The URL can be used to link to this page

Home My WebLink About6.1 Shannon Ctr Award Bod Attch 2 '$~ SHANNON COMMUNITY CENTER PROJECT INITIAL STUDY & MITIGATED NEGATIVE DECLARATION ATTACHMENT #2 ~ 'b U1--"1 SHANNON COMMUNITY CENTER REPLACEMENT INITIAL STUDY/ MITIGATED NEGATIVE DECLARATION Lead Agency: City of Dublin Prepared By: Jerry Haag, Urban Planner January 2007 Z:XhLbL+ 4 '6 ab 2 0<;( Table of Contents Introduction ................................................ ............................................................... ....2 Applicant/ Contact Person... ..................... .................................... ..... ................. ....... ..2 Project Location and Context................................. .....................................................2 Project Description............................................................................ ..... .......................3 Environmental Factors Potentially Affected....... ...................... .... ........................... .11 Evaluation of Environmental Impacts .. ...... ..................................... ..... ..... .............. ..15 Attachment to Initial Study. .............................................. ... ......... ....... ......... ....... ...... .25 1. Aesthetics ........ ...... ....... ................. ... ............ ... ....... ....... .................. ...... .25 2. Agricultural Resources................ .............................. .................... ..... ..26 3. Air Quality ..... ....... ... ...... ........ ... ....... ....... ................. ... .......... ................ .26 4. Biological Resources. .... ...... ... ....... ......... ..... ....... .......... ...... ...... ...... .......27 5. Cultural Resources........ ....... ........ ......... ................ ....... ......... ... ............ .37 6. Geology and Soils... ..... .......... ... ....... ....... ..... ... .... ........ .................... .......38 7. Hazards and Hazardous Materials.....................................................40 8. Hydrology and Water Quality ................~...........................................42 9. Land Use and Planning ...... ......... .............. ..... ... .... ... ............ ..... .... .......44 10. Mineral Resources.......... ........................................ ............... .......... ......45 11. Noise........................................... ..................................................... ...... .45 12. Population and Housing ........... .... ............ .... .... ............ .......................47 13. Public Services ........................ ..... .... ......... ..... .... .... ... ............... ............. .47 14. Recreation....... .................... ...... ............................. ...... ............ ........... ... .48 15. Transportation/ Traffic.. ......... ......... .................... ...... ....... ....... ........ .... .49 16. Utilities and Service Systems...............................................................50 17. Mandatory Findings of Significance ..................................................51 Initial Study Preparers................ .............. ... ............... ................... .... ........ ...... ...... .......52 Agencies and Organizations Consulted.... ........... ......... ... .... ... ............... .... ...... ..... ....52 References...... ................ .................. ........ .... ..... ...... ....... ........ ... .... ... ........ ... .... ....... ..... ... .52 Appendix I-Biological Reconnaissance ..... ........ ..... ....... .......... ........ ........... .... ....... ....53 Appendix 2-Geotechnical Exploration Report.. ......... ...... .......... ....... .... ...... ... ....... ....54 It,,r;b 0"1 City of Dublin Environmental Checklist/ Initial Study Introduction This Initial Study has been prepared in accord with the provisions of the California Environmental Quality Act (CEQA) and assesses the potential environmental impacts of implementing the proposed project described below. The Initial Study consists of a completed environmental checklist and a brief explanation of the environmental topics addressed in the checklist. The project consists of demolition of the Shannon Community Center and reconstruction of a new community center building, along with associated redecking of an existing pedestrian bridge, in the westerly portion of Dublin, Alameda County. Applicant/Contact Person City of Dublin Parks and Community Services Department 100 Civic Plaza Dublin CA 94568 Attn: Henna Lichtenstein, Project Manager (925) 8336645 Project Location and Context The project site is located in the western portion of Dublin within the northerly portion of existing Shannon Park. Shannon Park consists of approximately 9.7 acres of land located at the northwest corner of Shannon Drive and San Ramon Road and is maintained by the City of Dublin. In addition to the Shannon Community Center, Shannon Park includes a play area, a tot lot, picnic facilities, restrooms, jogging paths and a parking lot. The existing Community Center consists of a single story building constructed by Alameda County in the 1970's and significantly upgraded in 1988. Interior improvements include meeting facilities, a kitchen and a preschool. The Community Center was an active facility, housing many recreation classes and programs. However, the facility was closed in 2004 when the City identified extensive water damage and mold throughout the building. Exhibit 1 depicts the regional setting of Dublin and Exhibit 2 shows the location of the project site in context with nearby features, including roadways. Topographic conditions within Shannon Park include rolling topography with the Park bisected by Koopman Creek, which flows from west to east through the Park. The Creek supports riparian vegetation including stands of mature oak trees and other City of Dublin Page 2 Initial Study/Shannon Center Project January 2007 I~J20~ riparian vegetation. Other vegetation in the Park includes a variety of introduced and non-native trees, shrubs, groundcover and turf. The Shannon Community Center building is sited in the northerly portion of the Park. Existing land uses adjacent to the Park include single-family residential dwellings to the north, east and west of the park. A combination church and private school associated with the church exists south of Shannon Park. Proj ect Description The proposed project includes the demolition of the existing Shannon Community Center and reconstruction of a new community center building in approximately the same location as occupied by the existing building. Exhibit 3 is a site plan showing the location of the proposed reconstructed building within Shannon Park. The current building includes approximately 13,000 square feet of enclosed floor area plus a 3,000 open deck area, whereas the proposed building would include approximately 19,000 square feet of floor area. The proposed facility reflects a somewhat larger building and a smaller deck area than now exists, but within approximately the same footprint. Exhibit 4 shows the proposed floor plan for the building. The main floor of the proposed building would contain a large multi-purpose events room, smaller multi-purpose rooms, a pre-school and associated outdoor play area, a kitchen, offices, public restrooms and storage areas. A large covered entry court would be located on the south side of the building. A lower floor would include only an unconditioned storage area. The replacement Shannon Community Center would continue to offer the same recreational and community services to Dublin residents that was provided by the existing facility. Some of the rooms in the new facility would be larger than in the current building in order to meet current building codes as well as to provide enhanced services to the west Dublin current and anticipated population. Exhibit 5 depicts proposed exterior elevations of the building. The reconstructed building would have a height of approximately 35 feet to the top of the roof from existing grade along the northerly elevation. This is approximately the same height as the existing building. Other portions of the building would have varying heights based on a varying roofline. The overall design would be contemporary Mission style, with a horizontal roofline, building overhangs and multi-paned windows. Roof material would consist of composite roof tiles. Exterior building material would include stucco with concrete and stone wainscoting. The structure would be painted a cream color. The building has been planned as an energy-efficient "LEED silver building." The LEED (Leadership in Energy and Environmental Design) designation is granted to buildings meeting energy efficient and sustainability criteria established by the United States Green Building Council. City of Dublin Initial Study/Shannon Center Project Page 3 January 2007 %~2 Associated with the reconstructed community center would the replacement of decking material for the existing pedestrian bridge over Koopman Creek on the south side of the building. A small number of'trees would be planted around the building. The project also includes removal of invasive, non-native plant species and replanting with native plant species within and adjacent to Koopman Creek. Other than the improvements described above, there would be no other construction included in this proposed project. Existing access to and from Shannon Park will remain off of Shannon Drive and no changes would occur to the existing parking lot of other park improvements. Preliminarily, demolition of the existing building would occur in early 2007 and construction of the replacement building would be completed in early 2008. City of Dublin Initial Study/Shannon Center Project Page 4 January 2007 '11J ~o~( ~ .2 '0 () >. ~ " '" ~ ~ ~ Livermore <') ... ~ ... <"'> o '" (<:> ? ~ ~ 'u :;; -< ~ " '" Exhibit 1 REGIONAL LOCATION CITY OF DUBLIN SHANNON COMMUNITY CENTER PROJECT INITIAL STUDY I'MITIGATED NEGATIVE DECLARATION N ! 6 , 8 , 10 miles I 2 , 4 , Blue Ox Associates, Berkeley, ColiforrJa 8-15~2006 ---- ---- ---- ---- ---- ---- - ---- ---- [CITY OF SAN RAMON] /........ . 1 ['0-1-- .;<y~ C1 % POl.->- ""(1"""" oSOe,. OV0.'OV-?- "<: , - . &"'_-------.1 . I . I . .-.-..... . I . I . I . I . .I I . I [CITY OF PLEASANTON] Exhibit 2 PROJECT LOCATION o -.-.- City Limit o I 1/4 , 1/2 , 3'4 , CITY OF DUBLIN SHANNON COMMUNITY CENTER PROJECT INITIAL STUDY I MITIGATED NEGATIVE DECLARATION N I 1 mile ~~~--->--~~p~~-"--- ! .i r i i i i i i ! i '+ j, .".~J 1 i .,;:+ '.1 ,1 .. j 1 :1 I /"",_-'-<<-<~;::;:~VENUE '~=,-=-""","""...<:'-" ~ ~ "' SI c o '" o U ~ j ~ i " '~ '" ~ ~ " ::l 0:; SOURCE: Dahlin Group, August 2006. CITY OF DUBLIN SHANNON COMMUNITY CENTER PROJECT INITIAL STUDY I MITIGATED NEGATIVE DECLARATION Il~20~ <fl ~ :P ~ .0 ('Z. ;. :P '0 ~ Exhibit 3 SITE PLAN _n_n_..___ Shannon Park boundary o , 50 100 150 200 feet , , , I r-----, I I B B I I L____-1 SOURCE: Dahlin Group, August 2006. CITY OF DUBLIN SHANNON COMMUNITY CENTER PROJECT INITIAL STUDY I MITIGATED NEGATIVE DECLARATION 12~ ..:~,~ IQJ STOR. RM. []i!] BfCl'. ~ KIT01&l ~ MUl.1\.I'IJIlPOeSE #1 MUI.~ #2 [![] GEl PIens IlOOM ~ PllE-RJHCI1OH ~ , ;._~, LOB8Y !::!!J -:\ r= -.= ~,=-_::-:._:y- -;-- - - - - - "- - - - - - - - -;:;.-.-"-"''''- - -- -:-:,,--'- I I IglQJ] m Pl.AYYNiD ~ emrr 00UIlr ~ I I L____.....J ~ SIORAGE []i!] i., .. PIIf5OIC)OI. #2 0El . I I I I - I I I L_____________________ o o Exhibit 4 MAIN FLOOR PLAN o 32 feet 8 , 16 +1~~'-'-'-'-'-'- ::::-"I. ~...-r r~:tt/fIJ(" ~ _._"_._._._.~._.- _.~~~ <'-if~~ ..--.tr--.----..r----.",..-...~~.--..J ~:. 1t '--;O:~ :::::::::::l. -- -~ .oM......... 0NORTH ELEVATION ~~.- -'-'- _._._.-._._.~~ ~k'-' -.- _._._.~ +1Ym...-.-.- ~. ~~._._._._.- -'~" +Tr..:Jf-.-.- -.-.-"-' ~. .:-.~~ '...... ,~ . - . - . - . -n.i::I+ '-'-'~4 .&+-- +1%".... ..,-o~ G)EAST ELEVATION ~ 0WEST ELEVATION . . .",~ . -'.- . - . - . - . - . - . - - ~V~..~..~.~.~..-:- '~~.' . r-:::::: ~. -"_._._.-T:'~ _._.-.~ ~.< ,.-~.-.-. ~:i~'-"-' .~~ @OUTH ELEVATION SOURCE: DatJ/in Group, August 2006. . . Exhibit 5 " \".,\) 0: O- N BUILDING ELEVATIONS CITY OF DUBLIN SHANNON COMMUNITY CENTER PROJECT INITIAL STUDY { MITIGATED NEGATIVE DECLARATION o 8 16 32 feet ~. I '-fob 1..0-' 1. Project description: Demolition of the existing approximately 13,000 square foot Shannon Community Center and construction of a replacement 19,000 square foot (approximately), one story community center building in approximately the same location as the existing building within Shannon Park. The project also includes replacement of the decking material on an existing pedestrian bridge just south of the new community center building. No changes to other portions of Shannon Park are proposed. 2. Lead agency: City of Dublin Parks and Community Services Department 100 Civic Plaza Dublin CA 94568 3. Contact person: Herma Lichtenstein Project Manager (925) 8336645 4. Project location: Generally located on the north side of Shannon Park, which is located in the northwest comer of San Ramon Road and Shannon Road. 5. Project sponsor: City of Dublin 6. General Plan designation: Low Density Residential 7. Zoning: R-1-Single Family Residential 8. Public agency required approvals: · Approval of Conditional Use Permit (City of Dublin) . Approval of demolition and building plans (City of Dublin) . Approval of Streambed Alteration Agreement (California Department of Fish & Game) City of Dublin Initial Study/Shannon Center Project Page 10 January 2007 l5(fb20~ Environmental Factors Potentially Affected The environmental factors checked below would be potentially affected by this project, involving at least one impact that is a "potentially significant impact" as indicated by the checklist on the following pages. x Aesthetics - Agricultural x Air Quality Resources x Biological x Cultural Resources - Geology / Soils Resources x Hazards and - Hydrology /Water - Land Use/ Hazardous Quali ty Planning Materials - Mineral Resources -- Noise -- Population/ Housing -- Public Services - Recreation - T ransportation/ Circulation -- Utilities / Service x Mandatory Systems Findings of Significance Determination (to be completed by Lead Agency): On the basis of this initial evaluation: _ I find that the proposed project could not have a significant effect on the environment and the previous Negative Declaration certified for this project by the City of Dublin adequately addresses potential impacts. _ I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because the mitigation measures described on an attached sheet have been added to the project. A Negative Declaration will be prepared. -X_ I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because revisions in the project have been made or agreed to by the project proponent. A Mitigated Negative Declaration will be prepared. _ I find that although the proposed project may have a significant effect on the environment, but at least one effect 1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and 2) has been addressed by mitigation measures based on earlier analysis as described on the attached sheets, if the effect is a "potentially significant impact" or "potentially significant unless mitigated." A Supplemental Environmental Impact Report is required, but must only analyze the effects that remain to be addressed. City of Dublin Initial Study/Shannon Center Project Page 11 January 2007 IGot 2.o~ b _ I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because all potentially significant effects (a) have been analyzed adequately in an earlier EIR pursuant to applicable standards, and (b) have been avoided or mitigated pursuant to that earlier EIR, including revisions or mitigation measures that are imposed on the proposed proj ect. Signature: ~ pi; ~ "-'> JJzl Printed Name: Jer\ ~ Date: ~ \,{o 1- For: ~ 0+ O"""f...:- City of Dublin Initial Study/Shannon Center Project Page 12 January 2007 \'frb20 4 Evaluation of Environmental Impacts 1) A brief explanation is required for all answers except "no impact" answers that are adequately supported by the information sources a lead agency cites in the parenthesis following each question. A "no impact" answer is adequately supported if the referenced information sources show that the impact simply does not apply to projects like the one involved (e.g. the project falls outside a fault rupture zone). A "no impact" answer should be explained where it is based on project-specific factors as well as general factors (e.g. the project will not expose sensitive receptors to pollutants, based on a project-specific screening analysis). 2) All answers must take account of the whole action involved, including off-site as well as on-site, cumulative as well as project-level, indirect as well as direct, and construction as well as operational impacts. 3) Once the lead agency has determined that a particular physical impact may occur, then the checklist answers must indicate whether the impact is potentially significant, less-than-significant with mitigation, or less-than-significant. "Potentially Significant Impact" is appropriate if there is substantial evidence that an effect may be significant. If there are one or more "Potentially Significant Impact" entries when the determination is made, an EIR is required. 4) "Negative Declaration: Less-than-Significant With Mitigation Incorporated" applies where the incorporation of mitigation measures has reduced an effect from "Potentially Significant Impact" to a "Less-than-Significant Impact." The lead agency must describe the mitigation measures and briefly explain how they reduce the effect to a less-than-significant level (mitigation measures from Section 17, "Earlier Analysis/' as described in (5) below, may be cross-referenced). 5) Earlier analyses may be used where, pursuant to the tiering, program EIR, or other CEQA process, an effect has been adequately analyzed in an earlier EIR or negative declaration. Section 15063 (c) (3) (D). In this case, a brief discussion should identify the following: a) Earlier Analysis Used. Identity and state where they are available for review. b) Impacts Adequately Addressed: Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on the earlier analysis. c) Mitigation Measures. For effects that are "Less- Than-Significant with Mitigation Measures Incorporated/, describe the mitigation measures which were incorporated or refined from the earlier document and the extent to which they address site-specific conditions for the project. 6) Lead Agencies are encouraged to incorporate into the checklist references to information sources for potential impacts (e.g. City of Dublin Page 13 Initial Study/Shannon Center Project January 2007 1'3 Vb 2.01 general plans, zoning ordinances, etc.). Reference to a previously prepared or outside document should, where appropriate, include a reference to the page or pages where the statement is substantiated. 7) Supporting Information Sources: A source list should be attached and other sources used or individuals contacted should be cited in the discussion. 8) This is a suggested form and lead agencies are free to use different formatsi however, lead agencies should normally address the questions from this checklist that are relevant to a project's environmental effects in whatever format is selected. 9) The explanation of each agency should identify the significance criteria or threshold, if any, used to evaluate each question and the mitigation measures identified, if any, to reduce the impact to a less than significant level. City of Dublin Initial Study/Shannon Center Project Page 14 January 2007 1'1f>b'lo*? Environmental Impacts (Note: Source of determination listed in parenthesis. See listing of sources used to determine each potential impact at the end of the checklist) Note: A full discussion of each item is found following the checklist. 1. Aesthetics. Would the project: a) Have a substantial adverse effect on a scenic vista? (Source: 6) b) Substantially damage scenic resources, including but not limited to trees, rock outcroppings, and historic buildings within a state scenic highway? (Source: 6) c) Substantially degrade the existing visual character or quality of the site and its surroundings? (Source: 6) d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area? (Source: 6) 2. Agricultural Resources Would the project: a) Convert Prime Farmland, Unique Farmland or Farmland of Statewide Importance, as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to a non-agricultural use? (Source: 1, 7) b) Conflict with existing zoning for agriculture use, or a Williamson Act contract? (Source: 1) c) Involve other changes in the existing environment which, due to their location or nature, could result in conversion of farmland to a non-agricultural use? (Source: 6) 3. Air Quality (Where available, the significance criteria established by the applicable air quality management district may be relied on to make the following determinations). Would the project: a) Conflict with or obstruct implementation of the applicable air quality plan? (Source: 1) b) Violate any air quality standard or contribute substantially to an existing or projected air quality violation? (Source: 7) City of Dublin Initial Study/Shannon Center Project Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X X X X X X Page 15 January 2007 c) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors? (7) d) Expose sensitive receptors to substantial pollutant concentrations? (Source: 6) e) Create objectionable odors affecting a substantial number of people? (Source: 5) 4. Biological Resources. Would the project a) Have a substantial adverse effect, either directly through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies or regulations, or by the California Department of Fish and Game or the U.S. Fish and Wildlife Service? (Source: 2) b) Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies or regulations or by the California Department of Fish and Game or the U.S. Fish and Wildlife Service? (Source: 2) c) Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including but not limited to marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption or other means? (Source: 2) d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? (Source: 2) e) Conflict with any local policies or ordinances protecting biological resources, such as tree protection ordinances? (Source: 2) City of Dublin Initial Study/Shannon Center Project ;}Q I1b 2.0 ~ Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X X X X X Page 16 January 2007 f) Conflict with the provision of an adopted Habitat Conservation Plan, Natural Community Conservation Plan or other approved local, regional or state habitat conservation plan? (Source: 1) 5. Cultural Resources. Would the project a) Cause a substantial adverse impact in the significance of a historical resource as defined in Sec. 15064.5? (Source: 1) b) Cause a substantial adverse change in the significance of an archeological resource pursuant to Sec. 15064.5 (Source: 7) c) Directly or indirectly destroy a unique paleontological resource, site or unique geologic feature? (Source: 7) d) Disturb any human remains, including those interred outside of a formal cemetery? (Source: 7) 6. Geology and Soils. Would the project a) Expose people or structures to potential substantial adverse effects, including the risk of loss, injury, or death involving: i) Rupture of a known earthquake fault, as delineated on the most recent Earthquake Fault Zoning Map issued by the State Geologist or based on other substantial evidence of a known fault (Source: 3) ii) Strong seismic ground shaking (3) iii) Seismic-related ground failure, including liquefaction? (3) iv) Landslides? (3) b) Result in substantial soil erosion or the loss of topsoil? (3) c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or similar hazards (Source: 3) d) Be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property? (Source: 3) City of Dublin Initial Study/Shannon Center Project "'2 I Grb"20 Potentiall y Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X X X X X X X X X Page 17 January 2007 e) Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater? (Source: 3) 7. Hazards and Hazardous Materials. Would the project: a) Create a significant hazard to the public or the environment through the routine transport, use or disposal of hazardous materials (Source: 5) b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? (Source: 4) c) Emit hazardous emissions or handle hazardous materials or acutely hazardous materials, substances, or waste within one- quarter mile of an existing or proposed school? (Source: 4) d) Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Sec. 65962.5 and, as a result, would it create a significant hazard to the public or the environment? (Source: 7) e) For a project located within an airport land use plan or, where such a plan has not been adopted within two miles of a public airport of public use airport, would the project result in a safety hazard for people residing or working in the project area? (Source: 1) f) For a project within the vicinity of private airstrip, would the project result in a safety hazard for people residing or working in the project area? (Source: 1) g) Impair implementation of or physically interfere with the adopted emergency response plan or emergency evacuation plan? (Source: 7) City of Dublin Initial Study/Shannon Center Project 2. 2\)b 2..D( Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X X X X X Page 18 January 2007 1. ?~b::;? h) Expose people or structures to a significant risk of loss, injury or death involving wildland fires, including where wildlands are adjacent to urbanized areas or where residences are intermixed with wildlands? (Source: 6) 8. Hydrology and Water Quality. Would the project: a) Violate any water quality standards or waste discharge requirements? (Source: 5) b) Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g. the production rate of existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted? (Source: 5,6) c) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on- or off- site? (Source: 5, 6) d) Substantially alter the existing drainage pattern of the site or areas, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site? (Source: 6) e) Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? (Source: 5, 6) f) Otherwise substantially degrade water quality? (Source: 5, 6) g) Place housing within a lOO-year flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood delineation map? (Source: 5) City of Dublin Initial Study/Shannon Center Project Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X , ! X X X X X Page 19 January 2007 j 4lrl 20"'1 V ,&It) '(.0" h) Place within a 100-year flood hazard area structures which would impede or redirect flood flows? (Source: 4) i) Expose people or structures to a significant risk of loss, injury, and death involving flooding, including flooding as a result of the failure of a levee or dam? (4) j) Inundation by seiche, tsunami or mudflow? (2) 9. Land Use and Planning. Would the project: a) Physically divide an established community? (Source: 1, 6) b) Conflict with any applicable land use plan, policy, or regulation of an agency with jurisdiction over the project (including but not limited to the general plan, specific plan, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental effect? (Source: 1, 6) c) Conflict with any applicable habitat conservation plan or natural community conservation plan? (1, 6) to. Mineral Resources. Would the project a) Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state? (Source: 1) b) Result in the loss of availability of a locally important mineral resource recovery site delineated on a local general Plan, specific plan or other land use plan? (Source: 1) 11. Noise. Would the proposal result in: a) Exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? (Source: 1, 6) b) Exposure of persons or to generation of excessive groundbome vibration or groundbome noise levels? (Source: 1,4) c) A substantial permanent increase in ambient noise levels in the project vicinity above existing levels without the project? (Source: 1, 7) City of Dublin Initial Study/Shannon Center Project Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X X X X X X X X Page 20 January 2007 d) A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? (Source: 5) e) For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working n the project area to excessive noise levels? (Source: 1) f) For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? (Source: 1) 12. Population and Housing. Would the project a) Induce substantial population growth in an area, either directly or indirectly (for example, through extension of roads or other infrastructure)? (Source: 6) b) Displace substantial numbers of existing housing, necessitating the construction of replacement housing elsewhere? (6) c) Displace substantial numbers of people, necessitating the construction of replacement of housing elsewhere? (Source: 6) 13. Public Services. Would the proposal: a) Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered government facilities. the construction of which could cause significant environmental impacts, in order to maintain acceptable service rations, response times or other performance objectives for any of the public services? (Sources: 5, 6) Fire protection Police protection Schools Parks Other public facilities Solid Waste City of Dublin Initial Study/Shannon Center Project Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X I X X X X X X X X Page 21 January 2007 14. Recreation: a) Would the project increase the use of existing neighborhood and regional parks or recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated (Source: 5) b) Does the project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? (Source: 5) 15. Transportation and Traffic. Would the project: a) Cause an increase in traffic which is substantial in relation to the existing traffic load and capacity of the street system (Le. result in a substantial increase in either the number of vehicle trips, the volume to capacity ratio on roads or congestion at intersections)? (5) b) Exceed, either individually or cumulatively, a level of service standard established by the County Congestion Management Agency for designated roads or highways? (5) c) Result in a change in air traffic patterns, including either an increase in traffic levels or a change in location that results in substantial safety risks? (5) d) Substantially increase hazards due to a design feature (e.g. sharp curves or dangerous intersections) or incompatible uses, such as farm equipment? (5) e) Result in inadequate emergency access? (5) f) Result in inadequate parking capacity? (5) g) Conflict with adopted policies, plans or programs supporting alternative transportation (such as bus turnouts and bicycle facilities) (5) City of Dublin Initial Study/Shannon Center Project 2& Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Miticmtion X X X ! X X X X X X Page 22 January 2007 16. Utilities and Service Systems. Would the project a) Exceed wastewater treatment requirements of the applicable Regional Water Quality Control Board? (5) b) Require or result in the construction of new water or wastewater treatment facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? (5) c) Require or result in the construction of new storm water drainage facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? (5) d) Have sufficient water supplies available to serve the project from existing water entitlements and resources, or are new or expanded entitlements needed? (5) e) Result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project's projected demand in addition to the providers existing commitments? (5) f) Be served by a landfill with sufficient permitted capacity to accommodate the project's solid waste disposal needs? (5) g) Comply with federal, state and local statutes and regulations related to solid waste? (5) 17. Mandatory Findings of Significance. a) Does the project have the potential to degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number of or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? City of Dublin Initial Study/Shannon Center Project 2.1rrb 20 ~'1 Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact Mitigation X X X X ! X ! X X X Page 23 January 2007 b) Does the project have impacts that are individually limited, but cumulatively considerable? ("Cumulatively considerable" means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects and the effects of probable future projects). c) Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? 2S6b 20 ~7 Potentially Less Than Less than No Significant Significant Significant Impact Impact With Impact MitiQation X X Sources used to determine potential environmental impacts 1. City of Dublin General Plan 2. Biological Resources Reconnaissance (WRA Associates) 3. Geotechnical Evaluation (ENGEO) 4. Pre-Demolition Asbestos Report (Kellco) 5. Discussion with City staff or service provider 6. Site Visit 7. Other Source XVII. Earlier Analyses a) Earlier analyses used. Identify earlier analyses and state where they are available for review. None were used in the preparation of this Initial Study. City of Dublin Initial Study/Shannon Center Project Page 24 January 2007 "2. '1 ~'b 204 Attachment to Initial Study Discussion of Checklist (Note: CEQA Guideline Section15025 normally require that baseline environmental conditions be based on site conditions existing conditions at the time environmental review of a proposed project is commenced. For this particular project, the environmental analysis is based on the operation of the Shannon Community Center that exists on the project site, but which was closed in 2004. The prior operation has been used as the baseline condition based on the long-term historic use of the Center in Shannon Park). 1. Aesthetics Environmental Setting The project is set in the urbanized portion of Dublin within Shannon Park, an existing city park. Shannon Park includes large turf areas, trees, a play area and a parking lot. Land uses surrounding Shannon Park include single-family dwellings and a combination church and school to the south. The Dublin General Plan does not designate any adjacent roadways as scenic highways. A number of safety and security lights have been installed within the Shannon Park area, in the parking lot, on the existing Community Center building and on adjacent streets. Project Impacts a) Have a substantial adverse impact on a scenic vista? NI. The objective of the proposed project is to replace the existing Shannon Community Center building with a more modern and functional facility that complies with current building codes. The proposed building would be of similar scale and height as the existing building, so that there would be no change to impacts of any scenic vistas from surrounding properties. A small number of older trees around the existing building are proposed to be removed, but would be replaced with new, drought tolerant tree species. Therefore, no impacts are anticipated regarding the creation of an adverse impact on a scenic vista. b) Substantially damage scenic resources, including state scenic highway? NI. The objective of the proposed project is to replace the Shannon Community Center building with a building of similar size and scale in approximately the same location as the existing building. No impacts are therefore anticipated with regard to substantial damage to scenic resources, including state scenic highways. c) Substantially degrade existing visual character or the quality of the site? NI. The project site has been developed within Shannon Park, which is a community park, and the construction of a replacement community center building on the north side of Shannon Park, within the existing building footprint would not result in a City of Dublin Initial Study/Shannon Center Project Page 25 January 2007 iJb2 0 "'1 substantial degradation of the visual character or quality of the site. No impacts would therefore result. ':>) '" d) Create light or glare? LS / M. Although the project site and surrounding area contains several sources of light and glare as discussed in the Environmental Setting section, above, approval and implementation of the proposed project would add new exterior building light fixtures. Depending on the location of the new fixtures, potentially significant sources of light and glare could impact adjacent residences north of the proposed building. The following measure is recommended to reduce this impact to a less-than significant level: Mitigation Measure 1. Exterior light fixtures shall be designed or equipped with cut-off lenses to ensure that no spill over of light or glare occurs outside of Shannon Park. This mitigation measure shall be included on final building plans and specifications. 2. Agricultural Resources Environmental Setting The project site is located within the urbanized portion of western Dublin. Although underlying soils are likely considered prime agriculture soils, the project site and adjacent areas have been urbanized for a number of years. The project site is not zoned for agricultural use and no Williamson Act contract is in place on the project site. Project Impacts a,c) Convert prime farmland to a non-agricultural use or involve other changes which could result in conversion of farmland to a non-agricultural use? NI. The project site lies within an urbanized portion of Dublin and approval of the proposed project to replace the Shannon Community Center with a similar building of the same function would have no impact with regard to conversion of prime farmland to a non-agricultural use or otherwise convert farmland to a non-agricultural land use. b) Conflict with existing zoning for agricultural use, or a Williamson Act contract? NI. No Williamson Act contract exists on the project site nor is the site zoned for an agricultural use. No impacts would therefore result. 3. Air Quality Environmental Setting The project is within the Amador Valley, a part of the Livermore sub-regional air basin distinct from the larger San Francisco Bay Area Air Basin. The Livermore sub-air basin is surrounded on all sides by high hills or mountains. Significant breaks in the hills surrounding the air basin are Niles Canyon and the San Ramon Valley, which extends northward into Contra Costa County. City of Dublin Initial Study/Shannon Center Project Page 26 January 2007 ~\rJ1 201 o Project Impacts a) Would the project conflict or obstruct implementation of an air quality plan? NT. The proposed project includes construction of an enclosed community center within an existing community park. The project would not increase the population of Dublin on which the most recent Clean Air Plan is based or otherwise conflict or obstruct the implementation of the Bay Area Air Quality Management District (BAAQMD) Clean Air Plan. Thus no impact would result. b) Would the project violate any air quality standards? LS/M. The proposed project would include limited amounts of grading and excavation for the proposed building foundation and demolition of an existing building, as well as construction of a new community center building. Thus this project would involve activities that could exceed Bay Area Air Quality Management District air quality standards and would result in a potentially significant impact. The following measure is recommended to ensure that such impacts comply with the District's air quality standards, and are reduced to a less-than-significant level: Mitigation Measure 2. Grading and demolition activities shall include the following to ensure compliance with BAAQMD air quality standards. a) Graded areas shall be watered frequently to minimize emissions of fugitive dust. b) Off-hauled material shall be covered. c) Driveway entrances used by haul trucks shall be swept frequently. c) Would the project result in cumulatively considerable air pollutants? NI. The proposed project is consistent with the Dublin General Plan, which is the basis for BAAQMD's regional Clean Air Plan. For the reasons noted in "a," the proposed project would not contribute to emissions exceeding BAAQMD significance thresholds. No impacts are anticipated. d,e) Expose sensitive receptors to significant pollutant concentrations or create objectionable odors? NT. Sensitive receptors in the project area include a private school south of Shannon Park, and nearby residential uses north of the park. The on-going operation of the community center would involve similar uses and activities as were operated in the existing Shannon Community Center building. The existing center involved no exposure to significant pollutant concentration or objectionable odors and it is not anticipated that the proposed replacement community center would generate significant pollution concentrations or generate significant odors. Thus, no impact is anticipated. 