % ryi;d�Rsu: -- 'vzc. t '° he des s-icati'on"bf"-d=ai=ges during the Vie= months may have occurred during the--prehistoric.-=period and mayr-e=laia` the=lack.- of-preh±stori.-c-mab .tat -o.—-tes along the middle reaches of this and other major drainages in the region. Much of Subdivision 5736 was inThere, was a sparse scatter'-of-White'-Cak (Quercus kelioggii) andiffil Oak. (9. a;:rifolia) cn the shad-ier-'portians"'of•Ythe- s-1ope5s fla=king Tassajara Valley. Confi-ned-t-o--the--streambed of Tassaja-ra Creek were such native species as-9Calif-,orn3a Buckeye (Aesculus californica);.r-Sxcamorg (Plat-anus racemosa) , larger representdtives of-:'Whtte:':-O k and Skye*Gak-, and" species of4Willow (Salix sr,. ) . Miner':-s:Lettuce (C1aytonia terfoliata) , a 1 af.7 green gathered b. the prehistoric peoples of this region, was observed in C-4. 3I(3=-aat-j_ve vegetation within the �- clude the F3Ihi and mem:a h ~* ==t corner of the parcel. Several iselazae � .vee observed along Tassajara Creed. have now entirely supplanted the na:a-,,ce�.:,.s: .. A.lthoug h almost all of the active =21, ed, the overall environmental setting of: =a I-;=-=cam -F,=,,IEj waL-. probably similar to its appearance at s..:.rs=.-'M y_ Irchaeo loci cal 3ackz ound Prehistoric Period Subdivision 5736 was =within the :."ff t=- 74Id2;-=„ a tribelet (i.e . , a politically au t�� x:;. ac� Z= - 440G persons who inhabited permanent ,.vimaznt --=I—] cms� sites within well-deli:ed territor.iaL' -^^ )) 7r to a linguistic group. called the B&,� : twdk.. L-.m= vm=-- one of five Bay Miwok.-speaking tri r�� area surrounding YLt. Diablo . T.he ('-77-x,c���:�' F..uea� in early historic accounts. as 3olb=„ ��:Tr� ;y inhabited the area south. of Ut. Di-glitli Sam. Ma== and San Joaquin .?alle.ys.. Aa early historic source stated ttm- MM "ate =L-7, t which lit . Diablo was 'knawn. to old resided hereabouts for 40 or 50 yew„ za 7123e. =T,g=� d5EEMas _Bo lbones" (SMZ th .and. Elliot 1879) Mmam= ztc5.=e_-s concludecL. that:.-the :3ay,M!wok_-speak7� l ,=- :fid cn===;wa the :Kt.. Diablo ;.region,for approximate 1„ $., Because of the .sudden and early it sa�,,.:'a= M ltb=_ „ very little is 'known about their mtF cif might be assumed that the. F:olwon f s fLff .similar to that of other aboriginal. _ ='�Ps tl= . Za12 .:fornia. In general, each tribelet; ,; occupied town that . served as a pal1„ moi_ �- monial center. These larger towns: w a=.=q=a&, tier majority of the population during wd=d:-T .tr:Lz.. Mn t±Le spring, the tribelet split up into smm 11.. f amtO7 t.=a-di .- - C-5. . These groups inhabited a series of summer camps in various sections of the tribelet area that were situated near water and seasonally available food sources . Based on early accounts , the main occupation centers of the vTiolwon may have been along Marsh Creek, the major drainage in this area. Sites found on smaller tributaries. or near springs on the higher slopes of Mit. Diablo were presumably suer camp sites . Historic Period The Spanish-Mexican period dates from 1772 - 1846 . S ub- divis ion 5736 was not within any land grant made by. the Mexican government , although it may have been used as grazing areas for cattle during this period. 7Gith the discovery of gold in 1848 , the American period began, and an influx. of Euro-American settlers arrived in the interior tralleys of Contra Costa County. Historic sources indicate only that fruit orchards were planted in the T assa- jara Palley as early as 1856 , but the historic record is not specific enough to indicate the exact locations of these early f arms . Of the historic community of Tassajara, onl.7 an historic residence at 1501 Finley Road and the Tassajara Schoolhouse at the intersection of Finley Road and 01d School Road remain, and both these historic structures were well outside the boundaries of the subject parcel. The Tassajara Schoolhouse was a one story, wood frame build- ing in the Stick sytle of Victorian architecture . associated with the s.choolhouse were two outhouses , and two outbuildings that may have served as stables . The schoolhouse was being restored at the time of this investigation, and could be con- sidered in a good' state of preservation. Investigation Methods and Results A record and literature search relevant to the subject parcel was conducted at the Northwest Regional Center of tae Cali- fornia Archaeological Survey and tae District 01 Clearinghouse C-6. of the Socieyty for California 3_,chaeclog7, adjuncts of the- Archaeolog7 Laboratory, Sonoma State University. No prehistoric or historic sites had been recorded within or immediately adjacent to Subdivision 573c . The field reconnaissance was implemented on. February, 14, 1980 by the author and three experienced archaeological tech- nicians . The reconnaissance consisted of 3n .on-foot examination of the a cued surface and of all exposed soil profiles . All flat portions of the parcel , i.ncludiag the valley floor , ridge tors , and slapes of less than 30 degrees were i.nte_- sively examined. Drainages were followed in order to exanine terraces suitable for prehistoric utilization.. Only slopes steeper than 30 degrees were not examined in an intensive manner , but these were traversed if at all possible . Trowels were occasionally employed to clear vegetation and examine surface soils . The field investigation more than met the. standards far a mixed strategy investigation as described in "'Recommended Procedures for Archaeological I pact. Evaluat1. published. b.7 the .Society for California archaeology. In tae Det. Diablo area, evidence of prehistoric cultural aati.vZty" would include such -attributes as :-. locally darkened soil, . referred_._to as middens. that had been formed. as a. by- product of human habitation; implements of. flaked obsidian, chert,..and/or basalt; ground _ stone. implements such as mortars or pestles ;. burned and heat-fractured rock; burned and broken animal _and bird. bones ; and ,fragments of_.human bone . _ _- ..more more common.-. indicators _of .aa..historic" site ~might rin clude ,the. following attributes : . a scatter .of fragments of wand-blown or purpled glass ; a scatter of fragments of ceramic ware ; a scatter of metal fragments , especially square nails ; and remnants of buildings cr foundations of buildings . No archaeological material of any kind was discovered during the course of the field investigation: - Although -it is possible that prehistoric peoples utilized the subject Parcel for hunting or gathering various food sources ,. it can re.3sonably be concluded beat no archaeological resources are to be found on the surface of Subdivision 5730 . It seems unlikely fast buried archaeological materials will be encountered during construction. However , if any cultural. materials (sucs as those previously described) are encountered during the proposed residential development, it is recommended that work in the '—mediate area be halted, and a qualified archaeologist or- a representative from the American Indian Council, San Pablo be contacted in order to evaluate the finds . Other than this precaution, no further recommendations are warranted. Bibliozramh4 Benn?hoff ,, J. I.