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Home My WebLink AboutItem 6.1 GHAD Fallon CrossingG~~~ OF DpB~~ ~ i9;.~.~~-;~~Z ; STAFF REPORT C I T Y C L E R K ~ ~ ~ DUBLIN CITY COUNCIL File # ^~]~~^-~O^!~^ ~~LIFpR~l~ DATE: August 16, 2011 TO: Honorable Mayor and City Councilmembers FROM: Joni Pattillo, City Manager SUBJEC • esolution Approving the Formation of the Fallon Crossings Geologic Hazard Abatement District (GHAD), Approving the Plan of Control, and Appointing the Dublin City Council as the Board of Directors of the GHAD Prepared By: Mark Lander, City Engineer EXECUTIVE SUMMARY: Condition of Approval No. 11 for the Fallon Crossings development (Tract 7617) requires creation of a Geologic Hazard Abatement District (GHAD), encompassing the property within the development,. prior to filing of the first final map for the project. To satisfy this requirement, Standard Pacific Homes, the developer, has submitted a petition to create the Fallon Crossings Geologic Hazard Abatement District. The territory to be annexed pursuant to the Petition for Annexation is currently owned by the developer. The boundaries of the territory to be annexed and the boundaries of the Fallon Crossings development are the same. In connection with the petition, a Fallon Crossings GHAD Ptan of Control has been prepared. The proposed Plan of Control describes the work contemplated for the GHAD, including maintenance and monitoring activities, including slopes, debris benches, maintenance roads, trails, fencing, concrete lined drainage ditches, subdrains, subdrain outlets, retaining walls, storm drain improvements, and the water quality and detention basins. If adopted, the Fallon Crossings GHAD Plan of Control would address geologic hazards within the Fallon Crossings development. FINANCIAL IMPACT: There is no immediate fiscal impact. Once the Fallon Crossings Geologic Hazard Abatement District ("Fallon Crossings GHAD") has been formed and a funding mechanism has been approved by the Board of Directors and affected property owners, costs associated with the operation of the Falton Crossings GHAD will be offset by assessments paid by property owners within the District. The proposed assessments are supported by a detailed Engineer's Report prepared by a registered professional engineer certified by the State of California and will be considered at a subsequent GHAD Board date in accordance with Proposition 218. Page 1 of 3 ITEM NO. ~. RECOMMENDATION: Staff recommends that the City Council: (1) Receive Staff presentation; (2) Open the Public Hearing and receive comments from the public; (3) Close the Public Hearing and deliberate; and (4) Adopt the Resolution Approving the Formation of the Fallon Crossings Geologic Hazard Abatement District (GHAD), Approving the Plan of Control, and Appointing the Dublin City Council as the Board of Directors of the GHAD ~ R iewed By Public Works Director DESCRIPTION: uApproved ~y/ Assistant City Manager Division 17 of the California Public Resources Code establishes legal standards for geologic hazard abatement district ("GHAD") formation, GHAD financing and the scope of GHAD authority (§§ 26500-26654). California Public Resources Code section 26567 provides that, after ~sufficient notice and a hearing at which the owners of no more than 50 percent of the assessed valuation of the proposed district object to its formation, a new GHAD may be formed by resolution of the City Council. The adoption of the resolution approving the formation of the Fallon Crossings GHAD, and the selection of the initial Board of Directors are the next steps in the creation of the Fallon Crossings GHAD. ANALYSIS: State law authorizes the formation of geologic hazard abatement districts to prevent, mitigate, abate, and control geologic hazards. The proposed Fallon Crossings GHAD would include maintenance and monitoring activities, including slopes, debris benches, maintenance roads, trails, fencing, concrete lined drainage ditches, subdrains, subdrain outlets, retaining walls, storm drain improvements, and the water quality and detention basins, as well as potential geologic hazards such as landslides, within the Fallon Crossings development. Pursuant to the Public Resources Code, the City Council adopted Resolution 115-11 on July 19, 2011, accepting the Petition for Formation for creation of the Fallon Crossings Geologic Hazard Abatement District. The petition was executed by the owner of 100 percent of the property within the proposed Fallon Crossings GHAD. The resolution set a public hearing for August 16, 2011 and required noticing by mail the owner of real property within the proposed Fallon Crossings GHAD at~least