4. Biological Resources The following section is based on a biological reconnaissance report prepared for the project site by WRA (August 2006). This report is incorporated by reference into this Initial Study and is included as Appendix 1 to this Initial Study. City of Dublin Initial Study/Shannon Center Project Page 27 January 2007 ;, ?l>b (;.) "''! Environmental Setting Special status species Potential occurrence of special status species on the project site was evaluated by first determining which special status species occur in the vicinity of the project site through a literature and database search. Database searches for known occurrences of special status species were made for the Dublin 7.5 minute USGS quadrangle. The following sources were reviewed to determine which special status plant and wildlife species have been documented to occur in the vicinity of the project site: California Natural Diversity Database records (CNDDB) (CDFG 2006) United States Fish and Wildlife S service (USFWS) Quadrangle Species Lists (USFWS 2006) California Native Plant Society (CNPS) Electronic Inventory records (CNPS 2006) California Department of Fish and Game (CDFG) publication "California's Wildlife, Volumes I-III" (Zeiner et al. 1990) CDFG publication" Amphibians and Reptile Species of Special Concern in California" (Jennings and Hayes 1994) A site visit was conducted to search for suitable habitats on the project site for those species identified as occurring within the vicinity. Potential for special status species to occur on the project site was then evaluated according to the following criteria: (1) Not Present. Habitat on and adjacent to the site is clearly unsuitable for the species requirements (foraging, breeding, cover, substrate, elevation, hydrology, plant community, site history, disturbance regime). (2) Unlikely. Few of the habitat components meeting the species requirements are present, and/ or the majority of habitat on and adjacent to the site is unsuitable or of very poor quality. The species is not likely to be found on the site. (3) Moderate Potential. Some of the habitat components meeting the species requirements are present, and/ or only some of the habitat on or adjacent to the site is unsuitable. The species has a moderate probability of being found on the site. (4) High Potential. All of the habitat components meeting the species requirements are present and/ or most of the habitat on or adjacent to the site is highly suitable. The species has a high probability of being found on the site. (5) Present. Species is observed on the site or has been recorded (i.e. CNDDB, other reports) on the site recently. The assessment was intended to identify suitable habitat for special status species known to occur in the vicinity in order to determine their potential to occur on or near the project site. The site visit did not constitute a protocol-level survey and was not intended to determine the actual presence or absence of a species; however, if a special status species was observed during the site visit, its presence was recorded and City of Dublin Page 28 Initial Study/Shannon Center Project January 2007 3~J "1 discussed. Appendix B contained in the WRA report (see Initial Study Appendix 1) presents the evaluation of potential for occurrence of special status plant and wildlife species known to occur in the vicinity of the project site with their habitat requirements, occurrence classification, and basis for occurrence classification. The Shannon Community Center building and the area immediately around it were the focus of this assessment as the building is scheduled for demolition and rebuilding. A perennial creek running out of Koopman Canyon runs along the southern border of the building west to east, then turns north through a culvert and under a bike path, running along the west side of San Ramon Road. Shannon Park is located just to the south of the creek and a parking lot is located in the southeast corner of the property. The northern border of the site is comprised of non-native annual grassland and landscaped vegetation. A small strip of non-native annual grassland is present along the northern boundary of the project site. Non-native annual grassland typically occurs in open areas of valleys and foothills throughout California, usually on fine textured clay or loam soils that are somewhat poorly drained. Non-native grassland is typically dominated by non-native annual grasses and forbs along with scattered native wildflowers. Plant species observed in this area include slender wild oat (Avena barbata), black mustard (Brassica nigra) and bristly ox-tongue (Picris echioides). The annual grassland on the project site is regularly mowed and thus represents low value habitat for special status plant and wildlife species. A perennial creek that drains Koopman Canyon runs along the southern border of the Community Center. A bridge connects the existing Community Center building to the park and parking area to the south. A closed canopy overstory consisting predominantly of coast live oak associated with native riparian species such as willows (Salix sp.) and California buckeye (Aesculus californica) as well as introduced black locust (Robinia pseudoacacia), is growing along the edge of the creek. As the creek turns north under the bike path, the over-story disappears and the creek continues into a man-made channel that is overgrown with a combination of non-native vegetation species and native wetland plants. Coast live oak and California buckeye trees observed along the creek corridor may have a diameter of over 24 inches and therefore may be considered heritage trees by the City of Dublin tree protection ordinance. Based upon a review of available resources and databases described in Section 2.3.1, four special status plant species have been documented to occur in the general vicinity of the project area. No special status plant species were observed on the project site during the assessment site visit. Appendix B contained in the full reconnaissance report (see Initial Study Appendix) summarizes typical habitat requirements for these species and provides a rationale for their potential for occurrence within the project area. The biological site assessment occurred during the blooming period of three of the four special status plant species with a potential to occur in the Study Area, including Congdon's tarplant (Centromadia parryi ssp. congdonii), Diablo helianthella (Helianthella castanea), and saline clover (Trifolium depauperatum var. hydrophilum). None of these City of Dublin Page 29 Initial Study/Shannon Center Project January 2007 ..2 .I vt.. ".;,; ..,., <"'+ -.) '1'liU .:c.,-,. I potentially blooming species were observed and all three are unlikely to occur on the site. Although the site visit occurred outside of the blooming period of hairless popcorn flower (Plagiobothrys glaber), no suitable habitat for this species, consisting of meadows or seeps, was present on-site. This species is unlikely to occur on the project site. Ninety special status species of wildlife have been recorded in the vicinity of the project area. Appendix B contained in the biological reconnaissance report (see Appendix 1) summarizes the potential for occurrence for these species on the project site. No special status wildlife species were observed on the project site during the site assessment. No special status wildlife species have a high potential to occur on the project site. Nine special status wildlife species have a moderate potential to occur on the project site. These species, their status, habitat requirements, and known distribution are discussed below. California red-legged frog (Rana aurora draytonii)' Federal Threatened, CDFG Species of Concern. The California red-legged frog is dependent on suitable aquatic, estivation, and upland habitat. During periods of wet weather, starting with the first rainfall in late fall, red-legged frogs disperse away from their estivation sites to seek suitable breeding habitat. Aquatic and breeding habitat is characterized by dense, shrubby, riparian vegetation and deep, still or slow-moving water. Breeding occurs between late November and late April. California red-legged frogs estivate (a period of inactivity) during the dry months in small mammal burrows, moist leaf litter, incised stream channels, and large cracks in the bottom of dried ponds. The Koopman Creek may have water flows that are too high for breeding habitat in the winter but it may provide dispersal habitat for this species. The nearest recorded occurrence of this species is approximately 1.5 miles to the southwest. Western pond turtle (Clemmys marmorata), CDFG Species of Special Concern. The western pond turtle is the only native turtle in central and northern California. This turtle is uncommon to common in suitable aquatic habitat throughout California, west of the Sierra-Cascade crest. Western pond turtles inhabit perennial aquatic habitats, such as lakes, ponds, rivers, and streams, which provide submerged cover and basking structures. Western pond turtles prefer to nest on unshaded slopes close to their aquatic habitat, and hatchlings require shallow water with relatively dense emergent and submergent vegetation for foraging. The creek that extends through the project site may provide suitable aquatic habitat for this species. American Bittern (Botaurus lentiginosus), CDFG Species of Special Concern. American Bittern occurs in fresh emergent wetlands, often hiding, resting, and roosting solitarily amidst tall, dense, emergent vegetation, on ground, or near ground on logs, stumps, or on emergent plants. Their nest is a platform of matted emergent aquatics usually in shallow water, but sometimes floating, or on the ground. The riparian habitat in the project site may provide suitable foraging habitat. White-tailed Kite (Elanus leucurus), CDFG Fully Protected Species. White-tailed Kites are associated with annual grasslands, agricultural areas, scrub habitats, wet meadows, and emergent wetlands throughout the lower elevations of California. Nesting generally occurs in shrubs or small trees. Individuals are likely to forage City of Dublin Page 30 Initial Study/Shannon Center Project January 2007 over open areas of the site throughout the year. The history of human disturbance and scarcity of suitable, isolated trees and shrubs reduces the likelihood of kites nesting however this species may forage on the project site. Cooper's Hawk (Accipiter cooperi), CDFG Species of Special Concern. This hawk is associated with woodland and forest habitats throughout California. Although nest sites are usually found in isolated areas, this species frequently occurs in urban habitats in winter and during migration. This species has the potential to forage and nest in the trees on the project site. Rufous Hummingbird (Selasphorus rufus), USFWS Bird of Conservation Concern. Rufous Hummingbird is a common migrant and uncommon summer resident in California. It occurs in a wide variety of habitats as long as they provide abundant nectar sources. Shrubs in the project site provide suitable nesting habitat and nectar sources. Loggerhead Shrike (Lanius ludovicianus), CDFG Species of Special Concern, Loggerhead Shrike is a common resident and winter visitor in lowlands and foothills throughout California. It prefers open habitats with scattered trees, shrubs, posts, fences, utility lines or other perches. Nests are usually built on a stable branch in a densely foliaged shrub or small tree and are usually well-concealed. The project site contains suitable nesting and foraging habitat. Yuma myotis (Myotis yumanensis), CDFG Species of Special Concern. Yuma myotis is a bat species found throughout most of California at lower elevations in a wide variety of habitats. Day roosts are found in buildings, trees, mines, caves, bridges, and rock crevices. Night roosts are usually associated with buildings, bridges or other man-made structures. The vacant Community Center building and bridge may provide suitable roosting habitat for this species. San Francisco dusky-footed woodrat (Neotomafuscipes annectens). CDFG Species of Special Concern. This species occurs in forest habitats of moderate canopy and moderate to dense understory. It is also found in chaparral habitats and feeds mainly on woody plants: live oak, maple, coffeeberry, alder, and elderberry. Nests are constructed out of leaves, shredded grass, and other material. The project site contains suitable nest sites for this species. Eighteen species of wildlife were observed in or adjacent to the project site during the site assessment (see Appendix A of the biological assessment contained in the Initial Study). All of the wildlife observed on the project site are commonly found species, and many are adapted to occupying disturbed or urban areas. No special status wildlife species were observed. Wetlands and Waters of the US The project site was surveyed to determine if any wetlands and waters potentially subject to jurisdiction by the US Army Corps of Engineers, Regional Water Quality Control Board (RWQCB), or CDFG were present. The assessment was based primarily on the presence of wetland plant indicators, but may also include any observed indicators of wetland hydrology or wetland soils. Any potential wetland areas were City of Dublin Page 31 Initial Study/Shannon Center Project January 2007 3~ab ~ identified as areas dominated by plant species with a wetland indicator status 1 of OBL, FACW, or FAC as given on the US. Fish and Wildlife Service List of Plant Species that Occur in Wetlands. Evidence of wetland hydrology can include direct evidence (primary indicators), such as visible inundation or saturation, surface sediment deposits, algal mats and drift lines, or indirect indicators (secondary indicators), such as oxidized root channels. Some indicators of wetland soils include dark colored soils, soils with a sulfidic odor, and soils that contain redoximorphic features as defined by the Corps Manual and Field Indicators of Hydric Soils in the United States. The preliminary waters assessment was based primarily on the presence of unvegetated ponded areas or flowing water, or evidence indicating their presence such as a high water mark or a defined drainage course. Collection of additional data will be necessary to prepare a delineation report suitable for submission to the Corps. No evidence of jurisdictional wetlands was observed on the site. The only likely waters of the U.S. on the site is Koopman Creek, and Section 404 jurisdiction would extend to the ordinary high water line along this creek. A formal jurisdictional delineation would not be necessary on this site unless grading activities are proposed within the creek channel, and no such grading activities are proposed. The proposed project does include removal and replanting of vegetation in and along Koopman Creek channel, but this activity is not anticipated to not affect the creek channel. Regulatory framework The following paragraphs discuss the regulatory context of the biological assessment, including applicable laws and regulations that were applied to the field investigations and analysis of potential project impacts. Special Status Species. Special status species include those plants and wildlife species that have been formally listed, are proposed as endangered or threatened, or are candidates for such listing under the federal Endangered Species Act (ESA) or California Endangered Species Act (CESA). These Acts afford protection to both listed and proposed species. In addition, California Department of Fish and Game (CDFG) Species of Special Concern, which are species that face extirpation in California if current population and habitat trends continue, US. Fish and Wildlife Service (USFWS) Birds of Conservation Concern, sensitive species included in USFWS Recovery Plans, and USFWS special status invertebrates are considered special status species. Although California and USFWS species of concern generally have no special legal status, they are given special consideration under the California Environmental Quality Act (CEQA). In addition to regulations for special status species, the Migratory Bird Treaty Act of 1918 protects most birds in the United States, including non-status species. Under this legislation, destroying active nests, eggs, and young is illegal. Plant species on California Native Plant Society (CNPS) Lists 1 and 2 are also considered special status plant species. Impacts to these species are considered significant according to the California Environmental Quality Act (CEQA). CNPS List 3 and 4 plants have little or no protection under CEQA, but are included in this analysis for completeness. The 1 OBL = Obligate, always found in wetlands (> 99% frequency of occurrence); FACW = Facultative wetland, usually found in wetlands (67-99% frequency of occurrence); FAC = Facultative, equal occurrence in wetland or non-wetlands (34-66% frequency of occurrence). City of Dublin Initial Study/Shannon Center Project Page 32 January 2007 ~~ J assessment also includes species of local concern as indicated by the USFWS list for the quad/ county, or as designated by a City or County. Sensitive Biological Communities. Sensitive biological communities include habitats that fulfill special functions or have special values, such as wetlands, streams, and riparian habitat. These habitats are regulated under federal regulations (such as the Clean Water Act), state regulations (such as the Porter-Cologne Act, the California Department of Fish and Game's Streambed Alteration Program, or local ordinances or policies (City Tree Ordinances, Special Habitat Management Areas or General Plan Special Land Use areas). Waters of the United States. The US. Army Corps of Engineers (Corps) regulates "Waters of the United States" under Section 404 of the Clean Water Act. "Waters of the US." are defined broadly as waters susceptible to use in commerce, including interstate waters and wetlands, all other waters (intrastate waterbodies, including wetlands), and their tributaries (33 CFR 328.3). Potential wetland areas, according to the three criteria used to delineate wetlands stated in the Corps of Engineers Wetlands Delineation Manual (1987), are identified by the presence of (1) hydrophytic vegetation, (2) hydric soils, and (3) wetland hydrology. Areas that are inundated for sufficient duration and depth to exclude growth of hydrophytic vegetation are subject to Section 404 jurisdiction as "other waters" and are often characterized by an ordinary high water line (OHW). Other waters, for example, generally include lakes, rivers, and streams. The placement of fill material into "Waters of the U.S." (including wetlands) generally requires an individual or nationwide permit from the Corps under Section 404 of the Clean Water Act. No fill is proposed within Koopman Creek. Waters of the State. The Porter-Cologne Act defines waters of the State as "any surface water or groundwater, including saline waters, within the boundaries of the state." The Regional Water Quality Control Board (RWQCB) protects all waters in its regulatory scope, but has special responsibility for wetlands, riparian areas, and headwaters. These waterbodies have high resource value, are vulnerable to filling, and are not systematically protected by other programs. RWQCB jurisdiction includes "isolated" wetlands and waters that may not be regulated by the Corps under Section 404. "Waters of the State" are regulated by the RWQCB under the State Water Quality Certification Program, which regulates discharges of fill, and dredged material under Section 401 of the Clean Water Act and the Porter-Cologne Water Quality Control Act. Projects that require a Corps permit, or fall under other federal jurisdiction, and have the potential to impact "Waters of the State," are required to comply with the terms of the Water Quality Certification determination. If a proposed project does not require a federal permit, but does involve dredge or fill activities that may result in a discharge to "Waters of the State," the RWQCB has the option to regulate the dredge and fill activities under its state authority in the form of Waste Discharge Requirements or Certification of Waste Discharge Requirements. Streams, Lakes, and Riparian Habitat. Streams and lakes, as habitat for fish and wildlife species, are subject to jurisdiction by the California Department of Fish and Game under Sections 1600-1616 of the State Fish and Game Code. Alterations to or work within or adjacent to streambeds or lakes generally require a 1602 Lake and Streambed Alteration Agreement. The term stream, which includes creeks and rivers, is defined in the City of Dublin Page 33 Initial Study/Shannon Center Project January 2007 California Code of Regulations (CCR) as follows: "a body of water that flows at least periodically or intermittently through a bed or channel having banks and supports fish or other aquatic life. This includes watercourses having a surface or subsurface flow that supports or has supported riparian vegetation" (14 CCR 1.72). In addition, the term stream can include ephemeral streams, dry washes, watercourses with subsurface flows, canals, aqueducts, irrigation ditches, and other means of water conveyance if they support aquatic life, riparian vegetation, or stream-dependent terrestrial wildlife (CDFG ESD 1994). Riparian is defined as, "on, or pertaining to, the banks of a stream;" therefore, riparian vegetation is defined as, "vegetation which occurs in and/ or adjacent to a stream and is dependent on, and occurs because of, the stream itself" (CDFG ESD 1994). Removal of riparian vegetation, such as that proposed, also requires a Section 1602 Lake and Streambed Alteration Agreement from CDFG. Other Sensitive Plant Communities. Sensitive plant communities include habitats that fulfill special functions or have special values. Natural communities considered sensitive are those identified in local or regional plans, policies, regulations, or by the California Department of Fish and Game (CDFG). CDFG ranks sensitive communities as "threatened" or "very threatened" and keeps records of their occurrences in its Natural Diversity Database. Sensitive plant communities are also identified by CDFG on their List of California Natural Communities Recognized by the CNDDB. Protected Trees. According the City of Dublin Heritage Tree Ordinance, a "heritage tree" is defined as any of the following: -Any oak, bay, cypress, maple, redwood, buckeye and sycamore tree having a trunk or main stem of twenty-four (24) inches or more in diameter measured at four (4) feet six (6) inches above natural grade; -A tree required to be preserved as part of an approved development plan, zoning permit, use permit, site development review or subdivision map; -A tree required to be planted as a replacement for an unlawfully removed tree. Under this ordinance, no person may remove, cause to be removed, or effectively remove any heritage tree from any property within the city of Dublin without obtaining a permit from the Director. All applicants for demolition, grading, or building permits on property containing one or more heritage trees shall also prepare a tree protection plan. Project Impacts a) Have a substantial adverse impact on a candidate, sensitive, or special-status species? LS/M. No impacts to special status plant species are anticipated since no species were observed during the site biological reconnaissance visit and none are expected to occur on the site. Disturbed habitat conditions, the lack of species- specific habitat requirements and the past incursion of exotic plant species preclude the occurrence of any potentially occurring special status plant species. Of the 90 special status wildlife species known to occur in the vicinity of the project site, nine were determined to have the potential to occur on the project site. Most of the species found in the review of background literature occur in habitats not found in the project site. Habitat suitability for grassland and City of Dublin Page 34 Initial Study/Shannon Center Project January 2007 a-1ab riparian associated species on the project site is reduced due to regular mowing of the site and development and human use on site and adjacent to the site. There is a potential for the proposed project to impact several special-status wildlife species. Protected Avian Species. The biological assessment prepared for this project determined that five sensitive bird species might use the project site for breeding and foraging. These include Cooper's Hawk, rufous hummingbird, loggerhead shrike, Yuma myotis and San Francisco dusky-footed woodrat. The Migratory Bird Treaty Act of 1918 protects most birds in the United States, including non- status species. Under this legislation, destroying active nests, eggs, and young is illegal. The potential for such harm during demolition and construction activities would be a potentially significant impact. Precautions shall be undertaken before and during construction to ensure no such harm or harassment occurs. The following mitigation measure is therefore required to reduce this impact to a less-than-significant level. Mitigation Measure 3. a) If shrubs or trees are to be trimmed or removed during construction, such trimming or removal of vegetation within or near the construction footprint may occur only during the non-breeding season (August through February); or b) Pre-construction breeding bird surveys shall be conducted by a qualified biologist during the breeding season within 30 days of the start of construction. Surveys shall be conducted within suitable nesting habitat in or near the project area. A 50-foot radius minimum exclusion zone shall protect all active nests identified at that time. Exclusion zones would vary depending on each species. The exclusion zone shall remain in place until all young have fledged. Since some birds may have three broods, avoidance could possibly extend into August. California red-legged frog and Western pond turtle. The California red-legged frog has a documented occurrence approximately 1.5 miles to the southwest of the project site. The project site may provide potential breeding habitat though there is a higher potential of the area being used for dispersal habitat. Western pond turtles also have the potential to use the aquatic habitat in the project site. There is also suitable turtle nesting habitat in the uplands adjacent to the creek. Disturbance of the habitat during construction of the proposed project could result in potentially significant impacts to these special-status species and the following measure is recommended to reduce this impact to a less-than- significant level. Mitigation Measure 4. An exclusion fence shall be installed and maintained during the construction period, spring through fall, in between the creek and the construction area, to ensure no red-legged frogs or pond turtles enter the construction site. The location of the fence shall City of Dublin Page 35 Initial Study/Shannon Center Project January 2007 11.0,,,,.<1 20"1 -r vO... ( be selected by a qualified biologist to ensure that no wetlands, waters of the US or waters of the state are impacted. Grading of the site shall only occur between April and November to minimize impacts to dispersing frogs. Yuma myotis One special status bat species, the Yuma myotis, has a moderate potential to occur on the project site and its roost sites are protected by the California Department of Fish and Game. Snags, trees, unoccupied buildings and bridges are an important habitat requirement for bats. Removal or disturbances of these could result in a potentially significant impact and the following measure is recommended to mitigate this impact to a less-than-significant level. Mitigation Measure 5. a) If snag, tree, building or bridge removal or improvements are to take place during summer months when bats may be roosting, a bat roost survey shall be conducted by a qualified biologist. If no roosting bats are found, no further mitigation steps would be required. If bats are detected, a 50-foot wide buffer exclusion zone shall be established around each occupied snag or tree until the roosting period has ended; or b) Alternatively, construction activities shall be limited to the times of the year when bats are not breeding nor hibernating. Bat surveys would not be necessary if tree, snag or building removal were to occur in September and October, after the bat-breeding season and before the bat hibernation season. San Francisco dusky-footed woodrat. The stick houses of the San Francisco dusky-footed woodrat may occur on the project site. The availability of suitable- sized sticks may limit the number of woodrat houses. Construction and construction related activity have the potential to disturb the houses of the woodrat, potentially causing abandonment or destroying the houses all together. This would be a potentially significant impact and the following mitigation measure is recommended to reduce this impact to a less-than-significant level: Mitigation Measure 6. W oodrat houses shall be flagged by a biologist and avoided during construction activities. The potential presence of flags shall be noted on final construction plans and specifications. If avoidance of woodrat houses is unavoidable, sticks from the dismantled house should be kept on site, near the dismantled house if possible. b, c) Have a substantial adverse impact on riparian habitat or federally protected wetlands? LS / M. Approval and construction of the proposed project would occur outside the limits of identified wetlands, waters of the US or waters of the state. However, grading and demolition activities could impact the creek that bisects the project site, which would be a potentially significant impact. Adherence to Mitigation Measure 4 , which requires installation of an exclusion fence adjacent to the Koopman Creek, would reduce impacts to wetlands and riparian habitats to a less-than-significant level. Removal and replacement of vegetation would City of Dublin Page 36 Initial Study/Shannon Center Project January 2007 L.H U ~t take place on the bank of Koopman Creek and a Section 1602 permit would need to be obtained from the California Department of Fish and Game prior to this activity. d) Interfere with movement of native fish or wildlife species? NI. The proposed project would not block or impede the movement of fish or wildlife along the Koopman Creek corridor, since no obstructions would be constructed as part of the project. No impacts are therefore anticipated. e) Conflict with local policies or ordinances protecting biological resources? LS/M. Approval and construction of the proposed project could remove or damage trees protected by the City's Heritage Tree ordinance adjacent to the existing Community Center building. This would be a potentially significant impact and the following measure is recommended to mitigate this impact to a less-than- significant level. Mitigation Measure 7. a) The landscape plan prepared for the project shall include specific measures to protect trees, including but not limited to placement of exclusion fencing around protected trees, limitation regarding storage of materials and equipment inside of the fencing, selective pruning of branches prior to demolition and construction activities and similar steps. b) The landscape plan shall incorporate replacement trees at a 1:1 ratio for each protected tree that must be removed to implement the proposed project. f) Conflict with any adopted Habitat Conservation Plans or Natural Community Conservation Plans? NI. The project site is not located within the boundaries of a habitat conservation plan. No impacts are therefore anticipated. 5. Cultural Resources Environmental Setting The project area is located within an urbanized portion of the City of Dublin. The existing Shannon Community Center building is less than fifty years old and would not quality for state or federal listing as an historic resource. Project Impacts a) Cause substantial adverse change to significant historic resources? NI. The existing Shannon Community Center building is less than fifty years old and would not quality as a historic resource, so no impacts are anticipated with regard to significant historic resources. b, c) Cause a substantial adverse impact or destruction to archeological or paleontological resources? LS / M. Demolition of the existing building and construction of the proposed new building could uncover previously unsurveyed historical, City of Dublin Page 37 Initial Study/Shannon Center Project January 2007 Li' 2 ~"', i..} . ./ , prehistoric or Native American artifacts. This would be a potentially significant impact that would be reduced to a less-than-significant impact by adherence to the following mitigation measure: Mitigation Measure 8. Wording shall be added on final construction plans and specifications to the effect that if archeological or Native American materials or artifacts are identified, work on that portion of the project shall cease until a resource protection plan conforming to CEQA Guidelines Section 15064.5 and the Dublin Zoning Ordinance is prepared by a qualified archeologist and/ or paleontologist and approved by the City of Dublin Community Development Director or an authorized representative. Project work may be resumed in compliance with such plan. If human remains are encountered, the County Coroner shall be contacted immediately and the provisions of State law carried out. d) Disturb any human remains, including those interred outside of a formal cemetery? LS / M. A remote possibility exists that historic or pre-historic human resources could be uncovered in the project site during construction activities that would be a potentially significant impact. Adherence to Mitigation Measure 8 would reduce this potential impact to a less-than-significant level. 6. Geology and Soils Environmental Setting A geotechnical exploration and fault hazard analysis of the proposed project was completed in June 2006 by ENGEO Incorporated. This report is incorporated by reference into this Initial Study and is included as Appendix 2 of this document. The project site is located at the east margin of the East Bay Hills, an uplifted block of folded and faulted sedimentary rocks. The site was graded in the early 1970's to construct Shannon Park and the existing Community Center building. Grading consisted of shallow cuts and fills to create building pads, parking lots and walkways. The project site and surrounding area lies within an Earthquake Fault Zone (formerly Alquist-Priolo Special Studies Zone). Such areas have been created by the State of California that include active faults and fault traces. No structures intended for human habitation may be constructed across active faults or fault traces and for properties within an Earthquake Fault Zone. State Law also requires preparation of a site-specific geotechnical analysis to identify the specific location of any faults near proposed construction. To meet the requirements of the Alquist-Priolo Act, the ENGEO report fulfills this requirement, since this report summarizes the results of site-specific boring and trenching to identify the location of faults or fault traces within the project site. The ENGEO report indicates that the entire project site lies within the Earthquake Fault Zone of the Calaveras Fault trace, with the fault trace extending generally parallel to San Ramon Road east of the project site. Trenching near the site by ENGEO did not find evidence of faulting through the existing Community Center building site. The report recommends that a minimum 50-foot wide setback be established and maintained from City of Dublin Page 38 Initial Study/Shannon Center Project January 2007 i' evidence of fault traces and the edge of the proposed Community Center building. The report also recommends that special mat building foundations be designed for the proposed replacement facility to minimize seismic damage from any fault activity. The ENGEO report also found that site soils have a high potential for expansivness, which is a tendency for the soil to shrink or swell based on the presence of moisture. Recommendations included in the report would provide for foundation design to minimize structural damage due to soil expansiveness. Project Impacts a) Expose people or structures to potential substantial adverse impacts, including loss, injury or death related to ground rupture, seismic ground shaking, ground failure, or landslides? LS/M. The project site is located within an Earthquake Fault Zone and construction of the proposed replacement Shannon Center building could result in a potentially significant impact related to ground rupture and severe ground shaking as a result of nearby ground faulting. A site-specific geotechnical exploration and fault hazard evaluation has been completed by the firm of ENGEO, Incorporated (see Appendix 2) to ensure compliance with the Alquist- Priolo Act. The ENGEO exploration included site borings and trenching to determine the precise nature of faults or fault traces on the project site. The exploration concluded that there is no evidence of previous surface fault rupture through bedrock or native soils across the width of the existing Shannon Community Center building, or for distances of up to 115 west of the existing building or for up to 60 feet east of the existing building. Figure 6, included in the ENGEO evaluation, has determined that the nearest fault is located approximately 120 feet west of the existing building. The following measures, as included in the ENGEO report, shall be included in project plans to ensure that the impacts related to ground rupture will be reduced to a less-than-significant level: Mitigation Measure 9. A structural setback of at least 50 feet shall be provided between the proposed replacement Shannon Community Center building and the nearest fault trace, as verified in writing by a California- registered Geotechnical Engineer or equivalent. No habitable structures shall be constructed in this setback area. Habitable structures located at distances between 50 and 100 feet of the nearest fault trace shall be supported by a mat foundation on a geotechnically improved subgrade as further identified in the ENGEO report as a Special Foundation Zone. The ENGEO evaluation also determined that the proposed replacement building would be subject to the effects of considerable ground shaking in the event of a moderate to high seismic event within the San Francisco Bay region. The effects of such ground shaking could be reduced to a less-than-significant level by adherence to current seismic building codes enforced by the City of Dublin. b) Is the site subject to substantial erosion and/or the loss of topsoil? LS / M. Demolition and construction of the proposed project improvements could result in erosion from the site into adjacent Koopman Creek, impacting the quality of water in the creek. This would result in a potentially significant impact. The following measure City of Dublin Page 39 Initial Study/Shannon Center Project January 2007 yy shall be followed to ensure that erosion impacts are reduced to a less-than- significant level. Mitigation Measure 10. Prior to issuance of a demolition permit, a Storm water Pollution Prevention Plan shall be prepared that complies wi th the Alameda County Clean Water Program to minimize erosion into Koopman Creek during project construction and post construction operation of the proposed facility. The Plan, at minimum, shall include requirements to place fiber maps, silt fences and similar features adjacent to the creek to minimize erosion into Koopman Creek during construction and use of Best Management Practices during project operation to minimize runoff of untreated storm water into the creek. The Plan shall be approved by the Dublin City Engineer prior to commencement of demolition. c,d) Is the site located on soil that is unstable or expansive or result in potential lateral spreading, liquefaction, landslide or collapse? LS/M. The ENGEO evaluation (Appendix 2) concludes that the project site is underlain by soils with a high shrink-swell potential that could result in a potentially significant impact to building foundations proposed for the replacement Shannon Community Center building by causing cracking and differential settlement. The following measure shall be implemented as part of foundation plans for the proposed replacement building. Mitigation Measure 11. Building foundations shall be designed to specifications provided by a California-registered Geotechnical Engineer or equivalent. The foundation system may likely include conventional spread footings in combination with a structural mat foundation system, such as a post-tensioned mat or conventional reinforced mat system. e) Have soils incapable of supporting on-site septic tanks if sewers are not available? NT. The proposed Shannon Community Center would contain restrooms that would be connected to sanitary sewers maintained by the Dublin San Ramon Services District, so there would be no use of and no impact related to septic systems. 7. Hazards and Hazardous Materials Environmental Setting The project site and surrounding area contains Shannon Park and the existing Shannon Community Center building. Maintenance of the park and the building requires use of normal and customary lawn chemicals and compounds used for building maintenance, such as paints, solvents and similar substances. These are used by City staff or contract personnel and stored in secure locations. The project proposes no change to this existing practice. A pre-demolition inspection analysis of the existing Shannon Community Center building was completed in September, 2005 by the firm of Kellco Services, Inc., an independent asbestos and lead based paint consulting firm headquartered in Hayward. City of Dublin Page 40 Initial Study/Shannon Center Project January 2007 ."f .t. A copy of this report is available for review at the Dublin Parks and Community Services Department during normal business hours, and is incorporated by reference. The Kellco report found that quantities of asbestos were included within various building materials used to construct the existing building. These materials included tape joint compound, vinyl flooring and base plaster. The report also notes the presence of lead based paints in the building. The project site is not located within close proximity of any public or private airport or airstrip. Project Impacts a) Create a significant hazard to the public or the environment through the routine transport, use or disposal of hazardous materials? NT. There would be no impact with regard to transport, use or disposal of hazardous materials since the proposed project involves construction of a replacement community center building in approximately the same location as the current building. No activities planned for the proposed building would involve transport, use, handling or disposal of substantial amounts of hazardous materials. b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? LS/M. Based on the findings of the Kellco report, demolition of the existing building could release asbestos, lead based paint and other potentially hazardous substances into the atmosphere. This would be a potentially significant impact and the following mitigation measure is recommended to reduce this impact to a less-than-significant level: Mitigation Measure 12. Prior to demolition of the existing Shannon Community Center building, a hazardous materials removal plan shall be prepared a registered environmental professional consistent with EP A, OSHA, State of California OSHA, the California Department of Toxic Substances Control, the Bay Area Air Quality Management District and Alameda County Environmental Health Department criteria and standards. The plan shall detail how materials will be removed from the building and disposal site(s). Demolition shall be undertaken by state licensed contractors and include a worker safety plan. The plan shall be approved by the City of Dublin Building Official prior to commencement of demolition. c) Emit hazardous materials or handle hazardous materials or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? NT. Although a private school exists to the south of the project site and within one mile of the project site, approval and implementation of the proposed project would have no impact with regard to this topic, since the proposed community center building would not handle or release significant levels of hazardous materials during the normal course of operations. d) Is the site listed as a hazardous materials site? NT. No properties comprising the project area are listed on the State of California Department of Toxic Substances Control as City of Dublin Page 41 Initial Study/Shannon Center Project January 2007 41.1) t:/J.. 0 &l( an identified hazardous site as of August 14,2006. There is therefore no impact with regard to this topic. e,f) Is the site located within an airport land use plan of a public airport or private airstrip? NT. The project area is not located near a public or private airport, airfield or airstrip. No impacts are therefore anticipated regarding airport safety issues. g) Interference with an emergency evacuation plan? NT. The proposed project would include the construction of a replacement community center building within a City park. No emergency evacuation plan would be affected since no roadways would be blocked. No impact would therefore result. h) Expose people and structures to a significant risk of loss, injury or death involving wildland fires or where residences are intermixed with wildlands? NT. The project site is located in urbanized area and does not include residential structures that would involve intermixing of residences with wildlands so that no impacts would result. 