- 1977 Ethnogeography of the Plains Miwok. Center for Archaeological Research at Davis (5) . Smith and Elliot 1879 Illustrations of Contra Costa County, C-3-1 rnia. Facsimile reprint by the Contra Costa County His-- torical Society, 1952- C-8. let-. P�tn4 r9y3 j' :j�^,1 ,ti/��t'�.. '"�•{i�_��•,ti•"`.:...:i���'')`jl�i /,,.T�? i��%r�71 �:2t3D�\":� 'F." !,..•r"r.:tet t r. } :�•�; �. //..':a:.�'• ' ` t tr�"�/l•,�.1��\it1i L.� ✓r �if'y s, r��ir� %!'!�•• •r.lrly'tii �71 `:,..,r, .t ,,,;. - =s. t y ' '�•�, 1r�'v t �. fN } �1 1T ti'v':�...T l,i 1�)}"D!�' J )it••a1' '. f ) �,``' •!� ,t/..;j.:. ` ! 1 4 t1. .`�. . f}�;�����,'�1 !f 1('.�i't }�: It�_w�`-...r��..•�"l:_..,; '� r l y'it. .�i n. `t`,.('��l/ -;i'. '�} jn-• v�'•`'"''.:... "'I .:.` •�� .,ry� '1'`�" tis ' ti.?`��j:' t��:-._vim-�'�+�,,,"'r `�'`._ �_ t• ' }:'.a'. ,�.. ;t�� f tiu,: �.• b�', •"'I-=r' D Y T C \ r f!'f '\F- ,5�` j.+.- ..- �.r--� .M1� `� 'Z;7 , �,e1rr-C-;'!�►r`Vr„� �J"�/��},v�•.•--••. 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Ts '.� 113 r• �j` a (,'"r� 1�..'�^"',. � 1 tet. //1J} 'i.n�°d:.a r s�:•;,.� '1 FFe ..,y s• ) i 's ' iQn of Subd=Q Appendix B. Water Quality Study Tassajara Creek drains an area used extensively by grazing cattle. This commonly results in E. Coli concentrations in the water which render it unsuitable for drinking particularly during periods of heavy runoff. The biological community of a stream (particularly its aquatic insects and other macro invertebrates) can be used as an expedient indicator to gauge if the water has been subjected to severe pollution sources over a period of time. Chemical analysis only provides instantaneous data on the condition of stream water at the time of sampling. The macroinvertebrates of Tassajara Creek were campled:=:February.--.-Z,*.198t3; by means of a series.�of-- ive:-one two-fro t dlE4avi}iles collected Into 7a-250. . a icrori focmd.ta have a.high ` n i5ei e macro invertebrates found are listed ifollowing aS e h e act t h a ubs s 1 numbers and diversity of invertebrates characteristic of uncontaminated streams of the central California inland coastal area werefound shortly after a period of heavy rain and stream scouring warrants an assessment that Tassajara Creek.has.a-good:mater-quality and supports'a healthy biological community» Table B-1: Aquatic Organisms Found Number found 34 Ephemeroptera Baetidae Baetis so 22 Plecoptera Nemouridae Nemoura 1 Plecoptera Pteronarcidae Pteronarcyssp. 1 Megaloptera Corydalidae Dysmicohermes sem. 15 Zygoptera Coenagrionidae Argia sa. 4 Trichoptera Hydropsychidae Hydropsyche so. 5 Trichoptera Leptoceridae 3 Diptera Tipulidae Tioula sp. 29 Diptera Simuliidae 3 Diptera Chironomidaerap= Other macroinvertebrates found 12 Amphipoda 56 Oligochaeta B-1. iii. EENG.. - ENGINEERS AND GEOLOCISTS • CONSULTANTS IN THE APPL.E0 EARTH SCIENCES INCORPORATED In Reply October 5,- 1979 - Please Refer to : N9-1494=31 Bryan and Murphy Associates , Inc. P. 0. Box 287 - Walnut Creek, California 94596 Subject: Bruce Flanagan Property Camino Tassajara and Johnston Road` Contra Costa. County, California PRELIMINARY SOIL AND GEOLOGICRECONNAISSANCE Gentlemen: As requested, we have conducted a Soil -and Geologic Feasibility Investigation of the subject site. Study included a review of pertinent literature, air photo study, a site reconnaissance and two percolation tests conducted according to the Specifications of Contra Costa County. • We conclude that the proposed 52+ lot subdivision is feasible pending compliance with the recommendations of this report: Following are our specific co=ments Site Location and Descrittion The site is located northeast of the intersection bet7een Camino j Tassajara and Johnston Road in Contra Costa County, California ( igure. I) . The western portion of the site consists of- flat alluvial pasture land with farm buildings existing in the northwestern corner. Tassajara Creek drains southerly across the mid portion of the site, separating the above mentioned flat land from rolling hills to the. east. These hills rise to a high of 861 feet in the northeastern corner. Vegetation consists of annual grasses and sparsely scattered oak trees . Ranch lands , some of them in the process- of being subdivided, surround the "site on all sides . Gemology Sedimentary rocks belonging to the Contra Costa Grour, underlie the site. Exposures of siltstone were noted in the stream cuts during our reconnaissance, but conglomerate, sandstone and claystone could also be expected to occur in the vicinity. These rocks strike northwesterly. Dips appear to vary from northeasterly in the southwest part of the site, i to southwesterly in the northeast, due to an east-westerly trending synclinal structure. Contra Costa County (1976) maps this syncline as offset approxir:ately k mile right laterally by a fault trending northeasterly across the site (Figure 2) . More recent work by Wagner ® 2150 SHATTUCK AVENUE, SUITE 400, BERKELEY, CALIFORNIA 94704 • PHONE (415) 543-8800 11-I- 11 Bryan and Murphy Associa!:cs , Inc . v9-1494-11j1 Bruce Flanagan Property Occober 5 . 1979 Camino Tassajara and Johnston Road page 2 " 7ontra Cos to County, California (1978) shows nQ faulting on site and the syncline thus not offset. Our air photo analysis and field reconnaissance work iridtcates that if faulting is present, there is no surficiai indication that it is any monger active and thus is not likely to affect site development. General site geology is shown on Figure 3 . Soils Hilly portions of the site have a soil cover of approximately 3 feet, consisting of tan silty clay showing large shrinkage cracks , indicative of expansive qualities . The U. S .. Department of Agriculture (1977) classifies this soil as- Diablo clay with general plasticity index of 25-30 and low strength characteristics . . - t The western valley portion contains thick alluvial- soils consisting of gray brown silty clay classified as Conejo clay. This soil has plasticity index ratings of 10-20, moderately slow permeability ratings and low strength characteristics. The northeastern and southeastern. small valley portions contain Brentwood �. -1ay. and Cropley clay respectively. These soils have moderate to high shrink-spell potentials andlow strength' characteristics Percolation Tess Two percolation tests were =.un in the locations shown on Figure 3 , on F October .4, 1979 according to the Specifications of Contra Costa County. Results obtained are as follows : Length of Distribution Line per Bedroom as Rule _�~� : _ Time for Water to Fall I Required by County X30 Minutes 250 feet ; 40 Minutes 300 -feet These test results can be assumed to be fairly representative of remaining site hill and valley locations and show the soils to have moderately slow permeability, but to be capable of supporting percolation from septic systems.. Slope Stabilitv General.'slope stability is good. Natural hill grades average 30% or less ind generally show no signs .of downslope movement. Two .noticeabLe landslide'. swale areas are shown on Figure 3 . Steep river cut slopes are located'iii_the mid southern portion of the site and show evidence of creep and shallorg sloughing. Shallow (less than 10 feet deep) sliding is also in evidence on small patches in the northeastern corner of ch.e site near a spring area. _ D-2. j c UA _ 7. C6 uj cn • '• t a G ' .r'. _ ""`.