8. Hydrology and Water Quality Environmental Setting Local surface water Koopman Creek, a small tributary of Alamo Creek, flows in an east-west direction through the project site that transitions into a pipe that parallels San Ramon Road and runs through a series of Zone 7 facilities eventually discharging into Alamo Creek, a major north-south regional drainage facility. The project area is located within the jurisdiction of Zone 7 of the Alameda County Flood Control and Water Conservation District (Zone 7). Zone 7 provides maintenance of regional drainage facilities within this portion of Alameda County. Surface water quality Water quality in California is regulated by the U.s. Environmental Protection Agency's National Pollution Discharge Elimination System (NPDES), which controls the discharge of pollutants to water bodies from point and non-point sources. In the San Francisco Bay area, this program is administered by the San Francisco Bay Regional Water Quality Control Board (RWQCB). Federal regulations issued in November 1990 expanded the authority of the RWQCB to include permitting of stormwater discharges from municipal storm sewer systems, industrial processes, and construction sites that disturb areas larger than one acre of land area. The City of Dublin is a co-permittee of the Alameda County Clean Water Program, which is a coordinated effort by local governments in Alameda County to improve water quality in San Francisco Bay. Flooding The project site lies outside of a 100-year flood hazard area as mapped by the Federal Emergency Management Agency, although a small portion of southerly extent of Shannon Park does lie within a 100-year flood hazard area (Community Panel Number City of Dublin Initial Study/Shannon Center Project Page 42 January 2007 4"'1 i;lb t. CP 060705 0001 B). This designation does not include the location of the Community Center however. Project Impacts a) Violate any water quality standards or waste discharge requirements? LS I M. Demolition and reconstruction of the proposed community building, and post construction operations, could result in soil erosion or release of oils and other debris from the site into Koopman Creek. This would be a potentially significant impact and adherence to Mitigation Measure 10 would reduce this impact to a less-than- significant level. Minimal and less-than-significant increases in the amount of wastewater generation from the proposed project over historic flows from the existing Community Center building is anticipated so there would be no violation of waste discharge requirements. b) Substantially deplete groundwater recharge areas or lowering of water table? LS. The proposed project would have approximately the same building footprint as the current building, so that there would be a less-than-significant impact regarding a reduction in the amount of water discharge areas. Since the proposed building would be connected to Dublin San Ramon District's water system that does not rely significantly on groundwater, there would be no impact for this topic as well. c) Substantially alter drainage patterns, including streambed courses such that substantial siltation or erosion would occur? NT. The proposed project would not result in significantly changed topographic elevations from existing conditions that would substantially alter existing drainage patterns or existing streamcourses so that no impact would result. Mitigation Measure 10 is included in this Initial Study to minimize erosion into nearby bodies of water. d) Substantially alter drainage patterns or result in flooding, either on or off the project site? LS. The proposed project would not significantly alter existing drainage patterns, since the project includes replacement of a Community Center building of approximately the same size and in the same location. Although a small increase in the amount of runoff from the site is anticipated due to a somewhat larger building, the quantity of such increases would be less-than-significant. e) Create stormwater runoff that would exceed the capacity of drainage systems or add substantial amounts of polluted runoff? LS. Less-than-significant increased quantities of stormwater runoff is anticipated since the project would include replacement of an existing building with an approximately similarly sized building in the same location as the existing building. f) Substantially degrade water quality? LS/M. Water quality degradation would result from erosion and other releases during demolition, construction and post- construction operations for the project. This is a potentially significant impact and has been addressed above in item" a," and will be mitigated to less-than- significant through Mitigation Measure 10 as described above. City of Dublin Initial Study/Shannon Center Project Page 43 January 2007 zo, g) Place housing within a 1 DO-year flood hazard area as mapped by a Flood Insurance Rate Map? NT. The project does not include a housing component, so no impacts are anticipated. h, i) Place within a lOO-year flood hazard boundary structures that impeded or redirect flood flow, including dam failures? NT. Refer to item" g," above. j) Result in inundation by seiche, tsunami or mudflows? NT. The project area is located well inland from San Francisco Bay or other major bodies of water to be impacted by a tsunami or seiche. No impacts would therefore result. 9. Land Use and Planning Environmental Setting Existing land uses The project site has been developed with a two-story community center building that is an integral part of Shannon Park. Surrounding land uses Surrounding uses include single-family detached dwellings to the north, east and west of the project site. A church and private school exists to the south of Shannon Park. Regulatory setting The Dublin General Plan designates the project site as "Parks/Public Recreation," more specifically as a Community Park within this land use designation. The Dublin Zoning Ordinance designates the site as R-l, Single Family Residential District. This district requires the issuance of a conditional use permit for community clubhouses and community facilities. Project Impacts a) Physically divide an established community? NT. The project site is currently occupies by an existing community center building that is proposed to be removed to allow for construction of the proposed building. Therefore, no established community would be divided and no impact would occur. b) Conflict with any applicable land use plan, policy or regulation? NT. The proposed project would be consistent with City of Dublin General Plan and zoning designations so that there would be no conflict with applicable land use plans or other land use regulatory programs and no impact would result. c) Conflict with a habitat conservation plan or natural community conservation plan? NT. The project area is not located within a habitat conservation plan area or natural community conservation plan area. City of Dublin Initial Study/Shannon Center Project Page 44 January 2007 . i,," 20 ~, 10. Mineral Resources Environmental Setting The project area contains no known mineral resources. This is based on the City of Dublin General Plan document. Project Impacts a, b) Result in the loss of availability of regionally or locally significant mineral resources? NT. The project site is currently developed and construction of the proposed replacement building on the same site would result in no impacts to mineral resources. 11. Noise Environmental Setting The City defines "noise" as a sound or series of sounds that are intrusive, irritating, objectionable and/ or disruptive to daily life. Noise is primarily a concern with regard to noise sensitive land uses such as residences, schools, churches and hospitals. Although noise is controlled around commercial, industrial and recreation uses, community noise levels rarely exceed maximum recommended levels for these uses. Regulatory setting The Noise Element of the General Plan identifies the following primary sources of noise in Dublin: traffic noise from freeways and major roadways within the community and noise generated by the BART line adjacent to the 1-580 freeway. The Noise Element identifies the following maximum noise exposure levels by land use type. Community centers are not specified in the table, but the most applicable category to be schools, churches and nursing homes. Therefore, based on this table, the maximum noise exposure level for the project is 70 dB. Table 1 City of Dublin Land Use/Noise Compatibility Standards (decibels) Land Use Normally Conditionally Normally Clearly Acceptable Acceptable Unacceptable Unacceptable Residential 60 or less 60-70 70-75 75+ Lodging Facilities 60-70 70-80 80+ -- Schools, churches, 60-70 70-80 80+ - nursing homes Neighborhood 60 or less 60-65 65-70 70+ parks Office / Retail 70 or less 70-75 75-80 80+ Industrial 70 or less 70-75 75+ - Source: Dublin General Plan Noise Element, Table 9-1 The City of Dublin also enforces an interior noise standard of 45 decibels for residential dwellings. City of Dublin Initial Study/Shannon Center Project Page 45 January 2007 2.0 '::i Figure 9-2 contained in the Noise Element of the Dublin General Plan notes that the project site lies in a portion of the community that is expected to be subject to exterior noise levels between 60 and 65 decibels. Project Impacts a) Would the project expose persons or generation of noise levels in excess of standards established by the General Plan or other applicable standard? NT. The proposed project would include a continuation of the existing Shannon Community Center uses. The type of land use associated with the proposed project would be approximately the same as the current use with the same hours of operation, so there would be no change regarding the exposure of people or the generation of noise in excess of City standards and no impacts would result. b) Exposure of people to excessive groundborne vibration or groundborne noise levels? NT. The proposed project does not include major construction or operation elements that would result in significant groundborne vibration levels, so no impacts are anticipated with regard to vibration. c) Substantial increases in permanent in ambient noise levels? NT. The level of permanent noise associated with the proposed community center building would be approximately the same as noise levels associated with the previous use of the project site and no impacts would occur with regard to substantial increases n permanent noise levels. d) Substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels without the project? LS / M. Increased levels of short-term construction noise generated on the project site could result in potentially significant levels of noise on adjacent residents and users of Shannon Park. This would be caused by use of heavy construction vehicles and equipment, such as trucks, compressors saws and similar equipment. The following mitigation shall be required for the project: Mitigation Measure 13. Prior to demolition of the existing Shannon Community Center building, a Construction Noise Management Plan shall be prepared and approved by the Dublin Community Development Department to minimize construction noise. At minimum, the Plan shall establish days and hours of construction operations, including delivery of construction materials and equipment maintenance, notification of park users and residents as to the start date and duration of the project and the name and phone number of a noise coordinator for concerns regarding constriction noise. The Construction Noise Management Plan shall be made a part of construction plans and specifications to be implemented by project contractors. e, f) For a project located within an airport land use plan, would the project expose people to excessive noise levels? NT. No portions of the project area are located within an airport referral area. No impacts are therefore anticipated in terms of this topic. City of Dublin Initial Study/Shannon Center Project Page 46 January 2007 SltQ 20 12. Population and Housing Environmental Setting The Association of Bay Area Governments (ABAG), the Council of Governments organization responsible for preparing and tracking population and demographic changes within the Bay Area region anticipates that the Bay Area will continue to grow at a steady rate. Factors contributing to this growth include a favorable climate, recreational activities, top universities and career opportunities. Over the next 20 years, the population is expected to increase to more than 8 million persons, a 16% increase over the current (2005) population. Population increases are expected to be primarily due to increases in births and longer life expectancies rather than significant in-migration. Project Impacts a) Induce substantial population growth in an area, either directly or indirectly? NT. Approval of the proposed project would not increase population growth since it would represent a replacement of a similar land use on the same site. No impacts are therefore anticipated. b,c) Would the project displace substantial numbers of existing housing units or people? NT. The project site is occupied by an existing community center building that would be demolished to allow the proposed building to be constructed. No impact would result with regard to displacement of an existing population or dwellings on the project site. 13. Public Services Environmental Setting The following provide essential services to the community: · Fire Protection. Fire protection services are provided by the Alameda County Fire Department. The Department provides fire suppression, emergency medical response, fire prevention, education, building inspection services and hazardous material control. The nearest station is Station 16, located south of the project site at 7494 Donohue Drive near downtown Dublin. This station contains one engine company and one truck company. · Police Protection: Police and security protection is provided by the Alameda County Sheriff. · Schools. The Dublin Unified School District provides K-12 educational services for properties in the project area lying west of Tassajara Road. · Library Services: Alameda County Library service. City of Dublin Initial Study/Shannon Center Project Page 47 January 2007 20'1 . Maintenance. Maintenance of streets, roads and other governmental facilities are the responsibility of the City of Dublin. Project Impacts a) Fire protection? NT. Approval of the proposed project and construction of the replacement Shannon Community Center on the same site would not require the construction of new or expanded fire facilities by the Alameda County Fire Department, since the Department is currently providing service to the current community center building from Station 16. No impacts are therefore anticipated regarding fire protection impacts. b) Police protection? NT. Similar to fire protection, there would be no impacts with regard to police protection, since no new or expanded police services would be required to serve the proposed Shannon Community Center building. c) Schools? NT. There would be no impact to school service should the proposed project be approved since the project does not include a residential component. d) Other governmental service, including maintenance of public facilities? NT. The proposed community center building would be constructed to current building codes and standards by the City of Dublin to minimize the need for maintenance by the City. No impacts are anticipated regarding maintenance services. e) Solid waste generation? NT. The proposed project would generate approximately the same volume of solid waste as the existing facility, so no impact would result regarding solid waste generation. The proposed community center building would contain space for short-term storage of recycling that could incrementally decrease the volume of solid waste. 14. Recreation Environmental Setting The project site is located on the north side of Shannon Park, a 9.7-acre community park that provides a play area, picnic area, an open turf area, a jogging path, restrooms and a parking lot. Project Impacts a) Would the project increase the use of existing neighborhood or regional parks? LS. The proposed project includes construction of a replacement community center building on the same site as an existing community center building. The replacement building is approximately the same size as the current building and would offer approximately the same facilities and programs as the current building. Depending on the programs offered at the replacement building, there could be a small increase in the usage of the proposed community center building, but this increase is not anticipated to result in a significant increase in the use of Shannon Park over existing use patterns, so this impact would be less-than- significant. City of Dublin Initial Study/Shannon Center Project Page 48 January 2007 t-. -....,; b) Does the project include recreational facilities or require the construction of recreational facilities? NT. Recreational classes and programs that occurred at the existing community center before its closure are expected to continue in the reconstructed facility. The physical effects of the project are addressed in related topic areas of this Initial Study. The project would have no impact on the level of recreational services and will not generate the need for recreational facilities. 15. Transportation/Traffic Environmental Setting The project site is served by San Ramon Road that provides regional access from San Ramon in the north to the I-S80 freeway and Pleasanton to the south. San Ramon Road also provides for community-wide access to the project site for Dublin residents. Shannon Drive provides local access to the project site for residents west of San Ramon Road. Both roadways currently operate at acceptable levels of service, according to the Dublin Public Works Department. Project Impacts a) Cause an increase in traffic which is substantial to existing traffic load and street capacity? LS. The proposed project would include construction of a replacement Community Center building within Shannon Park. Although the size of the replacement building would be approximately 6,000 square feet larger than the existing building, increases in traffic volumes on adjacent roads are anticipated to be less- than-significant, since adequate capacity exists on adjacent streets to accommodate the any anticipated peak hour traffic increases. b) Exceed, either individually or cumulatively, a LOS standard established by the County CMAfor designated roads)? NT. San Ramon Road is identified as an "MTS Route" by the Alameda County Congestion Management Agency (ACCMA). Since the proposed increase in floor space associated with the Shannon Community Center would generate significantly fewer than 100 p.m. peak hour trips, the level of significance used by the ACCMA, the proposed project would have no impact regarding a CMA designated roadway. c) Change in air traffic patterns? NT. The proposed project would have no impact on air traffic patterns, since it involves a proposed replacement Community Center building. d) Substantially increase hazards due to a design feature or incompatible use? NI. No changes to roads or parking lots located near the proposed building are required so that no impacts are anticipated regarding traffic hazards due to a design feature or an incompatible land use. City of Dublin Initial Study/Shannon Center Project Page 49 January 2007 54 "'1 e) Result in inadequate emergency access? NT. The proposed Community Center building would not block any road or emergency route since it would be located on the north side of a community park. No impacts are therefore anticipated. f) Inadequate parking capacity? NT. No impacts to parking capacity is anticipated since the project would replace a similar use on the same site and an existing parking lot serves Shannon Park and the existing Community Center building. g) Hazards or barriers for pedestrians or bicyclists? NT. The proposed building would be located in approximately the same location as the existing community center building so that no hazards for wither pedestrians or bicyclists would be created and no impacts would result. 16. Utilities and Service Systems Environmental Setting The project area is served by the following service providers: · Water supply: Dublin San Ramon Services District (DSRSD) · Sewage collection and treatment: DSRSD · Storm drainage: City of Dublin · Solid waste service: Livermore Dublin Disposal Service · Electrical and natural gas power: Pacific Gas and Electric Co. · Communications: AT&T (formerly SBC) Project Impacts a) Exceed wastewater treatment requirements of the RWQCB? NT. The proposed project would include construction of a replacement community center building with one of approximately the same size and use. No impacts to wastewater treatment requirements adopted by the Regional Water Board is therefore anticipated. b) Require new water or wastewater treatment facilities or expansion of existing facilities? NT. Since the proposed project would not substantially increase the amount of wastewater generated by the Shannon Community Center there would be no impact regarding this topic. c) Require new storm drainage facilities? NT. Implementation of the proposed project would not significantly increase the amount of impervious surfaces on the project site, so that no new storm drain facilities would be required as part of the project and no impact would result. d) Are sufficient water supplies available? NT. Use of the proposed Community Center building would not significantly increase the need for water supplied by DSRSD City of Dublin Page 50 Initial Study/Shannon Center Project January 2007 J:, D1.."'" :;;.;,;; -u ~ over and above that used by the existing building. The proposed building would also include water saving plumbing fixtures that were not included in the existing building. No impacts are therefore anticipated with regard to water supplies. e) Adequate wastwater capacity to serve the proposed project? NI. See response to "a/' above. e, f) Solid waste disposal? NI. The proposed project is not anticipated to generate additional solid waste over and above that generated by the existing facility so that no impact would result. g) Comply with federal, state and local statutes and regulations related to solid waste? NT. The existing service provider will ensure adherence to federal, state and local solid waste regulations should the proposed project be approved. No impacts are anticipated in this regard. 17. Mandatory Findings of Significance a) Does the project have the potential to degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, reduce the number of or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? No. Based on the foregoing Initial Study, the proposed project would not substantially reduce the habitat of fish or wildlife species, threaten to eliminate a plant or wildlife population, restrict the range of a special-status species or eliminate any example of California history or prehistory. b) Does the project have impacts that are individually limited, but cumulatively considerable? ("Cumulatively considerable" means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects and the effects of probable future projects). No. No such cumulative considerable impacts have been identified in the Initial Study. c) Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? No. No such impacts have been discovered in the course of preparing this Initial Study. City of Dublin Initial Study/Shannon Center Project Page 51 January 2007 Initial Study Preparers Jerry Haag, Urban Planner, project manager Jane Maxwell, report graphics Agencies and Organizations Consulted The following agencies and organizations were contacted in the course of this Initial Study: City of Dublin Herma Lichtenstein, Project Manager, Parks and Community Services Department Jeri Ram, AICP, Community Development Director Ray Kuzbari, Senior Transportation Engineer Frank Navarro, Associate Civil Engineer California Department of Toxic Substances Control (DTSC) Website Project Architects Gregor Markel, Dahlin Group References Dublin General Plan, City of Dublin, Updated through 2/05 Geotechnical Exploration and Fault Hazard Analysis Evaluation for the Shannon Community Center, ENGEO, June 2006 Parks and Recreation Master Plan, City of Dublin, 2004 update Pre-Demolition Asbestos Inspection Documentation, Shannon Community Center. Kellco Services, Inc., September 2005 City of Dublin Initial Study/Shannon Center Project Page 52 January 2007 ! "'I Appendix l-Biological Reconnaissance City of Dublin Initial Study/Shannon Center Project Page 53 January 2007 Shannon Community Center Biological Assessment DUBLIN, ALAMEDA COUNTY CALIFORNIA Prepared For: Jerry Haag 2029 University Avenue Berkeley, CA 94704 (510) 644-2106 Contact: Tom Fraser fraser@wra-ca.com Date: July 2006 Iwra ENVIRONMENTAL CONSULTANrs 2169-G EOSl Froncisoo B;vd., Son Iloloel, CA 94901 (415) 454-8868 lei (415) 454-012910x info@wro-oo.oom www.wro-co.com 20'9 TABLE OF CONTENTS 1.0 INTRODUCTION ........................................................ 1 2.0 REGULATORY BACKGROUND. . .. . .. .. . .. ..... .. .... ... . .. . . . . ...... .. ...1 2.1 Special Status Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2.2 Sensitive Biological Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.0 METHODS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 Biological Communities ............................................. 5 3.1.1 Non-sensitive Biological Communities........................... 5 3.1.2 Sensitive Biological Communities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2 Special Status Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2.1 Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2.2 Site Assessment ........................................... 6 4.0 RESULTS ............................................................. 7 4.1 Biological Communities ............................................. 8 4.1.1 Non-sensitive Biological Communities........................... 8 4.1.2 Sensitive Biological Communities........ ... . . .. .. . ... ... .. . . . . .8 4.2 Special Status Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2.1 Plants.................................................... 8 4.2.2 Wildlife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.0 SUMMARY AND RECOMMENDATIONS.. . . . ...... ... . .......... ........ .. . . 10 5.1 Biological Communities ............................................ 11 5.2 Special Status Plant Species ........................................ 11 5.3 Special Status Wildlife Species ...................................... 11 7.0 REFERENCES....... ...... .... ..... . . ................ ............. ... . 14 LIST OF APPENDICES Appendix A- List of Observed Plant and Animal Species Appendix B- List of Potential Special Status Plant and Animal Species Appendix C- Study Area Photographs LIST OF FIGURES Figure 1. Study Area Location Map ............................................. 2 J:.: <..J 1.0 INTRODUCTION On June 14, 2006, WRA, Inc. biologists conducted an assessment of biological resources at the Shannon Community Center Building (Study Area) located in Dublin, California in Alameda County (Figure 1). The purpose of the assessment was to gather information necessary to complete a review of biological resources under the California Environmental Quality Act (CEQA) for the Shannon Community Center project proposed for construction in the Study Area. This report describes the results of the assessment site visit, which assessed the Study Area for (1) the presence of special status species; (2) potential to support special status species; and (3) presence of other sensitive biological resources protected by local, state, and federal laws and regulations. This report also contains an evaluation of potential impacts to special status species and sensitive biological resources that may occur as a result of the proposed project and potential mitigation measures to compensate for those impacts. A biological assessment provides general information on the potential presence of sensitive species or habitats. The biological assessment is not an official protocol level survey for listed species that may be required for project approval by local, state, or federal agencies. However, specific findings on the occurrence of any species or the presence of sensitive habitats may require that protocol surveys be conducted. This assessment is based on information available at the time of the study and on site conditions that were observed on the date of the site visit. 2.0 REGULATORY BACKGROUND The following sections explain the regulatory context of the biological assessment, including applicable laws and regulations that were applied to the field investigations and analysis of potential project impacts. 2.1 Special Status Species Special status species include those plants and wildlife species that have been formally listed, are proposed as endangered or threatened, or are candidates for such listing under the federal Endangered Species Act (ESA) or California Endangered Species Act (CESA). These Acts afford protection to both listed and proposed species. In addition, California Department of Fish and Game (CDFG) Species of Special Concern, which are species that face extirpation in California if current population and habitat trends continue, U.S. Fish and Wildlife Service (USFWS) Birds of Conservation Concern, sensitive species included in USFWS Recovery Plans, and USFWS special status invertebrates are considered special status species. Although California and USFWS species of concern generally have no special legal status, they are given special consideration under the California Environmental Quality Act (CEQA). In addition to regulations for special status species, most birds in the United States, including non-status species, are protected by the Migratory Bird Treaty Act of 1918. Under this legislation, destroying active nests, eggs, and young is illegal. Plant species on California Native Plant Society (CNPS) Lists 1 and 2 are also considered special status plant species. Impacts to these species are considered significant according to the California Environmental Quality Act (CEQA). The CNPS List 3 and 4 plants have little or no protection under CEQA, but are included in this analysis for completeness. The assessment also includes species of local concern as indicated by the USFWS list for the quad/county, or as designated by a City or County. (PO 20011 .f $,o,.L.t:, '~':.. , " i -::-. __) 'f':'_ 'Z;:"~- -.. ~ \ 1%';,;-" <.. 111,' ^)::.~."::1. ~ ..,.. ..;, ...J_ ,-.. , " &'t ,.,',-- ~J\.' ~ "i ":'\ ~ I., ',,"......, -';;'.:, -". ,. .'. , ~, ~~~ ~J:';~~~_. '<C~2.t;:::'" ~. ....\.. . ^"".t';_':~' 0;' .\ ....~ , '-'~, ',. ". ~~~~;:;~:i.,' ',. ~./ '.) C~h~~:~~ .-' '..,.....-.~:".......- ',,- \., ".:0,.'. "'i: ,'. .,., ",'---,~". Dcnti$uP("lllt ~'., ~ "~ ",-,,;,,.;,, ./ "_ ,'"jOl"'l -C" ~ , P!.;~t~~. : .'/..~;-, 'iIIN~<: '. ., . .' ;~:;'7'~\ ~ '~.:.:, ~-,.. ~)ot'./ ~'"" C1'~-:-\ .~ \., ~::;Jt:;. 'IVJH J. ~.:~/~ ~ , .. 1- " ,..- /:.-_:-': .../ ~:;;, ; . . ~ , - . ,- 1.,-' . , ~ (. t, ,. ~' ,~~~ -, ~ :::~::~, ~,.. -:. " " - -~ '\.:!~, . ." -,..,. "-...., ..' o 0.5 .~... Miles Figure 1. Location Map Dublin Shannon Community Center EIR Study Area Dublin, California ENVIRONMEI'lTAl CONSUllANIS C8te: June 2006 Basemap: lSGSTOpo Quad MIlp By: Mc:h4Cl1 Rochdht Mlepath:L:'AClId 200OFilel\1&lOO\16056\ ArcMap\L.OcatIOMMap.mxd Critical Habitat Critical habitat is a term defined and used in the Federal Endangered Species Act. It is a specific geographic area(s) that contains features essential for the conservation of a threatened or endangered species and that may require special management and protection. The FESA requires Federal agencies to consult with the USFWS to conserve listed species on their lands and to ensure that any activities or projects they fund, authorize, or carry out will not jeopardize the survival of a threatened or endangered species. In consultation for those species with critical habitat, Federal agencies must also ensure that their activities or projects do not adversely modify critical habitat to the point that it will no longer aid in the species' recovery. In many cases, this level of protection is similar to that already provided to species by the FESA "jeopardy standard." However, areas that are currently unoccupied by the species but which are needed for the species' recovery, are protected by the prohibition against adverse modification of critical habitat. 2.2 Sensitive Biological Communities Sensitive biological communities include habitats that fulfill special functions or have special values, such as wetlands, streams, and riparian habitat. These habitats are regulated under federal regulations (such as the Clean Water Act), state regulations (such as the Porter-Cologne Act, the California Department of Fish and Game's Streambed Alteration Program, or the California Environmental Quality Act), or local ordinances or policies (City or County Tree Ordinances, Special Habitat Management Areas or General Plan Special Land Use areas). Waters of the United States The U.S. Army Corps of Engineers (Corps) regulates "Waters of the United States" under Section 404 ofthe Clean Water Act. "Waters of the U.S." are defined broadly as waters susceptible to use in commerce, including interstate waters and wetlands, all other waters (intrastate waterbodies, including wetlands), and their tributaries (33 CFR 328.3). Potential wetland areas, according to the three criteria used to delineate wetlands stated in the Corps of Engineers Wetlands Delineation Manual (1987), are identified by the presence of (1) hydrophytic vegetation, (2) hydric soils, and (3) wetland hydrology. Areas that are inundated for sufficient duration and depth to exclude growth of hydrophytic vegetation are subject to Section 404 jurisdiction as "other waters" and are often characterized by an ordinary high water line (OHW). Other waters, for example, generally include lakes, rivers, and streams. The placement of fill material into "Waters of the U.S." (including wetlands) generally requires an individual or nationwide permit from the Corps under Section 404 of the Clean Water Act. Waters of the State "Waters of the State" are defined by the Porter-Cologne Act as "any surface water or groundwater, including saline waters, within the boundaries of the state." The RWQCB protects all waters in its regulatory scope, but has special responsibility for wetlands, riparian areas, and headwaters. These waterbodies have high resource value, are vulnerable to filling, and are not systematically protected by other programs. RWQCB jurisdiction includes "isolated" wetlands and waters that may not be regulated by the Corps under Section 404. "Waters of the State" are regulated by the RWQCB under the State Water Quality Certification Program which regulates discharges of fill and dredged material under Section 401 of the Clean Water Act and the Porter-Cologne Water Quality Control 3 ~ Act. Projects that require a Corps permit, or fall under other federal jurisdiction, and have the potential to impact "Waters ofthe State," are required to comply with the terms of the Water Quality Certification determination. If a proposed project does not require a federal permit, but does involve dredge or fill activities that may result in a discharge to "Waters of the State," the RWQCB has the option to regulate the dredge and fill activities under its state authority in the form of Waste Discharge Requirements or Certification of Waste Discharge Requirements. Streams, Lakes, and Riparian Habitat Streams and lakes, as habitat for fish and wildlife species, are subject to jurisdiction by the California Department of Fish and Game under Sections 1600-1616 of the State Fish and Game Code. Alterations to or work within or adjacent to streambeds or lakes generally require a 1602 Lake and Streambed Alteration Agreement. The term stream, which includes creeks and rivers, is defined in the California Code of Regulations (CCR) as follows: "a body of water that flows at least periodically or intermittently through a bed or channel having banks and supports fish or other aquatic life. This includes watercourses having a surface or subsurface flow that supports or has supported riparian vegetation" (14 CCR 1.72). In addition, the term stream can include ephemeral streams, dry washes, watercourses with subsurface flows, canals, aqueducts, irrigation ditches, and other means of water conveyance if they support aquatic life, riparian vegetation, or stream- dependent terrestrial wildlife (CDFG ESD 1994). Riparian is defined as, "on, or pertaining to, the banks of a stream;" therefore, riparian vegetation is defined as, "vegetation which occurs in and/or adjacent to a stream and is dependent on, and occurs because of, the stream itself' (CDFG ESD 1994). Removal of riparian vegetation also requires a Section 1602 Lake and Streambed Alteration Agreement from CDFG. Other Sensitive Plant Communities Sensitive plant communities include habitats that fulfill special functions or have special values. Natural communities considered sensitive are those identified in local or regional plans, policies, regulations, or by the California Department of Fish and Game (CDFG). CDFG ranks sensitive communities as 'threatened' or 'very threatened' and keeps records of their occurrences in its Natural Diversity Database. Sensitive plant communities are also identified by CDFG on their List of California Natural Communities Recognized by the CNDDS. Impacts to sensitive natural communities identified in local or regional plans, policies, regulations or by the CDFG or USFWS must be considered and evaluated under CEQA (California Code of Regulations: Title 14, Div. 6, Chap. 3, Appendix G). Specific habitats may also be identified as sensitive in City or County General Plans or ordinances. Protected Trees According the City of Dublin city ordinance for tree protection, a "heritage tree" is defined as any of the following: Any oak, bay, cypress, maple, redwood, buckeye and sycamore tree having a trunk or main stem of twenty-four (24) inches or more in diameter measured atfour (4) feet six (6) inches above natural grade; A tree required to be preserved as part of an approved development plan, zoning permit, use permit, site development review or subdivision map; A tree required to be planted as a replacement for an unlawfully removed tree. 4 No person may remove, cause to be removed, or effectively remove any heritage tree from any property within the city of Dublin without obtaining a permit from the Director. All applicants for demolition, grading, or building permits on property containing one or more heritage trees shall prepare a tree protection plan pursuant to Section 5.60.090. (Ord. 5-02 S 2 (part): Ord. 29-99 S 1 (part)). 3.0 METHODS On June 14, 2006, the Study Area was traversed on foot to determine (1) plant communities present within the Study Area, (2) if existing conditions provided suitable habitat for any special status plant or wildlife species, and (3) if sensitive habitats were present. All plant and wildlife species encountered were recorded, and are summarized in Appendix A. 3.1 Biological Communities Biological communities present in the Study Area were classified based on existing plant community descriptions described in the Preliminary Descriptions of the Terrestrial Natural Communities of California (Holland 1986). However, in some cases it is necessary to identify variants of community types or to describe non-vegetated areas that are not described in the literature. Biological communities were classified as sensitive or non-sensitive as defined by CEQA and other applicable laws and regulations. 3.1.1 Non-sensitive Biological Communities Non-sensitive biological communities are those communities that are not afforded special protection under CEQA, and other state, federal, and local laws, regulations and ordinances. These communities may, however, provide suitable habitat for some special status plant or wildlife species and are identified or described in Section 4.1.1 below. 3.1.2 Sensitive Biological Communities Sensitive biological communities are defined as those communities that are given special protection under CEQA and other applicable federal, state, and local laws, regulations and ordinances. Applicable laws and ordinances are discussed above in Section 2.0. Special methods used to identify sensitive biological communities are discussed below. Wetlands and Waters The Study Area was surveyed to determine if any wetlands and waters potentially subject to jurisdiction by the Corps, RWQCB, or CDFG were present. The assessment was based primarily on the presence of wetland plant indicators, but may also include any observed indicators of wetland hydrology or wetland soils. Any potential wetland areas were identified as areas 5 '20 dominated by plant species with a wetland indicator status' of OBL, FACW, or FAC as given on the U.S. Fish and Wildlife Service List of Plant Species that Occurin Wetlands (Reed 1988). Evidence of wetland hydrology can include direct evidence (primary indicators), such as visible inundation or saturation, surface sediment deposits, algal mats and drift lines, or indirect indicators (secondary indicators), such as oxidized root channels. Some indicators of wetland soils include dark colored soils, soils with a sulfidic odor, and soils that contain redoximorphic features as defined by the Corps Manual (Environmental Laboratory, 1987) and Field Indicators of Hydric Soils in the United States (NRCS, 2002). The preliminary waters assessment was based primarily on the presence of unvegetated, ponded areas or flowing water, or evidence indicating their presence such as a high water mark or a defined drainage course. Collection of additional data will be necessary to prepare a delineation report suitable for submission to the Corps. Other Sensitive Biolooical Communities The Study Area was evaluated for the presence of other sensitive biological communities, including riparian areas, sensitive plant communities recognized by CNDDB. If present in the Study Area, these sensitive biological communities were mapped and are described in the Section 4.1.2 below. 3.2 Special Status Species 3.2.1 Literature Review Potential occurrence of special status species in the Study Area was evaluated by first determining which special status species occur in the vicinity of the Study Area through a literature and database search. Database searches for known occurrences of special status species included the Dublin 7.5 minute USGS quadrangle. The following sources were reviewed to determine which special status plant and wildlife species have been documented to occur in the vicinity of the Study Area: California Natural Diversity Database records (CNDDB) (CDFG 2006) USFWS Quadrangle Species Lists (USFWS 2006) CNPS Electronic Inventory records (CNPS 2006) CDFG publication "California's Wildlife, Volumes I-III" (Zeiner et al. 1990) CDFG publication "Amphibians and Reptile Species of Special Concern in California" (Jennings and Hayes 1994) 3.2.2 Site Assessment A site visit was conducted to search for suitable habitats within the Study Area for those species identified as occurring within the vicinity. Potential for special status species to occur in the Study Area was then evaluated according to the following criteria: 1 OBL = Obligate, always found in wetlands (> 99% frequency of occurrence); FACW = Facultative wetland, usually found in wetlands (67-99% frequency of occurrence); FAC = Facultative, equal occurrence in wetland or non-wetlands (34-66% frequency of occurrence). 6 .(p r; (1) Not Present. Habitat on and adjacent to the site is clearly unsuitable for the species requirements (foraging, breeding, cover, substrate, elevation, hydrology, plant community, site history, disturbance regime). (2) Unlikely. Few ofthe habitat components meeting the species requirements are present, and/or the majority of habitat on and adjacent to the site is unsuitable or of very poor quality. The species is not likely to be found on the site. (3) Moderate Potential. Some of the habitat components meeting the species requirements are present, and/or only some of the habitat on or adjacent to the site is unsuitable. The species has a moderate probability of being found on the site. (4) Hiqh Potential. All of the habitat components meeting the species requirements are present and/or most of the habitat on or adjacent to the site is highly suitable. The species has a high probability of being found on the site. (5) Present. Species is observed on the site or has been recorded (I.e. CNDDB, other reports) on the site recently. This assessment is intended to identify suitable habitat for special status species known to occur in the vicinity in order to determine their potential to occur within the Study Area. The site visit does not constitute a protocol-level survey and is not intended to determine the actual presence or absence of a species; however, if a special status species is observed during the site visit, its presence will be recorded and discussed. Appendix B presents the evaluation of potential for occurrence of special status plant and wildlife species known to occur in the vicinity of the Study Area with their habitat requirements, occurrence classification, and basis for occurrence classification. Recommendations for further surveys are made in Section 5.0 below for species with a moderate or high potential to occur in the Study Area. 4.0 RESULTS The Shannon Community Center building and the area immediately around it was the focus of this assessment as it is scheduled for demolition and rebuilding. A perennial creek running out of Koopman Canyon runs along the souther border of the building west to east, then turns north through a culvert and under a bike path, running along the west side of San Ramon Road. A public park is located just to the south of the creek and a parking lot is located in the southeast comer of the property. The northern border of the building is composed of non-native annual grassland and landscaped vegetation. Private residences border the property to the west and to the north. Shannon Road borders the park to the south, San Ramon Road borders the property to the east. Landscaping vegetation surrounds the Community Center building. 7 IJ Ltt!b 20""1 4.1 Biological Communities 4.1.1 Non-sensitive Biological Communities Non-native annual qrassland Non-native annual grassland typically occurs in open areas of valleys and foothills throughout California, usually on fine textured clay or loam soils that are somewhat poorly drained (Holland 1986). Non-native grassland is typically dominated by non-native annual grasses and forbs along with scattered native wildflowers. Common species found in the non-native grasslands of northern and central California include wild oats (Avena spp.), brome grasses (Bromus spp.), wild barley (Hordeum spp.), Italian and perennial ryegrass (Lolium multiflorum and Lolium perenne), field bindweed (Convolvulus arvensis), fiddle neck (Amsinckia spp.), and California poppy (Eschscholzia ealiforniea), among many other species. A small strip of non-native annual grassland is present along northern boundary ofthe Study Area. Plant species observed in this area include slender wild oat (Avena barbata), black mustard (Brassiea nigra) and bristly oxtongue (Pieris eehioides). The annual grassland in the Study Area is regularly mowed and thus represents low value habitat for special status plant and wildlife species. 4.1.2 Sensitive Biological Communities Riparian A perennial creek that drains Koopman Canyon runs along the southern border ofthe Community Center. A bridge connects the Community Center to the park and parking area to the south. A closed canopy overstory consisting predominantly of coast live oak associated with native riparian species such as willows (Salix sp.) and California buckeye (Aesculus californica) as well as introduced black locust (Robinia pseudoacacia), growing along the edge ofthe creek. As the creek turns north under the bike path, the over-story disappears and the creek continues into a man- made channel that is overgrown with a combination of non-native vegetation species and native wetland plants. Protected Trees Coast live oak and California buckeye trees observed along the creek corridor may have a DBH of over 24 inches and therefore may be considered heritage trees by the City of Dublin tree protection ordinance. 4.2 Special Status Species 4.2.1 Plants Based upon a review of available resources and databases described in Section 2.3.1, four special status plant species have been documented to occur in the general vicinity of the Study Area. No special status plant species were observed in the Study Area during the assessment site visit. Appendix B summarizes typical habitat requirements for these species and provides a rationale for 8 l.i^ l~b 20 their potential for occurrence within the Study Area. The site assessment occurred during the blooming period of three of the four special status plant species with a potential to occur in the Study Area, including Congdon's tarplant (Centromadia parryi ssp. congdonit), Diablo helianthella (Helianthella castanea), an saline clover (Trifolium depauperatum var. hydrophilum). None of these potentially blooming species were observed. Although the site visit occurred outside of the blooming period of hairless popcorn flower (Plagiobothrys glaber), no suitable habitat for this species, consisting of meadows or seeps, was present on-site. This species is not expected to occur within the Study Area. 4.2.2 Wildlife Ninety special status species of wildlife have been recorded in the vicinity of the Study Area. Appendix B summarizes the potential for occurrence for these species in the Study Area. No special status species were observed in the Study Area during the site assessment. No special status wildlife species have a high potential to occur in the Study Area. Nine special status wildlife species have a moderate potential to occur in the Study Area. These species, their status, habitat requirements, and known distribution are discussed below. California red-legged frog (Rana aurora draytonii), Federal Threatened, CDFG Species of Concern. The California red-legged frog is dependent on suitable aquatic, estivation, and upland habitat. During periods of wet weather, starting with the first rainfall in late fall, red-legged frogs disperse away from their estivation sites to seek suitable breeding habitat. Aquatic and breeding habitat is characterized by dense, shrubby, riparian vegetation and deep, still or slow-moving water. Breeding occurs between late November and late April. California red-legged frogs estivate (period of inactivity) during the dry months in small mammal burrows, moist leaf litter, incised stream channels, and large cracks in the bottom of dried ponds. The creek may have water flows that are too high fro breeding habitat in the winter but it may provide dispersal habitat for this species. The nearest occurrence is approximately 1.5 miles to the southwest. Western Pond Turtle (Clemmys marmorata), USFWS Species of Concern, CDFG Species of Special Concern. The western pond turtle is the only native turtle in central and northern California. This turtle is uncommon to common in suitable aquatic habitat throughout California, west of the Sierra-Cascade crest. Western pond turtles inhabit perennial aquatic habitats, such as lakes, ponds, rivers, and streams, that provide submerged cover and basking structures (Zeiner et. al. 2000). Western pond turtles prefer to nest on unshaded slopes close to their aquatic habitat, and hatchlings require shallow water with relatively dense emergent and submergent vegetation for foraging (Jennings and Hayes 1994). The creek in the Study Area may provide suitable aquatic habitat for this species. American bittern (Botaurus lentiginosus), Federal Species of Concern, CDFG Species of Special Concern. The American bittern occurs in fresh emergent wetlands, often hiding, resting, and roosting solitarily amidst tall, dense, emergent vegetation, on ground, or near ground on logs, stumps, or on emergent plants. Their nest is a platform of matted emergent aquatics usually in shallow water, but sometimes floating, or on the ground. The riparian habitat in the Study Area may provide suitable foraging habitat. White-tailed Kite (Elanus leucurus), CDFG Fully Protected Species. White-tailed kites are 9 /.pi 704:J associated with annual grasslands, agricultural areas, scrub habitats, wet meadows, and emergent wetlands throughout the lower elevations of California. Nesting generally occurs in shrubs or small trees. Individuals are likely to forage over open areas of the site throughout the year. The history of human disturbance and scarcity of suitable, isolated trees and shrubs reduces the likelihood of kites nesting however this species may forage in the Study Area. Cooper's Hawk (Accipiter coope,,), CDFG Species of Special Concern. This hawk is associated with woodland and forest habitats throughout California. Although nest sites are usually found in isolated areas, this species frequently occurs in urban habitats in winter and during migration. This species has the potential to forage and nest in the trees in the Study Area. Rufous Hummingbird (Selasphorus rufus), USFWS Species of Concern. The rufous hummingbird is a common migrant and uncommon summer resident in California. It occurs in a wide variety of habitats as long as they provide abundant nectar sources. Shrubs in the Study Area provide suitable nesting habitat and nectar sources. Loggerhead Shrike (Lanius ludovicianus), CDFG Species of Special Concern, USFWS Species of Concern. The loggerhead shrike is a common resident and winter visitor in lowlands and foothills throughout California. It prefers open habitats with scattered trees, shrubs, posts, fences, utility lines or other perches. Nests are usually built on a stable branch in a densely- foliaged shrub or small tree and are usually well-concealed. The Study Area contains. suitable nesting and foraging habitat. Yuma myotis (Myotis yumanensis), Federal Species of Concern, CDFG Species of Special Concern. The Yuma myotis is found throughout most of California at lower elevations in a wide variety of habitats. Day roosts are found in buildings, trees, mines, caves, bridges, and rock crevices. Night roosts are usually associated with buildings, bridges or other man-made structures (Philpott 1996). The vacant Community Center building and bridge may provide suitable roosting habitat. San Francisco dusky-footed woodrat (Neotoma fuscipes annectens). CDFG Species of Special Concern. Occurs in forest habitats of moderate canopy and moderate to dense understory. Also found in chaparral habitats. Feeds mainly on woody plants: live oak, maple, coffee berry, alder, and elderberry. Nests are constructed out of leaves, shredded grass, and other material. The Study Area contains suitable nest sites for this species. Eighteen species of wildlife were observed in or adjacent to the Study Area during the site assessment (Appendix A). All of the wildlife observed in the Study Area are commonly found species, and many are adapted to occupying disturbed or urban areas. No special status wildlife species were observed. 5.0 SUMMARY AND RECOMMENDATIONS One sensitive plant community was identified within the Study Area. One special status plant species and nine special status wildlife species have a moderate or high potential to occur within the Study Area. The following sections present recommendations for future studies and/or measures to avoid or reduce impacts to these species and sensitive habitats. 10 5.1 Biological Communities Riparian Most of the Study Area is developed or composed of landscaping vegetation and nonnative annual grassland, which is not a sensitive biological community. However, the Study Area does contain riparian habitat potentially within the jurisdiction ofthe Corps under Section 404 of the Clean Water Act and RWQCB under the Porter Cologne Act and Section 401 of the Clean Water Act and section 1602 of the California Fish and Game Code relating to Streambed Alteration Agreements. CDFG has the authority to regulate work that will "substantially divert or obstruct the natural flow of, or substantially change or use any material from the bed, channel, or bank of, any river, stream, or lake, or deposit or dispose of debris, waste, or other material containing crumbled, flaked, or ground pavement where it may pass into any river, stream, or lake." Construction related activities can be regulated by CDFG under Section 1602 of the Code. Because of the proximity of the creek, CDFG may enter into a streambed alteration agreement with the project proponent which may impose conditions to ensure no net loss of values or acreage of the creek and associated riparian habitat. Current understanding of the project plan indicates that no work will be necessary within the creek bed, and as a result, no permits should be required. Protected Trees It is recommended that the City of Dublin consult with a certified arborist to determine if the proposed project will result in the removal of heritage trees and to prepare a tree protection plan if any significant project-related impacts are expected to occur. 5.2 Special Status Plant Species Of the four special status plant species known to occur in the vicinity of the Study Area, no species were observed during the site visit and none are expected to occur on-site. Disturbed habitat conditions, the lack of species-specific habitat requirements, and the incursion of exotic plant species would preclude the occurrence of any potentially occurring special status plant species. 5.3 Special Status Wildlife Species Of the 90 special status wildlife species known to occur in the vicinity of the Study Area, nine were determined to have the potential to occur in the Study Area. Most of the species found in the review of background literature occur in habitats not found in the Study Area. Habitat suitability for grassland and riparian associated species in the Study Area is reduced due to regular mowing of the site and development and human use on site and adjacent to the site. Avian Species This assessment determined that five sensitive bird species may use the Study Area for breeding and foraging. Most birds in the United States, including non-status species, are protected by the Migratory Bird Treaty Act of 1918. Under this legislation, destroying active nests, eggs, and young is illegal. As a result, precautions should be undertaken before and during construction to insure no harm or harassment of avian species. 11 70 2O~j If shrubs or trees are to be trimmed or removed during construction, mitigation should include the removal of vegetation within or near the construction footprint during the non-breeding season (August through February). Another alternative is to conduct pre-construction breeding bird surveys in spring. Surveys should be conducted within suitable nesting habitat near the project areas. All active nests identified at that time should be protected by a 50-foot radius minimum exclusion zone. Exclusion zones would vary depending on each species. The exclusion zone would remain in place until all young have fledged. Since some birds may have three broods, avoidance could possibly extend into August. Herpetofauna The California red-legged frog has a documented occurrence approximately 1.5 miles to the southwest of the Study Area. The Study Area may provide potential breeding habitat though there is a higher potential of the area being used for dispersal habitat. Western pond turtles also have the potential to use the aquatic habitat in the Study Area. There is also suitable turtle nesting habitat in the uplands adjacent to this drainage. An exclusion fence should be installed and maintained during the construction period, spring through fall, in between the creek and the construction area, to ensure no red-legged frogs or pond turtles enter the construction site. Mass grading should only occur between April and November to minimize impacts to dispersing frogs. Bats One special status bat species, the Yuma myotis (Myotis yumanensis), has a moderate potential to occur in the Study Area and its roost sites are protected by the California Department of Fish and Game. Snags, trees, unoccupied buildings and bridges are an important habitat requirement for bats. If snag, tree, building or bridge removal or improvements is to take place during summer months when bats may be roosting, a bat roost survey should be conducted. If no roosting bats are found, no further mitigation would be required. If bats are detected, a 50-foot buffer exclusion zone should be established around each occupied snag or tree until the roosting period has ended. Another approach would be to limit construction activities to the times of the year when bats are not breeding nor hibernating. Bat surveys will not be necessary if tree, snag or building removal were to occur in September and October, after the bat breeding season and before the bat hibernation season. San Francisco Duskv-footed Woodrat The stick houses of the San Francisco dusky-footed wood rat may occur in the Study Area. Construction and construction related activity have the potential to disturb the houses of the wood rat and potentially causing abandonment or destroying the houses all together. Woodrat houses should be flagged and avoided during construction activities. If avoidance of woodrat houses is unavoidable, sticks from the dismantled house should be kept on site, near the dismantled house if possible. The availability of suitably sized sticks may limit the number of woodrat houses in an area. 12 \ .! !;JV 1'2 Jb2D'i 13 7.0 REFERENCES California Department of Fish and Game. 2006. Natural Diversity Database, Wildlife and Habitat Data Analysis Branch. Sacramento. California Native Plant Society. 2006. Electronic Inventory of Rare and Endangered Vascular Plants of California. California Native Plant Society, Sacramento, California. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Department of the Army, Waterways Experiment Station, Vicksburg, Mississippi 39180-0631. Hickman, J.C. (ed.) 1993. The Jepson manual: higher plants of California. University of California Press. Holland, R. F. 1986. Preliminary Descriptions of the Terrestrial Natural Communities of California. Prepared for the California Department of Fish and Game, Sacramento, California Jennings, Mark R. 2004. An Annotated Check List of Amphibians and Reptile Species of California and Adjacent Waters. Third, revised edition. California Department of Fish and Game. Leidy, Robert A. October 2003. Historical Distribution and Current Status of Steelhead (Oncorhynchus mykiss),Coho Salmon (0. kisutch), and Chinook Salmon (0. tshawytscha) in Streams of the San Francisco Estuary, California. National Oceanic and Atmospheric Administration (NOAA). National Marine Fisheries Service distribution maps for California Salmonid species. Natural Resources Conservation Service (NRCS). 2002. Field Indicators of Hydric Soils in the United States, version 5.0. GW. Hurt, P.M. Whited, eds. USDA, NRCS in cooperation with the National Technical Committee for Hydric Soils, Fort Worth, TX. Reed, Jr., Porter B. 1988. National List of Plant Species That Occur in Wetlands: National Summary. U.S. Fish & Wildlife Service. BioI. Rep. 88 (24). 244 pp. Shaffer, H.B., G.M. Fellers, S Randal Voss, J.C. Oliver and G.B. Pauly. 2004. Species boundaries, phylogeography and conservation genetics of the red-legged frog (Rana aurora/draytonil) complex. Molecular Ecology, Vol Stebbins, R.C. A Field Guide to Western Reptiles and Amphibians, 3'd Edition. 2003. The Peterson Field Guide Series, Houghton Mifflin Company, New York. U.S. Department of Agriculture, Soil Conservation Service. 19XX. Soil Survey of XX County. California. In cooperation with the University of California Agricultural Experiment Station. United States Fish and Wildlife Service (USFWS). 20XX. Quadrangle Species Lists, Sacramento Fish and Wildlife Service. 14 Zeiner, D. C., W. F. Laudenslayer, Jr., K. E. Mayer, and M. White. 1990. California's Wildlife, Volume I-III: Amphibians and Reptiles, Birds, Mammals. California Statewide Wildlife Habitat Relationships System, California Department of Fish and Game, Sacramento. 15 w'7 ~f)b . -7 rib v' APPENDIX A LIST OF OBSERVED PLANT AND ANIMAL SPECIES APPENDIX A LIST OF OBSERVED PLANT AND ANIMAL SPECIES Appendix B. List of plant and animal species found in the Study Area on June 14, 2006. SCIENTIFIC NAME COMMON NAME Wildlife Birds Callipepfa cafifornica California Quail Mefanerpes formicivorus Acorn Woodpecker Poecile rufescens Chestnut-backed Chickadee Columba fivia Rock Dove Zenaida macroura Mourning Dove Aphe/ocoma cafifornica Western Scrub Jay Sturnus vulgaris European Starling Mimus polyglottos Northern Mockingbird Sayornis nigricans Corvus brachyrhynchos Black Phoebe American Crow Turdus migratorius American Robin Carpodacus mexicanus House Finch Passer domesticus House Sparrow Hyla Regilla Pacific Treefrog Odocoileus hem;onus Deer (scat) Sciurus niger Eastern Fox Squirrel (nest) Thomomys botta Botta's Pocket Gopher (burrows) Plants Acacia melanoxlyon black acacia Acer palmatum Japanese maple A-1 1 "Z-Dq SCIENTIFIC NAME COMMON NAME Aesculus califomica buckeye Arundo donax giant reed A vena barbata slender wild oat Baccharis pilularis coyote brush Brassica nigra black mustard Camellia sp. camellia Carduus pycnocephalus Italian thistle Conium macula turn poison hemlock Cotoneaster panosa cotoneaster Cynodon dactylon Bermuda grass Cyperus eragrostis umbrella sedge Ficus carica fig tree Geranium sp. geranium Hedera helix English ivy Juglans regia English walnut Malva sp. malva Metrosideros excels us New Zealand Christmas tree Picris echioides bristly oxtongue Prunus sp. cherry tree Quercus agrifolia coast live oak Raphanus sativa wild radish Robinia pseudoacacia black locust Rosmarinus officina/is rosemary Rubus ursinus California blackberry Rubus discolor Himilayan blackberry Salix lasiolepis arroyo willow Taraxacum officinale dandelion Toxicodendron diversilobum poison oak A-2 , { ...." ,{ SCIENTIFIC NAME COMMON NAME Tragopodon porrifolius Typha latifolia Urtica dioica Vicia sp. oyster plant cattail stinging nettle vetch A-3 Zeo "( APPENDIX B LIST OF POTENTIAL SPECIAL STATUS PLANT AND ANIMAL SPECIES IN THE STUDY AREA J 2--0 ~ Appendix A. Special status plant and animal species that may occur, or are known to occur in habitats similar to those found in the Shannon Community Center Study Area. list compiled from the California Department of Fish and Game (CDFG), Natural Diversity Database (2006), U.S. Fish and Wildlife Service (USFWS) Species Lists, and California Native Plant Society (CNPS) Electronic Inventory search of Dublin quadrangle, Alameda County and a review of other CDFG lists and publications (Jennings and Hayes 1994, Zeiner et al. 1990). SPECIES Mammals Townsend's western big-eared bat Corynorhinus townsendii townsendii small-footed myotis Myotis cilio/abrum long-eared myotis Myotis evotis fringed myotis Myotis thysanodes long-legged myotis Myotis voJans STATUS' CSC WBWG WBWG WBWG WBWG HABITAT Primarily found in rural settings in a wide variety of habitats including oak woodlands and mixed coniferous-deciduous forest. Day roosts highly associated with caves and mines. Very sensitive to human disturbance. Commonly found in arid uplands of California. Feeds on a variety of small flying insects. Seeks cover in caves, buildings, mines, crevices, and occasionally under bridges. Primarily a forest associated species. Day roosts in hollow trees, under exfoliating bark. rock outcrop crevices and buildings. Other roosts include caves, mines and under bridges. Associated with a wide variety of habitats including mixed coniferous-deciduous forest and redwood/sequoia groves. Buildings, mines and large snags are important day and night roosts. Generally associated with woodlands and forested habitats. Large hollow trees, rock crevices and buildings are important day roosts. Other roosts include caves, mines and buildings. POTENTIAL FOR OCCURRENCE Unlikely. Human presence in Study Area Likely precludes presence. Unlikely. Human presence in Study Area likely preciudes presence. Unlikely. Suitable forested habitat not present. Unlikely. Suitable forested habitat not present. Unlikely. This species prefers a more forested habitat. SPECIES POTENTIAL FOR OCCURRENCE STATUS. HABITAT Yuma myotis Myotis yumanensis greater western mastiff bat Eumops perotis californicus pallid bat Antrozous pallidus San Francisco dusky-footed wood rat Neotoma fuscipes annectens salt-marsh harvest mouse Reithrodontomys raviventris Am erican badger Taxidea taxus San Joaquin kit fox Vulpes macrotis mutica WBWG CSC CSC CSC FE. SE CSC FE.ST Known for its ability to survive in urbanized environments. Also found in heavily forested settings. Day roosts in buildings. trees. mines. caves, bridges and rock crevices. Night roosts associated with man-made structures. Found in a wide variety of habitat. Distribution appears to be tied to large rock structures which provide suitable roosting sites. including cliff crevices and cracks in boulders. Occupies a variety of habitats at low elevation including grasslands. shrublands, woodlands. and forests. Most common in open. dry habitats with rocky areas for roosting. Occurs in forest habitats of moderate canopy and moderate to dense understory. Also found in chaparral habitats. Feeds mainly on woody plants; live oak, maple. coffeeberry, alder, and elderberry Found only in the saline emergent wetlands of San Francisco bay and its tributaries. Pickleweed is primary habitat. Do not burrow. build loosely organized nests. Require higher areas for flood escape. Found in many habitat types where burrowing mammals occur; most common in grassland communities. Found in annual grasslands or grassy open stages with scattered shrubby vegetation. Need loose-textured sandy soils for burrowing and suitable prey base. Moderate Potential. Vacant Community Center building may provide roost site. Unlikely, Suitable roost site not available. Unlikely. Suitable roost site not a va ila ble, Moderate Potential. No woodrat houses were detected but habitat is suitable for this species. Not Present. No salt marsh habitat present. Not Present. Human disturbance likely precludes presence. Not Present. Suitable habitat not present. SPECIES Birds Common Loon Gavia immer California Brown Pelican Pefecanus occidenta/is cafifornicus Double-crested Cormorant Phalacrocorax auritus American Bittern Botaurus fentiginosus Great Blue Heron (rookery) Ardea alba Great Egret (rookery) Ardea alba Snowy Egret (rookery) Egretta thula White-faced Ibis Pfegadis chihi STATUS' CSC FE, SE CSC SLC SLC SLC SLC CSC HABITAT W inter in estuarine and subtidal marine habitats along coast, San Francisco Bay. Found in estuarine, marine subtidal, and marine pelagic waters along the coast. Nest on rocky or low brushy slopes of undisturbed islands. Nests along coast on sequestered islets, usually on ground with sloping surface or in tall trees along lake margins. Occurs in fresh emergent wetlands, often hiding, resting, and roosting solitarily amidst tall, dense, emergent vegetation, on ground, or near ground on log, stump, or on emergent plants. Inhabits freshwater, mudflats, tidal shallows. and marshes. Nest in colonies in large trees. Feeds and rests in fresh, and saline emergent wetlands, along the margins of estuaries, lakes, and slow-moving streams, on mudflats and salt ponds, and in irrigated croplands, and pastures. Nests and roosts in trees. Widespread along shores of coastal estuaries, fresh and saline emergent wetlands, ponds, slow-moving rivers, irrigation ditches, and wet fields. Feeds primarily on small fish, crustaceans and large insects. Prefers to feed in fresh emergent wetland, shallow lacustrine waters, and muddy ground of wet meadows and irrigated or flooded pastures and croplands. ~O":r POTENTIAL FOR OCCURRENCE Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. Moderate Potential. Suitable aquatic habitat present. Unlikely. Suitable rookery habitat not present. Unlikely. Suitable rookery habitat not present. Unlikely. Suitable rookery habitat not present. Not Present. Suitable habitat not present. SPECIES White-tailed Kite Elanus leucurus Bald Eagle Haliaee/us leucocephalus Northern Harrier Circus cyaneus Sharp-shinned Hawk Accipi/er stria/us Cooper's Hawk Accipler cooperi Ferruginous Hawk Bu/eo regalis Swainson's Hawk Buteo swainsoni Golden Eagle Aquila chrysae/os STATUS' eFP FT,SE ese ese ese ese ese HABITAT Year-long resident of coastai and valley lowlands; rarely found away from agricultural areas. Preys on small diurnal mammals and occasional birds, insects, reptiles, and amphibians. Requires large bodies of water, or free-flowing rivers with abundant fish adjacent snags or other perches. Nests in large, old-growth, or dominant live tree with open branchwork. Found in open grasslands, prairies, and marshes. Tend to nest near water. Generally associated with woodland habitats. Typically nests in isolated areas away from human disturbance. Inhabits areas with dense tree stands or patchy woodlands. Usually nests in deciduous riparian areas or second-growth conifer stands near streams. Frequents open grasslands, sagebrush flats, desert scrub, low foothills surrounding valleys and fringes of pinyon-juniper habitats. ST Breeds in stands with few trees in juniper-sage flats, riparian areas and oak savannah. Requires adjacent suitable foraging areas such as grasslands or grain fields supporting rodent populations. pO t r.::r~;t POTENTIAL FOR OCCURRENCE Moderate Potential. May hunt in grassland and nest in riparian area. Not Present, Suitable habitat not present. Unlikely. Suitable habitat not present. Unlikely. Suitable habitat not present. Moderate Potential. May hunt and nest in riparian area. Unlikely. Development in area likely precludes presence. Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. Found in rolling foothills with open grasslands, scattered trees, and cliff-walled canyons ,," d. 'I'b...... ')r 't> ""'t (,,! '"" ....) SPECIES POTENTIAL FOR OCCURRENCE STATUS' HABITAT American Peregrine Falcon Falco peregrinus anatum Prairie Falcon Falco mexicanus California Black Rail Lateral/us jamaicensis coturniculus California Clapper Rail Ral/us longirostris obso/etus Western Snowy Plover Charadrius alexandrinus nivosus Mountain Plover Charadruis montanus Long-billed Curlew Numenius americanus California Least Tern (nesting colony) Sterna antil/arum browni Caspian Tern (nesting colony) Sterna caspia FD,SE CSC ST FE,SE FT,CSC CSC CSC FE, SE BCC W inters throughout Central Valley. Requires protected cliffs and ledges for cover. Feeds on a variety of birds, and some mammals, insects, and fish. Found in arid and semi-arid plains, this is a falcon of open country which nests on rock cliffs in river gorges and occasionally in timbered mountains. Nests are often scraped on ledges although old stick nests of ravens or others raptors will be used. Rarely seen resident of saline. brackish, and fresh emergent wetlands in the San Francisco Bay area. Nest in dense stands of pickleweed Found in tidal salt marshes of the San Francisco Bay. Require mudlfats for foraging and dense vegetation on higher ground for nesting. Found on sandy beaches, salt pond levees and shores of large alkali lakes. Need sandy gravelly or friable soils for nesting. Winter resident in short grasslands and plowed fields below 1000m. W inters in large coastal estuaries, upland herbaceous areas. and croplands. Breeds in northeastern California in wet meadow habitat. Breeding colonies in San Francisco Bay found in abandoned salt ponds and along estuarine shores. Nests on barren to sparsely vegetated site near water. Nests in small colonies inland and along the coast at fresh-water lakes and marshes. Unlikely, Development in area likely precludes presence. Unlikely. Development in area likely precludes presence. Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. Unlikely. Development in area likely precludes presence. Unlikely. Development in area likely precludes presence. Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. 8 Db 20"" SPECIES STATUS' POTENTIAL FOR OCCURRENCE HABITAT Western Burrowing Owl Athene cunicu/aria hypugea CSC Unlikely. Suitable habitat not present. No ground squirrel burrows detected. Long-eared Owl Asio otus CSC Short-eared Owl Asio flammeus CSC Black Swift CyseJoides niger CSC Vaux's Swift Chaetura vauxi CSC Costa's Hummingbird Ca/ypte costae SLC Rufous Hummingbird Selasphorus rufus SLC, BCC Allen's Hummingbird Se/asphorus sasin SLC Frequents open grasslands and shrublands with perches and burrows. Preys upon insects, small mammals, reptiles, birds, and carrion. Nests and roosts in old burrows of small mammals. Inhabit open woodlands, forest edges, riparian strips along rivers, hedgerows, juniper thickets, woodlots, and wooded ravines and gullies. Breeding habitat must include thickly wooded areas for nesting and roosting with nearby open spaces for hunting. Found in open, treeless areas with elevated sites for perches and dense vegetation for roosting and nesting. Tule patches/tall grass needed for nesting and daytime seclusion. Nests in riparian jungles of willow, often mixed with cottonwoods with thick lower story Forages high in the air over most terrain and habitats but prefers rivers/lakes. Requires large hollow trees for nesting. Occurs in arid habitats such as desert washes. edges of desert riparian and valley foothill riparian, coastal scrub, desert scrub, desert succulent shrub, lower-elevation chaparral, and palm oasis. Found in a wide variety of habitats that provide nectar-producing flowers. A common migrant and uncommon summer resident of California. Breeds in sparse and open woodlands, coastal redwoods, and sparse to dense scrub habitats. Distribution highly dependent on abundance of nectar sources. Unlikely. Suitable habitat not present. Not Present. Suitable habitat not present. Unlikely. Suitable habitat not present. Unlikely. Suitable habitat not present. Unlikely, Suitable habitat not present. Moderate Potential, Suitable habitat present. Unlikely. Suitable habitat not present. 'BLa "'j ~" l r\' .".."./ , SPECIES STATUS' POTENT~LFOROCCURRENCE HABITAT LeWIS's Woodpecker Melanerpes lewis SLC,BCC California Horned Lark Eremophila alpestris actia CSC Purple Martin Progne subis CSC Bank Swallow Riparia riparia California Thrasher Toxostoma redivivum SLC Loggerhead Shrike Lanius ludovicianus CSC Yellow Warbler Dendroica petechia brewsteri CSC Yellow-breasted Chat Icteria virens CSC Unlikely. No nearby occurrences. Uncommon winter resident occurring on open oak savannahs, broken deciduous and coniferous habitats. Frequents grasslands and other open habitat with low, sparse vegetation. Nests on ground in the open. Aerial insectivores that nest in open and semiopen areas, including savannas, cultivated lands, fields, parks, pastures, near lakes and marshes and in towns and suburbs. ST Migrant in riparian and other lowland habitats in western California. Nests in riparian areas with vertical cliffs and bands with fine-textured or sandy soils in which to nest. Common resident of foothills and lowlands in cismontane California. Occupies moderate to dense chaparral habitats and extensive thickets in young or open valley foothill riparian habitat. Prefers open habitats with scattered shrubs, trees, pots, utility lines from which to forage for large insects. Nest well concealed above ground in densely-foliaged shrub or tree. Nests in riparian stands of willows, cottonwoods, aspens, sycamores, and alders. Also nests in montane shrubbery in open conifer forests. Breeds in riparian thickets and woodlands, particularly those dominated by willows and cottonwoods. Unlikely. Development in area likely precludes presence. Unlikely. Grass is mowed regularly. Unlikely. No nearby occurrences. Not Present. Suitable habitat not present. Unlikely. No nearby occurrences. Moderate Potential. Suitable habitat present. Unlikely. No nearby occurrences. SPECIES Unlikely. Suitable habitat not present. STATUS' HABITAT POTENTIAL FOR OCCURRENCE Hermit Warbler Dendroica occiden/alis Saltmarsh Common Yellowthroat Geothlypis trichas sinuosa Bell's Sage Sparrow Amphispiza belli Alameda (South Bay) Song Sparrow Melospiza me/odia pusil/u/a Tricolored Blackbird Age/aius tricolor Lawrence's Goldfinch Carduelis lawrencei Reptiles and Amphibians western pond turtle C/emmys marmora/a California horned lizard Phrynosoma corona/um fron/ale SLC CSC CSC CSC CSC BCC CSC CSC Frequents mature stands of conifers with open to dense canopy for breeding. Frequents low, dense vegetation near water including fresh to saline emergent wetlands. Brushy habitats used in migration. Forages among wetland herbs and shrubs for insects primarily. Prefers dense chaparral and scrub habitats in breeding season. Found in more open habitats in winter. Found in saline emergent wetlands of the south bay. Require low, dense vegetation for cover and nesting. Usually nests over or near freshwater in dense cattails, tules, or thickets of willow, blackberry, wild rose or other tall herbs. Inhabits oak woodlands, chaparral, riparian woodlands, pinyon-juniper associations, and weedy areas near water during the breeding season.; highly erratic and localized in occurrence Occurs in perennial ponds, lakes, rivers and streams with suitable basking habitat (mud banks, mats of floating vegetation, partially submerged logs) and submerged shelter. Occurs in valley-foothill hardwood, conifer and riparian habitats, as well as in pine-cypress juniper and annual grass habitats. Prefers sand areas, washes, flood plains and wind- blown deposits. Not Present. Suitable habitat not present. Unlikely. Suitable habitat not present. Unlikely. Suitable habitat not present. Unlikely. No dense cattail and tule stands. Unlikely. No nearby occurrences. Moderate Potential. Suitable aquatic habitat present in adjacent creek. Unlikely. Development in area likely precludes presence. SPECIES silvery legless lizard Anniella pulchra pulchra San Joaquin coachwhip (whipsnake) Masticophis flagellum ruddocki Alameda whipsnake Masticophis fateratis euryxanthus giant garter snake Thamnophis gigas California tiger salamander Ambystoma californiense western spadefoot toad Scaphiopus hammondii Foothil yellow-legged frog Rana boytii California red-legged frog Rana aurora draytonii Fishes STATUS' ese esc FT,ST FT,ST FT,CSC ese esc FT, ese HABITAT Found in safldy or loose loamy soils under sparse vegetation. Soil moisture is essential. Found in ope"" dry habitats with little or no tree cover. Found in valley grassland and saltbush scrub in the San Joaquin Valley. Needs mammal burrows for refuge and egg-laying. Prefers a chaparral habitat with rock outcroppings and small mammal burrows for basking and refuge. Can occur n adjacent communities, including grassland and oak savanna. Fc'und in the east bay hills. Prefers freshwater marsh and low gradient streams. Has adapted to drainage channels and irrigatiofl ditches. Inhabits annlJal grass habitat and mammal burrows. Seasonal ponds and vernal pools crucial to bre.ed ing Occurs primarily in grasslands but occasionally populates valley-foothill hardwood woodlands. Feed on inse,cts, worms, and other invertebrate!:. Preferred habitat is freshwater streams and small rivers of woodland, chaparral, and forest. Associated with quiet perennial to intermittent ponds, stream pools and wetlands. Prefers shorelines with extensive vegetation. Documented to disperse through upland habitats afte,- rains. 1> 1"1... "",,>I' t POTENT~LFOROCCURRENCE Unlikely. Loamy soils minimal. Unlikely. Development in area likely precludes presence. Unlikely. Existing development in area likely precludes presence. Not Present. Suitable habitat not present. Unlikely. Upland and aquatic habitat of low quality. Unlikely. Suitable habitat minimal. Unlikely. No nearby occurrences. Moderate Potential. Nearest occurrence approximately 1.5 miles away. SPECIES POTENTIAL FOR OCCURRENCE STATUS' HABITAT river lam prey Lampetra ayresi green sturgeon Acipenser medirostris Delta smelt Hypomesus franspacificus longfin smelt Spirinchus tha/eichthys Sacramento splittail lotus Sacramento perch Archoplites interruptus Central Valley fall/late fall-run chinook salmon Oncorhynchus tshawytscha Central Valley spring-run chinook salmon Oncorhynchus tshawytscha CSC CSC FT,ST CSC CSC CSC CSC Anadromous fish found in the Sacramento-San Joaquin River delta. Anadromous fish that spawns in Sacramento river. Feeds in estuaries and bays, including San Francisco Bay. Sacramento-San Joaquin Delta. Seasonally in Suisun Bay, Carquinez Strait & San Pablo Bay. Seldom found at salinities> 10 ppt. Most often at salinities < 2ppt. Pelagic species that mature in freshwater areas of the Sacramento-San Joaquin estuary and river system. Splittail are primarily freshwater fish, but are tolerant of moderate salinity (saltiness) and can live in water with salinities of 10-18 parts per thousand. Found in Sacramento Delta. Historically found in the sloughs, slow-moving rivers and lakes of the central valley. Prefer warm water, aquatic vegetation is essential for young. Population spawning in the Sacramento & San Joaquin Rivers and their tributaries. Adults migrate upstream to spawn in cool, clear, well- oxygenated streams. Juveniles remain in fresh water for 1 or more years before migrating downstream to the ocean. FT Federal listing includes populations spawning in the Sacramento River & its tributaries. Adults migrate upstream to spawn in cool, clear, well-oxygenated streams. Juveniles remain in fresh water for 1 or more years before migrating downstream to the ocean Not Present. Suitable aquatic habitat not present. Not Present. Suitable aquatic habitat not present. Not Present. Suitable aquatic habitat not present. Not Present. Suitable aquatic habitat not present. Unlikely. Suitable aquatic habitat not present. Unlikely. Suitable aquatic habitat not present. Not Present. No historic distribution in Koopman Canyon Creek (Leidy, 2003). Not Present. No historic distribution in Koopman Canyon Creek (Leidy, 2003). SPECIES Coho salmon-central CA coast Oncorhynchus kisutch Central California Coastal steelhead Oncorhynchus mykiss tidewater goby Eucyc/ogobius newberryi Invertebrates longhorn fairy shrimp Branchinecta longiantenna vernal pool fairy shrim p Branchinecta Iynchi STATUS. SE, FE FT FE.CSC FE FT HABITAT State listing is lim ited to Coho south of San Francisco Bay. The Federal listing is Iim ited to naturally spawning populations in streams between Punta Gorda. Humboldt County and the San Lorenzo River. Santa Cruz County. Spawn in coastal streams at temps. from 4- 14C. Prefer beds of loose. silt-free, coarse gravel and cover nearby for adults. Federal listing includes all runS from the Russian River. south to Soquel Creek. inclusive. Includes the San Francisco and San Pablo Bay basins but excludes the Sacramento-San Joaquin River basins. Adults migrate upstream to spawn in cool. clear, well- oxygenated streams. Juveniles remain in fresh water for 1 or more years before migrating downstream to the ocean Found in the brackish waters of coastal lagoons, marshes, creeks. and estuaries. Unique among fishes of the Pacific coast, gobies are restricted to waters of low salinity in coastal wetlands. They feed along the bottom. preferring clean, shallow, slow-moving waters. Endemic to the eastern margin of the central coast mtns in seasonally astatic grassland vernal pools. Inhabit small, clear-water depressions in sandstone and clear-to-turbid clay/grass-bottomed pools in shallow swales. Inhabit small, clear-water sandstone- depression pools, grassy swales, slumps, or basalt-flow depression pools. POTENTIAL FOR OCCURRENCE Not Present. No historic distribution in Koopman Canyon Creek (Leidy, 2003). Not Present. No historic distribution in Koopman Canyon Creek (Leidy, 2003). Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. Not Present. Suitable habitat not present. :fI'i~ J SPECIES POTENTIAL FOR OCCURRENCE STATUS' HABITAT vernal pool tadpole shrimp Lepidurus packardi valley elderberry longhorn beetle Desmocerus californicus dimorphus Callippe silverspot butterfly Speyeria callippe callippe Bay checkerpsot butterfly Euphydryas editha bayensis Plants Congdon's tarplant Centromadia parryi ssp. congdonii Diablo helianthella Helianthella castanea saline clover Trifolium depauperatum var. hydrophilum hairless popcorn-flower PJagiobothrys glaber FE FT FE FT List1B List 1 B List 1B List 1A Pools commonly found in grass bottomed swales of unplowed grasslands. Some pools are mud-bottomed and highly turbid. Occurs in mature elderberry bushes in the Central Valley. Restricted to northern coastal scrub of the San Francisco Bay Area. Hostplant is Viola pedunculata. Restricted to native grasslands on outcrops of serpentine soil in the vicinity of San Francisco Bay. Plantago erecta is the primary host plant. Found in valley and foothill grassland. Blooming period: May-Oct (Nov). Months in parentheses are uncommon. Elevation range 1 - 230 meters Found in broadleafed upland forest, chaparral, Cismontane woodland, coastal scrub, riparian woodland. Also in valley and foothill grassland. Blooming period: Mar-Jun Elevation range 60 - 1300 meters Found in marshes and swamps, valley and foothill grassland, and vernal pools Blooming period: Apr-Jun Elevation range 0 - 300 meters Found in meadows, seeps, marshes, and swamps. Blooming period: Mar-May Elevation range 15 - 180 meters Not Present. Suitable habitat not present. Not Present. No elderberry detected. Unlikely. Host plant not detected. Unlikely. Neither host plant nor serpentine soil detected. Moderate Potential. Known from disturbed grassland sites in the Tri-Valley area. Unlikely. Suitable undisturbed habitat not present. Unlikely. Suitable habitat not present. Not Present. Suitable habitat not present. SPECIES . Key to status codes: STATUS' HABITAT FD FE FT Fe FPD NMFS Bee SSI RP SE ST SR Draft CSC CSC CFP WBWG SLC List 1A List 1B Federal De-listed Federal Endangered Federal Threatened Federal Candidate Federal Proposed for De-listing Species under the Jurisdiction of the National Marine Fisheries Service USFWS Birds of Conservation Concern USFWS Special Status Invertebrates Sensitive species included in a USFWS Recovery Plan or Draft Recovery Plan State Endangered State Threatened State Rare 4 April 2000 Draft CDFG Species of Special Concern CDFG Species of Special Concern CDFG Fully Protected Animal Western Bat Working Group High Priority species Species of Local Concern CNPS List 1A: Plants presumed extinct in California CNPS list 1 B: Plants rare, threatened or endangered in California and elsewhere 20" POTENTIAL FOR OCCURRENCE APPENDIX C REPRESENTATIVE PHOTOGRAPHS OF THE STUDY AREA q r\..J wt) Above: Mowed, non-native annual grassland adjacent to the Community Center. Below: Riparian habitat to the south of the Community Center. ENVIRONMENTAL CONSULTANTS Photographs taken June 14, 2006. '-f r1b &f City of Dublin Initial Study/Shannon Center Project '1S0b Appendix 2-Geotechnical Evaluation Page 54 January 2007 .b'" 'I' ~, GEOTECHNICAL EXPLORATION AND FAULT HAZARD EVALUATION SHANNON COMMUNITY CENTER PROPOSED REPLACEMENT OF COMMUNITY CENTER BUILDING DUBLIN, CALIFORNIA SUBMITTED TO CITY OF DUBLIN PARKS & RECREATION SERVICES DEPARTMENT DUBLIN, CALIFORNIA PREPARED BY . ENGEO INCORPORATED PROJECT NO. 7096.1.001.01 JUNE 8, 2006 COPYRIGHT iCi 2006 BY ENGEO INCORPORATED. THIS DOCUMENT MAY NOT BE REPRODUCED IN WHOLE OR IN PART BY ANY MEANS WHATSOEVER, NOR MAY IT BE QUOTED OR EXCERPTED WITHOUT THE EXPRESS WRITTEN CONSENT OF ENGEO INCORPORATED. : iiQ' 104 GEOTECHNICAL ENVIRONMENTAL WATER RESOURCES CONSTRUCTION SERVICES INCORPORATED Project No. 7096.1.001.01 June 8, 2006 Ms. Henna Lichtenstein Parks and Facilities Development Manager City of Dublin 100 Civic Plaza Dublin, CA 94568 Subject: Shannon Community Center Dublin, California GEOTECHNICAL EXPLORATION AND FAULT HAZARD EVALUATION Dear Ms. Lichtenstein: With your authorization, ENGEO Incorporated conducted a geotechnical exploration and fault hazard evaluation for the proposed replacement of the Shannon Community Center building, located at 11600 Shannon Avenue in Dublin, California. Based on the geotechnical data, it is our opinion that the proposed development is feasible from a geotechnical and geologic standpoint, provided the recommendations included in this report are incorporated into the project design. Weare pleased to be of service to you on this project, and if you have any questions regarding the contents of this report, do not hesitate to contact us. . Very truly yours, ENGEO INCORPORATED Reviewed by: t D~' Braggers, Jft&!,' ~~~s, PE av 2010 Crow Canyon Place. Suite 250 · San Ramon, CA 94583-4634 · (925) 866-9000 · Fax (888) 279-2698 www.engeo.com '6~EO INCORPORATED TABLE OF CONTENTS Page Letter of Transmittal INTR 0 D U CTI 0 N ................................................................................................................................... 1 Purpose and Scope .......... ................................................. .............................. ........................... 1 Site Location and Description. ............. ........... ....................... ...................... ................... .......... 2 Proposed Development......................................... .................................................................... 3 GEOLOGIC SETTING ........................ ...... ..... ......... ........................ :.... ........ ......................... ....... .... ..... 4 Regional Geology and Seismicity. ..................... .......................... ............. ............... ...... ...... ..... 4 GEOLOGIC SITE CHARACTERIZATION ........ .................................. ........................................... 6 PREVIOUS INVEST! G A TI ON..................................................................... ...... ...... ..... ...... .,............... 8 CURRENT STUDy............................................................................................................. ..................... 9 Field Exploration.................................................................. ........................ .............................9 Laboratory Testing................... ................. .............................................................................. 11 Subsurface Stratigraphy .......................................................................................................... 11 Groundwater Conditions ................................................................... ...................................... 12 D ISCUSSI 0 N AND CON CL USI ONS ..............................................................................................13 Seismic Hazards......................................................................................................... ..... ........ 13 Ground Rupture. ......... .............................. ....... ......... .......................... ............................... 13 Ground Shaking................................................................................................................. 14 Building Code Seismic Information ......... ............................. ..................................... ...... 15 Lurching.......................................................... .................................................................. 15 Liquefaction......................................... ........................................................... ................... 16 Densification Due to Earthquake Shaking ........................................................................16 Lateral Spreading ............... '_~"'"'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 16 Existing Fill................................ ............ .......... .................. ...................................................... 16 Expansive Soil......................... ........................ .......... .............. ......... .................... ............. ...... 17 Corrosion Potential.................................. ........................... ................. ................. ................... 17 RECOMMEND A TI 0 NS................................................ ...................................................................... 19 Structure Setbacks........................................... ....................................................... ......... ........ 19 Grading...................................... ....... .................. ............ ............... .......... ......... ................. ......20 Demolition and Stripping............................................ ...................................................... ...... 20 Fill Recompaction .......................................................... .........................................................21 Differential Fill.................................. ........ ........................................................... ............. ...... 22 Graded Slopes............................................ .......................................................... ....................22 Selection of Materials................. .................. .................... ..................................... .................. 23 . Fill Placement.................................................................... .......... ............................................23 Special Foundation Zone................................................ .............. ............................ ............... 24 7096.1.001.01 .June 8, 2006 1iO<;",~ ;.it)' EM3EO INCORPORATED TABLE OF CONTENTS (Continued) F oundati on Design .................................................................................................................. 25 Slab-On-Grade Construction................................................................................................... 27 Structural Mat Foundation Criteria..... ........ ............. ............... .............. ............. ...... ......... ...... 28 Post-Tensioned Mats ... .............................. ....................... ............. ....... .......... .... ...... ......... 28 Conventionally- Reinforced Mat ....................................................................................... 29 Subgrade Treatment for Structural Mat Foundations. ......................................................30 Foundation Concrete.. ...... ............... ...... .......... ..... .......... ....... ......... ...... ................... .......... ......30 Secondary Slab-on-Grade Construction .... .......... ....... ................... ......... ..... ....... .................... 30 Retaining Walls and Basement Walls ......................... .......... ..... ........................ ............. ........ 31 Preliminary Pavement Design........................................................................................... ...... 33 Drainage .......................................................................... ........................................................ 34 Requirements for Landscaping Irrigation.. ............ .............. ..................... ......... ..................... 35 Utilities.................................................................................................................................... 35 LIMIT A TIONS AND UNIFORMITY OF CONDITIONS .........................................................37 SELECTED REFERENCES FIGURES APPENDIX A - Boring Logs and Trench Log (ENGEO, 2005) APPENDIX B - Laboratory Test Results (ENGEO, 2006) APPENDIX C - Trench Logs by others APPENDIX D - Guide Contract Specifications 7096.1.001.01 June 8, 2006 H)O lJh:: :::;;, EfI3EO INCORPORATED INTRODUCTION Purpose and Scope The purpose of this geotechnical report is to address geologic and geotechnical hazards, as well as to provide recommendations regarding site grading, foundation design and site drainage for construction of the proposed residential development. The scope of our services included the following: . Reviewing available literature and geologic maps pertinent to the site. . Exploratory drilling of seven soil borings throughout the site. . Excavation and logging a 410-foot-Iong exploratory trench. . Sampling and laboratory testing of subsurface materials from the boreholes. . Analyzing the geotechnical and geologic data. . Reporting our findings and recommendations. This report was prepared for the exclusive use of City of Dublin and its design team consultants, in accordance with our agreement dated December 5, 2005. In the event that any changes are made in the character, design or layout of the development, the conclusions and recommendations contained in this report must be reviewed by ENGEO Incorporated to detennine whether modifications to the report are necessary. This document may not be reproduced in whole or in part by any means whatsoever, nor may it be quoted or excerpted. without the express written consent ofENGEO Incorporated. 7096.1.001.01 June 8, 2006 1 l 0 l.~u...:~D.Pl EM.3EO INCORPORATED Site Location and Description The site is located at Shannon Park in the City of Dublin, California (Figure 1, Site Vicinity Map). The ground surface at the majority of the site is gently sloping to the south and east. Along the northern side there are existing slopes with a maximum gradient of approximately 3:1 (horizontal: vertical). The existing building site is at approximate elevation 405 feet above mean sea level (msl). The park property is bounded by residences to the north and west, Shannon Avenue to the south and San Ramon Road to the east. An intermittent creek issuing from Koopman Canyon, west of the site, traverses the property from northwest to southeast. Currently, three crossings exist over the creek. Two of the crossing~ are pedestrian bridges: a single-span steel-frame bridge at the west and a three-span bridge at the center, which lead to the Community Center Building. The third crossing over the creek is located on the east side of the park and is a vehicular culvert crossing. The majority of the site is open-space recreation area which includes a kiosk, a fountain, a playground, picnic areas, pedestrian walkways and parking areas to the southeast side of the park. In addition, there is a parking area to the north and east of the existing building. There is currently a small structure at the northeastern corner of the park which serves as a cellular phone relay station. Vegetation includes maple trees and other trees, bushes and low grass scattered into the park. The City property was graded in approximately 1973 to create the existing parking areas and building pad. This grading included both cuts into the hill and placement of fills. The area south of the creek appears to have been graded by making shallow cuts and fills to create the existing rolling grassy areas and level paved areas. The existing Shannon Community Building consists of a 12,000-square-foot, one-story wood-frame building (Figure 2). It is located on the northern half of the site, just north of the creek. In the late 1970s, the building was expanded towards the east and south. This expansion was constructed partially below grade. It is our understanding that this side of the building has experienced minor damage, attributed by City personnel to insufficient water drainage. 7096.1.001.01 June 8, 2006 2 i'D r;t) EN3EO INCORPORATED Proposed Development We understand that it is proposed to demolish the existing building, and construct a new building to create the new Community Center. Based on discussions, the new 19,000-square-foot building will roughly occupy the same location and be slightly expanded to the west towards the kiosk and to the north towards the existing slope. According to the plans transmitted by Dahlin Group, the lower floor on the southeast comer of the proposed building will be a partially below grade. We expect that the foundation system for the proposed building may consist of (a) reinforced concrete mat, (b) post-tensioned slab, or (c) conventional spread footings and perimeter strip footing with a concrete slab-on-grade floor. The building loads are expected to be relatively light to moderate. It is anticipated to expand the main parking lot to the north and west by adding a new row of parking spaces. It is also likely that the upper parking lot be reconfigured. Grading is anticipated to consist of preparing the sub grade for the parking improvements and building slab-on-grade. This will require cuts in some areas and moisture conditioning and constructing new engineered fills. The area which now serves as a patio for the existing lower floor, will be backfilled with engineered fill (approximately 10 feet thick). According to our discussions, the deck of the central pedestrian bridge will be replaced. However, the foundation of the bridge is anticipated to be re-used. Our scope did not include an evaluation of the existing bridge foundation. 7096.1.001.01 June 8, 2006 3 IO?~OO EM3EO INCORPORATED GEOLOGIC SETTING Regional Geology and Seismicity The Shannon Community Center is located at the east margin of the East Bay Hills, an uplifted block offolded and faulted Cretaceous to Pliocene-age sedimentary rocks (Graymer, 1996, Figure 3). The uplift of the Coast Ranges has been driven by movements along faults within the San Andreas Fault system. Ancient and on-going fault movements have included both lateral (strike-slip) and vertical (thrust) displacements of the upper crust. The eastern and western geologic boundaries of the . uplifted ranges of the East Bay Hills are formed by the active Calaveras and Hayward Faults. The Hayward Fault is located approximately 7.5 miles southwest of the site. The main trace of the Calaveras Fault is located close to the east site boundary, while another apparently inactive trace of the Calaveras Fault is located approximately 400 feet west of the site. Un-named Upper Miocene non-marine bedrock is mapped between the two traces of the Calaveras Fault, including the area surrounding the subject site. Miocene Marine bedrock is mapped west of the western fault trace. Bedrock layers in the site vicinity are mapped striking north-northwest and dipping east (Graymer, 1974). Site-speci?c subsurface geologic conditions are discussed in greater detail later in this report. The right-lateral, strike-slip Calaveras fault is a major component of the San Andreas system, branching off the main San Andreas Fault south of Hollister. According to the CGS, the fault is not sufficiently active or well-defined north of the Town of Danville to be depicted on State hazard maps. The predominant sense of motion on the Calaveras fault is right-lateral, strike slip. A smaller component of vertical displacement is evident in some areas along the fault trace. The Calaveras fault has been divided into a northern and a southern segment, with the boundary located at Calaveras Reservoir. Oppenheimer and Lindh (1992) suggest that rupture of the entire 40-km-long northern Calaveras fault is possible and could generate a M7 earthquake. The 7096.1.001.01 June 8, 2006 4 IO~~O INCORPORATED Calaveras fault has generated a number of moderate-size earthquakes in historic time, including an 1861 Richter (ML) 5.9 event, an 1886 ML 5.4 event, an 1897 ML 6.2 event, a probable ML 6.5 event in 1911, the 1988 ML 5.1 Alum Rock event, the 1979 ML 5.9 Coyote Lake event, and the 1984 ML 6.2 Morgan Hill. The 1861 earthquake has been attributed to the Dublin-San Ramon segment of the fault. This event is reported to have caused 8.1 miles (13 km) of surface rupture, extending from San Ramon to Dublin (Toppozada et aI., 1981). The lack of a well-defined fault and the diffuse nature of seismicity at the northern end of the San Ramon Valley suggest that the Calaveras fault may die out north of Danville, with strain being transferred through the East Bay Hills to the Hayward faultIRogers Creek Faults (Unruh and Kelson, 2002). The long-term slip rate and contemporary creep rate for the southern Calaveras fault are approximately 15 :f:3 mmlyr (WGCEP, 2003), while the northern Calaveras fault has a long-term rate of 6 :f:l mmlyr_ (Kelson, et aI. 1996). The seismicity of the Bay Area is dominated by the major active strike-slip faults. The locations of known active faults are shown on Figure 4. The Working Group on Northern California Earthquake Probabilities (WGEP, 2003) recently evaluated the seismicity of the Bay Area. The WGEP estimated a 30-year probability of a moment magnitude (Mw) 6.7 earthquake on one of the active Bay Area Faults of 62 percent. The 30-year probability of a 6.7 Mw earthquake for the Calaveras and Hayward Faults were estimated at 11 percent and 27 percent, respectively. We perfonned a probabilistic seismic hazard analysis for project design purposes, described below in the discussion section of this report. 7096.1.001.01 June 8, 2006 5 (,}h zo q s:K3EO INCORPORATED GEOLOGIC SITE CHARACTERIZATION Our scope for this exploration included a review of previous consultants reports for the parcels adjacent to the site to the north (Terrasearch, 1976) and to the south (Harding-Lawson Associates, 1993) submitted to the State as part of the requirements of the Alquist-Priolo Act, as well as readily available published geologic literature. We also reviewed the State Fault Evaluation Report (FER) for the Calaveras Fault (FER 108, Hart, 1980) as well as a supplement to that report (Hart, 1981). Hart (1980; 1981) included exhibits depicting geomorphic features observed from historic aerial photographs as well as the locations previous consultant studies within the fault zone. Figure 5 depicts the site location with respect to the current State Earthquake Fault Hazard Zone boundaries and with respect to the active fault trace as defined by the State. According to Hart (1980), the main trace of the Calaveras Fault in the site vicinity is located approximately parallel to San Ramon Road. Hart describes this trace as well-defined bya narrow zone of steep linear scarps, offset drainages and groundwater barriers in Holocene alluvhnn. Hart (1981) describes a number of other fault traces west of the main trace, that were evaluated in the FER supplement. Traces 8 and 9 approximately correspond to the western trace of the Calaveras fault identified in Graymer (1994). In his conclusions regarding Trace 8 Hart says that it is ".. .not clearly the result of faulting and can not be traced to the north or south". With respect to Trace 9, Hart says "At least three trenches (possibly four) cross the feature and in no case was the presence of a recently active fault reported in soil or alluvial deposits". On the basis of his review of consultant trench logs, literature and aerial photograph review, and field reconnaissance, Hart (1981) concluded that there was a single active fault trace west of the City property. His conclusions are reflected on the current State maps. We reviewed aerial photographs covering the site flown in 1957 and in 1974. The 1957 photographs pre-date any significant grading in the vicinity of the park. At that time, the center of the park property was a low area between two northwest-trending bedrock ridges, occupied by the creek that issues from Koopman Canyon. In 1957, the natural creek bed extended to the original alignment of 7096.1.001.01 June 8, 2006 6 I f.Xo ffb ~D' EM3EO INCORPORATED San Ramon Road, and terminated into a drainage ditch. The area surrounding the end of the creek appears to be part of an alluvial fan deposited from the mouth of Koopman Canyon. In 1957, the alluvial fan extended through the low-lying area in the central part of the site. At that time, the ground surface along the mapped location of the main trace of the Calaveras Fault had been extensively modified by the construction of San Ramon Road. The alluvium underlies a portion of the existing building pad, as shown on Figure 6. In the 1974 aerial photographs, San Ramon Road has been widened, the park site has been graded and most of the existing improvements are in place. Based on comparison of the 1957 and 1974 photos, it appears that grading consisted of making cuts along the slopes at the north part of the park, and filling adjacent to San Ramon Road. It also appears that the former ridge area at the south side of the site was lowered by cuts and that fill was placed south of the creek channel at the locations of the existing parking lot and irrigated lawn areas. The approximate extent of engineered fill is depicted on Figure 6. 7096.1.001.01 June 8, 2006 7 \ r\ oh It; I ~I ifriEO INCORPORATED PREVIOUS INVESTIGATION We understand that the prior construction at Shannon Hills Park occurred under the supervision of Contra Costa County in approximately 1973. As described above, part of our scope included a review of the State FER documents for the Calaveras Fault. The state documents reference a prior report for the Shannon Hills Park by Earth Science Associates (ESA), completed in 1971. This study is described as a geologic and geotechnical report that included trenches across the main trace of the Calaveras Fault, and across the western trace (Trace 8 of Hart, 1981). Since this report was completed in 1971, prior to enactinent of the Alquist-Priolo Act, it was not submitted to the State for review and a copy does not exist in their files. However, ENGEO was able to obtain copies of trench logs that were originally included in the report from a later field trip guidebook (Haltenhoff, 1979). The trench locations were shown on a map at a scale of 1 "=2,000' in the guidebook. Based on review of the guidebook and ground elevations from the trench logs, we were able to approximately locate the trench across the main trace of the Calaveras Fault Trench T-l, (Appendix C). The approximate location of Earth Science Associates Trench T-l is shown on Figure 6. The log of Trench T -1 shows a groundwater elevation anomaly associated with a change in soil type at approximately 50 feet from the east end of the trench. The trench walls in this area are described as "abundantly slickensided" on the log. According to the description of these trenches in Haltenhoff (1979), ESA (1971) interpreted these features to be associated with the main trace of the Calaveras Fault. These logs were reviewed by Hart, (1980; 1981) who accepted the interpretation of ESA (1971). This trench, along with associated geomorphic features identified by Hart (1980; 1981), are apparently the basis for the location of the main fault trace on current State maps. 7096.1.001.01 June 8, 2006 8 \ ~.+ ~ ..,.;.-....'). t>,,- . ^i EM3EO INCORPORATED CURRENT STUDY Field Exploration The field exploration by ENGEO Incorporated consisted of seven soil borings and one exploratory trench. Prior to excavation and drilling operations, we retained a private utility locating company to .locate and mark underground utilities. Borings B-1 through B-7 were drilled to a maximum depth of 24.5 feet below the existing ground surface. All the borings were drilled on December 15, 2005, with a B-24 truck-mounted rig using a 4-inch solid stem auger. The locations of the borings are shown on Figure 2. The boring logs are presented in Appendix A. A 410-foot-long exploratory trench was excavated north of the existing building at the location shown on (Figure 2). The intent of the subsurface work was to explore for possible secondary traces of the Calaveras Fault east of the previously located main trace. In the original project scope submittal, ENGEO had proposed to excavate an exploratory trench for a length of approximately 350 feet. However, after selection of ENGEO for this project, and based on discussions with City personnel, it was decided to extend both ends of the exploratory trench in order to provide the maximum possible clearance. Accordingly, the trench was extended approximately 40 feet towards the west and 20 feet to the east, for a total excavated length of approximately 410 feet. Excavation wasperfonned with a rubber-tired backhoe. The trench walls were cleaned of smeared material, and supported with a temporary shoring system. The geologic conditions exposed in the south trench wall were logged by ENGEO Engineering Geologists under the supervision of the project Certified Engineering Geologist. Excavation, logging and backfilling of the entire trench lasted 5 days (December 12 to 16, 2005). The trench log is included in Appendix A 7096.1.001.01 June 8, 2006 9 , .'r>~'t ~o' INCORPORATED The east end of the trench excavation encountered 9 to 10 feet of artificial fill underlying the edge of the parking lot and the slope adjacent to San Ramon Road. At the east end, the trench depth reached approximately 11 to 12 feet below grade, which was the limit of the backhoe's capability. The far western portion of the trench (Stations 0+00 to 0+80) encountered very stiff stratified alluvial soils consisting of silty to sandy clay. Well-developed blocky soil structure with extensive clay skin development was observed in the clay soil horizons. The alluvium was observed to overly weathered bedrock. The bedrock surface was observed to rise to the ground surface east of Station 0+80. Between Stations 0+80 and 3+20, bedrock was covered by a thin layer of disturbed soil associated with the excavation made to develop the park. The bedrock consisted of weakly cemented olive-brown sandstone, and siltstone, with lenses of pebble conglomerate. Bedrock layers were observed to dip at shallow inclinations to the east between Stations 0+80 and 2+20. A gravel layer at Station 2+90 was observed to dip east. Beyond Station 3+20, the bedrock surface dropped in elevation, disappearing into the bottom of the trench at approximately Station 3+75. Engineered fill was observed overlying the native soils and bedrock east of Station 3+30. No evidence of shearing or offset of bedrock was observed in the walls of the trench. The bedrock conditions observed in the trench walls are typical of the Miocene nonmarine sediments identified at the site and surrounding areas on published maps. The alluvial soils at the west end of the trench displayed horizontal layers and development of pedogenic features typically associated with a significant age. The excavation required destruction of some of the existing pavement and walkway improvements, as well as some PVC irrigation pipes. After logging, the trench was backfilled with minimal compactive effort for most of the length, with the exception of the parking area Based on discussions, the City wishes to maintain access to the upper parking lot. Due to the resulting relatively deep trench in that area, it was considered that post-backfilling settlements might be excessive. Consequently, for the greatest portion of the trench along the parking lot, the soil was 7096.1.001.01 June 8, 2006 10 ~~b INCORPORATED placed back into the trench in approximately I-foot-thick lifts and compacted with a wheel compactor (not tested for compaction). Cold asphalt patch was then applied for an approximately 80-foot-long portion of the trench. Laboratory Testing Selected samples recovered during drilling were tested to determine the following soil characteristics: Soil Characteristic Natural Unit Weight and Moisture Content Plasticity Index Unconfined Compression Hydrometer Sulfate Content of soil pH of soil Testing Method ASTM D-2216 ASTM D-4318 ASTM D-2166 ASTM D-422-63 Caltrans Test Method 417 ASTM D-4972-89 Location of Results Appendix A Appendix B Appendix B Appendix B Appendix B Appendix B The applicable laboratory test results are shown on the boring log in Appendix A and individual test results are presented in Appendix B. Subsurface Stratigraphy Based on the boring log data, the paved areas are covered by asphalt concrete over aggregate base. A layer of fill, up to 2 feet in thickness, consisting of clayey gravel was encountered at some locations (Borings B-1 and B-5). As already mentioned, fill up to 9 to 10 feet in thickness was encountered on the east side of the upper parking area (Boring B-7, trench log), which consists of dark brown-black, stiff silty clay/fat clay of high plasticity. Native soils generally consist of a 2- to 6-foot-thick fat clay/silty clay layer. This soil layer exhibited high plasticity (Plasticity Index 36 to 45) and appears to be in general, very stiff in consistency with the exception of Boring B-3 Gust north of the creek) where it was found to be stiff. In the majority 7096.1.001.01 June 8, 2006 11 ~:~ INCORPORATED of the borings, this material was underlain by an 8- to 10-foot-thick layer of very stiff lean clay/silty clay/clay silt of generally low to medium plasticity, which locally contained lenses and pockets of dense clayey sand. Underneath these layers, bedrock was encountered in all borings (except B-6) during drilling at the following depths: BORING FEET BELOW Gk' A It-< B-1 6 B-2 3 B-3 17 B-4 12 B-5 2.5 B-7 10 The majority of the bedrock appears to be weak to moderately strong, weathered to moderately weathered siltstone and sandstone. Groundwater Conditions Groundwater was encountered in some of the exploration borings at the time of drilling at varying depths. In Boring B-3 Gust north of the creek) the water was first encountered at 13 feet below the ground surface and at a depth of 12 feet at the completion of drilling. In Boring B-6 (south of the creek), the water level was encountered at a depth of 10 feet. It is possible that the groundwater levels had not fully stabilized at the time of the measurements. Fluctuations in groundwater levels may occur seasonally and over a period of years because of precipitation, changes in drainage patterns, irrigation, water flow in the creek and other factors that may not be present at the time of this geotechnical exploration. 7096.1.001.01 June 8, 2006 12 II 2,z'h tot? Eri:3EO INCORPORATED DISCUSSION AND CONCLUSIONS It is our opinion, based on the exploration data and laboratory test results, that the project site is suitable for the proposed construction from a geotechnical standpoint. The recommendations included in this report, along with other sound engineering practices, should be incorporated in the design and construction of the project. I Seismic Hazards Seismic hazards can generally be classified as primary and secondary. Surface ground rupture, also called surface faulting, is considered to be a primary seismic hazard because it is an effect that is directly related to displacement along a fault. Secondary seismic hazards are typically related to the ground motion associated with an earthquake, and include ground shaking, lurch cracking, soil liquefaction, lateral spreading, landslides, and tsunamis and seiches. The risk of landslides, tsunamis or seiches is considered unlikely at the site. The risk of earthquake-induced ground rupture, ground shaking, liquefaction, densification, lateral spreading, and lurching are discussed below. Ground Rupture. Surface ground rupture is essentially the projection of the fault trace to the ground surface. The nature of the actual displacement of the ground surface during a seismic event is related to many complex factors such as the type of fault, the nature of surface soil layers, and the site topography. Observation of actual ground breaks_ in earthquake areas has typically shown that the majority of the surface fault displacement is concentrated in a narrow zone along the fault trace (Hart, 1997; Bray, 2001, Lettis, and others, 2000). However, lesser magnitude, distributed ground cracking has commonly been seen well away from the main trace (Bray, 2001). According to the Alquist-Priolo Act, in the. State of California, structures intended for human occupancy can not be constructed across active fault traces. Active fault 7096.1.001.01 June 8, 2006 13 ~~- 1 EM3EO INCORPORATED traces are those with are deemed to have moved within the Holocene (last 11,000 years). As depicted on Figure 5, the entire site is within the State of California Earthquake Fault Hazard Zone for the Calaveras Fault. The site-specific geologic conditions, based on the data described in this report, are depicted on Figure 6. The trench excavated by ENGEO for this report encountered no evidence of previous surface fault rupture throu~h bedrock or native soils across the width of the existing structure, or for distances approximately 115 feet to the west and 60 feet to the east of the structure. From Station 3+75 to Station 0+00 at the west end of the trench, it is our opinion that there is evidence for a lack of any previous Miocene or younger surface faulting, since the bedrock is of Miocene age and is not faulted. However, east of the disappearance of the bedrock into the trench base at Station 3+75, 35 feet from the east end of the trench, the data from the current trench study does not provide any useful information about Holocene or younger fault rupture, since the surface soils are likely to be relatively young deposits and the engineered fill was placed in the early 1970s. As described above, a previous site study (ESA, 1971) located features interpreted to be the main trace of the Calaveras Fault at the location shown on Figure 6. Presumably, the location of the current structure was based on the recommendations of ESA to avoid the active fault trace. The Terrasearch (1976) study north of the City property included trenches that did not encounter the Calaveras Fault, 'and therefore, constrain the possible western location of the fault. The locations of the Terrasearch trenches, the approximate location of the ESA trench, as well as the location of the ENGEO trench are depicted on Figure 2. The fault location, based on previous trench data, is interpreted approximately as shown on Figure 6. This location is approximately 120 feet east of the current structure. Ground Shaking:. An earthquake of moderate to high magnitude generated within the San Francisco Bay Region could cause considerable ground shaking at the site. To mitigate the shaking effects, all structures should be designed using sound engineering judgment and the latest Uniform Building Code (UBC) requirements as a minimum. 7096.1.001.01 June 8, 2006 14 "t i~iJ'\ bO~ EM3EO INCORPORATED Seismic design provisions of current building codes generally prescribe minimum lateral forces applied statically to the structure, combined with the gravity forces of dead-and-live loads. The code-prescribed lateral forces are generally considered to be substantially smaller than the comparable forces that would be associated with a major earthquake. Therefore, structures should be able to (1) resist minor earthquakes without damage, (2) resist moderate earthquakes without structural damage but with some nonstructural damage, and (3) resist major earthquakes without collapse but with some structural as well as nonstructural damage. Conformance to the current building code recommendations does not constitute any kind of guarantee that significant structural damage would not occur in the event of a maximum magnitude earthquake; however, it is reasonable to expect that a well-designed and well-constructed structure will not collapse or cause loss oflife in a major earthquake (SEAOC, 1996). Building Code Seismic Information. Based on the subsurface soil conditions encountered and local seismic sources, the site structures should be designed using the following information, based on Chapter 16 of the 1997 Uniform Building Code: Categorization/Coefficient Soil Profile Type (Table 16-J) Seismic Zone (Figure 16A-2) Seismic Zone Factor (Table 16-1) Seismic Source Type (Table 16-U) Near Source Factor Na (Table 16-S) Near Source Factor Ny (Table 16-T) Seismic Coefficient Ca(0.40xNa) (Table 16-Q) Seismic Coefficient Cy (0.56xNy) (Table 16-R) .Calaveras Fault located 9 km from site. Design Value Sc 4 0.4 B 1.3 1.6 0.52 0.90 Lurching. Ground lurching is a result of the rolling motion imparted to the ground surface during energy released by an earthquake. Such rolling motion can cause ground cracks to fonn. 7096.1.001.01 June 8, 2006 15 II EM3EO INCORPORATED The potential for the formation of these crac:ks is considered greater at contacts between deep alluvium and bedrock. Such an occurrence is possible at the site as in other locations in the Bay Area, but based on the site location, it is our opinion that the offset is expected to be minor. Liquefaction. Liquefaction is a phenomenon in which saturated cohesionless soils are subject to a temporary, but essentially total, loss of shear strength because of pore pressure build-up under the reversing cyclic shear stresses associated with earthquakes. ENGEO evaluated the liquefaction potential at the site. As already stated, the subsoil at the site consists of primarily cohesive material. Therefore, the liquefaction potential at the site is considered generally low. Densification Due to Earthquake Shaking. Densification of the sandy soils above and below the groundwater level can cause settlement during an earthquake. Based on the subsurface conditions, we judge the risk for densification due to seismic shaking to be low. Lateral Spreading. Lateral spreading is a failure within a nearly horizontal soil zone (possibly due to liquefaction) that causes the overlying soil mass to move toward a free face or down a gentle slope. Due to the low risk for liquefaction and the anticipated subsurface conditions, it is our opinion that the potential for lateral spreading at the site is low. Existing Fill As described previously, the site was previously graded and up to 10 feet of existing fill was noted at the east edge of the park. We anticipate that this fill was engineered under the observation of ESA, although no fill compaction report is currently available. Proof rolling is recommended to identify soft areas and then establish sub-excavation requirements. Any localized soft compressible soils should be excavated and recompacted. The sub grade should 7096.1.001.01 June 8, 2006 16 ~%o INCORPORATED be scarified to a depth of 12 inches, moisture conditioned, and recompacted in place. Any debris, such as concrete blocks, should be removed at this time. Following removal and recompaction, conventional strip and spread footings with a slab-on-grade floor or a mat foundation can be used to support the structures. An approximately 410-feet-long exploratory trench was excavated for the geologic reconnaissance. It may become necessary to excavate either the upper portion or all of the backfilled material and compact it with engineered fill. This is further discussed into the "Recommendations" section of this report. Expansive Soil Expansive soils shrink and swell as a result of moisture changes. Building damage due to volume changes associated with expansive soils can be reduced by proper foundation design and/or proper soil preparation. The soil at the site in the upper 5:l:: feet displays high Plasticity (pI of 36 to 45). Design criteria that address this level of expansion potential are presented with the "Foundations" section of this report. Corrosion Potential Chemical testing for corrosion potential of the subsoil included sulfate content and pH testing in the upper ::!:5 feet. The purpose of the testing was to determine the sulfate concentrations of soils on pads for comparison with the recommendations of the Uniform Building Code (1997) regarding appropriate cement content and concrete strength design parameters. The following table from on the 1997 UBC (Table 19-A-4), provides guidelines to mitigate sulfate attack on concrete in contact with soil. 7096.1.001.01 June 8, 2006 17 I rlt$Q 'tD Gi ENGEO INCORPORATED Sulfate Sulfate In Soil Maximum Minimum Exposure Cement Type Water- Cement Strength mglkg (%) Ratio F' c (psi) Negligible 0-1,000 0.00-0.10 II 0.55* 3,000* Moderate 1,000 - 2,000 0.10 - 0.20 II, IP(MS), IS(MS) 0.50 4,000 Severe 2,000 - 20,000 0.20 - 2.00 V 0.45 4,500 Very Severe Over 20,000 over 2.00 V plus pozzolan 0.45 4,500 Note: ... Recommended Practice to Minimize Attack on Concrete by Sulfate Soils and Water provided by the Cement Technical Committee ofCalifomia The sulfate content of the sample tested was found to be between 77 and 130 mg/kg (0.008 to 0.013 percent by weight). The pH of the soil was 8.26 to 8.42. The results are presented in Appendix B. In accordance with the criteria presented in Table 19-A-4 of the 1997 Uniform Building Code (UBC), the soil is classified in the negligible sulfate exposure range. Cement type, water-cement ratio and concrete strength are not specified by the UBC for this range but recommendations are provided by the Cement Technical Committee of California in the above table. 