`..:.�'`•!. _ \ •. :t. !;.��. ,`: j •'�'• � s.a CPS � 4r `ik- yam, r ll� LU NO = ,nom .. rl.\tit':`: .\•�.' - .1��. .5 }��,i ,�`'��i• �r�� ti/ F WA J Z '� r \..v J �/ �. \,` }{ire r ^% 1• yJj9 �m � ~\ \'�J,,� �.'/• -/.- .`�;\ 111� "��,.-f-� .�-"'_-- '/•� ;r'(��� 1���`v' { j Z o "'. op- t r }'i•� - r �� � ♦�,• CSS cf3 U-4 pow0 til tn Q ya r v� CIS 111 r � 77 .R. souther+ half) �', '�.,•... ` - i`• \\•'`'. \� �' -.� ice. -;\'�� _ � � �\� ' \1•,• / �'•„'.�..• r!• ..+�..."•y�.•a �f� `lam�-�, . j - n , r � ° Vic, ji. ::` '•• :• ' I It IN ir CID l T �� CS 7t (,,,� ,..2 fir: •..: :t VA u u ` - • _ 1„v� r1• X77 �M l.ti� � •. Y � ti♦ w �• M ,. 1 1TtV 'J tt• . Ti 7/ 'd` Te � ••�I \t T• Tn �- x • tt a � F To41 C.t 71 4 6t A ��,f ee !\ •\ ►:' / ', (\ � ` Ts _» to T.t Te f» n To. t► 7e-E _ TO ` V� � t. � Tet `o T Qat _ Quate'rnar;r alluvium To Orinda formation _ fault, dashed where approximate, dotted where concealed geologic contact strike and .dip of bedding FIGURE Flanagan Property No Contra Costa County, California - ENCI:u, INCORPORATED GEOLOGY i E14GINEE4S ONO GEOLOGISTS SCALE 1" = 1 'Mlle CONSULTANTS IN TwE A�et,(ED SGS 1:9-1494-BL EAWTr+ sc(EHcas DATE October 1979 NO. 2 15 0 SHATTUCK AVENUE. SUITE 400, BERKELEY, CALIFORNIA 9.703 • PHONE 15 543.88,16 — n_c t `` I t i I •� t S i • E 77-1 l E � off MG r � I I �. � I i i G7UtfL F7lfE ll�t - - -- �� -�---- -�---- -- -- -r- - ... I f U R Flanagan Property F}NO. Contra Costa County, California INCORPORATEDI SITE LOCATZOv 1 ENGINEERS ANO GEOLOGISTS SCALE ltt = 4262 ' JO3 CONSUL-,ANTS IN T►+E APPLIED DATE ,./Csober 1979 NO. N9-149[:_81 EAATFM SCIENCES 2150 SHATTi;CK' AVENL;E, SUITE 400. BERKELEY. CALIFORNIA 94704 • PHONE (4 , 5) 548.8800 D-5. Bry_nn and Murphy Associates , Inc. N9-1494-31 Brr;ce Flanagan Property October 5 , 1 ;79 Camino Tsssalara and Johnston Road Page 4 :ontra Costa County, California References 1. Brabb , E.E. , Sonneman, H. S . and Switzer, J.R. Jr. , 1971, Preliminary Geologic Map of the Mt. Diablo-Byron Area, Contra Costa County, - Alameda and San Joaquin Counties , California, U. S . Geological Survey, Basic Data Contribution 28 . 2. Pacific Aerial. Surveys , 1957 , Air Photographs AV-253-27-34 and 35 , Scale 1:12000. 3. U. S . Department of Agriculture, 1977, Soil Survey of Contra Costa County. 4, Tiagner, Jesse Ross, 1978 , Late Cenozioc History of the Coast Ranges East of San Francisco Bay, Ph.D. Thesis, University of California, Berkeley, 160 pages . r 1- D-4• Aryan and Murphv Associates ,. Inc . N9-14.94-91 Bruce Flanagan Property October 5 , 1979 Camino Tcissa j ara and Jotins tocl Road Paw 3 'ontra Costa County , CaliEornia Seismicity The nearest active fault is the Calaveras fault, approximately 8 miles west of the site. An active section of the Pleasanton fault is located a similar distance to the southwest, and the Mt. Diablo fault (considered potentially active) , is located 4 miles northwest. Since 1934, over 200 earthquakes have occurred in Central Contra Costa.. County. Ten of these had Richter magnitudes of 4. 0 to 5 . 4. In addition, a swarm of .low magnitude earthquakes , the Danville Swarm., occurred near Danville in 1970. Therefore, although primary surface fault rupture is not a problem, moderate ground shaking can be expected, as a result of seismic -activity in the Bay Area, during the lifetime of any construction on site. Conclusions and Recommendations 1. Site subdivision into large site single family 10 acre± lots appears geotechnically feasible. L. The percolation capacities of the soils are adequate to support septic systems . Site specific percolation tests should be undertaken when building placement has been decided. 3 . - Attention. will need to be given to ground water supply and its relation to septic systems . A number of existing wells have already a been drilled. 4.. A detailed soil investigation should be. undertaken prior to any site development, and should address problems such as soil shrink-swell potential. No further geologic work is necessary for the proposed use. Very truly yours., EN GE Inc. William B . Wigg ' n • Copies : 4 to Client f , D-3. CALIFORNIA ENVIRONMENTAL QUALITY ACT NOTICE OF Completion of Environmental Impact Report ❑ Negative Declaration of Environmental Significance CONTRA COSTA COUNTY PLANNING DEPARTMENT P.O. Box 951 Martinez, California 94553 Telephone: (415) 372-2091 Contact Person Dolores Petersen Project Description and Location: SUBDIVISION 5736 FLANAGAN RANCH (Owners and Developers: Bruce and Joan Flanagan) A request for approval of a tentative map to subdivide 323.6 acres into 52 lots in a General Agricultural District (A-2). Subject property lies southeast of the intersection of Tassajara Road and Finley Road, fronting on the east side of Tassajara Road and the north side of Johnston Road, in the Tassajara Valley area. (CT 355 1) (Assessor's Parcels 204-080-001, 204-090-001, 204-100-001 and 204-110-001) ❑ Justification for Negative Declaration is attached. The Environmental Impact•Report is available for review at the address below: Contra Costa County Planning Department 4th Floor, North Wing, Administration Building Pine & Escobar Streets Martinez, California Review Period for Environmental Impact Report or Negative Declaration: `�r( thru By Z, ee 0 0'2ro Planninn r)ena.M Pnt Representative Planning Departm( t Contra County Administration Building, North Wing Costa P.O. Box 951 County Martinez. California 94553 Anthony A.Oehaesus Oirector of Planning Phone:372-2024 October 30, 1980 RESPONSES TO COMMENTS ON THE DRAFT EIR FOR SUBDIVISION 5736 (Bruce and Joan Flanagan) IN THE TA55AJARA AREA This document is Contra Costa County's responses to comments received on the Draft Environmental Impact Report for Subdivision 5736. This document with the Draft EIR and materials in the project file may be considered a Final EIR if the Planning Commission wishes to certify the EIR as complete and adequate under the Calif ornia Environmental Quality Act and State and County Guidelines. Under Subdivision Application 5736 the owner/developers, Bruce and Joan Flanagan, propose to subdivide 323.6 acres from four existing parcels into 52 single-family parcels. The project site is located northeast of the intersection of Camino Tassajara and Johnston road, north to Finley Road. Parcels range in size from 5.00 to 9.75 acres, averaging 5.88 acres. Access to the development would be from either Camino Tassajara or Johnston Road. The Draft EIR was