7096.1.001.01 June 8, 2006 18 \ I ~ a;.) toi Ef\GEO . INCORPORATED RECOMMENDA TIONS Structure Setbacks Typically, structural setbacks of 50 feet are recommended when a fault trace can be defmed through mapping. The intent of structure setbacks is to provide for uncertainties in the locations of fault traces, and to reduce the potential for damaging effects of distributed ground cracking. A 50-foot structure setback from the interpreted location of the main Calaveras Fault trace is depicted on Figure 6. No habitable structures should be constructed in this zone. Due to the uncertainty of the exact location of the ESA Trench T-l, we recommend that any habitable structures planned at distances between 100 feet and 50 feet from the main fault trace be supported on a mat foundation constructed on a geotechnically improved sub grade as described below. The intent of the recommended Special Foundation Zone is to minimize the risk of damage from distributed ground cracking to structures within 100 feet of the interpreted active fault trace. The limits of this special sub grade zone are depicted on Figure 6. The limits of the recommended Special Foundation Zone overlap the end of the ENGEO trench. The western limit of the proposed zone is approximately 25 feet west of Station 3+75 of the ENGEO trench, where the bedrock surface dropped below the trench base. The recommended Special Foundation Zone can, therefore, be considered to be an effective 25-foot offset from Station 3+75 of the ENGEO trench. As described above, Hart (1980; 1981), and previous studies (T errasearch, 1976, ESA, 1971) found no evidence for an active western trace of the Calaveras Fault. It is, therefore, our opinion that no setback from the west end of the ENGEO trench is required. 7096.1.001.01 June 8, 2006 19 ~~o INCORPORATED Grading No grading plans were available at the time of the preparation of this report; however, based on the site conditions and existing grades, we anticipate grading may involve relatively minor cuts and fills in order to create the building pad and the surrounding development for the new Shannon Community Center building, as well the sub grades for the parking area expansion(s) or reconfiguration. Pending the environmental site assessment (by others), the need for site remediation may require overexcavation and replacement of the site soils at locations where. Underground Storage Tanks or septic tanks are possibly located and/or other areas that may be subject to environmental treatment. ENGEO should be notified at least 72 hours prior to grading in order to coordinate its schedule with the grading contractor. Grading operations should meet the requirements of the Guide Contract Specifications included in Appendix D and must be observed and tested by ENGEO's field representative. Ponding of stormwater, except within engineered sediment detention basins, must not be allowed at the site and particularly on the building pads during work stoppage for rainy weather. Before the grading is halted by rain, positive slopes should be provided to carry surface runoff in a controlled manner to a discharge point approved by the Civil Engineer. Demolition and Stripping Site development should be initiated with the removal of the existing building, the existing paved parking lot, concrete slabs, retaining walls, fences and other installations, as well as machinery, etc. which presently occupy the site. In addition, it should commence with the excavation and removal of the building foundation, buried structures, including abandoned utilities, septic tanks and their leach fields, if any exist. 7096.1.001.01 June 8, 2006 20 \ 1. f) vb EM3EO INCORPORATED Following the demolition of existing improvements, site development should include removal of vegetation (if any), debris, loose soil, and soft compressible materials in any location to be graded. As a minimum, tree roots should be removed at least 3 feet below the existing grades. The actual depth of tree root removal should be determined by the Geotechnical Engineer's representative at the time of grading. Any soft compressible soils should be removed from areas to receive fill or structures, or those areas to serve as borrow. Subject to approval by the Landscape Architect, strippings and organically contaminated soils can be used in landscape areas. Otherwise, such soils should be removed from the project site. Any topsoil that will be retained for future use in landscape areas should be stockpiled in areas where it will not interfere with grading operations. All excavations from demolition and stripping below design grades should be cleaned to a firm undisturbed soil surface determined by the Geotechnical Engineer. This surface should then be scarified, moisture conditioned, and backfilled with compacted engineered filL The requirements for backfill materials and placement operations are the same as for engineered fill. No loose or uncontrolled backfilling of depressions resulting from demolition or stripping is permitted. Fill Recomoaction As described previously, a two-foot-thick layer of fill was encountered at some of the soil borings. In order to provide a competent subgrade, the fill should be removed. Proof rolling is recommended to identify soft areas and then establish sub-excavation requirements, as necessary . Depending on the nature of the improvements that will be proposed upon the exploratory trench (which was dug for the geologic reconnaissance and then backfilled with minimal compactive effort - not tested for compaction), it may become necessary to excavate the upper portion of, or 7096.1.001.01 June 8, 2006 21 17 I r 1 -11\:':' ~EO INCORPORATED all of the backfilled material and compact with engineered fill. This is recommended in order to avoid future settlement or soil subsidence underneath the proposed development. In general, if building foundations or roadway/parking sub grades are proposed, the entire depth of the trench should be excavated and recompacted with engineered fill. If patios, walkways, pedestrian paths, etc. are proposed, then excavation and compaction of the upper .5 feet should be sufficient. Differential Fill A review of the project plans found that the differential fill thickness underneath the building pad could reach or exceed 10 feet in some areas. It can be anticipated that significant variations in material properties may occur in areas which are underlain by different soil conditions. It is our opinion that there is a potential for significant differential in swell characteristics or settlement where fill thicknesses vary across the building pad if not mitigated during site grading. Such situations can be detrimental to building performance. Accordingly, we recommend that remedial grading be performed to reduce differential fill thickness to no more than five feet across the building pad. This will provide a uniform thickness of engineered fill within the entire foundation area. The base of the subexcavated area should be scarified by cross ripping, moisture conditioning, recompaction and then constructed to pad grade with engineered fill. Graded Slopes The height of cut and fill slopes should be less that 15 feet. Therefore, it is recommended that graded cut or fill slopes be no steeper than 2:1 (horizontal:vertical). All fill slopes (existing and proposed) should be adequately keyed into firm natural materials unaffected by shrinkage cracks. All cut slopes should be observed the project Geotechnical Engineer at the time of grading to verify uniformity in exposed conditions and to determine if they should be re-built as engineered fill slopes and to determine if toe drainage is necessary. 7096.1.001.01 June 8, 2006 22 ~. 2. 0*1 vO EM3EO INCORPORATED Selection of Materials With the exception of any organically-contaminated material (soil which contains more than 3 percent organics), the site soils seem to be suitable for use as engineered fill. The existing fills will be observed during grading and unsuitable materials, if any, will be identified. If it is desired to utilize aggregate base material which is excavated from the existing parking lot, this may be used as fill material and should be mixed with on-site soil. The asphaltic concrete material may be crushed and mixed with on-site soil and can be used as fill material in the new roadway subgrades. Alternatively, with careful mixing and blending, it may be possible to reuse the asphaltic concrete and aggregate base as aggregate subbase or aggregate base in the new roadway sections. Recycled asphaltic concrete should not be used in building pad or landscape areas. The Geotechnical Engineer should be informed when import materials are planned for the site. Import materials should be submitted and approved by the Geotechnical Engineer prior to delivery at the site and should conform to the reqUirements provided in Section 2.02B of Part I of the Guide Contract Specifications. Fill Placement After removal of the loose soil, the exposed non-yielding surface should be scarified to a depth of 12 inches, moisture conditioned, and recompacted to provide adequate bonding with the initial lift of fill. All fills should be placed in thin lifts. The lift thickness should not exceed 12 inches or the depth of penetration of the compaction equipment used, whichever is less. 7096.1.001.01 June 8, 2006 23 \~:;i) r;'J') ~oq EM3EO INCORPORATED The following compaction control requirements should generally be applied to all fills: Test Procedures: ASTM D-1557. Required Moisture Content: Not less than 3 percentage points above optimum moisture content for clayey soils. Clean granular deposits (less than 12 percent passing the No. 200 sieve) should be moisture conditioned to not less 2 percentage points above optimum moisture content. Minimum Relative Compaction: Not less than 90 percent for clayey soils. Clean granular deposits (less than 12 percent passing the No. 200 sieve) should be compacted to not less than 95 percent. It is important that all site preparation, including demolition and stripping, is done under the observation of the Geotechnical Engineer's qualified field representative and should be carried out according to the requirements contained herein and within the Guide Contract Specifications in Appendix D. The final grading plans should be submitted to the Geotechnical Engineer for reVIew. Special Foundation Zone As previously discussed, we recommend that any habitable structures planned at distances between 100 feet and 50 feet from the interpreted location of the main fault trace be constructed on mat foundation supported on a geotechnically-improved subgrade as described below. The location of this special foundation zone is depicted on Figure 6. The primary surface rupture is expected to be concentrated near the interpreted location of the main fault trace, as discussed above. However, based on experience, there is the potential for low-level distributed ground defonnation to occur in the special foundation zone. Recently published studies by Bray (2000), suggest that the effects of ground deformation on structures can be reduced by using geotechnically improved foundation 7096.1.001.01 June 8, 2006 24 (' l~~~ '1 INCORPORATED sub grades and by using reinforced structural mat foundations with subgrade isolation measures. The geotechnically-improved sub grade should consist of two layers of geogrid (OX 1400HS or approved equivalent) approximately 2~ feet apart to provide a 5-foot-thick reinforced layer beneath the mat. The bottom layer of grid should be placed at a depth of 5 feet below final pad grade. The soil within this zone should be compacted as previously discussed. The structural mat subgrade isolation system should consist of a layer 'Of sand (minimum four inches thick) placed on the compacted fill sub grade covered by two layers of vapor retarder (specified below in the discussion of vapor-retarder materials). The intent of these recommendations is to provide a reinforced sub grade zone that will resist propagation of ground cracking to the surface and to isolate the overlying mat from horizontal ground shear deflections by using the recommended subgrade isolation system. Structures within the zone should be designed to be founded at grade with no embedded components such as a basement. The recommendations f'Or the special f'Oundation zone are not intended to constitute any kind of guarantee that significant structural damage would not occur in the event of a maximum magnitude earthquake; their intent is to prevent structural collapse or cause loss of life. Foundation Design Major considerations in foundation design for this project are the high seismicity and the swell potential of the site's foundation soils. In order to reduce the effects of the potentially expansive soils, the foundations should be suffidently stiff to move as rigid units with minimum differential movements. It is our opinion that conventional spread footings with a slab-on-grade foundation system in combination with a structural mat foundation system (post-tensioned mat or conventional reinforced 7096.1.001.01 June 8, 2006 25 Igt:e,€01 INCORPORATED mat) are appropriate for support of the proposed community center structure. ENGEO should review foundation plans when they become available. Conventional Footing System. The proposed community center structure may be supported by a conventional perimeter strip and isolated interior footing system. Spread footings should be designed utilizing to the following design criteria, which should be confirmed following mass grading: Maximum Allowable Bearing Pressure: 2,500 psf for dead-plus-live loads. This value can be increased by 30 percent to include seismic or wind loads. Minimum Depth of Footing: Single Story - At least 12 inches below lowest pad grade. Two Story - At least 24 inches below lowest pad grade. Minimum Footing Width: Single Story - 12 inches. Two Story - 18 inches. Using these design values, up to 3/4 inch of total settlement may occur as loads are applied to the footings. Differential settlement between individual footings may equal ~ of the estimated total settlement. The Geotechnical Engineer should review foundation plans when they become available. Footing trenches should be cleared of all loose materials. The Geotechnical Engineer or his field representative should observe the footing trenches prior to concrete placement. - Lateral Resistance. Resistance to short duration (earthquake-induced) lateral loads may be provided by frictional resistance between the foundation concrete and the subgrade soils and by passive earth pressure acting against the side of the foundation. A coefficient of friction of 0.35 can be used between concrete and the subgrade. A uniform pressure of 1,000 psf can be used to evaluate the passive resistance that can be developed on the foundation elements for transient loads. The upper one foot of soil should be excluded from passive pressure computations unless it is confined by 7096.1.001.01 June 8, 2006 26 \2~dh Zo~l EM3EO INCORPORATED pavement or concrete slab. A combination of both friction and passive pressure may be used if one of the values is reduced by 50 percent. Slab-On-Grade Construction It is our understanding that concrete slabs will be used in conjunction with spread footings for living floor. If the potential for a damp slab is undesirable or if moisture-sensitive floor coverings are proposed, it is recommended to use a vapor retarder beneath the slab-on-grade floor. Accordingly, concrete slabs can be constructed on grade utilizing the following design guidelines. a. Concrete slabs should be at least 5 inches thick, depending on intended use. The slab-on-grade should be placed on a capillary break consisting of 6 inches of %-inch clean crushed rock. Class 2 aggregate base should not be used as a capillary break. However, for driveways, where moisture migration is not a consideration, the clean crushed rock may be replaced with Class 2 aggregate base. b. The Structural Engineer should consider using a tough, vapor retarding membrane that meets ASTM E 1745 - 97 Class A requirements (Section 2.05D, Part I of Guide Contract Specifications) to minimize moisture transmission through the concrete slab. Tbis membrane may be protected from damage during construction by overlying a 2-inch-thick layer of sand, if recommended by others (architect, structural, etc.). c. A modulus of subgrade reaction of 100 pounds per square inch (psi) per inch of deflection for site soils can be used in the slab design. The slab reinforcing should be designed by the Structural Engineer. As a minimum, the slab reinforcement should consist of No. 4 bars spaced 18 inches on center each way. The use of high strength concrete with a low water-cement ratio will also assist in reducing the potential for vapor transmission through the slab. Some cracking of the slabs-on-grade should be anticipated at the site as a result of concrete shrinkage. Frequent control joints should be provided to control the cracking. As a general guideline, control joint spacing for interior space slabs-on-grade should not exceed 20 feet. For 7096.1.001.01 June 8, 2006 27 I"'). 1 ~..' . ',I ;::,"';1 t.. Jr- ;"if' ; E EO INCORPORATED exterior space slabs-on-grade the control joints can be spaced 5 to 10 feet apart. Added steel or slab thickness would also serve to improve the performance of the slabs. Sub grade materials should not be allowed to desiccate between grading and the construction of the concrete slabs. The floor slab sub grade should be uniformly presoaked prior to placing the plastic vapor retarder membrane. Foundation subgrade soils should be protected from seepage by providing impermeable plugs within utility trenches as described in the "Utilities" section of this report. Structural Mat Foundation Criteria As an alternative to shallow spread footing foundations, the proposed structures may be supported on a rigid mat foundatio~ system. If a mat foundation is used, building loads will be more evenly distributed and the effects of settlement should be expected to be somewhat less in comparison to a system of continuous and spread footings. Either post-tensioned mats or conventional reinforced mats may be used. Structural mats may need to be stiffened to reduce differential movements from heaving or settlement to a value compatible with the proposed superstructure type and architectural finishes. Post-Tensioned Mats. Should be designed according to methods recommended in the Post Tensioning Institute "Design and Construction of Post -Tensioned Slabs-on-ground, Second Edition", dated 1996. Soil-design parameters are presented below. Center Lift Condition: Edge Moisture Variation Distance, em= 5.0 feet Differential Soil Movement, Ym = 2.6 inches 7096.1.001.01 June 8, 2006 28 \ l.c~ b'Q ENGEO INCORPORATED Edge Lift Condition: Edge Moisture Variation Distance, em = 4.0 feet Differential Soil Movement, Ym= 1.1 inch Recommended minimum mat thickness: 10 inches with 2-inch thickened edge if sand bedding is used and the minimum backfill height against the foundation at the perimeter should be 6 inches. Conventionally-Reinforced Mat. Alternatively, the residential structures may be supported utiliZing a conventionally reinforced mat foundation using the following design parameters: Edge Cantilever Span Distance: Interior Span Distance: Recommended minimum mat thickness: 4 feet 8 feet 10 inches with 2-inch thickened edge if sand bedding is used. The minimum backfill height against the mat at the perimeter should be6 inches. The mats should be designed to impose a maximum allowable bearing pressure of 2,000 pounds per square foot (psi) for dead-plus-live loads. This value may be increased by one-third when considering transient loads, such as wind or seismic. A modulus of sub grade reaction of 100 pounds per square inch (psi) per inch of deflection for native undisturbed soils or compacted fill can be used in the slab foundation design. The mat reinforcing should be designed by the Structural Engineer. The final foundation plans should be reviewed by the Geotechnical Engineer when they become available to verify conformance with these design criteria, and if desired, the actual foundation materials could be sampled once finished pads are achieved and tested to determine if the parameters presented herein remain applicable. 7096.1.001.01 June 8, 2006 29 I " ! ~ :) EM3EO INCORPORATED Sub~ade Treatment for Structural Mat Foundations. The subgrade material under a mat foundation should be uniform and the mat should be placed neat against the undisturbed soil. The pad subgrade should not be allowed to dry before placing concrete and should have a moisture content of at least 4 percentage points over optimum just prior to the placement of concrete. The pad sub grade should be checked by the Geotechnical Engineer prior to concrete placement for compliance with these moisture requirements and to confirm the adequacy of the bearing soil. Soft or loose soils present at the bottom of the excavation should be removed and replaced with engineered fill or lean concrete. Foundation Concrete The sulfate content of the sample tested was found to be between 77 and 130 mg/kg (0.008 to 0.013 percent by weight). The pH of the soil was 8.26 to 8.42. In accordance with the criteria presented in Table 19-A-4 of the 1997 Uniform Building Code (UBC), the soil is classified in the negligible sulfate exposure range. Cement type, water-cement ratio and concrete strength are not specified by the UBC for this range. We recommend consideration be given to a concrete design that includes Type II cement, a maximum water-cement ratio of 0.55 and a minimum compressive strength of 3,000 psi. Structural engineering requirements for strength design may result in more stringent concrete specifications. It is recommended that additional testing be performed after grading has been completed and pad grades established to verify these recommendations. Secondary Slab-on-Grade Construction Secondary slabs include exterior walkways, driveways and steps. Secondary slabs-on-grade should be designed specifically for their intended use and loading requirements. Cracking of the exterior 7096.1.001.01 June 8, 2006 30 ~~"t INCORPORATED flatwork is nonnal as it is part of the concrete curing process and should be expected. Frequent control joints should be provided during slab construction for control of cracking. Secondary slabs-on-grade should have a minimum thickness of 4 inches and should be underlain by a 4-inch-thick layer of clean, crushed rock or gravel. As a minimum requirement, slabs-on-grade should be reinforced with steel bars; in our experience, welded wire mesh may not be sufficient to control slab cracking. The Structural Engineer should design the actual slab reinforcement. Exterior slabs should slope away from the building to prevent water from flowing toward the foundations. Consideration should be given to lightly moistening the site soils just prior to concrete placement. Retaining Walls and Basement Walls Unrestrained drained retaining walls constructed on level ground may be designed for active lateral equivalent fluid pressures determined as follows: Backfill Slope Condition (horizontal:vertical) Level 4:1 3:1 2:1 Active Pressure (pounds per cubic foot) 70 75 80 85 As discussed, basement walls are proposed along the perimeter of the lower floor. A temporary 1: 1 cut slope behind the basement walls may be used during construction. Restrained (at-rest) drained basement walls may be designed for lateral equivalent fluid pressures of 95 pounds per cubic foot (pet). In addition, a uniform load of 100 psf acting against the upper 5 feet of the basement walls (deriving from the slab weight) should be included. If a spread footing is 7096.1.001.01 June 8, 2006 31 J :~~,;- f ~,t E/i!l,EO INCORPORATED designed within a horizontal distance of less than the design height of the wall, ENGEO should be consulted and provide recommendations related to the surcharge effect on the basement walls. The basement walls should be back drained and waterproofed. A water stop seal should be located at the wall/footing interface. Passive pressures acting on retaining walls and basement walls may be assumed as 250 pounds per cubic foot (pcf) provided that the area in front of the retaining wall is level for a distance of at least 10 feet or three times the depth of foundation and keyway, whichever is greater. The upper one foot of soil should be excluded from passive pressure computations unless it is confined by pavement or concrete slab. The friction factor for sliding resistance may be assumed as 0.35. A combination of both friction and passive pressure may be used if one of the values is reduced by 50 pe:r:cent. It is recommended that retaining wall and basement wall footings be designed using an allowable bearing pressure of 2,500 pounds per square foot (psf) in native firm materials or fill. These values may be increased by one third for transient loading conditions. Appropriate safety factors against overturning and sliding should be incorporated into the design calculations. All retaining walls and basement walls should be provided with drainage facilities to prevent the build-up of hydrostatic pressures behind the walls. Wall drainage may be provided using a 4-inch-diarneter perforated pipe embedded in Class 2 permeable material (Part I of Guide Contract Specifications, Section 2.05B), or free-draining gravel surrounded by synthetic filter fabric. The width of the drain blanket should be at least 12 inches. The drain blanket should extend to about one foot below the finished grades. As analtemative, prefabricated synthetic wall drain panels can be used. The upper one foot of wall backfill should consist of on-site clayey soils. Drainage should be collected by perforated pipes and directed to an outlet approved by the Civil Engineer. Synthetic filter fabric should meet the minimum requirement listed in the Guide Contract Specifications. 7096.1.001.01 June 8, 2006 32 , ."'~., '" 1,.. O. ."\ ' ..', ./' '>.., " "'" I ..,.,,,) ,.."! \;', ,,' ' E .0 INCORPORATED All backfill should be placed in accordance with recommendations provided above for engineered fill. Light equipment should be used during backfill compaction to minimize possible overstressing of the walls. Preliminary Pavement Design The following preliminary pavement sections have been determined for Traffic Indices of 4.0 to 7.0, and an assumed R-value of 5. According to methods contained in Topic 608 of Highway Design Manual by CAL TRANS, the following minimum asphaltic concrete pavement sections are recommended: I Traffic Index I AC I AB I (in.) (in.) 4.0 3.0 6.5 5.0 3.0 10.0 6.0 3.5 13.0 7.0 4.0 15.5 Notes: AC is asphaltic concrete AB is aggregate base Class 2 Material with minimum R = 78 The Traffic Index should be detennined by the Civil Engineer or appropriate public agency. These sections are for estimating purposes only. Actual sections to be used should be based on R-value tests perfonned on samples of actual subgrade materials recovered at the time of grading. Pavement materials and construction should comply with the specifications and requirements of the Standard Specifications by the State of California Division of Highways and City of Dublin requirements, and also meet the following minimum requirements. . All clayey pavement subgrades should be scarified to a depth of 12 inches below finished sub grade elevation, moisture conditioned to at least 3 percent above optimum moisture, and 7096.1.001.01 June 8, 2006 33 /:; ~~O~ INCORPORATED compacted to at least 90 percent relative compaction and in accordance with City requirements. Sandy subgrade soils should be compacted to at least 95 percent relative compaction. . Subgrade soils should be in a stable, non-pumping condition at the time aggregate base materials are placed and compacted. . Adequate provisions must be made such that the sub grade soils and aggregate baserock materials are not allowed to become saturated. . Aggregate Base material should meet current City requirements for Class 2 Aggregate Base and should be compacted to at least 95 percent of maximum dry density. . Asphalt paving materials should meet current Caltrans specifications for asphaltic concrete. . All concrete curbs separating pavement and irrigated landscaped areas should extend into the subgrade and below the bottom of adjacent aggregate baserock materials. Drainage Improper drainage may result in fill saturation with consequent loss of compaction and fill strength. It is very important that all building pads be positively graded at all times to provide for rapid removal of surface water. Ponding of water under floors or seepage toward foundation systems at any time during or after construction must be prevented. Ponding of stonnwater must not be permitted on the building pads during prolonged periods of inclement weather. As a minimum requirement, finished grades should provide a slope gradient of at least 3 to 5 percent within 5 feet from exterior walls at right angles to them to allow surface water to drain positively away from the structures. For paved areas, the slope gradient can be reduced to 2 percent. Care should be exercised to ensure that landscape mounds and 7096.1.001.01 June 8, 2006 34 I;&../:rt b01 EN3EO INCORPORATED hardscape features do not interfere with these requirements. Sufficient area drains should be proyided around the buildings to remove excess surface water. In addition to area drains, we recommend the installation of a perimeter subdrain along the north, east and west sides of the building. Figures 7 and 8 present typical perimeter subdrain systems for spread footing foundations and mat foundations, respectively. Downspouts from roof drains should not be tied into the perimeter foundation drains. All pads should be drained individually. Stormwater from roof downspouts should be conveyed in closed drain systems to a solid pipe that discharges to the street or storm drain system. Requirements for Landscaping Irrigation If planting adjacent to a building is desired, the use of drought-tolerant plants that require very little moisture is recommended. Sprinkler systems should not be installed where they may cause ponding or saturation of foundation soils. Such ponding or saturation could result in undesirable soil swell, loss of compaction and consequent foundation and slab movements. Irrigation of landscaped areas should be strictly limited to that necessary to sustain vegetation. Excessive irrigation could result in saturation, weakening, and swelling of foundation soils. The Landscape Architect and prospective owners should be informed of the surface drainage requirements included in this report. Utilities Gravity flow utilities should consider the potential for soil settlement depending on the method selected to mitigate settlement concerns at the site. 7096.1.001.01 June 8, 2006 35 I'" - ,,", &~o INCORPORATED It is' recommended that utility trench backfilling be done under the observation of a Geotechnical Engineer. Pipe zone backfill (i.e. material beneath and immediately surrounding the pipe) may consist of a well-graded import or native material less than % inch in maximum dimension compacted in accordance with recommendations provided above for engineered fill. Trench zone backfill (i.e. material placed between the pipe zone backfill and the ground surface) may consist of native soil compacted in accordance with recommendations for engineered fill. Where import material is used for pipe zone backfill, we recommend it consist of fine- to medium-grained sand or a well-graded mixture of sand and gravel, and that this material not be used within 2 feet of finish grades. In general, uniformly graded gravel should not be used for pipe or trench zone backfill due to the potential for migration of (1) soil into the relatively large void spaces present in this type of material, and (2) water along trenches backfilled with this type of material. All utility trenches entering buildings and paved areas must. be provided with an impervious seal consisting of native materials or concrete where the trenches pass under the building perimeter or curb lines. The impervious plug should extend at least 4 feet to either side of the crossing. This is to prevent surface water percolation into the sands under foundations and pavements where such water would remain trapped in a perched condition. Care should be exercised where utility trenches are located beside foundation areas. Utility trenches constructed parallel to foundations should be located entirely above a plane extending down from the lower edge of the footing at an angle of 45 degrees. Utility companies and Landscape Architects should be made aware of this information. Utility trenches in areas to be paved should be constructed in accordance with City of Dublin requirements. Compaction of trench backfill by jetting should not be allowed at this site. If there appears to be a conflict between City or other agency. requirements and the recommendations contained in this report, this should be brought to the Owner's attention for resolution prior to submitting bids. 7096.1.001.01 June 8, 2006 36 13~ fi" wtt EtiB,EO INCORPORATED LIMITATIONS AND UNIFORMITY OF CONDITIONS This report is issued with the understanding that it is the responsibility of the owner to transmit the information and recommendations of this report to developers, contractors, buyers, architects, engineers, and designers for the project so that the necessary steps can be taken by the contractors and subcontractors to carry out such recommendations in the field. The conclusions and recommendations contained in this report are solely professional opinions. The professional staff of ENGEO Incorporated strives to perform its services in a proper and professional manner with reasonable care and competence but is not infallible. There are risks of earth movement and property damages inherent in land development. Weare unable to eliminate all. risks or provide insurance; therefore, we are unable to guarantee or warrant the results of our work. This report is based upon field and other conditions discovered at the time of preparation of ENGEO's work. This document must not be subject to unauthorized reuse, that is, reuse without written authorization of ENGEO. Such authorization is essential because it requires ENGEO to evaluate the document's applicability given new circumstances, not the least of which is passage of time. Actual field or other conditions will necessitate clarifications, adjustments, modifications or other changes to ENGEO's work. Therefore, ENGEO must be engaged to prepare the necessary clarifications, adjustments, modifications or other changes before construction activities commence or further activity proceeds. If ENGEO's scope of services does not include on-site construction observation, or if other persons or entities are retained to provide such services, ENGEO cannot be held responsible for any or all claims, including, but not limited to claims arising from or resulting from the performance of such services by other persons or entities, and any or all claims arising from or resulting from clarifications, adjustments, modifications, discrepancies or other changes necessary to reflect changed field or other conditions. 7096.1.001.01 June 8, 2006 37 I 3 ~7 ~ '2.,0 <J't EM3EO INCORPORATED SELECTED REFERENCES Blake, T. F., 1996, EQFAULT, A Computer Program for the Deterministic Prediction of Peak Horizontal Acceleration from Digitized California Faults. Bray, J. D., 2001, Developing Mitigation Measures for the Hazards Associated with Earthquake Surface Fault Rupture, in. Seismic Induced Failures Workshop, Japan Society for the Promotion of Science, University of Tokyo, Japan, pp 55-79, January 11-12,2001. California Department of Transportation, 1992, Highway Design Manual. Earth Science Associates. 1971, Report on Geologic and Soil Engineering Investigation of Shannon Park Community Center, ESA Project No. 1180, dated August, 1971. Graymer, R. W., Jones, D. 1. and Brabb, E. E., 1994, Preliminary Geologic Map Emphasizing Bedrock Fonnations in Alameda County, California: OFR 96-252. Haltenhoff, R., 1979, Recent Deformation along the Calaveras Fault, Hayward Fault, and other Fault Zones, Eastern San Francisco Bay Region, California: Geol. Soc. Amer., Cordilleran Section, Field Trip Guide. Harding Lawson Associates, 1993, Fault Hazard Evaluation, New Parish Center, Saint Raymond's Parish, Dublin California, Dated February 19,1993, HLA Project Number 23014.1. Hart, E. W. and Bryant, W. A., 1997, Fault Rupture Hazard Zones in California, California Division of Mines and Geology, Special Publication 42, Revised 1997. Hart, E. W. 1980, Fault Evaluation Report Calaveras and Verona Faults, Dublin Quadrangle, FER 108, California Division of Mines and Geology. Hart, E. W. 1981, Fault Evaluation Report Calaveras and Verona Faults, Dublin Quadrangle, FER 108, Supplement No.1, California Division of Mines and Geology. Idriss, 1. M., 1994, Procedures for Selecting Earthquake Ground Motions at Rock Sites, National Institute of Standards and Technology, NIST GCR 93-625. International Conference of Building Officials, 1997, Uniform Building Code. Kelson, K. 1., Simpson, G. D., Lettis, W. R., and Haraden, C. C., 1996, Holocene slip rate and recurrence of the northern Calaveras fault at Leyden Creek, eastern San Francisco Bay region: Journal of Geophysical Research, v. 101, no. B3, p. 5961-5975. 7096.1.001.01 June 8, 2006 ZD1 EM3EO INCORPORATED SELECTED REFERENCES (Continued) Kelson, K.L, Baldwin, J.N., and Randolph, C.E., 1998, Late Holocene slip rate and amounts of coseismic rupture along the central Calaveras fault, San Francisco Bay area, California: Final Technical Report, U.S. Geological Survey, Award 1434-HQ-97-GR-03151, 26 p. Lettis, W. and 21 other authors [2000] "Surface Fault Rupture," Earthquake Spectra Journal, Chapter 2 in the Special Volume on the Turkey Earthquake of August 17, 1999 Reconnaissance Report, 11-52. Oppenheimer, D.H. and Lindh, A.G., 1992, The potential for earthquake rupture of the northern Calaveras fault, in Proceedings of the Second Conference on Earthquake Hazards in the Eastern San Francisco Bay Area, Borchardt, G., Hirschfeld, S.E., Lienkaemper, J,J., McClellan, P., Williams, P.L. and Wong, LG. (eds.), California Department of Conservation, Division of Mines and Geology, p. 233-240. Post-Tensioning Institute; 1996, Design and Construction of Post-Tensioned Slabs-on-Ground, Second Edition. Pacific Aerial Surveys, 1957, Black and White Panchromatic Stereographic Aerial Photographs, Flight A V 253 Line 33 Frames 37 and 38 at 1:12,000 scale. Pacific Aerial Surveys, 1974, Black and White Panchromatic Stereographic Aerial Photographs, Flight A V 1101 Line 5 Frames 25 and 26 at 1: 12,000 scale. Peterson, et aI., 1996, Probabilistic Seismic Hazard Assessment for the State of California: California Division of Mines and Geology Open File Report 96-08. Sawyer, T. L., 1999, Assessment of Contractional Deformation Rates of the Mt. Diablo Fold and Thrust Belt, Eastern San Francisco Bay Region, Northern California: Final Technical Report by Piedmont Geosciences Inc. for the U. S. Geologic Survey National Earthquake Hazards Reduction Program. . Terrasearch, Inc., 1976, Soil and Geologic Investigation, Parcel 4010 San Ramon Road, Dublin, California, Terrasearch Project No. 1402-E, Dated March 12, 1976. Toppozada, T.R, Real, C., and Parke, D.L. 1981, Preparation ofisoseismial maps and summaries of reported effects of the pre-1900 California earthquakes, California Division of Mines and Geology Open-File Report 81-11, 181 p. Unruh, J. R., and Kelson, K. 1., 2002, Critical Evaluation of the Northern Termination of the Calaveras Fault, Eastern San Francisco Bay Area, California, Final Technical Report for the U.S. Geological Survey, National Earthquake Hazards Reduction Program, Project No. 1430. 7096.1.001.01 June 8, 2006 11'1 "0; '0 ;p. EN3EO SELECTED REFERENCES (Continued) SEAOC, 1996, Recommended Lateral Force Requirements and Tentative Commentary. INCORPORATED Working Group on California Earthquake Probabilities, 2003, Earthquake Probabilities in the San Francisco Bay Region: 2002 to 2031 - A Summary of Findings: USGS Open-File Report 03-214. 7096.1.001.01 June 8, 2006 )'1101 &.01 o ' ci ~ .. "" ~ ce o u ~ 8 ~ .'< ';~:'"~"~;'~:" ), ~ ,::;::'~/.: ... o ... :.-. " . "', ~:. ~ " ',,-,.: ~.', ,. ~ ~ Vl :z: o u .:.....< ' . ",..- :-~',~.- ~ -r ce o " .. b => " .. '" !:: ?o= :I ce o :z: a: ~ o Vl ~ ~ Vl :z: .. ~ >- :z: .. ~ l- ce :c ;!; ce " ~ ~ ~ 8 u ::> " " ce t; .. .. co ~ o :z: >- .. :I ~ Z .. :I ::> u " " Vl ~ 8 !< CC " .. .. " " ~ 8 <:> :z: .. >- .. <0 " " .. o BASE MAP SOURCE: MS STREETS AND TRIPS ! N o o FEm' 2000 MJmlRS 1000 ENGEO INCORPORATED EXCELLENT SERVICE SINCE 1971 ORIGINAL FIGURE PRINTEO IN COLOR VICINITY MAP SHANNON COMMUNITY CENTER DUBLIN, CALIFORNIA PROlBCl'NO.: 7096.1.001.01 DATE: JUNE 2006 IlRAV/NBY: SRP CHBCDDBY: DEB URENO 1 : ta lng W9 r 9 - ICIOI ap- . wg - __,_J COPYRIGHT C 7006 OY rNGro INCORPORATrO. THIS OOCUMrNT MAY NOT or RrPRooucro IN WHOLr OR IN PART BY ANY MrANS WHATsorvrR. NOR MAY IT or QUOTrO OR rXCrRPTro WITHOUT THr rXPRrss WRlTTrN CONsrNT Dr rNGrO INCORPORATro. .;--- .i~: \,U,.'\I! I , ;, ' \ \ \ \ 1\ Ll.,-,., I i \t \ " ,1'1\1 I .-, -T ",\" \+t'\ I ~l \ / \~L .tl I j \ 'I \ \ I! i \\i~ \ \ i 1 \' ~, . l ! \ I! \;) 'I \ I, 1\ 11\ \ '\\'~i , \ \ ' 1i"~ \", ' p"".,! i' .'~ jl;:"',"O"'1 !,~1\ .~. \ \ \1 \ 1, I \ \ .~, ''\,\U '\ \ \ II" ,I lill\ ,,:,:4,' .', tl \ ' " " . ',', \ \ \.\f\--\ 1\\>;'" dt, .;\ -.'" '\l.j 'I 'Iil' ,\\, \ \ \(\ I \ [. i\\'- ~\ II <~;-- -'\1\\ \\\. i, '-\''''__,\ \ \\ \~\~\ \ \'~~\, \ '" i, ,I \ \. 'j \\ '[ r-",~: ,;,. \~~;,. --' '~ (;,ollsr, "\' ) ..,~,....- " '10'-'1 "'f-"-- l1';"~f1 lrf:'l''' .';';'- .~' ~ ~ :,.-;;-::r '-""C 'J _ '.-_--' '''1 .'~- '"r'-" - {:.. ~"" -r'" ,. , ..,<:- \.~,. - :~_'~'" .~.ll~", - ~ . ".;. j_ .~ _ _ .,~'_' __F" -< ' ) ), --~":'''1 ..-,..-._u_".---.. ~ ~_.:-tC' .,!-" :}- ---- ~'.", .~r-~t~. .".J" ' ....~-~g, "~--\_"_,l~.: C:o"r.rell? ,J ':.r''.:'-~::i-:'~ '-~' ',-' . \ Gem'll' '" 1_.. ~ to:::., - ~-- --~...-.. .-... ...... -'-.....;; '~l!~ .> .~ . ,:.,:~~~~~:-=~.._..".~::~.~:=.._.~~~::.;.-.::._. --:- ~ -::':::.:;;~:__--- 'um______ 'q, ~ ~(:', ,~ 'j t "'-.... ....... .~...j'. .'-t.. i t... '" .( i~L '.,. }. " -,j! .. \ #1' ~ ,II:!::.... i "h' i U '\1 , II. , : I \ II I ""'- ',' I i ,I ~', i .,-~'1.1. ,.,"~ , ,..,-1 I -1: '\' i I , \ \, J, ~1 ..-I '1"'0'"'' "f,! I ' : l' v\r"l.i 0,">1 "j 1 ~~_ I ,~ .. - -.1-.' .... . ~ 'q,. .t ~I t..~..,. ~ .L.,._-, ...5 i I , , Dllflllll ;r\!'1~ , i.. I tJ I L PI':l:W'~'''<1 i:.~>( ;'''phr;l! " i !-~. - i I I \ ,- "'. ._/'7 j,' .. I ~ .. \0, /(:t;) [ ~.I ' ' (.~~~r(\_~: i Cd:'~~:~~_.,_".,_:,;; .~~~--_."..--- .,:.;: :* L:"!r ,if. ~- ;~1 -i n;.....~ ..2J~"~=""~oc~I,"~" A N EXPLANATION B-~ r, , APPROXIMATE LOCATION OF BORING . A.S SHOWlNGDBPIH NOTE: BORING LOCA TlONS AND DEPTHS ARE APPROXIMA TE_ ACTUAL LOCATIONS AND DEPTHS WILL BE DETERMINED BASED ON DISCUSSIONS WITH THE CITY OF DUBUN, o o FHE1' 50 APPROXIMATE LOCATION OF EXPLORATORY TRENCH BASE MAP SOURCE: HJW GEOSPA TlAL, INC. -C. t>J MJm!RS 25 ENGEO INCORPORATED EXCELLENT SERVICE SINCE 1971 SITE PLAN SHANNON COMMUNITY CENTER DUBLIN, CALIFORNIA PRomcrNO~ 7096.1.001.01 DATE: JUNE 2006 DRAWN BY: SRP CIIIDIlDBY: DEB 2 ~,~. ci ~ .:.----' .'.,:)II;':>::>'X~.-. ' '1:Jr~ \\.\ />-' "I :;" . -,....-.- i ~ .:;-.::::>.... <>..., 7S~ '\ \~(:..-.:/ :):~ --..~.i ": ~ _!::.::>, _ . "~....'" . ,:<!O \ \~"'- _'._ ~ __ L . ;.__n . ~ '-~''''''' ,.~v . -- . .~1 -.~ l' .. ~ -......' . .~ ~ .......;t..,. C' ~ fj " ,j/". \. ~ t~l ~ j . _ \ ,;p".,. ~ , _ ~ "..c, --..J . : ~.~~,~ ~~sl '1. . f I , ...... '- -.. . '-- ,.~ " 1:i I 50'...,. ...... '. - \~-., ~ ~..;.".... ::;.., 5 I '. ,...., ......, . . . ~ . "/ ". ;;: ...,..., +S~"'mc c:: -..... . ~ ',,_. ,II.;;).,; ~ , . .....,.._\ ....... '1r...' .' ,...,.~~ :.':>3 ~ .... c '" I- .. '" '" u 1:i '" o c '" b ::> o '" 1ft !:: >- -< '" '" o :z: 0< ~ a In !;( J: '" In Z ~ '" >- :z: -< >- 1ft ... '" -< .. ;!; '" a '" -' a J: '" ;!; o '" () ::> o o '" .. ... '" ... Gl I- a :z: ~ '" I- Z ... '" ::> u o " Ul ;: l- e I- -< '" a .. '" o u ;!; a ... '" z ... >- Gl '" a o N "..... "- " ':......._" Tm~\-". .... - - - -- BEDROCK CONTACT-DASHED WHERE GRADATIONAL OR APPROXIMATELY LOCATED ~ ---.. FAULT-DASBEDWHEREINFERRBD, DO'ITED WHERE CONCBALED, QUERIED WHERE EXISTENCE IS DOUBTFUL; DOUBLE ARROWS INDICATE STRJKB.SIJP MOVEMBNT AXIS OFFOLD -+- ANTICLINE -+- SYNWNE STRIKBAND DJPOF S'mATA u Y INCLINED X VERTICAL 8ASE MAP SOURCE: 0/88L[[, 1980 .J(" OVERTIJRNED ENGEO INCORPORATED EXCELLENT SERVICE SINCE 1971 ORIGINAL rlGOR( PRINTeD IN COLOR IY \\. "A.~'AIVI?'UU~) \\ ..\. /l.... " '-- , ~ ,/ . ::-- ~j ~an Hamon. · \; ~l,lrr., - \-illag'c · :8'~')' . . ;;,,'l~...n. 'T .-,.,., ,-". (' j't"--'-d'j: :~~C-s. .;;.....~.?. ,.,;,i.<:~.::,:-\:;:;~I'.I~""_'-!\~:'~i""'~' /,'.. " \'~ ~ v"- ". < ~ \~'", lO,h : "~I; , l;;'--c'~~~'.><,:~:~\-t-,~. .-J./'<- i '''::'^'\.':....-(. I'. i', . )1 i:--=;..-.....\ \. \ \\. ~'. F"'land()rskil . ., : ;iil . IJ :: "~'-J \, .' I:':~ \ .. \. U.t .....~..J " .', ,I "'/ ;., . "'-'. ,/' ~~: \ I :v Iihll:;E ~'~:~~-~~.~c' ~;i :_.~:'.~: ~~ 'J;~~t:1~::~~;~ \~ ..2'~~: '~ i{ J i .f, \" ., ., :.' p-;9 '. \'. " /'^i' \ f" '" '" >' I \~~.. \~~~/t;;;:' i) ~ ':, : "- ~:- Ii ,:-...{ ; /< lDoug-h(~rt ...., '., ~." J"-." -, i J I -~~~ ~-~-~-~------- ~~."-' t..'''~: ):j:+/ I <\. ;:,....<~ 1 . "-' -'-'/ j c I ,.'- , ~ I -....... . / J I .. ,-i~ I .'" .... '. /11/ \,'''' "'""'~ ,.... ,.. I ~ . ~ ....... ~J<id". \' ! ". MIL If{ ES ":;Murra,ySch_ O"".:'p.........;J' ~\~~~' -' 'Ct{ ---rh~afey.-_.~"... l ~ .. ,. /" . ~'>--: \..... I nu, \ 1- 'Cfet-":... =.':4' .\ -J . . ~'l "'~ . \ i . \:, I ~ \..\.\\.... ':\ I::: 'i ,.)1.....; ":r .....-;:....-/ I. ? \ '; I" '" I '.-" ! \\ J-"~ . C I <. ~\ I ~ .;: \ I C ~i' I -:2. 0\ ~1\ il. .. '1,.J}.'~-:-- ,~ '.~ \' 2 ; /" /".. /' /" . ,...--" 0.3 ! J"t5 s A Q a AlLUVIUM QTt TASSAJARAFORMATION T P s NONMARINE SANDSTONE T m s s SANDSTONE T m s I Sn.TSTONE . .. .. .. .... SANDSTONE BED A N o o .5 MlIJl KILOMIlTIlR 1 PROJBCTNO.: 7096.1.001.01 DATE: JUNE 2006 DRAWN BY: SRP CIIIlCXFDBY: DEB FIGURE NO REGIONAL GEOLOGY SHANNON COMMUNITY CENTER DUBLIN, CALIFORNIA 3 : "0 109 wg .dwg .j 0 ....: { , 9 ~%_ \.1- It.:~~ ~ ~ ~ ~ 1969 ~;;..., ... M5,? ~ . "'- M5.6 ~'SA~A ~~ ROSA \.'\ ll' ROSEVlUEO I \ \ SACRAMENTl(; ...1892 Mt>,t> oillo VISTA OLOm OSTOCKTON OLATHROP SALIDP MODESTOO A 1881 ~15,9 N 0 MILES 20 0 m.oMBTERS 40 EXPLANATION REGIONAL FAULTS CONSIDERED SIONIFICANI' POTENTIAL SEISMIC SOURCES.: _CLASSA) - CLASSB I!IY7 UBCaIAP7lill 16 - CLASSC _ BLIND THRUST FAULT ... APPROXIMATE LOCATION OF EPICBNTER, SHOWING YEAR OF OCCURRENCE AND MAGNITUDE "'BASED ON USGS OPEN FILE 96-706 ENGEO INCORPORATED 6<CELLENT SERVICE SINCE 1971 ORIGINAL fiGURE PRINTED IN COLOR \ PROJBCTNO~ 7096.1.001.01 DATB: ruNE 2006 DRAWN BY: SRP Clll!CKl!DBY: DEB FIGURE NO. REGIONAL FAULTING AND SEISMICITY SHANNON COMMUNITY CENTER DUBUN, CALIFORNIA 4 wg , 9 -f , wg '" '" ... '" ~ w w ~ I- ::> o :l: I- ~ '" w ll: '" w <.> >< w '" o Q W I- o ::> o ~~~( ~. ,,, >P\. "'ir ''': J It ~;~A\ \\ \\ , ,\ '\) . \\ \~ . ~ .\ . I . ~ to.; \\ ...,r~, ".'t ~ g !< '" o "- '" o o ., o w '" ~ ... o l- t} '" z o o t} t:: ii: ~ W m !:: >- << '" "" o z << w ~ o '" !;( :I: "' '" Z <C W :E. >- Z <C 1;; Ii: <C "- ~ '" D W ... o '" ~ ;;5 e o => Q o '" ~ '" W ... I- o Z >- <C '" I- Z W '" ::> o o '" '" i ci w ~ o "- '" 8 ., o w '" z w 1;; '" D D '" potentially ActIve Feults . A N Faults considered to heve been active during Holocene time and to nave a ~ relatively high potentiel for surface rupture; solid line where accur8telyloceted. ............. long dash where approximately located. shorl dash where inferred. dotted ........ where concealed; query (?) indicates additional uncertainty, Evidence of histor- ...... !f- . ie offset indie lied by veer of ellrthquske-aS80eiated event or C for displace- ment caused iJY creeP or possible creep. SpICllal Stuc\l.. Zone 1000n...... 0---0 These ars delineated as straight-line segments that connect encircled lurnirlg - . . points so.,!.s to define spacial studies zone SI..gments. . ' . o [ o FJmT 1000 MBTBRS ~oo I ENGEO o INCORPORATEO EXCELLENT SERVlCE SINCE 1<<711 ORIGINAL nGUR[ PRINTeD IN COLOR PRomcrNO~ 7096.1.001.01 DAm: JUNE 2006 DRAWN BY: SRP CIIIlCKBDBY: DEB FIGURE NO g BASE MAP SOURCE: HART. 1981 EARTHQUAKE FAULT HAZARD ZONE MAP SHANNON coMMUNITY CENTER DUBLIN, CALIFORNIA 5 : rc 109 wg rg - zooe . wg __.J COPYRIGHT C 2006 BY ENGEO INCORPORATED. 'THIS DOCUMENT MAY NOT BE REPRODUCED IN WHOLE OR IN PART BY ANY MEANS WHATSOEVER. NOR MAY IT BE OUOTED OR EXCERPTED WITHOUT THE EXPRESS WRITTEN CONSENT OF ENGEO INCORPORATED, o '" c; z /?: ." c; <= ~ ... '" ~ M C Z n o ... o '" MAIN CALAVERAS FAQL T TRACE, STATE MAP \ :}, MAIN CALAVERAS FAULT ":TRACE, BASED ON SITE STUDIES ~J ," ~l .I?l c, i Th{\ ! ~ I 1,1 t- A N o . o FBET 40 MBTBRS 20 EXPLANATION a I~ ENGINEERED FllL (1973) .g AU.UVIUM Qat Ill$,/ UPPER MIOCENE NONMARINE BEDROCK .i\ // GRADED AREA (CUT AND FIlL) ET-l LOCATION OF ENGEO TRENCH TI'-1 LOCATION OF TERRASEARCH TRENCH APPROXIMAlELOCATION OF HARm SYSTEMS TRENCH EST -1 A N BASE MAP SOURCE: ENGEO INCORPORATED EXCELLENT SERVICE SINCE 1911 SITE GEOLOGIC MAP AND RECOMMEDED SETBACKS SHANNON COMMUNITY CENTER DUBLIN, CALIFORNIA 6 DA1B: JUNE 2006 DRAWNDY: SRP CHIlCXBDDY: DEB ~ ~ ".,lj c l" " '" o ll. '" o u 0; o "' '" 3 "- o .. z "' In Z o u z ~ iX ;0 In In "' '" ll. X "' "' :I: .. .. " o :I: .. 3' i "1 j tS:t' TYPICAL SUBDRAIN SYSTEM - SPREAD FOOTING FOUNDATION ?:i '" '" o z ~ 1:; o In .. " :I: ;0 EXTERIOR WAlL c "' l- Ii; ... u x "' '" o o "' I- o " o IMPERVIOUS PLASTIC SHEET (10 MIL MIN.) 3% TO 5% WlTH1N 5' OF STRUCTURE COMPACl'ED NATIVE SOn.. ,'J>,' "' m !:: SOLID COILEcroR PIPE 4" PERFORATED PIPE In Z ;S '" >- z " >- m I- '" " ll. 0; 3. 1% FALL (MINIMUM) ON ALL TRENCHES AND DRAIN UNES 4, THE CLOSED COLlECTOR AND THE PERIMETER SUBDRAlN CAN BE CONS7RIICTCD IN A SINGLE TRENCH, IF DESIRED. HOWEVER. THE CLOSED COLLECTOR PIPE MUST BE PLACED ABOVE THE SUBDRAIN PIPE, AND IN NO C4SE SHOULD THE TWO SYSTEMS BE INTERCONNECTCD *FIL TER MEDIUM ALTERNA TlVE A - CLASS 2 PERMEABLE MAlERlAL MATERIAl SHAlL CONSIST OF CLEAN, COARSE SAND AND GRAVEL OR CRUSHED STONE, CONFORMING TO THE FOLLOWING GRADING REQUIREMENTS: SIEVE SIZE % PASSING SIEVE 1" 100 314' 90-100 3/8' 40.100 It4 25-40 118 18-33 #30 5-15 #50 Q.7 #200 Q.3 '" o "' .... o :I: ;0 ;!; S u " c o '" f; '" "' m l; z >- " '" I- Z ... ,. " u o o In ~ C "' .. " '" o ll. '" o u ;!; o "' '" 3 >- m '" o g NOTES: 1. ALL PIPE JOINTS SHALL BE GLUED 2. ALL PERFORATCD PIPE PLACED PERFORATIONS DOWN ALTERNA TlVE 8 - CLEAN CRUSHED ROCK OR GRAVEL WRAPPED IN FILTER FABRIC ALL FILTER FABRIC SHALL MEET TIiE FOllOWING MINIMUM AVERAGE ROLl VALUES UNlESS OTHERWISE SPECIAED BY ENGEO: GRAB STRENGTH (ASTM D-4632) MASS PER UNIT MEA (ASTM 0-4751) APPARENT OPENING SIZE (ASTM 0-4751) FLOW RATE (ASTM 0-4491) PUNCTURE STRENGTH (ASTM 0-4833) 180lbs 6 azlyd2 7Q.100 U.S. STD, SIEVE 8Ogallmlrv'lt 80Ibs ENGEO TYPICAL SUBDRAIN SYSTEM - SPREAD FOOTING FOUNDATION PROlECfNO,: 7096.1.001.01 SHANNON COMMUNITY CENTER DATE: JUNE 2006 INCORPORATED EXCELLENT SERVlCE SINCE 1971 DUBLIN, CALIFORNIA DRAWN BY: SRP OlECXBDBY: DEB NO SCALE FIGURE NO o 7 : ra Ing "-\ wg , g , u rom . W(] ,j zoq TYPICAL SUBDRAIN SYSTEM - MAT FOUNDATION EXTERIOR WALL IMPERVIOUS PLASTIC SHEET (10 MIL MIN.) 3% TO 5% WIniIN ISm (5') OF HOUSE ",' SOLID COlLECTOR PIPE FILTER MEDIUM. O.lm (4") PERFORATED PIPE NO TES: " ALL PIPE JOINTS SHALL BE GLUED 2, ALL PERFORATED PIPE PLACED PERFORATIONS DOWN 3. IX FALL (MINIMUM) ON ALL TRENCHES AND DRAIN LINES 4. THE CLOSED COLLECTOR AND THE PERIMETER SUBDRAIN CAN BE CONSTRUCTED IN A SINGLE TRENCH, IF DESIRED. HOWEVER, THE CLOSED COLLECTOR PIPE MUST BE PLACED ABOVE THE SUBDRAIN PIPE, AND IN NO CASE SHOULD THE TWO SYSTEMS BE INTERCONNECTED *F1LTER MEDIUM ALTERNA TIVE A ALTERNA TiVE B CLASS 2 PERMEABLE MATERIAL MATERIAL SHALL CONSIST OF CLEAN. COARSE SAND AND GRAVEL OR CRUSHED STONE. CONFORMING TO THE FOLLOWING GRADING REQUIREMENTS: CLEAN CRUSHED ROCK OR GRAVEL WRAPPED IN filTER FABRIC ALL FILTER FABRIC SHALL MEET THE FOLLOWING MINIMUM AVERAGE ROLL VALUES UNLESS OTHERWISE SPECIFIED BY ENGEO: sieve size I" 3/4" 3/8" #4 #8 #30 #50 #200 % PASSING sieve 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 GRAB STRENGTH (ASTM 0-4632) 180 lb. MASS PER UNIT AREA (ASTM 0-47::>1) 6 oZ/yd2 APPARENT OPENING SIZE (ASTM 0-47::>1) _ 70-100 U,S. STO, SIEVE FLOW RATE (ASTM 0-4491) 80 gol/min/ft PUNCTURE STRENGTH (ASTIA 0-4833) 80 lb. ENGEO INCORPORATED EXCELLENT SERVICE SINCE 1971 TYPICAL SUBDRAIN SYSTEM - MAT FOUNDATION SHANNON COMMUNITY CENTER DUBLIN, CALIFORNIA PR.OJBCTNO,: 7096,1.001.01 DATE: JUNE 2006 DRAWNBY: SRP CllBCKEDBY: DEB NO SCALE FIGURE NO 8 : ro lng wg , 9 u orom . wg Z <0 ;CO I-~ Wz 0::< O;c ::;;1- (/)0:: ..JW 5Clw (/)~> 0..J!!! w..J(/) 6;F- ~< C>:O .~ wo (/)~ O::..J ~~ U 0:: ~~ 0< :O:ow (/)(/)> ..J..JW OF-iii (/)<0 0:00 \1l~~ ~~~ 't~~ Wz ~~ I- MAJOR TYPES KEY TO BORING LOGS DESCRIPTION GRAVELS MORE THAN HALF COARSE FRACTION IS LARGER THAN NO.4 SIEVE SIZE SANDS MORE THAN HALF COARSE FRACTION IS SMALLER THAN NO,4 SIEVE SIZE CLEAN GRAVELS WITH · LITTLE OR NO FINES of:) GRAVELS WITH OVER 12 % FINES CLEAN SANDS WITH LITTLE OR NO FINES SANDS WITH OVER 12 % FINES SILTS AND CLAYS LIQUID LIMIT 50 % OR LESS I t GW - Well graded gravels or gravel-sand mixtures GP - Poorly graded gravels or gravel-sand mixtures GM - Silty gravels, gravel-sand and silt mixtures GC - Clayey gravels, gravel-sand and clay mixtures SW ~ Well graded sands, or gravelly sand mixtures SP - Poorly graded sands or gravelly sand mixtures 4 CLEAR SQUARE SIEVE OPENINGS 3/4" 3" GRAVEL BOULDERS FINE COARSE CONSISTENCY STRENGTH' 0-1/4 1/4-1/2 1/2-1 1-2 2-4 OVER 4 :'::..:::' ,...... ....... ':,:.::..:.... SM - Silty sand, sand-silt mixtures SC - Clayey sand, sand-clay mixtures ML - Inorganic silt with low to medium plasticity CL - Inorganic clay with low to medium plasticity OL - Low plasticity organic silts and clays MH - Inorganic silt with high plasticity CH - Inorganic clay with high plasticity OH - Highly plastic organic silts and clays PT - Peat and other highly organic soils GRAIN SIZES SILTS AND CLAYS LIQUID LIMIT GREATER THAN 50 % HIGHLY ORGANIC SOILS 200 SILTS AND CLAYS U.S. STANDARD SERIES SIEVE SIZE 40 10 SAND MEDIUM FINE RELATIVE DENSITY SANDS AND GRAVELS VERY LOOSE LOOSE MEDIUM DENSE DENSE VERY DENSE MOISTURE CONDITION DRY MOIST WET SATURATED BLOWS/FOOT is.P.T.} 0-4 4-10 10-30 30-50 OVER 50 Absence of moisture, dusty, dry to touch Damp but no visible water Visible freewater Below the water table SAMPLER SYMBOLS Modified California (3" O.D.) sampler California (2,5" O,D.) sampler S,P.T.' - Split spoon sampler Shelby Tube . El ~ []] I] l3J ~ NR Continuous Core Bag Samples Grab Samples No Recovery ENGEO INCORPORATED EXCElJ.ENT SERVICE SINCE 1971 COARSE SILTS AND CLAYS VERY SOFT SOFT MEDIUM STIFF STIFF VERY STIFF HARD BLOWS/FOOT is.PT.) 0-2 2-4 4-8 8-15 15-30 OVER 30 MINOR CONSTITUENT QUANTITIES (BY WEIGHT) TRACE Particles are present, but estimated to the less than 5% SOME 5 to 15% WITH 15 to 30% ........Y 30 to 50% LINE TYPES Solid - Layer Break Dashed - Gradational or approximate layer break GROUND-WATER SYMBOLS 5l.. Groundwater level during drilling .!: Stabilized groundwater level (S.P.T.) Number of blows of 140 lb. hammer falling 30" to drive a 2-inch 0.0. (1-318 inch LD.) sampler , Unconfined compressive strength in tons/sq. It.. asterisk on log means detennined by pocket penetrometer ENGEO NCORPORATED Geotechnical Exploration Shannon Community Center Dublin, CA 7096.1.001,01 LOG OF BORING 1-B1 DATE DRillED: December 15,2005 HOLE DEPTH (FT): 19,5 fl. HOLE DIAMETER: 4 in. SURF ElEV (FT-MSl): 395.5' lOGGED I REVIEWED BY: JE/AK DRilLING CONTRACTOR: RAM DRilLING METHOD: Solid Flight Auger HAMMER TYPE: 140#/30" drop '" (jj lii ell ell (jj c.. u. :E ~ ,5 .5 ell .<= .<= 0. a. a. E ell ell III 0 0 U) 0 0 .J::. 15 0, <= <:x 0 :E elle u. ell~ ~... 1::1: Cl -c.. Qi - ~ U)c.. '0 <= 00) 'O0l .c > ::l ()'ijj OJ 1:) E OJ 0 ll!~ <:- >- ...J () '2 t.;:::(1) DESCRIPTION U) Q; .3~ :J <:t;:: ~ o' Cl ~ .!!l'O ~13 Oc 0 ~c 0 CD oB <:(/) ...J :J~ Asphalt Aggregate Base SANDY GRAVEL (GW), light brown, wet, coarse-grained (Fill) STLTY-CLAY'(C-H)~bia~k':v~ry-Stiicn;oist----------------------------------------------------------- 29 25.3 94 1.4 5 2 SiL;=STONEci~ht-oiiv~-b-r(;wn:-.;.;~ak~-d;;Piy.;eathered------------------.--.------------------.--- 53 23.6 4.5+ . 10 3 4 61 4.5+ . 15 5 ~ Moderately strong in sample 80 21.5 4.5+ . 0 Ll ~ 20 6 -en 0> Bottom of boring approximately 19.5 feet .9 No groundwater encountered during drilling 0> c -g !!l ~ 0 7 0 Hi 0 ~ 25 !> {J '" 'e 8 ll. '" > ~ $ 0 ~ "t ~ 9 0 30 1.0" \;.:'~t., ENGEO NCORPORATED Geotechnical Exploration Shannon Community Center Dublin, CA 7096,1.001,01 LOG OF BORING 1-B2 LOGGED / REVIEWED BY: JE/AK DRILLING CONTRACTOR: RAM DRILLING METHOD: Solid Flight Auger HAMMER TYPE: 140#/30 .. drop DATE DRILLED: December 15, 2005 HOLE DEPTH (FT): 14.5 ft, HOLE DIAMETER: 4 in. SURF ELEV (FT-MSL): 406' .s::: '0 0, 'E c::x 0 1: ee u. .l!!~ 5~ Cl -0. 0 Qi 1: ~ en 0. "0 III .0 > ::l (j'ii) Q)"O E Q) 0 l!!~ ~ c::- ...J l;::Q) >- Iii (j .a~ c:: c::l;:: en ~ ::>13 o' Cl ~ ,!!l"O U<;::- 0 0 ~~ ~c. c::", ...J ii:i o~ ::>::::. l!! Q) Q) :2 .5: .r:: i5. Q) o a; Q) u. .5: .r:: i5. Gl o Q) c. >- I- Q) a. E III en DESCRIPTION o 0 Asphalt Aggregate Base SILTY CLAY (CH), black, moist SANDY SILTSTONE, light brown, weak to moderately strong, deeply weathered 56 15.7 114 4.5+' 5 Grades more/less sand 2 60 17.1 4.5+' 10 3 4 71 15 Bottom of boring approximately 14.5 feet No groundwater encountered during drilling 5 (; .c N ~ 20 6 '" .3 '" .1; (; S! 0 8 7 1!j 0 r- ID en 0 25 !:= ~ 'e- 8 n. " > ~ (; "' 8 ~ 9 0 30 ENGEO NCORPORATED Geotechnical Exploration Shannon Community Center Dublin, CA 7096,1.001.01 Gi CD u. ,EO .L: 1i CD o o f!! CD Gi ::a .EO .L: 1i CD o o Void under wood platform 0) a. ~ 0) C. E <11 (J) "to$( LOG OF BORING 1-B3 DATE DRillED: December 15, 2005 HOLE DEPTH (FT): 24.5 ft. HOLE DIAMETER: 4 in, SURF ElEV (FT-MSl): 406.7' lOGGED / REVIEWED BY: JE/AK DRilLING CONTRACTOR: RAM DRilLING METHOD: Solid Flight Auger HAMMER TYPE: 140#/30 " drop .L: 0 0, 'E cx 0 1: !e u. O)~ "E:E 0> -a. Qj ~ en a. (5 'E 00> '0<11 .a > ::3 U'Qi 0)'0 E 0) 0 ~3: c_ >- ..J U 'c ~Q) DESCRIPTION en :u .a~ ::)U- co; 3: ,!!!'O o' 0> ~ 0 ~c 0<;::- 0 iii ~o. Cu> ..J o~ ::)::;:. I .' "';;;; ENGEO NCORPORATED Geotechnical Exploration Shannon Community Center Dublin, CA 7096.1,001.01 LOG OF BORI NG 1-B4 DATE DRILLED: December 15, 2005 HOLE DEPTH (FT): 19 ft. HOLE DIAMETER: 4 in. SURF ELEV (FT-MSL): 406.5' LOGGED 1 REVIEWED BY: JE/AK DRILLING CONTRACTOR: RAM DRILLING METHOD: Solid Flight Auger HAMMER TYPE: 140#/30" drop .c -0 C. ;: c:x e! 0 1:: alo LL .!!z;- ~c.. a; Q) Q) 0) a; - C:.c en 0. al 0. 0 Q; .... 00) ~ LL :2 ~ > c: U"Gj 'O11l .c ::J al'O .S .S E al 0 f.I!:: .... c:- al ...J t;::Q) .c .c 0. DESCRIPTION >- Qi U .a~ "c c:<;:: en ;:)c;::- o' C. C. E 0) ~ ~ .~"tJ Uc;::- al Q) 11l 0 ~c ~u C:oo 0 0 en ...J co 0.3: ;:)~ 0 0 SILTY CLAY (CH), black, very stiff, moist Increased moisture with depth 46 22.5 102 4.0 . 5 SILTY CLAY (CL), dark brown, very stiff, moist (%<#200 = 76%) -CLAyWiTH-SAN-D-(CL)~~ii-~e--browj,~-v~;Y stiff~-moist:wit-h-iracesubro~;:;d~d-fi;:;e------------ pebbles. 2 30 23 1.5 . 10 3 -siLTs;:oNE~-i~htoii~e-brown-,-we;k.deep-iY-~eatiie-red--m--____n_______________________________ 4 71 15 5 l5 .D -<i "? "' Ol o -' Ol C 'C o 9:l o 8 ~ o r-- <5 '" o ~ tl " >[ Q. " > ~ o Moderately strong in sample 55-6" 19.2 20 6 Bottom of boring at approximately 19 feet No groundwater encountered during drilling 7 25 8 8 <)I r-- o 30 9 z,01 ENGEO N COR P 0 R A. TED Geotechnical Exploration Shannon Community Center Dublin, CA 7096.1,001.01 LOG OF BORING 1-B5 DATE DRILLED: December 15, 2005 HOLE DEPTH (FT): 14.5 ft. HOLE DIAMETER: 4 in. SURF ELEV (FT-MSL): 406.5' LOGGED I REVIEWED BY: JE/AK DRILLING CONTRACTOR: RAM DRILLING METHOD: Solid Flight Auger HAMMER TYPE: 140#130" drop .r: 0 0, .... Cx UI 0 C 1: ~e Qj CD lL 2~ OJ ....c. Qj Q) - s~ ~ enC. Q) c. 0 ~ 'E u. :2 ~ U'ijj "cco .c Q) :J Q)"C .E .E Q) E ..J 0 !!!3: .... c- >- U 'c l;:::Q) .r: .r: i5.. DESCRIPTION (f) ... .a~ :::le;::- Cl;::: 0. 0. E 2 3: .!!l"C o' OJ Oe;::- Q) Q) co .3 ~ 0 ~c ~O CUI 0 0 en iii oS :::l::::. 0 0 5" thick concrete walkway CLAYEY GRAVEL (GC), grey, wet, coarse-grained (FILL) SiLTSTO-NEj-ghioiive-t;ro,;;n,-';;eak-iQ-moderaieiY-strong:'deepiyweaitii;red--------------. 73 18.1 110 5 2 Moderately strong in sample 75 21.3 10 3 4 49 15 Bottom of boring at approximately 14.5 feet No groundwater encountered during drilling 5 5 .0 .n ~ 20 6 -;;; '" .9 '" .!; 5 !!! 0 8 7 ~ 0 ~ 0 25 ~ {j Q) 'e- 8 c.. Q) .2: n :J; 0 <D 0 0 N ..:. , 9 0 30 )5 to ENGEO NCORPORATED Geotechnical Exploration Shannon Community Center Dublin, CA 7096,1,001.01 LOG OF BORING 1-B6 DATE DRILLED: December 15, 2005 HOLE DEPTH (FT): 14.5 ft, HOLE DIAMETER: 4 in. SURF ELEV (FT-MSL): 399.5' LOGGED / REVIEWED BY: JElAK DRILLING CONTRACTOR: RAM DRILLING METHOD: Solid Flight Auger HAMMER TYPE: 140#/30 " drop .c (5 c, c: c:x l!! 0 .... ~e u.. Gl~ .c a; ~ Gl 'EE 0) ....a. 41 Gl a. '0 Qj c: 00) ~ Cf)a. ~ ~ t) '0; '0 III u.. J:l > ::> ~J2 .5: .5 E .3 0 l!13: .... Gl >- t) c: l;::Gl .c .c 0. DESCRIPTION Cf) .... .a~ ::>'tj C:l;:: Q. Q. E ~ ~ ,!!!'O o' Cl Oc 41 Gl III 0 ~ ~c ~o. C:(/l 0 0 Cf) ...J iii o~ ::>:::. 0 0 SILTY CLAY (CH), black, stiff, moist. with trace rootlets ( LL = 61, PI = 45) 4 Increased moisture in sample 33 26.6 93.2 2.75. 5 2 -SiL;=Y-CLAyWiTH-SAND(C-L}~-brown~-veiY-stiifmbist~-fiiie:graini;d-;;nd---------------- 41 3.75' 10 3 24 28.1 1.25. 15 Bottom of boring at approximately 14.5 feet Groundwater encountered at 10 feet during drilling 5 l5 .c cO ~ 20 6 '" '" .9 '" C 'C 0 !!l 0 8 7 ~ 0 fi5 ~ 25 !i; ~ 'e- 8 11. " .2: ~ (; 8 'i' .... g 0 30 1.--0 .<Pt. ENGEO NCORPORATED Geotechnical Exploration Shannon Community Center Dublin, CA 7096,1.001,01 LOG OF BORING 1-B7 DATE DRILLED: December 15, 2005 HOLE DEPTH (FT): 14.5 ft. HOLE DIAMETER: 4 in, SURF ELEV (FT-MSL): 401.5' LOGGED 1 REVIEWED BY: JE/AK DRILLING CONTRACTOR: RAM DRILLING METHOD: Solid Flight Auger HAMMER TYPE: 140#/30 .. drop l!! Qi ~ (J) Q) (J) 0. U. :2 >. I- .5 .5 (J) ~ ~ a. a. a. E Q) (J) as 0 0 CJ) 0 0 Asphalt Aggregate Base ~ 15 C, c: C:x 0 :E ~e u. Ql~ c:E 01 -0. Qj - ~ CJ)0. (5 c: 001 '0 as .0 > ::s U'w Ql'O E Ql 0 ~:: c:_ >. ~ U 'c l;:::Ql DESCRIPTION ... 2~ C:~ CJ) Q) :: ::>.;::- o' 01 ~ .!!l"O 0.;::- 0 0 ~c ~o C:rn ~ iii oS ::>::::- CLAY (CH), black, medium stiff, moist (FILL) 5 2 10 3 CLAYEY SILT (ML), light grey, very stiff, moist (WEATHERED SILTSTONE) Increased moisture with depth 4 15 2.5 . 15 5 ~ 17 2.75 . 0 .0 ,..; ~ 20 6 '<ii Cl 0 -' Cl SILTSTONE, olive brown <:: ." 0 ~ 0 8 7 1ll 81 0 t- l1i Ol 0 25 Bottom of boring at approximately 24.5 feet ~ 13 No groundwater encountered during drilling Q) 'e 8 "- Q) > ~ 0 '" 8 ~ t- 9 0 30 3000 l;:' Ul Co - CI) ... ~ 2000 Ul Ul l!! Co iij ~ 1000 15~1 "1 Unconfined Compression Test ASTM Test Method 02166 4000 o o 5 10 15 20 Percent Strain Unconfined Compressive Strength: 2870 pst 1.4 tst Sample Description: Very dark grayish brown CLAY. In itial Diameter: Initial Height: Strain Rate: Total Strain: 2.420 in. 5.06 in. 1.476 %/min 12.43 % Sample Number: Dry Unit Weight: Moisture Content: Depth ot Sample: B1@4' 94.3 pct 25.3 % 4.0 ft. EN GEO SHANNON PARK Job No.: Sample Number: Figure No. 7096.1.001.01 INCORPORATED Date: B1@4' 1/4/2006 Dublin, California ~b4 (Po ~D . Unconfined Compression Test ASTM Test Method 02166 8000 6000 c- UI E:: Gl .. ::::l 4000 UI UI E Q. ca 'x < ---- ~ 2000 Ii 0 . 0 5 10 15 20 Percent Strain Unconfined Compressive Strength: 2670 psf 1.3 tsf Sample Description: Very dark grayish brown silty CLAY to CLAY. Initial Diameter: 2.420 in. Sample Number: 83@4' Initial Height: 5.10 in. Dry Unit Weight: 98.6 pcf Strain Rate: 1.425 %/min Moisture Content: 23.9 % Total Strain: 20.05 % Depth of Sample: 4.0 ft. Job 7096.1.001.01 Figure EN GEO SHANNON PARK No.: No. Sample 83@4' Number: INCORPORATED Dublin, California Date: 1/4/2006 ENGEO Incorporated SULFATE TEST RESULTS CAL TRANS Test Method 417 Tested By: DS Project Name: Shannon Park Project Number: 7096,1.001,01 Date: January 6. 2006 Measurements less than 15 mg/kg are reported as Not Detectable (ND) Sample Number 1 2 Water Soluble Sulfate (S04) in Soil % by Weight 0.008 0,013 Sam Ie Location B4 @ 3,5' B1 @4' Matrix soil soil mg/kg 77 130 Office: 2010 Crow Canyon Place, Suite 250, San Ramon, CA 94583 Laboratory: 2057 San Ramon Valley Boulevard, San Ramon, CA 94583 \~i U)t1 LIQUID AND PLASTIC LIMITS TEST REPORT 60 /" Dashed line indicates the approximate ,,- 50 upper limit boundary for natural soils c,<(<. {'tJ 40 0 ~ ~ 30 () i= en ::i 20 ,,-"- 0.. ,,- ,,-"- ,,- ,,-"- 10 ,,- 7 CL-Ml ML or OL MH or OH 4 - I 10 30 50 70 90 110 UQUID UMIT 70 - - - .. ... 64 I- Z t:! 58 z o () c:: ~ 52 ~ 46 405 10 NUMBER OF BLOWS 20 25 30 40 MATERIAL DESCRIPTION LL . Very dark grayish brown silty CLA Y to CLAY with sand. 48 PL 12 PI 36 %<#40 %<#200 78.8 USCS CL-CH . Very dark grayish brown CLA Y with some sand. 61 16 45 CH Project No. 70%.1.001.01 Client: Project: Shannon Park Remarks: . B3 @ 4.0 feet . B6 @ 4.0 feet . Source: . Source: Sample No.: B3 @ 4' Sample No.: B6@4' ENGEO INCORPORATED GEOlECHNtCAL AND ENVIRONMENTAL CONSULTANTS MA"IERlALS TESTING Project name: Project number: Sample 1 2 STANDARD pH OF SOILS ASTM 0 4972-89 Shannon Park 7096.1.001.01 Description Very dark grayish brown CLAY Very dark grayish brown sandy CLAY Date: Tested by: BV A Location/Sou rce/Date B1 @4' B4 @ 3,5' 1/6/2006 pH 8.42 8.26 tO~ '2-0 tt Particle Size Distribution Report .E "' .5 .E.5~.5i "N ;l '" ;; ~ ~ ; i g ~ g ; ; ~ .5 .5 t:! ~ 0::: w z u.. I- Z W () 0::: w 0.. '" - - '" - 100 90 80 \: 70 ~ 60 . ~ ~ 50 r.. '- 40 ""c ~ 30 20 10 0 500 100 10 1 0,1 0.01 ~ 0.001 GRAIN SIZE - mm I % COBBLES I % GRAVEL I % SAND- % SILT T % CLAY I I I I 42.0 I 36.8 I SIEVE SIZE #200 PERCENT RNER 78.8 SPEC.* PERCENT PASS? (X=NO) Soil DescriDtion Very dark grayish brown silty CLAY to CLAY with sand. Trace organics. PL= 12 Atterbera Limits LL= 48 PI= 36 08S= 030= Cu= Coefficients 060= 0.0326 015= Cc= Classification AASHTO= 050= 0,0085 010= uses= CL-CH Remarks (no specification provided) Sample No.: 83 @ 4' Location: Source of Sample: Date: 01/06/06 Elev.lDepth: 4,0 feet ~NGEO GEOTECHNlCALAND ~J ENVIRONMENTAL CONSULTANTS INCORPORATED MA~STE~G Client: Project: Shannon Park . Pro'ect No: 70%.1.001.01 \~G Particle Size Distribution Report .E '" E .5 .Eg. .E.E .E.E MN ~~~ ;{ o .. ~ ~ ; i o 0 0 o .. 0 ; ;; ~ a::: w z u.. I- Z W U a::: w n.. ~ ~ - 100 90 , 60 70 . tl 60 t 50 '0. b. ~ 40 P:- c( "a 30 """0 20 10 0 500 100 10 1 0.1 0.01 ~ 0.001 GRAIN SIZE - mm I % COBBLES I % GRAVEL I % SAND % SILT I % CLAY I I I 1 45.1 I 31.2 I SIEVE SIZE #200 SPEC: PERCENT PASS? (X=NO) Soil Description Very dark grayish brown CLA Y with sand, PERCENT ANER 76,3 PL= Atterbera Limits LL= PI= 085= 030= 0.0018 cu= Coefficients 060= 0.0389 015= cc= Classification AASHTO= 050= 0.0207 010= USCS= Remarks (no specification provided) Sample No.: 84 @4' Location: Source of Sample: Date: 01106/06 Elev./Depth: 4.0 feet ~NGEO GEOTECHNlCALAND ~j ENVIRONMENTAL CONSULTANTS INCORPORATED MATIrnMLSTESTING Client: Project: Shannon Park Pro'ect No: 70%.1.001.01 ....:l... GROUI"iDWATElt LEVEL IN TRENCHES E D 10~ 211 3D' 40' so- sa' , 70' sa aO' 100. ~10' w 1211 --" TRENCH T.l WATER SEEP'lN.G AT 6..S~ O~PTH BEGUfN [riG ABOUT ST 1'1_ 15+00 FilL: OARK G.RAY FAT eLA v WITH CONCRETE AKC CEBB1S FATCLA.Y~ BLACK; ORGANIC; FJRMTOSTIr:F; DRY TO DAM NO GROUt~OWATER TO '9' OEPTH OU'JE~CK -- aCNe GM'1 --- 395 ~ w :w '\L 39D ~ z o \ S1 L. TV CLAY: GIlEEN1SH l:l85 ~ "GJlAY;mFF;MrifST 3BD w SANOSTONE:: DARK GREENiS'H GRAV; CLOSEt Y f .R:ACTU:RED; 1= R I ABLE; co- Hl:S5Vt: BUT BReAKS IN flPiGEflS'1"O WET SAN 0; \I'a'ET: G RAD'ES ONA RC rNTO RESIDUAL 51 L TV CLAY ;;;,C' s rL TV etA Y: OAR I( YE LLOWISH 'B ROWN; LOW FLASTlCITY; STIFF; OAMPTO MOIST; PART!ALLY SLICK. ENS C ED. MAYBE aUE TO D-ESl CCA- TJON GRAVELLY CLAY: MOO. YEL.LOW.SH eROWN~ WlTH oXles STAINS; 1= lHE TO .M ED. SA.,~ 0- STONE aFlA VEl... ROU HDED ~ATHERED ~ f · I POCKET OF SANDY GAAVEL ' \ SILTY CLAY: lOW PtASTlCITY J,..,.. CREAS I riG UPWAftO; MOIST TO WET; ABUNOANTL Y SL1CX'ENSlt)ED. moo P ROMI RENT CO/'IUUGA TE 5E:rS OF VE RTICA L Sl./ CK SURfACES 0 Rl ENT. ED 30-'+ TO TRENCH WAL.1.; 'NO PROM- I NENT SH"EAR ZONl:S 0 R f RACTU RES FAT CLAY~ EXPANSIVE; lNTERNAlLY SLrC'KEN- S[DEt); SLABS Off 'PARA l.l t:1.. TO TREEiCH WAt 1.5 ~'lHERE WET; CONTA11r11Ss:HEAR P'LANES OlPPtNG 2 . ~ DOWNSTfI E.A.1d. FROM CREE" MOVEMENT. TR~NCH T. ~ --- .. ... o ...... .. l- w UI 5 u.. z - :r: 10 Ii: w c S1l TV CLAY: MOOERATE BROMl ETC. I "\~'ffft;;...... 'OCKE.T 0 F SAN 0 -L .. ...... --- ,"" ". ~",.,. ---.....-....- --~---_.....-- SllTY CLAY: MCD-ERATE BROWJsl;GRAD'NETO OL.IVE SROWN AT STREAM CHANNEL~ PlAsTlC]TY VARIES LDWTO MEDIUM; MEDIUM PlASTIC: 'F ACIES IS LNTE.RNALl Y SLlCK'ENSrOED; co N- TAtNS M.a.N'Y STRJNGERS OF HO'FUZCNTA1.LY B.EDDED GRAVELLY CLAY AND SANOY SIt T. 1'5 CALAVERAS FA.ULT BACKHOE TRE:NCH LOGS SHANNON AVENUE SITE DUBUN..r::A 1971 EARTH SCEEJ.:.JCES ASSOClA'TES Pa!a Alto. C21t~crnia ,.,AJ\IY THSN HOR3Z0NTA 1. STA [t~GE AS 0 F . GRAVEL TH R01.JGHOUT U:PP'E A CLAY UNITS; NO EVfDENCE OF VERTICAL SHeARTNG [N TRENCH. \ SANDY SlLTY CLAY: M.OTTLED GREENISH GRAV . AND ORANGE~ LDW,Pl.ASTlCITY; HO'R1ZONi A 1.- 1 Y STRA TtFl ED; R ESlDUA L SOl L [i}. SILTY CLAY: aLIVE 9itOWN~ lNTERNAt.1.. Y !L1CKENSToen. 30 \ 40 \ 50 \ '0 \ 10 \ 80 \ go \ fOO \ __ .400 __ 39; 5 75- E. ~. 'f roof!, Black Claqeq 501 k' e. wifh f. era(,;J de<;iCC{/ /0(1 k fraqmenh roC __ 3'30 __ 3JS __ 380 __ 375 -,..2 .:---- . C/aq with . mock Silfq d disiccaf10n I roofs an qrave. , cracks __380 \ \ '\ \ '\ ~375 \ 100 -r-l. 5ilf wifh some - b.....Wt1 Sandy /. Of/ire y'elfOUlish I v olidated 1m ravel, poorlq coM q . d fhrOuqhauf \ sf" me \ no 110 370 . ~ Vert. -- '.5' HOfIZ. y~ ~ \ \ I!O \ '40 . \ \10 uh 2-0' EN:3EO INCORPORATED GUIDE CONTRACT SPECIFICATIONS PART I - EARTHWORK PREFACE These specifications are intended as a guide for the earthwork performed at the subject development project. If there is a conflict between these specifications (including the recommendations of the geotechnical report) and agency or code requirements, it should be brought to the attention of ENGEO and Owner prior to contract bidding. PART 1- GENERAL 1.01 WORK COVERED A. Grading, excavating, filling and backfilling, including trenching and backfilling for utilities as necessary to complete the Project as indicated on the Drawings. B. Subsurface drainage as indicated on the Drawings. 1.02 CODES AND STANDARDS A. Excavating, trenching, filling, backfilling, and grading work shall meet the applicable requirements of the Uniform Building Code and the standards and ordinances of state and local governing authorities. 1,03 SUBSURFACE SOIL CONDITIONS A. The Owners' Geotechnical Exploration report is available for inspection by bidder or Contractor. The Contractor shall refer to the findings and recommendations of the Geotechnical Exploration report in planning and executing his work. 1.04 DEFINITIONS A. Fill: All soil, rock, or soil-rock materials placed to raise the grades of the site or to backfill excavations. B. Backfill: All soil, rock or soil-rock material used to fill excavations and trenches. C. On-Site Material: Soil and/or rock material which is obtained from the site. 7096,1.001.01 June 8, 2006 1 11 i~~ INCORPORATED D. Imported Material: Soil and/or rock material which is brought to the site from off-site areas. E. Select Material: On-site and/or imported material which is approved by ENGEO as a specific-purpose fill. F. Engineered Fill: Fill upon which ENGEO has made sufficient observations and tests to confirm that the fill has been placed and compacted in accordance with specifications and requirements. G. Degree of Compaction or Relative Compaction: The ratio, expressed as a percentage, of the in-place dry density of the fill and backfill material as compacted in the field to the maximum dry density of the same material as determined by ASTM D-1557 or California 216 compaction test method. H. Optimum Moisture: Water content, percentage by dry weight, corresponding to the maximum dry density as determined by ASTM D-1557. 1. ENGEO: The project geotechnical engineering consulting firm, its employees or its designated representatives. 1. Drawings: All documents, approved for construction, which describe the Work. 1.05 OBSERV A nON AND TESTING A All site preparation, cutting and shaping, excavating, filling, and backfilling shall be carried out under the observation of ENGEO, employed and paid for by the Owners. ENGEO will perform appropriate field and laboratory tests to evaluate the suitability of fill material, the proper moisture content for compaction, and the degree of compaction achieved. Any fill that does not meet the specification requirements shall be removed and/or reworked until the requirements are satisfied. B. Cutting and shaping, excavating, conditioning, filling, and compacting procedures require approval of ENGEO as they are performed. Any work found unsatisfactory or any work disturbed by subsequent operations before approval is granted shall be corrected in an approved manner as recommended by ENGEO. C. Tests for compaction will be made in accordance with test procedures outlined in ASTM D-1557, as applicable. Field testing of soils or compacted fill shall conform with the applicable requirements of ASTM D-2922. D. All authorized observation and testing will be paid for by the Owners. 7096.1.001.01 June 8, 2006 2 \ 12 tfb Z.O?f EM3EO INCORPORATED 1.06 SITE CONDITIONS A. Excavating, filling, backfilling, and grading work shall not be performed during unfavorable weather conditions. When the work is interrupted by rain, excavating, filling, backfilling, and grading work shall not be resumed until the site and soil conditions are suitable. B. Contractor shall take the necessary measures to prevent erosion of freshly filled, backfilled, and graded areas until such time as pennanent drainage and erosion control measures have been installed. PART 2 - PRODUCTS 2.01 GENERAL A. Contractor shall furnish all materials, tools, equipment, facilities, and services as required for performing the required excavating, filling, backfilling, and grading work, and trenching and backfilling for utilities. 2.02 SOIL MA TERlALS A. Fill 1. Material to be used for engineered fill and backfill shall be free from organic matter and other deleterious substances, and of such quality that it will compact thoroughly without excessive voids when watered and rolled. Excavated on-site material will be considered suitable for engineered fill and backfill if it contains no more than 3 percent organic matter, is free of debris and other deleterious substances and conforms to the requirements specified above. Rocks of maximum dimension in excess of two- thirds of the lift thickness shall be removed from any fill material to the satisfaction of ENGEO. 2. Excavated earth material which is suitable for engineered fill or backfill, as determined by ENGEO, shall be conditioned for reuse and properly stockpiled as required for later filling and backfilling operations. Conditioning shall consist of spreading material in layers not to exceed 8 inches and raking free of debris and rubble. Rocks and aggregate exceeding the allowed largest dimension, and deleterious material shall be removed from the site and disposed off site in a legal manner. / 3. ENGEO shall be immediately notified ifpotential hazardous materials or suspect soils exhibiting staining or odor are encountered. Work activities shall be discontinued Within the area of potentially hazardous materials. ENGEO environmental personnel 7096.1.001.01 June 8, 2006 3 \-r, Ob ~O~ EM:3EO INCORPORATED will conduct an assessment of the suspect hazardous material to determine the appropriate response and mitigation. Regulatory agencies may also be contacted to request concurrence and oversight. ENGEO will rely on the Owner, or a designated Owner's representative, to make necessary notices to the appropriate regulatory agencies. The Owner may request ENGEO's assistance in notifying regulatory agencies, provided ENGEO receives Owner's written authorization to expand its scope of services. 4. ENGEO shall be notified at least 48 hours prior to the start of filling and backfilling operations so that it may evaluate samples of the material intended for use as fill and backfill. All materials to be used for filling and backfilling require the approval of ENGEO. B. Import Material: Where conditions require the importation of fill material, the material shall be an inert, nonexpansive soil or soil-rock material free of organic matter and meeting the following requirements unless otherwise approved by ENGEO. Gradation (ASTM D-421): Sieve Size Percent Passing 2-inch 100 #200 15 - 70 Plasticity (ASTM D-4318): Liquid Limit Plasticity Index <30 < 12 Swell Potential (ASTM D-4546B): Percent Heave Swell Pressure (at optimum moisture) < 2 percent < 300 psf Resistance Value (ASTM D-2844): Minimum 25 Organic Content (ASTM D-2974): Less than 2 percent A sample of the proposed import material should be submitted to ENGEO for evaluation prior to delivery at the site. 2.03 SAND A. Sand for sand cushion under slabs and for bedding of pipe in utility trenches shall be a clean and graded, .washed sand, free from clay or organic material, suitable for the intended purpose with 90 to 100 percent passing a No. 4 U.S. Standard Sieve, not more 7096.1.001.01 June 8, 2006 4 20Q EM3EO INCORPORATED than 5 percent passing a No. 200 u.s. Standard Sieve, and generally confonning to ASTM C33 for fme aggregate. 2.04 AGGREGATE DRAINAGE FILL A. Aggregate drainage fill under concrete slabs and paving shall consist of broken stone, crushed or uncrushed gravel, clean quarry waste, or a combination thereof. The aggregate shall be free from fines, vegetable matter, loam, volcanic tuff, and other deleterious substances. It shall be of such quality that the absorption of water in a saturated surface dry condition does not exceed 3 percent of the oven dry weight of the samples. B. Aggregate drainage fill shall be of such size'that the percentage composition by dry weight as determined by laboratory sieves (U. S. Series) will conform to the following grading: Sieve Size 112- inches I-inch #4 Percentage Passing Sieve 100 90 - 100 0-5 2.05 SUBDRAINS A. Perforated subdrain pipe of the required diameter shall be installed as shown on the drawings. The pipe(s) shall also conform to these specifications unless otherwise specified by ENGEO in the field. Subdrain pipe shall be manufactured m accordance with one of the following requirements: Design depths less than 30 feet - PerforatedABS Solid WallSDR35 (AS1MD-2751) - Perforated PVC Solid Wall SDR 35 (AS1M D-3034) - Perforated PVC A-2000 (AS1M F949) - Perforated Corrugated HDPE double-wall (AASHTO M-252 or M-294, Caltrans Type S, 50 psi minimum stiffuess) Design depths less than 50 feet - Perforated PVC SDR 23.5 Solid Wall (AS1M D-3034) - Perforated Sch. 40 PVC Solid Wall (AS1M-1785) - Perforated ABS SDR 23.5 Solid Wall (AS1M D-2751) - Perforated ABS DWV/Sch. 40 (ASTM D-2661 and D-1527) - Perforated Corrugated HDPE double-wall (AASHTO M-252 or M-294, Caltrans Type S, 70 psi minimum stiffuess) 7096.1.001.01 June 8, 2006 5 I ~16 a,b z 0 Itlt, EM3EO INCORPORATED Design depths less than 70 feet Perforated ABS Solid Wall SDR 15.3 (ASTM D-2751) - Perforated Sch. 80 PVC (ASTM D-1785) - Perforated Corrugated Aluminum (ASTM B-745) B. Permeable Material (Class 2): Class 2 permeable material for filling trenches under, around, and over subdrains, behind building and retaining walls, and for pervious blankets shall consist of clean, coarse sand and gravel or crushed stone, conforming to the following grading requirements: Sieve Size Percentage Passing Sieve I-inch %-inch 3/8-inch #4 #8 #30 #50 #200 100 90 - 100 40 - 100 25 - 40 18 - 33 5 - 15 0-7 0-3 C. Filter Fabric: All filter fabric shall meet the following Minimum Average Roll Values unless otherwise specified by ENGEO. Grab Strength (ASTM D-4632) ............................................... 180 Ibs Mass Per Unit Area (ASTM D-4751) .....................................6 ozJyd2 Apparent Opening Size (ASTM D-4751) ............................... 70-100 U.S. Std. Sieve Flow Rate (ASTM D-4491) ....................................................80 gallmin/tt2 Puncture Strength (ASTM D-4833) ........................................ 80 lbs D. Vapor Retarder: Vapor Retarders shall consist of PVC, LDPE or HDPE impermeable sheeting at least 10 mils thick. 2.06 PERMEABLE MATERIAL (Class 1; Type A) A. Class 1 permeable material to be used in conjunction with filter fabric for backfilling of subdrain excavations shall confonn to the following grading requirements: 7096.1.001.01 June 8, 2006 6 \~~o INCORPORATED Sieve Size Percentage Passing Sieve %-inch Y2-inch 3/8-inch #4 #8 #200 100 95 - 100 70 - 100 0-55 0-10 0-3 PART 3 - EXECUTION 3.01 STAKING AND GRADES A. Contractor shall lay out all his work, establish all necessary markers, bench marks, grading stakes, and other stakes as required to achieve design grades. 3.02 EXISTING UTILITIES A. Contractor shall verify the location and depth (elevation) of all existing utilities and services before performing any excavation work. 3.03 EXCAVATION A. Contractor shall perform excavating as indicated and required for concrete footings, drilled piers, foundations, floor slabs, concrete walks, and site leveling and grading, and provide shoring, bracing, underpinning, cribbing, pumping, and planking as required. The bottoms of excavations shall be firm undisturbed earth, clean and free from loose material, debris, and foreign matter. B. Excavations shall be kept free from water at all times. Adequate dewatering equipment shall be maintained at the site to handle emergency situations until concrete or backfill is placed. C. Unauthorized excavations for footings shall be filled with concrete to required elevations, unless other methods of filling are authorized by ENGEO. D. Excavated earth material which is suitable for engineered fill or backfill, as determined by ENGEO, shall be conditioned for reuse and properly stockpiled for later filling and backfilling operations as specified under Section 2.02, "Soil Materials." E. Abandoned sewers, piping, and other utilities encountered during excavating shall be removed and the resulting excavations shall be backfilled with engineered fill as required by ENGEO. 7096.1.001.01 June 8, 2006 7 11lvb J{)Pf ENC3EO INCORPORATED F. Any active utility lines encountered shall be reported immediately to the Owner's Representative and authorities involved. The Owner and proper authorities shall be pennitted free access to take the measures deemed necessary to repair, relocate, or remove the obstruction as determined by the responsible authority or Owner's Representative. 3.04 SUBGRADE PREP ARA nON A. All brush and other rubbish, as well as trees and root systems not marked for saving, shall be removed from the site and legally disposed of. B. Any existing structures, foundations, underground storage tanks, or debris must be. removed from the site prior to any building, grading, or fill operations. Septic tanks, including all drain fields and other lines, if encountered, must be totally removed. The resulting depressions shall be properly prepared and filled to the satisfaction ofENGEO. C. Vegetation and organic topsoil shall be removed from the surface upon which the fill is to be placed and either removed and legally disposed of or stockpiled for later use in approved landscape areas, The surface shall then be scarified to a depth of at least eight inches until the surface is free from ruts, hummocks, or other uneven features which would tend to prevent unifonn compaction by the equipment to be used. D. After the foundation for the fill has been cleared and scarified, it shall be made uniform and free from large clods. The proper moisture content must be obtained by adding water or aerating. The foundation for the fill shall be compacted at the proper moisture content to a relative compaction as specified herein. 3.05 ENGINEERED FILL A. Select Material: Fill material shall be "Select" or "Imported Material" as previously specified. B. Placing and Compacting: Engineered fill shall be constructed by approved and accepted methods. Fill material shall be spread in uniform lifts not exceeding 8 inches in uncompacted thickness. Each layer shall be spread evenly, and thoroughly blade-mixed to obtain unifonnity of material. Fill material which does not contain sufficient moisture. as specified by ENGEO shall be sprinkled with water; if it contains excess moisture it shall be aerated or blended with drier material to achieve the proper water content. Select material and water shall then be thoroughly mixed before being compacted. C. Unless otherwise specified in the Geotechnical Exploration report, each layer of spread select material shall be compacted to at least 90 percent relative compaction at a moisture content of at least three percent above the optimum moisture content. Minimum 7096.1.001.01 June 8, 2006 8 I ~l q EM3EO INCORPORATED compaction in all keyways shall be a minimum of 95 percent with a minimum moisture content of at least 1 percentage point above optimum. D. Unless otherwise specified in the Geotechnical Exploration report or otherwise required by the local authorities, the upper 6 inches of engineered fill in areas to receive pavement shall be compacted to at least 95 percent relative compaction with a minimum moisture content of at least 3 percentage points above optimum. E. Testing and Observation of Fill: The work shall consist of field observation and testing to determine that each layer has been compacted to the required density and that the required moisture is being obtained. Any layer or portion of a layer that does not attain the compaction required shall be reworked until the required density is obtained. F. Compaction: Compaction shall be by sheepsfoot rollers, multiple-wheel steel or pneumatic-tired rollers or other types of acceptable compaction equipment. Rollers shall be of such design that they will be able to compact the fill to the specified compaction. Rolling shall be accomplished while the fill material is within the specified moisture content range. Rolling of each layer must be continuous so that the required compaction may be obtained uniformly throughout each layer. G. Fill slopes shall be constructed by overfilling the design slopes and later cutting back the slopes to the design grades. No loose soil will be permitted on the faces of the finished slopes. H. Strippings and topsoil shall be stockpiled as approved by Owner, then placed in accordance with ENGEO's recommendations to a minimum thickness of 6 inches and a maximum thickness of 12 inches over exposed open space cut slopes which are 3: 1 or flatter, and track walked to the satisfaction ofENGEO. 1. Final Prepared Subgrade: Finish blading and smoothing shall be performed as necessary to produce the required density, with a unifonn surface, smooth and true to grade. 3.06 BACKFILLING A. Backfill shall not be placed against footings, building walls, or other structures until approved by ENGEO. B. Backfill material shall be Select Material as specified for engineered fill. C. Backfill shall be placed in 6-inch layers, leveled, rammed, and tamped in place. Each layer shall be compacted with suitable compaction equipment to 90 percent relative compaction at a moisture content of at least 3 percent above optimum. 7096.1.001.01 June 8, 2006 9 11'1 Ub Z~'1 EM3EO INCORPORATED 3.07 TRENCHING AND BACKFILLING FOR UTILITIES A. Trenching: 1. Trenching shall include the removal of material and obstructions, the installation and removal of sheeting and bracing and the control of water as necessary to provide the required utilities and services. 2. Trenches shall be excavated to the lines, grades, and dimensions indicated on the Drawings. Maximum allowable trench width shall be the outside diameter of the pipe plus 24 inches, inclusive of any trench bracing. 3. When the trench bottom is a soft or unstable material as determined by ENGEO, it shall be made firm and solid by removing said unstable material to a sufficient depth and replacing it with on-site material compacted to 90 percent minimum relative compaction. 4. Where water is encountered in the trench, the contractor must provide materials necessary to drain the water and stabilize the bed. B. Backfilling: 1. Trenches must be backfilled within 2 days of excavation to minimize desiccation. 