posted for circulation and comment on April 14, 1980. The County Planning Commission held public hearings on the Draft EIR on August 6, 1980. The Commission closed the hearing, but allowed for written comments on the Draft EIR. This document includes responses to comments received in writing and verbal testimony taken at the public hearing. Copies of all written comments are apended to this response document. DS/mba RESPONSE TO COMMENTS ON THE DRAFT EIR FOR SUBDIVISION 5736 (Bruce and Joan Flanagan) IN THE TASSAJARA AREA This document is Contra Costa County's responses to comments received on the Draft EIR for Subdivision 5736. The written review period for this EIR ran from April 14, 1980 to May 15, 1980. Verbal testimony was received before the County Planning Commission on August 6, with written comments to be accepted until August 15, 1980. In accordance with the requirements of the California Environmental Quality Act, and the State and County Guidelines for processing environmental documents, these responses to comments and the Draft EIR constitute a Final EIR. For the purpose of making a decision on the project the Planning Commission may find the EIR adequate. 1. Letter from Brian Hunter, Regional Manager, Department of Fish and Game, Region 3; dated April 22, 1980. Comments 1 through 13. 2. Letter from Joan Flanagan, project owner; dated May 13, 1980. Comments 14 and 15. 3. Letter from Jim Parsons of Bryan and Murphy Associates, Inc., project engineers; dated May 13, 1980. Comment 16. 4. Letter from T.M. Gerow, Contra Costa County Director of Environmental Health; dated May 20, 1980. Comments 17 through 19. 5. Comments presented at the public hearing, including comments from: Joan Flanagan Bruce Flanagan Will Perry Margaruite Primrose Jim Fisher James Silva and Elizabeth Kilham Comments 20 through 36. 6. Letter from Vernon L. Cline, Public Works Director; dated March 13, 1980. Comments 37 through 42. STATE Of CALIFORNIA—RESOURCES AGENCY EDMUND G. BROWN JR.,Governor DEPARTMENT OF FISH AND GAM�,o Post Office Box 47 Yountville, CA 94599 RPR (707) 944-2443 April 22, 1980 Contra Costa County Planning Department County Administration Bldg., North Wing Post Office Box 951 1 Marti.-iez, CA 94553 Subject: Draft EIR for Subdivision 5736 Gentlemen: Department personnel have reviewed the subject report and find it lacks adequate assurances that the completed project, as proposed, will not have detrimental impacts to riparian vegetation and water quality within Tassajara Creek and three tributaries which flow through the site. In addition, it 1 fails to include adequate mitigation for detrimental impacts. For these reasons, we feel this project does not meet the requirements of CFQ,, Section 15011.6(a, b). The project, as proposed, does not appear to adhere to four provisions of the Subdivision Map Act (Chapter 1154, Statutes of 1978) which state "A legislative body of a City or County shall deny approval of a final or tentative map if it. makes any of the following findings": A. That the proposed map is not consistent with applicable general and specific plans. 2 B. That the design or improvements of the proposed subdivision is not consistent with applicable general and specific plans: C. That the site is not physically suitable- for the type of-develop— ment. D. That the site is not physically suitable for the proposed density of development. This subdivision, like many others in rural settings, represents a land use change whose individual effect may seem insignificant but whose cumulative 3 effect results in significant losses to both aquatic life and wildlife resources. It is air view that any filling or modification of this creek and the riparian habitat would have adverse effects-' on the wildlife within the creek reaches. Contra Costa Cocsn_ Planning -2- April 22, 19K DeT:^rtment T:e str c= retic:es include valuable wildlife habitat. Riparian vegetation, alrea�r in short supply, is being destroyed at an alarming rate throughout the cou:^t;,-, yct it is capable of supporting a wider variety of wildlife in Tore abr:.dsnc t ,--n almost any other habitat type. Fish and wildlife habitat asscci::� :c. :r_th remaining "natural" stream reaches have high regional tialuas ter.: these values require specific recognition and preservation. The De-=_`. - has direct jurisdiction pursuant to Fish and Gaze Code Section in rebs:: to any proposed activities that would substantially divert or obstr_ct the natural flow or substantially charge the bed, channel or bank o= any strc-m. Through this vehicle the Department is mandated to take e-,;arf possible precaution to ensure protection of riparian habitat and -streams. Under Section 160, of the California Fish and Game Code, the project sponsor is rec;::red to notify the Department of Fish and Game of any proposed stream c:_ nel alterations. The provisions of this section are intended to protect and conserve California's fish and wildlife resources. in order to protect these creeks and to mitigate for potential indirect a_vers� :r..pacts upon water quality, we recommend the following wildlife miti gat_on ,seasur-2s be incorporated in this project: 1.- No development should be permitted within a 100-foot wide corridor aic::lg each side of the creeks. The point of measurement for this core dor shoLl.d begin at the top of the bark of the creek, rather th=. at the centerline of the creek. The habitat area, when measured 4 frc- the top of the bank, would provide for a uniform setback from the creek and a more sufficient undisturbed depth of area. The habitat area, when measured from the center of the creek would vary, per!:-r:ps considerably, based on the width of the creek. On wide areas of -the creek there could be little area remaining for an adequate rina an zone as recommended in these conditions. 2. An adequate flood control right-of-dray should be provided adjacent to 5 the creek. to insure future flood control- needs :•:ithout,. having to _u destroy creeic vegetation. �. All areas disturbed should be replanted with native,. drought-resistant vegetation; including the larger, slower-growing trees seldom planted 6 by homeowners (sycamore, cottonwood, valley oak, blue oak and coast live oak). .0 4. The development drainage system should be designed to eliminate au,gmcntation .of runoff prior to developing the site. 5. To reduce erosion, grading and land preparation should be restricted to the period of May to October. All erodible slopes must be hydro- mulched or otherwise stabilized by October 15. This will reduce deposition of sediments and the chances of degrading water quality in the creek. Contra Costa Count, Planning -3- April 22, 1920 Derartmcnt 6. Sediment retention basins should be large enough to adequately impau.-id maxi.nl.Lm runoff. The City should ensure the future maintenance g of the retention basin throughout the life of the project. Oil traps should be utilized on-site to catch grease and oil. 10 7. No horse trail shall be closer than 50 feet from the creek. Point of measurement is from the top of the bank of the creek. S. Prior to approval of any final map, sufficient excavations or tests shop be performed on each lot and the Health Department and/or 11 Reginal 3oard shall certify the adequacy of a septic tar-k system on each lot. If the tests indicate an inadequacy on any lot on the . tentative man, such lot shall be combined with adjoining lot or lots by merger and shown on the final map. 9. No septic tart or leachfield shall be located within 150 feet of any IZ stream. r'here alternatives are available, leaching systems shall be located array from mature oak trees to prevent root rot fungus. io meet CF.GJA requirements these mitigation measures should be incorporated into the development proposal along with the EIR recommendations or it should be demonstrated t at mitigation measures are not feasible. ',•:e believe the draft EIR has identified substantial environmental impacts 13 and has not provided or only suggested mitigation measures to compensate for losses of fish an,' wildlife resources. The final LIR should not be considered co-plete or be certified until mitigation measures are incorporated into the project. Please send us a copy of the material which will be added to the Draft .documert in order for its certification as a Final. We also request a copy of any construction or use permits that are issued as a result of the determination for certification of the document. State EIR guidelines, Section 15146, require lead agencies to respond to all co.^unents/recommendations received on the Draft MR and to include them in the final document. We recommend your staff consult Mr. Robert Huddleston, Wildlife Biologist, at our Yountville office, telephone (707) 94.4-2443, regarding the wildlife aspects of your proposed project. Sincerely, Brian Hunter Regional Manager Region 3 Contra Costa County Planning Department ;nhr° ' �` r' County Administration Bldg. North WIng r! ' r Post Office Box 951 MAY Martinez , CA 94553 Dear Planners , There were a few .items in the EIR for Subdivision 5736 which should be clarified. They are as follows : on page 4 Surrounding Area. There are fifty-two homes on one. to four 14 acre parcels on the north side of the property, and another ten homes on the south and west sides . On page 11- Related projects . The last phase of Blackhawk is less than 15 3 , 000 feet away from the property. The two mile figure was probably confused with the location of the proposed Blackhawk shopping center which is approximately that distance . Thank you for your attention, Joan. Flanagan • J BRYAN & MURPHY ASSOCIATES, INC. rONTRaci4i7 CIVIL ENGINEERS P.O. BOX 287. WALNUT CREEK. CA 9AS97 • 1233 ALPINE ROAD. WALNUT CREEK. CA 9A996 14 H (4 tfJ) 030-6500 May 13, 1980 Job No. 4882-2 BRUCE & JOAN FLANAGAN SUBD 5736 - E. I . R. Contra Costa County Planning Department P. 0. Box 951 Martinez, CA 94553 Attention: Dale Sanders Dear Dale, Please accept this letter and blueline print of the aerial photograph as a written comment in response to Page 4, Item 2, Paragraph 2. The paragraph as written in the report is brief and somewhat mis- leading. The enclosed aerial photograph dipicts use of the land more accurately. 16 It should be pointed out that there are 52. parcels on + 143.35 acres or an average size of 2.76 acres. All parcels shown on the photograph were created as of June 1979, and parcel acreage was taken from the Contra Costa County assessor's map books. Thank you for making these comments and photograph part of the record. Yours trulY� Jim Parsons BRYAN & MURPHY ASSOCIATES, INC. JP/bc Encl cc: Bruce & Joan Flanagan w/aerial & tentative map showing revised phases HEALTH DEPARTMENT De ` Contra Costa County TO: Anthony A. Dehaesus DATE: May 20, 1980 Director of Planning FROM: T, w, SUBJECT: Draft Environmental Impact Dir ctor a Health Report for Subdivision 5736 Tassajara area This department has reviewed the Draft Environmental Impact Report for Subdivision 5736, Tassajara area, and makes the following comments: 1. The applicant .is required to make application to this department for the installation of individual sewage disposal systems. Each building site will require 17 investigation and testing for placement of drainfields. No building permit shall be issued until such time as the investigation by the Health Officer has been made after final grading for each building site. The applicant is advised that should the soil be found to be unsuitable for the installation of an individual sewage disposal system after grading the parcel will be rejected. 2: It has not been demonstrated that water is available on all parcels. Each parcel must support its own water supply as a community supply serving only 52 lots will 1g not be allowed. The applicant is required to make application to this department for the installation of individual water supply systems. 3. Any residential development in the County that is converting I9 previously undisturbed agricultural land will increase the intrusion of certain undesirable vectors into the community causing increase demand "for services. TMG:JLK:sm cc: East-Central Office �6. m 4A Y 10/78 51A r • COMMENTS ON EIR - Flanag_., Ranch - Subdivis ,on #5736 t-.cVAPC 8-6-80) JOAN FLANAGAN explained their proposal . Responding to motorcycles mentioned in the EIR, trails will be posted against motorcycles and she will do all in her power to prevent them from using the trails and area. Addressing EIR questions, the land is now used as grazing, leased out but does not begin to pay the taxes on the land. The walnuts are included in the grazing lease and the walnu_ production will continue. Referring to open space, the majority of houses do not cover more than 1/4 acre, leaving 4-3/4 acres open, so open space will be preserved. EIR mentioned streams and pollution. There are now several head of cattle on that propert,, and "if they aren't polluting that stream, I don't know what is". "People have been dumping their garbage in the stream for years. With people living on the property, ;.nis will be discontinued. The animals will not be .roaming up and down the streams." Commercial services were mentioned in the EIR. Presently they are -either Danville or 20 Pleasanton. According to what she has read, in 1984 the shopping center in Blackhawk will be completed, less than- 3 miles away. According to the Danville Postmaster, there will be a Blackhawk post office opened in 1984. The concern in the EIR for the amount of gas used to get to these services, most people drive more than 3 miles now to get to stores. As far as inducing growth in the area, she felt it was a case of supply and demand. They 21 have been approached by a number of people interested in 5 acre parcels. When the demand runs out, people will not subdivide. 0Item #8 in the EIR, she didn't think any horseman would ride down the center of the creek. 