2. Bedding material shall be sand and shall not extend more than 6 inches above any utility lines. 3. Backfill material shall be select material. 4. Trenches shall be backfilled as indicated or required and compacted with suitable equipment to 90 percent minimum relative compaction at the required moisture content. . 3.08 SUBDRAINS A. Trenches for subdrain pipe shall be excavated to a minimum width equal to the outside diameter of the pipe plus at least 12 inches and to a depth of approximately 2 inches below the grade established for the invert of the pipe, or as indicated on the Drawings. B. The space below the pipe invert shall be filled with a layer of Class 2 permeable material, upon which the pipe shall be laid with perforations down. Sections shall be joined as recommended by the pipe manufacturer. 7096.1.001.01 June 8, 2006 10 j;\'~l i;j""~ iI' r-. ",. EM3EO INCORPORATED C. Rocks, bricks, broken concrete, or other hard material shall not be used to give intermediate support to pipes. Large stones or other hard objects shall not be left in contact with the pipes. D. Excavations for subdrains shall be filled as required to fill voids and prevent settlement without damaging the subdrain pipe. Alternatively, excavations for subdrains may be filled with Class I permeable material (as defined in Section 2.06) wrapped in Filter Fabric (as defined in Section 2.05). 3.09 AGGREGATE DRAINAGE FILL A. ENGEO shall approve finished subgrades before aggregate drainage fill is installed. B. Pipes, drains,.conduits, and any other mechanical or electrical installations shall be in place before any aggregate drainage fill is placed. Backfill at walls to elevation of drainage fill shall be in place and compacted. C. Aggregate drainage fill under slabs and concrete paving shall be the minimum uniform thickness after compaction of dimensions indicated on Drawings. Where not indicated, minimum thickness after compaction shall be 4 inches. D. Aggregate drainage fill shall be rolled to form a well-compacted bed. E. The finished aggregate drainage fill must be observed and approved by ENGEO before proceeding with any subsequent construction over the compacted base or fill. 3.10 SAND CUSHION A. A sand cushion shall be placed over the vapor retarder membrane under concrete slabs on grade. Sand cushion shall be placed in uniform thickness as indicated on the Drawings. Where not indicated, the thickness shall be 2 inches. 3.11 FINISH GRADING A. All areas must be finish graded to elevations and grades indicated on the Drawings. In areas to receive topsoil and landscape planting, finish grading shall be performed to a uniform 6 inches below the grades and elevations indicated on the Drawings, and brought to fmal grade with topsoil. 3.12 DISPOSAL OF WASTE MATERIALS A. Excess earth materials and debris shall be removed from the site and disposed of in a legal manner. Location of dump site and length of haul are the Contractor's responsibility. 7096.1.001.01 June 8, 2006 11 1ot1 EM3EO INCORPORATED P ART II - GEOGRID SOIL REINFORCEMENT 1. DESCRIPTION: Work shall consist of furnishing geogrid soil reinforcement for use in construction of reinforced soil slopes and retention systems. 2. GEOGRID MATERIAL: 2.1 The specific geogrid material shall be preapproved by ENGEO. 2.2 The geogrid shall be a regular network of integrally connected polymer tensile elements with aperture geometry sufficient to permit significant mechanical interlock with the surrounding soil or rock. The geogrid structure shall be dimensionally stable and able to retain its geometry under construction stresses and shall have high resistance to damage during construction, to ultraviolet degradation, and to all forms of chemical and biological degradation encountered in the soil being reinforced. 2.3 The geogrids shall have an Allowable Strength (T a) and Pullout Resistance, for the soil type(s) indicated, as listed in Table I. 2.4 Certifications: The Contractor shall submit a manufacturer's certification that the geogrids supplied meet the respective index criteria set when geogrid was approved by ENGEO, measured in full accordance with all test methods and standards specified. In case of dispute over validity of values, the Contractor will supply test data from an ENGEO-approved laboratory to support the certified values submitted. 3. CONSTRUCTION: 3.1 Delivery, Storage, and Handling: Contractor shall check the geogrid upon delivery to ensure that the proper material has been received. During all periods of shipment and storage, the geogrid shall be protected from temperatures greater than 140 OF, mud, dirt, dust, and debris. Manufacturer's recommendations in regard to protection from direct sunlight must also be followed. At the time of installation, the geogrid will be rejected if it has defects, tears, punctures, flaws, deterioration, or damage incurred during manufacture, transportation, or storage. If approved by ENGEO, tom or punctured sections may be repaired by placing a patch over the damaged area. Any geogrid damaged during storage or installation shall be replaced by the Contractor at no additional cost to the owner. 7096,1.001.01 June 8, 2006 12 . <\ lJb iter, €MiEO INCORPORATED 3.2 On-Site Representative: Geogrid material suppliers shall provide a qualified and experienced representative on site at the initiation of the project, for a minimum of three days, to assist the Contractor and ENGEO personnel at the start of construction. If there is more than one slope on a project, this criterion will apply to construction of the initial slope only. The representative shall also be available on an as-needed basis, as requested by ENGEO, during construction of the remaining slope(s). 3.3 Geogrid reinforcement may be joined with mechanical connections or overlaps as recommended and approved by the Manufacturer. Joints shall not be placed within 6 feet of the slope face, within 4 feet below top of slope, nor horizontally or vertically adjacent to another joint. 3.4 Geogrid Placement: The geogrid reinforcement shall be installed in accordance with the manufacturer's recommendations. The geogrid reinforcement shall be placed within the layers of the compacted soil as shown on the plans or as directed. The geogrid reinforcement shall be placed in continuous longitudinal strips in the direction of main reinforcement. However, if the Contractor is unable to complete a required length with a single continuous length of geogrid, a joint may be made with the Manufacturer's approval. Only one joint per length of geogrid shall be allowed. This joint shall be made for the full width of the strip by using a similar material with similar strength. Joints in geogrid reinforcement shall be pulled and held taut during fill placement. Adjacent strips, in the case of 100 percent coverage in plan view, need not be overlapped. The minimum horizontal coverage is 50 percent, with horizontal spacings between reinforcement no greater than 40 inches. Horizontal coverage of less than 100 percent shall not be allowed unless specifically detailed in the construction drawings. Adjacent rolls of geogrid reinforcement shall be overlapped or mechanically connected where exposed in a wrap around face system, as applicable. The Contractor may place only that amount of geogrid reinforcement required for immediately pending work to prevent undue damage: After a layer of geogrid reinforcement has been placed~ the next succeeding layer of soil shall be placed and compacted as appropriate. After the specified soil layer has been placed, the next geogrid reinforcement layer shall be installed. The process shall be repeated for each subsequent layer of geogrid reinforcement and soil. Geogrid reinforcement shall be placed to lay flat and pulled tight prior to backfilling. After a layer of geogrid reinforcement has been placed, suitable means, such as pins or small piles of soil, shall be used to hold the geogrid reinforcement in position until the subsequent soil layer can be placed. 7096.1.001.01 June 8, 2006 13 l~"~f. wCf t) t . EM3 0 INCORPORATED Under no circumstances shall a track-type vehicle be allowed on the geogrid reinforcement before at least six inches of soil have been placed. Turning of tracked vehicles should be kept to a minimum to prevent tracks from displacing the fill and the geogrid reinforcement. If approved by the Manufacturer, rubber-tired equipment may pass over the geosynthetic reinforcement at slow speeds, less than 10 mph. Sudden braking and sharp turning shall be avoided. During construction, the surface of the fill should be kept approximately horizontal. Geogrid reinforcement shall be placed directly on the compacted horizontal fill surface. Geogrid reinforcements are to be placed within three inches of the design elevations and extend the length as shown on the elevation view unless otherwise directed by ENGED. Correct orientation of the geogrid reinforcement shall be verified by ENGEO. Table I Allowable Geogrid Strength With Various Soil Types For Geosynthetic Reinforcement In Mechanically Stabilized Earth Slopes (Geogrid Pullout Resistance and Allowable Strengths vary with reinforced backfill used due to soil anchorage and site damage factors. Guidelines are provided below.) MINIMUM ALLOW ABLE STRENGTH, Ta (lb/ft)* SOIL TYPE GEOGRID GEOGRID GEOGRID Type I Type II Type ill A. Gravels, sandy gravels, and gravel-sand-silt 2400 4800 7200 mixtures (GW, GP, GC, GM & SP)** B. Well graded sands, gravelly sands, and sand-silt 2000 4000 6000 mixtures (SW & SM)** C. Silts, very fme sands, clayey sands and clayey 1000 2000 3000 silts (SC & ML)** . D. Gravelly clays, sandy clays, silty clays, and 1600 3200 4800 lean clays (CL)** * All partial Factors of Safety for reduction of design strength are included in listed values. Additional factors of safety may be required to further reduce these design strengths based on site conditions. ** Unified Soil Classifications. 7096.1.001.01 June 8, 2006 14 \'6t.fob EM3EO INCORPORATED PART III - GEOTEXTILE SOIL REINFORCEMENT 1. DESCRIPTION: Work shall consist offuniishing geotextile soil reinforcement for use in construction of reinforced soil slopes. 2. GEOTEXTILE MATERIAL: 2.1 The specific geotextile material and supplier shall be preapproved by ENGED. 2.2 The geotextile shall have a high tensile modulus and shall have high resistance to damage during construction, to ultraviolet degradation, and to all forms of chemical and biological degradation encountered in the soil being reinforced. 2.3 The geotextiles shall have an Allowable Strength (Ta) and Pullout Resistance, for the soil type(s) indicated as listed in Table II. 2.4 Certification: The Contractor shall submit a manufacturer's certification that the geotextiles supplied meet the respective index criteria set when geotextile was approved by ENGEO, measured in full accordance with all test methods and standards specified. In case of dispute over validity of values, the Contractor will supply the data from an ENGEO-approved laboratory to support the certified values submitted. 3. CONSTRUCTION: 3.1 Delivery, Storage and Handling: Contractor shall check the geotextile upon delivery to ensure that the proper material has been received. During all periods of shipment and storage, the geotextile shall be protected from temperatures greater than 140 OF, mud, dirt, dust, and debris. - Manufacturer's recommendations in regard to protection from direct sunlight must also-be followed. At the time of installation, the geotextile will be rejected if it has defects, tears, punctures, flaws, deterioration, or damage incurred during manufacture, transportation, or storage. If approved by ENGEO, torn or punctured sections may be repaired by placing a patch over the damaged area Any geotextile damaged during storage or installation shall be replaced by the Contractor at no additional cost to the owner. 3.2 On-Site Representative: Geotextile material suppliers shall provide a qualified and experienced representative on site at the initiation of the project, for a minimum of three days, to assist the Contractor and ENGEO personnel at the start of construction. If there is more than one slope on a project, this criterion will apply to construction of the initial slope 7096.1.001.01 June 8, 2006 15 q (;6 U? EM3EO INCORPORATED only. The representative shall also be available on an as-needed basis, as requested by ENGEO, during construction of the remaining slope(s). 3.3 Geotextile Placement: The geotextile reinforcement shall be installed in accordance with the manufacturer's recommendations. The geotextile reinforcement shall be placed within the layers of the compacted soil as shown on the plans or as directed. The geotextile reinforcement shall be placed in continuous longitudinal strips in the direction of main reinforcement. Joints shall not be used with geotextiles. Adjacent strips, in the case of 100 percent coverage in plan view, need not be overlapped. The minimum horizontal coverage is 50 percent, with horizontal spacings between reinforcement no greater than 40 inches. Horizontal coverage of less than 100 percent shall not be allowed unless specifically detailed in the construction drawings. Adjacent rolls of geotextile reinforcement shall be overlapped or mechanically connected where exposed in a wrap around face system, as applicable. The Contractor may place only that amount of geotextile reinforcement required for immediately pending work to prevent undue damage. After a layer of geotextile reinforcement has been placed, the succeeding layer of soil shall be placed and compacted as appropriate. After the specified soil layer has been placed, the next geotextile reinforcement layer shall be installed. The process shall be repeated for each subsequent layer of geotextile reinforcement and soil. Geosynthetic reinforcement shall be placed to lay flat and be pulled tight prior to backfilling. After a layer of geotextile reinforcement has been placed, suitable means, such as pins or small piles of soil, shall be used to hold the geotextile reinforcement in position until the subsequent soil layer can be placed. Under no circumstances shall a track-type vehicle be allowed on the geotextile reinforcement before at least six inches of soil has been placed. Turning of tracked vehicles should be kept to a minimum to prevent tracks from displacing the fill and the geotextile reinforcement. If approved by the Manufacturer, rubber-tired equipment may pass over the geotexti1e reinforcement as slow speeds, less than 10 mph. Sudden braking and sharp turning shall be avoided. During construction, the surface of the fill should be kept approximately horizontal. Geotextile reinforcement shall be placed directly on the compacted horizontal fill surface. Geotextile reinforcements are to be placed within three inches of the design elevations and extend the length as shown on the elevation view unless otherwise directed by ENGEO. Correct orientation of the geotextile reinforcement shall be verified by ENGEO. 7096.1.001.01 June 8, 2006 16 ~EO INCORPORATED Table II' Allowable Geotextile Strength With Various Soil Types For Geosynthetic Reinforcement In Mechanically Stabilized Earth Slopes (GeotextilePullout Resistance and Allowable Strengths vary with reinforced backfill used due to soil anchorage and site damage factors. Guidelines are provided'below.) MINIMUM ALLOW ABLE STRENGTH, Ta (lb/ft)* SOIL TYPE GEOTEXTILE GEOTEXTILE GEOTEXTILE Type I Type II Type III A. Gravels, sandy gravels, and gravel-sand-silt 2400 4800 7200 mixtures (GW, GP, GC, GM & SP)** B. Well graded sands, gravelly sands, and 2000 4000 6000 sand-silt mixtures (SW & SM)** C. Silts, vel}' fine sands, clayey sands and 1000 2000 3000 clayey silts (SC & ML)** D. Gravelly clays, sandy clays, silty clays, 1600 3200 4800 and lean clays (CL)** * All partial Factors of Safety for reduction of design strength are included in listed values. Additional factors of safety may be requ,ired to further reduce these design strengths based on site conditions. ** Unified Soil Classifications. 7096.1.001.01 June 8, 2006 17 l '6~ r.r~ 1-0 'f EN3gd INCORPORATED PART IV - EROSION CONTROL MAT OR BLANKET 1. DESCRIPTION: Work shall consist of furnishing and placing a synthetic erosion control mat and/or degradable erosion control blanket for slope face protection and lining of runoff channels. 2. EROSION CONTROL MATERIALS: 2.1 The specific erosion control material and supplier shall be pre-approved by ENGEO. 2.2 Certification: The Contractor shall submit a manufacturer's certification that the erosion mat/blanket supplied meets the criteria specified when the material was approved by ENGED. The manufacturer's certification shall include a submittal package of documented test results that confIrm the property values. In case of a dispute over validity of values, the Contractor will supply property test data from an ENGEO-approved laboratory, to support the certified values submitted. Minimum average roll values, per ASTM D 4759, shall be used for confonnance determinations. 3. CONSTRUCTION: 3.1 Delivery, Storage, and Handling: Contractor shall check the erosion control material upon delivery to ensure that the proper material has been received. During all periods of shipment and storage, the erosion mat shall be protected from temperatures greater than 140 OF, mud, dirt, and debris. Manufacturer's recommendations in regard to protection from direct sunlight must also be followed. At the time of installation, the erosion matlblanket shall be rejected if it has defects, tears, punctures, flaws, deterioration, or damage incurred during manufacture, transportation, or storage. If approved by ENGEO, tom or punctured sections may be removed by cutting OUT a section of the mat. The remaining ends should be overlapped and secured with ground anchors. Any erosion matlblanket damaged during storage or installation shall be replaced by the Contractor at no additional cost to the Owner. 3.2 On-Site Representative: Erosion control material suppliers shall provide a qualified and experienced representative on site, for a minimum of one day, to assist the Contractor and ENGEO personnel at the start of construction. If there is more than one slope on a project, this criteria will apply to construction of the initial slope only. The representative shall be available on an as-needed basis, as requested by ENGEO, during construction of the remaining slope(s). 7096.1.001.01 June 8, 2006 18 ~o INCORPORATED 3.3 Placement: The erosion control material shall be placed and anchored on a smooth graded, firm surface approved by the Engineer. Anchoring tenninal ends of the erosion control material shall be accomplished through use of key trenches. The material in the trenches shall be anchored to the soil on maximum 1 ~ foot-centers. Topsoil, if required by construction drawings, placed over final grade prior to installation of the erosion control material shall be limited to a depth not exceeding 3 inches. 3.4 Erosion control material shall be anchored, overlapped, and otherwise constructed to ensure performance until vegetation is well established. Anchors shall be as designated on the construction drawings, with a minimum of 12 inches length, and shall be spaced as designated on the construction drawings, with a maximum spacing of 4 feet. 3.5 Soil Filling: If noted on the construction drawings, the erosion control mat shall be filled with a fine grained topsoil, as recommended by the manufacturer. Soil shall be lightly raked or brushed on/into the mat to .fill the mat voids or to a maximum depth of 1 inch. 7096.1.001.01 June 8, 2006 19 Z: ... ~.'1 .',' ~ f. Uj0) (). EM3EO INCORPORATED PART V - GEOSYNTHETIC DRAINAGE COMPOSITE 1. DESCRIPTION: Work shall consist of furnishing and placing a geosynthetic drainage system as a subsurface drainage medium for reinforced soil slopes. 2. DRAINAGE COMPOSITE MATERIALS: 2.1 The specific drainage composite material and supplier shall be preapproved by ENGEo. 2.2 The drain shall be of composite construction consisting of a supporting structure or drainage core material surrounded by a geotextile. The geotextile shall encapsulate the drainage core and prevent random soil intrusion into the drainage structure. The drainage core material shall consist of a three dimensional polymeric material with a structure that permits flow along the core laterally. The core structure shall also be constructed to permit flow regardless of the water inlet surface. The drainage core shall provide support to the geotextile. The fabric shall meet the minimum property requirements for filter fabric listed in Section 2.05C of the Guide Earthwork Specifications. 2.3 A geotextile flap shall be provided along all drainage core edges. This flap shall be of sufficient width for sealing the geotextile to the adjacent drainage structure edge to prevent soil intrusion into the structure during and after installation. The geotextile shall cover the full length of the core. 2.4 The geocomposite core shall be furnished with an approved method of constructing and connecting with outlet pipes or weepholes as shown on the plans. Any fittings shall allow entry of water from the core but prevent intrusion of backfill material into the core material. 2.5 Certification and Acceptance: The Contractor shall submit a manufacturer's certification that the geosynthetic drainage composite meets the design properties and respective index criteria measured in full accordance with all test methods arid standards specified. The manufacturer's certification shall include a submittal package of documented test results that confirm the design values. In case of dispute over validity of design values, the Contractor will supply design property test data from an ENGEO-approved laboratory, to support the certified values submitted. Minimum average roll values, per ASTM D 4759, shall be used for determining conformance. 7096.1.001.01 June 8, 2006 20 !4 c-6 ~ ENGEO INCORPORATED 3. CONSTRUCTION: 3.1 Delivery, Storage, and Handling: Contractor shall check the geosynthetic drainage composite upon delivery to ensure that the proper material has been received. During all periods of shipment and storage, the geosynthetic drainage composite shall be protected from temperatures greater than 140 OF, mud, dirt, and debris. Manufacturer's recommendations in regards to protection from direct sunlight must also be followed. At the time of installation, the geosynthetic drainage composite shall be rejected if it has defects, tears, punctures, flaws, deterioration, or damage incurred during manufacture, transportation, or storage. If approved by ENGEO, tom or punctured sections may be removed or repaired. Any geosynthetic drainage composite damaged during storage or installation shall be replaced by the Contractor at no additional cost to the Owner. 3.2 On-Site Representative: Geosynthetic drainage composite material suppliers shall provide a qualified and experienced representative on site, for a minimum of one half day, to assist the Contractor and ENGEO personnel at the start of construction with directions on the use of drainage composite. If there is more than one application on a project, this criterion will apply to construction of the initial application only. The representative shall also be available on an as-needed basis, as requested by ENGEO, during construction of the remaining applications. 3.3 Placement: The soil surface against which the geosynthetic drainage composite is to be placed shall be free of debris and inordinate irregularities that will prevent intimate contact between the soil surface and the drain. 3.4 Seams: Edge seams shall be formed by utilizing the flap of the geotextile extending from the geocomposite's edge and lapping over the top of the fabric of the adjacent course. The fabric flap shall be securely fastened to the adjacent fabric by means of plastic tape or non- water-soluble construction adhesive, as recommended by the supplier. Where vertical splices are necessary at the end of a geocomposite roll or panel, an 8-inch-wide continuous strip of geotextile may be placed, centering over the seam and continuously fastened on both sides with plastic tape or non-water-soluble construction adhesive. As an alternative, rolls of geocomposite drain material may be joined together by turning back the fabric. at the roll edges and interlocking the cuspidations approximately 2 inches. For overlapping in this manner, the fabric shall be lapped and tightly taped beyond the seam with tape or adhesive. Interlocking o{ the core shall always be made with the upstream edge on top in the direction of water flow. To prevent soil intrusion, all exposed edges of the geocomposite drainage core edge must be covered. Alternatively, a 12-inch-wide strip of fabric may be utilized in the same manner, fastening it to the exposed fabric 8 inches in from the edge and folding the remaining flap over the core edge. 7096.1.001.01 June 8, 2006 21 \ t ~ to! EM3EO INCORPORATED 3.5 Soil Fill Placement: Structural backfill shall be placed immediately over the geocomposite drain. Care shall be taken during the backfill operation not to damage the geotextile surface of the drain. Care shall also be taken to avoid excessive settlement of the backfill material. The geocomposite drain, once installed, shall not be exposed for more than seven days prior to backfilling. 7096.1.001.01 June 8, 2006 22 Shannon Center Project Mitigation Monitoring and Reporting Program February 2007 Mitigation Measure Implementing Monitoring Monitoring Verification Responsibility Responsibility Schedule Mitigation Measure 1 (Aesthetics). Exterior light Project Architect Dublin Planning Construction Plans fixtures shall be designed or equipped with cut-off Division and Parks and Specifications lenses to ensure that no spill over of light or glare and Community occurs outside of Shannon Park. This mitigation Services measure shall be included on final building plans Department and specifications. Mitigation Measure 2 (Air Quality). Grading and Project Contractor Dublin Planning Prior to issuance of demolition activities shall include the following to Division and Parks a grading permit ensure compliance with BAAQMD air quality and Community standards. Services a) Graded areas shall be watered frequently to Department minimize emissions of fugitive dust. b) Off-hauled material shall be covered. c) Driveway entrances used by haul trucks shall be swept frequently. m X ~ - OJ - -t OJ Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 3 (Biological Resources). Project Contractor Dublin Planning Prior to issuance of a) If shrubs or trees are to be trimmed or Division and Parks a demolition permit removed during construction, such trimming and Community or removal of vegetation within or near the Services construction footprint may occur only during Department the non-breeding season (August through February); or b) Pre-construction breeding bird surveys shall be conducted by a qualified biologist during the breeding season within 30 days of the start of construction. Surveys shall be conducted within suitable nesting habitat in or near the project area. A 50-foot radius minimum exclusion zone shall protect all active nests identified at that time. Exclusion zones would vary depending on each species. The exclusion zone shall remain in place until all young have fledged. Since some birds may have three broods, avoidance could possibly extend into August. ~ -3.> ..:: \..l Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 2 cY Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 4 (Biological Resources). An Project Contractor Dublin Planning Prior to issuance of exclusion fence shall be installed and maintained Division and Parks a demolition permit during the construction period, spring through and Community fall, in between the creek and the construction Services area, to ensure no red-legged frogs or pond turtles Department enter the construction site. The location of the fence shall be selected by a qualified biologist to ensure that no wetlands, waters of the US or waters of the state are impacted. Grading of the site shall only occur between April and November to minimize impacts to dispersing frogs. Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin (' Page 3 ._~ cJl Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 5 (Biological Resources). Project Contractor Dublin Planning During project a) If snag, tree, building or bridge removal or Division and Parks construction in improvements are to take place during summer and Community summer months months when bats may be roosting, a bat roost Services survey shall be conducted by a qualified Department biologist. If no roosting bats are found, no further mitigation steps would be required. If bats are detected, a 50-foot wide buffer exclusion zone shall be established around each occupied snag or tree until the roosting period has ended; or b) Alternatively, construction activities shall be limited to the times of the year when bats are not breeding nor hibernating. Bat surveys would not be necessary if tree, snag or building removal were to occur in September and October, after the bat-breeding season and before the bat hibernation season. Mitigation Measure 6 (Biological Resources). Project Contractor Dublin Planning Prior to issuance of W oodrat houses shall be flagged by a biologist Division and Parks a demolition permit and avoided during construction activities. The and Community potential presence of flags shall be noted on final Services construction plans and specifications. If avoidance Department of woodrat houses is unavoidable, sticks from the dismantled house should be kept on site, near the dismantled house if possible. -- ...i) Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 4 -P l..:..T~- .. Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 7 (Biological Resources). Project Landscape Dublin Planning Included in final a) The landscape plan prepared for the project Architect Division and Parks project landscape shall include specific measures to protect and Community plan trees, including but not limited to placement Services of exclusion fencing around protected trees, Department limitation regarding storage of materials and equipment inside of the fencing, selective pruning of branches prior to demolition and construction activities and similar steps. b) The landscape plan shall incorporate replacement trees at a 1:1 ratio for each protected tree that must be removed to implement the proposed project. Mitigation Measure 8 (Cultural Resources): Project Architect Dublin Planning Included on final Wording shall be added on final construction plans Division and building plans and and specifications to the effect that if archeological Community specifications or Native American materials or artifacts are Services identified, work on that portion of the project shall Department cease until a resource protection plan conforming to CEQA Guidelines Section 15064.5 and the Dublin Zoning Ordinance is prepared by a qualified archeologist and/ or paleontologist and approved by the City of Dublin Community Development Director or an authorized representative. Project work may be resumed in compliance with such plan. If human remains are encountered, the County Coroner shall be contacted immediately and the provisions of State law carried out. Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 5 J) ~ ry ',' Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 9 (Geology and Soils). Project Architect Dublin Planning Included on final A structural setback of at least 50 feet shall be Division and Parks building plans and provided between the proposed replacement and Community specifications Shannon Community Center building and Services the nearest fault trace, as verified in writing Department by a California-registered Geotechnical Engineer or equivalent. No habitable structures shall be constructed in this setback area. Habitable structures located at distances between 50 and 100 feet of the nearest fault trace shall be supported by a mat foundation on a geotechnically improved sub grade as further identified in the ENGEO report as a Special Foundation Zone. Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 6 Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 10 (Geology and Soils). Project Contractor Dublin Planning Prior to issuance of Prior to issuance of a demolition permit, a Division and Parks a demolition permit Stormwater Pollution Prevention Plan shall and Community be prepared that complies with the Alameda Services County Clean Water Program to minimize Department erosion into Koopman Creek during project construction and post construction operation of the proposed facility. The Plan, at minimum, shall include requirements to place fiber maps, silt fences and similar features adjacent to the creek to minimize erosion into Koopman Creek during construction and use of Best Management Practices during project operation to minimize runoff of untreated stormwater into the creek. The Plan shall be approved by the Dublin City Engineer prior to commencement of demolition. Mitigation Measure 11 (Geology and Soils). Project Architect Dublin Planning Included on final Building foundations shall be designed to Division nt and building plans and specifications provided by a California- Parks and specifications registered Geotechnical Engineer or Community equivalent. The foundation system may likely Services include conventional spread footings in Department combination with a structural mat foundation system, such as a post-tensioned mat or conventional reinforced mat system. Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 7 ~ ~ Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 12 (Hazards). Prior to Project Contractor Dublin Planning Prior to issuance of demolition of the existing Shannon Community Division and Parks a demolition permit Center building, a hazardous materials removal and Community plan shall be prepared a registered environmental Services professional consistent with EP A, OSHA, State of Department California OSHA, the California Department of Toxic Substances Control, the Bay Area Air Quality Management District and Alameda County Environmental Health Department criteria and standards. The plan shall detail how materials will be removed from the building and disposal site(s). Demolition shall be undertaken by state licensed contractors and include a worker safety plan. The plan shall be approved by the City of Dublin Building Official prior to commencement of demolition. ..J) Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 8 d~..~ . .. ,- Mitigation Measure Implementing Responsibility Monitoring Responsibility Monitoring Schedule Verification Mitigation Measure 13 (Noise). Prior to Department of Dublin Planning Prior to issuance of demolition of the existing Shannon Community Parks and Division a demolition permit Center building, a Construction Noise Community Management Plan shall be prepared and Services approved by the Dublin Community Development Department to minimize construction noise:At minimum, the Plan shall establish days and hours of construction operations, induding delivery of construction materials and equipment maintenance, notification of park users and residents as to the start date and duration of the project and the name and phone number of a noise coordinator for concerns regarding constriction noise. The Construction Noise Management Plan shall be made a part of construction plans and specifications to be implemented by project contractors. Shannon Center Project Mitigation Monitoring and Reporting Program City of Dublin Page 9 N \) C It fb 10~ February 20, 2007 City of Dublin Shannon Center Project Response to Environmental Comments Introduction The City of Dublin issued a Mitigated Negative Declaration for this project on January 5, 2007 to ensure California Environmental Quality Act compliance. The proposed project includes demolition of the existing approximately 13,000 square foot Shannon Community Center and construction of a replacement 19,000 square foot (approximately), one story community center building in approximately the same location as the existing community center building. The project also includes replacement of the decking material on an existing pedestrian bridge just south of the new community center building. The project site is located on the north side of Shannon Park, which is located in the northwest corner of San Ramon Road and Shannon Road. The City of Dublin published and circulated an Initial Study and Draft Mitigated Negative Declaration on January 5, 2007 for a 30-day public review period that ended on February 5, 2007. Clarifications and Modifications to the Initial Study The following modifications and corrections are made and incorporated by reference in the Initial Study. Deletions are struck out and revised text is underlined. 1) Page 10, item 6, the General Plan land use designation for the project site is "Community Park," not "Low Density Residential." 2) Page 39, item "a," li ne 15, change this sentence to read as follows: "Figure 6, included in the ENGEO evaluation, has determined that the nearest fault is located approximately 120 west east of the existing building." City of Dublin Response to Comments Shannon Center Project Page 2 February 2007 t1b 1. 0 Comments Received Four comment letters were received: No. State Agency Comments Date 1 State of California, State Clearinghouse 2/6/07 Local Agency Comments 2 Dublin Police Services Department 1/29/07 3 Zone 7 2/5/07 4 Dublin San Ramon Services District 2/5/07 Copies of these letters are attached. Each response corresponds numerically to the number of responses. Responses The following are responses to each of the comment letters. 1) State of California State Clearinghouse Comment 1: The State comment period for this Mitigated Negative Declaration closed on February 5,2007 and no state agencies submitted comments by that date. This letter acknowledges that the City of Dublin has complied with State Clearinghouse requirements for state review pursuant to CEQA. Response: This comment is acknowledged and no further response is necessary. 2) Dublin Police Services Department Comment 2.1: The project design should provide for crime prevention through environmental design features, including natural surveillance, territoriality, access control and premises liability. City of Dublin Response to Comments Shannon Center Project Page 3 February 2007 '2 ? (ib'2 Response: This comment is acknowledged and the Parks and Community Services Department will consult with the Police Services Department to include crime reduction features into the final design of the Shannon Center building. Comment 2.2: The planning of parking facilities needs to be adequate to fulfill the parking of persons with disabilities and other types of planned uses for the venue. There are also a generous number of curb-side parking spaces in the area. Response: The proposed project involves reconstruction of an existing building within Shannon Park. The adjacent park includes sufficient parking, including handicapped parking spaces, to accommodate future uses of the reconstructed community center building. Comment 2.3: The lighting plan should be designed to the standards set forth in the Dublin Security Ordinance. Light levels are needed to give visitors and staff a feeling of natural surveillance during night hours. Response: The proposed project will include a lighting plan that complies with the City's Securi ty Ordinance. The lighting plan must also comply with Mitigation Measure 1 contained in the Initial Study that requires exterior light fixtures to be equipped with cut-off lenses to ensure there would be no spill- over of light outside of Shannon Park. Comment 2.4: There are no anticipated increases in police calls for service for the proposed project. The Police Services Department suggests that neighbors be notified during the demolition and construction phases of the project. If surrounding neighbors are contacted via letters, they should be asked to help with site surveillance of the construction site and report trespassers or suspicious activity. Response: This comment is noted. Mitigation Measure 13 contained in the Initial Study requires the preparation and approval of a Construction Noise Management Plan and approval by the Community Development Department prior to building demolition. The Noise Management Plan requires notification of surrounding neighbors. The Dublin Parks and Community Services Department may include the wording on such advance notification letters as requested by the Police Services Department. Comment 2.5: The Police Services Department recommends a number of conditions of project approval, including but not limited to consistency with the Nonresidential Security Ordinance, installation of site lighting, installation of City of Dublin Response to Comments Shannon Center Project Page 4 February 2007 :tO~1J street addresses, minimizing the height of site landscaping, installation of temporary construction fencing, filing of a police emergency contact business card and others. Response: Suggested conditions of approval will be considered by the City of Dublin in approving this project. 3) Zone 7 Comment 3.1: Item lid" on page43 of the Init ial Study notes that a small increase in the amount of stormwater runoff is anticipated. The City is requested to provide the hydrological analysis depicting the anticipated increase in runoff. A hydrologic analysis may be required after review of the hydrology. Response: The Dublin Parks and Community Services Department will consult with Zone 7 staff regarding additional hydrologic information for this project. Comment 3.2: The parcel may be subject to Zone 7 drainage fees. Please provide a site plan identifying impervious surfaces on the site. Response: The comment is noted and the applicant will contact Zone 7 staff regarding payment of any fees based on the project site plan. 4) Dublin San Ramon Services District Comment 4.1: The commenter notes that existing sewer system pipelines have adequate capacity to collect wastewater from the proposed project. Coordination with DSRSD staff is recommended to ensure that proposed construction will not conflict with DSRSD facilities and that new water and sewer lines are completed in conformance with DSRSD standards and specifications. Response: The project engineer will consult with DSRSD staff regarding installation of sewer and water lines to ensure compliance with DSRSD standards and specifications. Comment 4.2: According to DSRSD' s 2005 Urban Water Management Plan, sufficient potable water exists to serve the proposed project. If there is a need for additional fire flow to the site DSRSD should be contacted regarding installation of any new water lines to meet fire flow requirements. City of Dublin Response to Comments Shannon Center Project Page 5 February 2007 , zo~ Po 2-0~ Response: This comment is acknowledged and, as noted in the response to Comment 4.1, DSRSD staff will be consulted regarding the need to install upgraded or additional water lines to serve the proposed project. Comment 4.3: DSRSD's Pu mp Station 2C is located on the southerly portion of the project site and serves water to Pressure Zone 2. Coordination with DSRSD should occur to ensure that construction activities do not interfere with pump station operations or associated pipelines. Response: Refer to the Response to Comment 4.1 regarding the intent of the Parks and Community Services staff to consult with DSRSD staff to ensure that DSRSD facilities are not damaged during project construction. Comment 4.4: The Initial Study describes the project site as having a General Plan designation of Low density Residential, however, the commenter believes the appropriate designation is Community Park. Response: The commenter is correct, the Land Use Element Designates the project site as Community Park, not Low Density Residential. Please refer to the Corrections and Modifications section of this document.