22 The banks are very steep and not a wise thing to do. Any worry about the banks or pollutic of the creek, she felt was unnecessary. The easement will be 25' out from the edge of the creek. Some. of the people living there worry about services. There is a new substation of the Sheriff's office opening up in Alamo: next Monday. That will put them (sheriffs) 1/2 hour closer to Tassajara if needed. It' s very rare in any subdivision that the services are 23 there first. Once the people are there and the taxes are paid, then the services are in demand. The majority of people out there have nct wanted public water or public sewers ; they haven't wanted to pay for it. With a well on each parcel , that will be needing the need. With 5 acres in which to put. the septic field, . there isn't much problem about pollution. BRUCE. FLANAGAN further explained their proposal and. progression. He explained the wells in existence and there is water. Have drilled wells producing from 12 to 30 gallons. They now have 18 wells, producing adequate water. He spent two days with representative 24 of the Contra Costa Environmental Health Dept. walking over each parcel ,on the ranch in order for them to determine whether or not there is the ability for geographic septic tank locations; obviously they couldn't check the pert by walking over it. At this point, each lot has ample ability for location of both septic and well . Addressing the question of roadways, they purchased flat cars for bridges but Public Works would not allow those; have prescribed concrete box or culvert or archway. They had hoped to keep the rural atmosphere by providing 16 and 20 foot roadways; Public Works have asked 25 a minimum of 28 feet. Tassajara Fire has indicated clearance for two engines is sufficien-L talking about 20 feet. A requirement of Tassajara Fire District is a system of fire hydrants every 1 ,000 feet; Waddition, supplementary fire fighting equipment to be determined later. EIR - .Subdivision 5736 Page 2 Fish and Game had a concern about the streams on the property. 2 streams run dry in the summertime; one of the main streams partially dry, spring fed. Have created a stock pond 26 a little bit less than 2 million gallons of water, also spring fed and have offered that to the Fire District for the pumpers if needed. This is not a part of the requirement of the Fire District. Their property is surrounded by 52 homesites to the north, ranging from 2 acres to 4, 5, 7 2� and a few 10 acres. They are talking about 52 homesites on a parcel 3 times the size of the referenced 52 homesites. The EIR states if this development should be allowed, the children and the activity of 2$ these homes would disturb the party who has land to the east. He has cattle on his land now and there doesn't seem to be a l.ot of problem with the 52 homesites surrounding him. To the south of them, there are 5 acre parcels. To the west, there are some divisions of 12 acre and 8-acre parcels. It does seem farfetched for them to be accused of initiating Z9 a wholesale movement of smaller homes and what they are proposing is something that will be a compliment to the lifestyle now enjoyed by the residents there. They will live on the property and will be there; are building their own home there. There were no items of historical significance in the EIR_ There are no endangered 30 species on the property. They do have some skunks, raccoons, gopher snakes with running cattle - have horses. They intend to retain title to the horse trails and give everybody easements to those trails. The CC&Rs will address restrictions as to the structures, type of structures, size, 31 outbuildings- and the number of animals of the people living on the ranch. They are making every valid effort in order to have something and create something that's going to satisfy most people, the most. ardent conservationists. They will provide a working open space. WILL PERRY, has a ranch at the end of Johnston Road. He has. nothing but trouble with people on horses and motorcycles; they think it is open space and can ride all over your property. It just doesn't work out to have horse trails. He farmed the Johnston Ranch 3 2 for 1'0" years; it has 4 wells, 3 very poor- and one good well on the whole ranch. They have got a water situation. Where will they get the water for fire hydrants and things like that? Kids go on your property, leave gates open and let the cattleout, destroy your- property. That is his opinion of having too many houses in that area. He has lives there- 15 years. MARGARUITE PRIMROSE, one of the 52 homeowners already in the area. They would like a 3 3 guarantee that their well and septic tanks will continue to function properly with the development of this property. They have heard the wells on the property were very poor. JIM FISHER stated with major developments, fire protection, etc. can become a problem. Mr. Flanagan hasn't addressed the problems of erosion, ravines, with regard to streets. All the drainage from 7 parcels goes down to 2 parcels. at the bottom of the hill . He has access on Laurie Lane, -.which stubs onto Johnston Road which is very narrow, winding and a one' lane bridge at the creek. His concern is water, and he cited several parcels 3 4 without supporting water. Except for the development on Finley, he (Flanagan) is surrounded by large acreage. He feels they have to address the water, septic leach fields flood control , and the safety factor of the narrow roads and bicycles. They also have deer, pheasant, quail , hawks , coyotes and year by year, they are getting less and Tess. ♦ J EIR - Subdivision 5736 Page 3 JAMES SILVA, Country Lane adjoining this property. His concern basically is with water and septic tanks. He cited an incident adjacent to the subject property, where a well D was drilled, built the house and then the well ran dry; they are now using a neighbor's well . The other 50+ homes in the area have to be considered; if they run out of water or it gets contaminated, what happens? The impact of 52 homes on the existing homes relative to water, has to be considered. How much water is really there, especially if there is a drought. The overall development is an outstanding idea. ELIZABETH KILHAM stated the EIR stated this would be a detriment to agriculture and stated the reasons. She supports the EIR on this point. She is unaware of the EIR 6 addressing the fact that you need to have organized recreational areas; a question ought to be addressed to Zone 7. The need to conserve energy (driving distance) is addressed in the EIR. MR. FLANAGAN, in rebuttal , referring to Mr. Perry's comments on the lack of water, they have cattle and the troughs are always full with water pumped from these wells.. The wind mill is now pumping. They do not intend to shift their people on horseback onto Mr. Perry's property; will have trails on their own property. Their phasing of. the development was in part, to determine the adequacy of water and possible impact on other wells in the area. One of the requirements of Public Works is a prorata amount per lot toward the widening of the bridge Mr. Fisher referred to on Johnston Road and other off- site improvements. Upon the Motion of COMMISSION WRIGHT, Seconded by COMMISSIONER SCHLENOORF, the hearing .on the EIR was closed,with- written comments allowed for 10 days and the hearing continued to September 17, 1980 by a vote of 6 AYES (Best absent) . PURUC WORKS DEPARTME I r CONTRA COSTA COUNTY Date: March 12, 1980 To: A. A. Dehaesus, Director of Planning Attention: Harvey Rragdon, Assistant Director, Current Planning From: Vernon L. Cline, Public Works nirector �,J �T�_ By: William R. Gray, Assistant Public %1 orks Director, Land [`r opment Subject: Flanagan Ranch EIR We have reviewed the draft ETR for Subdivision 5714, Flanagan Ranch, and have the following comments: 1. Tassajara Creek and its tributary which run throw^.h the 5u'sdivisi0n are 37 natural -reeks susceptible to eru.:ion alone the bank!;. Frith c-rceks and all culverts within the F :bdivision, including Lhe culvert taking, the creek: flow under Johnston Load, should he analyzed to c'eterrnine the ext,t ing capacity ;end needed improvements. Determinatic! rpt ruc,ott amo,.miN and c t� c'ity .:,Idlyses rnt.rst i;c reviewed and approver: h%. th- County Public `A'orks fi'partment. Z. The horse trait within the crFe?� is not c•, ^ropriate loct:tion. Eesid,:es 3g decreasing the water quality, the trail would add to the e�:i• ring erosion or-)blems along the h-,nks. 3. Before the railroad flat car can be used fcr the Rruce Drivc• hridee across 39 Tassajara Creel:, the Public Works Departn•c•nt tnUst review and approve this flat car for use as a road bridge. 4. If the streets within the subdivi•;;or, are FTuoosed to be Courty maintained 40 ,treets the typical ,.i^tion must conform, to County standar, street width requirements. The minimum pavement widt must be 28 to 3? feet w:de. 5. The County Ordinance Code will •requirr that -Johnston'.Road', Camino Tassajara, and Finley Road =he improved *along the frontage of this 41 subdivision,. Also, off site road improvements may b^ necesse v such as the intersection of Johnston Road :end Camino Tassaiara and the i-inlev ^.oad, ':amino Tassajara Intersection to mitis:: le traffic problems at tr.ese loe-atic--- created by this subdi-isiOn. 6. In additicn, the impact of this revelooment on Cro-.3. ranycn •'.oad, Camino 42 rassajara and Sycamore Valle: tt oad must be discussed. These roads all :ave finite capacities, and wer sized assuming ver: little development in he Tassajara Vallev. If the T,ssajara Valley is allowed to develop to the ricnsities proposed in this subdivision, it may he necessary to r(,r.onsider the read regctirements ne(.essary tc ;crvice the area. Thank volt for the opportunity to revi- this draft EIR. if you have .,ray questions concern:nj!. the above, rIv.)%e contact C Flynn at .'072-4197. p jj Flan Rnc kLITt I?. Comment 1. Response: The EIR provides adequate mitigation measures for all identified significant adverse environmental impacts. Mitigation of insignificant impacts, such as those mentioned in comments 7 and 9, were found not feasible. Comment 2. The San Ramon Valley Area Planning Commission on September 17, 1980 approved a Commission initiated rezoning study for the Tassajara area (2218-RZ) which left the level area of the Flanagan Ranch in General Agricultural A-2 and recommended Exclusive Agricultural District A-40 for the remainder of the ranch. In so doing, the Planning Commission in effect found 5 acre zoning consistent with the General Plan. The revised map received on October 15th 1980 was submitted in response to the Commission action as 5 acre parcels are proposed on land recommended to remain A-2 and a 40 acre lot (including the Flanagan house) and a remaining ParcelA of 131 acres indicated on the land recommended for A-40. Comment 3. Response: The EIR on page iv, number 11, makes the same finding regarding cumulative impact of the project. Comment 4. Response: The recommendation is made for a 100-foot wide no-development corridor along each side of the creeks. This would require a corridor 210 to 240 feet wide. Several of the parcels, such as numbers 12, 16, 33, and 34, would have the home location severiy restricted. The mitigation measure is thus amended into the EIR as follows: * No development should be permitted within a 100-foot wide corridor along each side of the creeks when feasible. The point of measurement for this corridor should begin at the top of the bank of the creek. Comment 5. Response: The ETR (page 26) states flood control installations should be designed to the requirements of the County Flood Control District. Page 28 states that all riparian vegetation not required to be removed for flood control purposes should be retained. Comment 6. Response: The EIR is amended to include the following mitigation measure: * All areas disturbed should be replanted with drought-resistant vege- tation including shrubs and trees. Comment 7. Response: On page 22 of the EIR it was stated that increased (augmented) runoff from the development is not a significant adverse impact but a cumulative one. To require the installation of stormwater detention facilities on such a development is not considered feasible. Comment 8. Response: It is anticipated the development would be conducted in accordance with existing laws, specifically the County grading ordinance. Hence the.suggested mitigation measure would be redundant. Comment 9. Response: Sizing sediment basins to impound "maximum" runoff is not feasible. Sediment control structures are normally designed to handle the 10- or 15-year storm, or as required by the County. The function of a sediment basin is not to impound runoff but to retain the runoff only long enough to settle out sediment. The requirement for oil traps on a five- acre minimum parcel size development is not considered feasible. The cost - 2 - of collecting the small amount of oil and grease generated by such a develop ment is not balanced by the benefits. (Personal communication, Dr. Peter Russell, Oil and Grease Project Leader, Association of Bay Area Governments, Berkeley). Comment 10. Response: The EIR is amended to include the following mitigation measure: * No horse trail shall be closer than 50 feet from the top of the bank of the creek. Comment 11. Response: Page 27 of the EIR states that a site-specific percolation study must be conducted to confirm the ability of each parcel's soil to function for septic tank and drain field uses. See also the response to comments 17 through 19 from the County Health Department. Comment 12. Response: All septic tank and leach field locations must be approved by the County Health Department. It is not expected they would approve a location creating a health or water quality hazard. The EIR is amended to incorporate the following mitigation measure: * Where feasible, leaching systems shall be located away from mature oak trees to prevent root rot fungus. Comment 13. Response: The EIR has provided a list of suggested mitigation measures to compensate for identified adverse impacts. These measures may or may. not be made conditions of approval of the tentative map at the discretion of the County. Certification of a final EIR and approval of a tentative map are distinct actions. Comment 14. Response: Page four of the EIR is amended to read: Surrounding Area: Areas contiguous to the north contain 52 single family dwellings on lot sizes ranging from 1.04 to 4.41 acres (A-2 zoning). The western border of the site is Camino Tassajara. The southern project boundary is Johnston Road and an 8.16 acre tri- angular piece of land containing two single-family homes. Six additional homes are found across the roads on the west and south sides. The eastern . . . Comment 15. Response: Page 11 of the EIR is amended to read: Related Projects and Plans: Less than two miles northwest of Subdivision 5736 is the center of the 2185-unit Blackhawk develop- ment. The last phase of this development will approach within 3000 feet of Subdivision 5736. Although . . . Comment 16. Response: See response to comment 14. Comment 17. Response: Page 27 of the EIR states that a site-specific percolation study must be conducted to confirm the ability of each parcel's soil to function for septic tank and drain field uses. The comment presents additional information on county health department procedures. - 3 - r � Comment 18. Response: Page 27 of the EIR states that a site-specific groundwater investigation must be conducted to confirm the existence of adequate well yield prior to approval of the Tentative Map. The current joint study by the County and the U.S. Geological Survey should provide additional information on available groundwater. Comment 19. Response: Agreed. Page 26 of the EIR is amended to include the following adverse environmental effect which cannot be avoided if this project is implemented: 12. The conversion of previously undisturbed agricultural land-into residential development will increase the intrusion of certain unde- sirable vectors into the community causing increased demand for County Health Department services. Comment 20. Response: The primary concern of the energy section of the EIR on page 20 was the distance involved in future residents commute to work. While shopping and postal services may be provided within several miles in the mid-1980s, the future residents will still be required to commute substantial distances to work. Comment 21. Response: While "supply and demand" is a factor, the County General Plan and zoning requirements are designed to provide the supply of housing in the most efficient and logical pattern. Comment 22. Response: The EIR was not concerned with the mature horseman, but rather the younger equestrians who might be tempted to splash through the creeks. See response to comment 10 regarding setback from the creek. Comment 23. Response: It is common to have public services available to new subdivisions when they are located near existing urban areas. Comment 24. Response: See response to comments 17 and 18. Comment 25. Response: Comment is informational requiring no response. Comment 26. Response: Department of Fish and Game concerns have been addressed in reponses to comments 1 through 13. Comment 27. Response: See response to comment 14. Comment 28. Response: The additional 52 homes would increase the potential for disturbance to agricultural land to the east. See also comment 32. Comment 29. Response: The EIR does not mention "initiating a wholesale movement of smaller homes" into the area. The proposed.project may be a compliment to the lifestyle of those neighbors on small parcels but would conflict with the lifestlyle of those engaged in agriculture in the area. The project was described in the EIR as conflicting with the San Ramon Valley Area General Plan insofar as the primary intent of the designation for the area, General Open Space, is primarily intended to be the protection of natural resources and rural, agricultural land uses. The County Board of Supervisors have questioned the viability of agriculture on five-acre parcels as allowed on A-2 zoned land and planned for this project. - 4 - Comment 30. Response: Comment is inform atiomfl:wxsii�i�rrmre�a�. Comment 31. Response: Comment is informatiomflneapiiun :were arra. Comment 32. Response: Source of water is &caawi�d im tltx-- iM?anrW da response to comment 18. Potential for vandalism iz azUki iin tthe and in response to comment 28. Comment 33. Response: Such guarantees zz thw Temp *—efd aum —t possible. The County Health Department cannot gum&=�Wkth auy,,cenmfirtry how long a groundwater supply with last. The tg? Eiz?a sh�uii#;+d� : ctrl to produce factual information for each lot apprauetd!y:hies%itidWhiiun tt an adequate domestic water supply is available cff -t'Mo'mm MizMt#y MW quality to support the development of a single lc& Comment 34. Response: Comment expreses cmu=-. ; , Irina; ITIM protection, drainage, water supply, septic leach 2. mlft„ %, trmnzs w tation safety, and wildlife. All items have been=-m}��l:int EIR. Comment 35. Response: Comments regarding vrg :ss *-anxdseF Ajr-tUnlG have been addressed in the EIR and in response tDawn renxM1'Tan&Ia. Comment 36. Response: The applicant propos hainie traiis: throuFgh the property as one source of recreation. There is am (Mnurnpr uicesne:rn-',:kw park and recreation development on the property- Comment ropertyComment 37. Response: The comment has bte.w ar icap tech nt�eviaURilly into the EIR on page 26. Comment 38. Response: See water quality mi&i !dm measures-disaisamd on pages 27 and 28. Comment 39. Response: The comment has I "hMMqIDrM=5EU prsMi37u EDY into the EIR on page 7. Comment 40. Response: The comment has bt2m i 'grAvi n Eft into the EIR on page 7. Comment 41. Response: The comment has bzmn ihmwgerwta prrevibnaft into the EIR on page 28. Comment 42. Response: See pages 9 and 24 of tftm MM- "- "Piann i ng Department Contra County Administration Building, North Wing Costa COUnty P.O. Box 951 Martinez, California 94553 Anthony A. Dehaesus Director of Planning Phon072-2091 November 4, 1980 ADDENDUM TO RESPONSES TO COMMENTS ON THE DRAFT EIR SUBDIVISION 5736 (Bruce and Joan Flanagan) IN THE TASSAJARA AREA The attached comment on the Final EIR was inadvertently not included in the response document. Responses to comments 17, 18, 34 and 35 address this comment. DP/mb5a A CONTRA PCSTA COUNrY J AUc I9 II ii AM TO Aug"t. 15, 1980 ` A,%noZd Jonas, C ue� Subdcvcscon Afu4t�atcon 0 _ Corr,ttca Co.s.ta County P.Cann ng Depah rneirt P. 0. Box 951 Man ti.nez, Ca. 94553 In ne6u enee to the Ftanagan E. I. R., we kcque�s.t a complete a.tudy o6 .the hydreotogy o6 .the Ta zajana Area ad a uuit gattiitg measure not covered in .said E. 1. R. mm.Lgumzte P,tunuze Et.czabeth K.iOtani cc: . D,%. O tt yn H. Wood Ricl Ltd Kennett Linda Beat J- M.iehaee Hayu Joseph HZuch Susanna Sclzeendca4 ,veP,sopi Wti.gli.t Alid,tcto Young r