twenty (20) days before the hearing date. Copies of the July 19 Staff Report (Attachment 3), the Petition for Formation (Attachment 4), and the Plan of Control (Attachment 5) are attached. At the public hearing, if the owners of more than 50 percent of the assessed valuation of property within the territory to be annexed do not object to the formation, at the close of the hearing, the City Council may decide whether or not to form the Fallon Crossings GHAD. Page 2 of 3 If the City Council wishes to approve the formation of the Fallon Crossings GHAD, the City Council must adopt a resolution approving the formation of the Fallon Crossings GHAD and appointing members to act as the Board of Directors for the Fallon Crossings GHAD. Under the GHAD law, the City Council may appoint five (5) real property owners within the District or the ~ City Council itself, to act as the Board of Directors. In this case, there is only a single property owner, and it is therefore only practical to appoint the City Council as the Board of Directors. As described in the Staff Report for the July 19, 2011 City Council meeting, the City Council must, in future actions, take additional steps to make the Fallon Crossings GHAD operational, including passing a budget and levying of an assessment.. The Board of Directors must pass a budget and levy an assessment. Levying the assessment requires two steps: (a) approval of the engineer's report and the initiation of the assessment ballot proceeding, and (b) following the 45-day notice period required by Proposition 218, a public hearing to tabulate the assessment ballots and approve or deny the assessment. NOTICING REQUIREMENTS/PUBLIC OUTREACH: Notice of this hearing and a copy of the Staff Report were provided to Standard Pacific Homes, owner of the Fallon Crossings development, at least twenty days before this hearing. ATTACHMENTS: 1) Location Map 2) Resolution Approving the Formation of the Fallon Crossings Geologic Hazard Abatement District (GHAD), Approving the Plan of Control, and Appointing the Dublin City Council as the Board of Directors of the GHAD 3) July 19, 2011 Staff Report (w/o Attachments) 4) Petition for Formation 5) Plan of Control ~ G:\GHAD\Fallon Crossings GHAD\Staff Report, Fallon Crossings - Public Hearing GHAD Formation, 8-16-11.doc Page 3 of 3 ~t~ ~Nnt c~~' _,~/ `. ~q ~•'i~ ~So~yy ~~i~ ~ ~ ~ ~ \'. ~ Y ~ LlN ~ H2-001756 ~ 0 \ ~ ~,0 ~ ~ / A 5P~ ~~A~ ~ o ~ VARWS ':~p, 9 7-2 14 300 ~ ~'.:.'°.~ ~ FR£ORICH 200H-109067 ~. (lis laA h (he lod e ~. s.«:, a:i~,~. u,. e.o:~ aermn LI NJJRSUlT IO1.BJ' L13 N59'l1;76'W 3AG7' f1 NIJTIY'W'W 7I7.15' LI6 N67VYJI'W SI.H' lJ NI/72'OSY S0.IJ' Lil M63b252"W 3217' l1 NA5:T755'W 18(1' LIB N70Y6'SJ"W 51.50' L5 L6 NH9S5'S9'W N6(71'16Y 53208' BSB9' (19 LZO N69SIYCW N69175'iT -500' 19.J8' U N6TI.12G"W J7J6' LT! 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( ~&{ J r FX E~~:~~~,s a ' \°Z y' _ "°-J~ 6;n~w P A R C£ L M A P 9 O 7 5 ~ ~ ~ ~ __ ~ ~ _ _ ~~ ~ 7rv ua.vucv~ Rf£TSPBI ({J ~ T~RA T 75d 0 7 5 4 0 J/!' ~qbY q~eE . .eceaszer ~r/ 0 ~ ~5 '~ t~ DETA/L A" xor ro scvc J~~.~~ ~~4781 PIOL (1) B@EfNCLi (/) 1RACi 7H1 - 279 Y 6H , (7) RECOT7 C1~ SVRIEY N0. lLbS - 16 NS Jl " (JJ RELU9] ~` SLRLEY N4 319 - 9 RS ]J (IJlR1C!]510-_Y_ (S) OEED - 100916527 (b') L1EE0 - 700U6fM97 NOTES: ALL MONUMENT TIE lJNES ARE AT RICHT ANCLES TO 7HE MONUTAENT l1NE UNLESS OIHERKISE NOTFD. BASIS OF BEARINGS 1HE BEAftINC N64'll'Ifi'E~ OF iHE AIONUMENT tJNE M TASSAJMA HOAD AS SHOWN ON 1RACT 7441, FllEO IN BOOK Y79 OF AfAPS AT PAGE 68, ALAMEDA COUNTY RECOROS, IS TAKEN AS ME BA515 OF 9EARINGS FOR THIS 4M. _ LEGEND - - - - ~ TRACT BOUNDARY UNE LOT UNE - -. _.._..._.......... AIONUMENT UNE ..................._....__.... ---_ NONUMENT IIE L1NE ~ ------- NEW EASFJAENT l1NE AS NOlEO - - - EXISPNG EASEMENT UNE AS NOTED E%ISPNC LOT l1NE OO ' SET qTY pF pUBLIN STANDMD MONU4ENT STAAIPED RCE 25281 • ' FOUND POINT, AS NOIED EVAE EMEftCENCY YEWCLE ACCESS EASEMENT PSE PUBLIC SERNCE EASEAIENT SSE SANITMY SEWER EASEAIENT WlE WATER LINE EASEMENT P4SE ' PRIVATE WATEA l1NE EASEIAENT -- PSAE PRIVAIE S7REET ACCE55 EASEA/ENT PSDE P0.1VA7E STORM DRAIN EASEMENT 1Q EVAE. PSE, SSE, HLE, PSAE, PSDE, SOE GE CRADINC EASEAIENT NAE AIAIN7ENANCE ANO ACCE55 EASEMENT SDE STOFtM DRAIN EASEAIFJJT ~ EX. OOSTINC (AI-N) MONUMENT TO MONUMENT (R) ftADIAL (T) TOTAL ( OATA )(1)- RECORD ~ATA @ REFERENCE ~ SFNF SEARCHED FOR, NOMINC FOUND SO.FT. SWME FEET IP IRON PIPE ~ ~ REl1NWISHAIENT OF A9UTTER'S ftIGHTS ~ ~ SHEE7 COVERA6E ~ Q SHEET NUM9ER TRACT 7617 FALLON CROSSING 6EING A 9UBDIVISION OR TH6 PARCEL OE9CRIBED IN 7HE WCUYEMI9 RECOMED ON APRIL I4, 2005 IN WCUI~NT N0. 200514B52T, PECORUED ON AUGU9T 2B, 2010 Q7 WC171~NT H0. " 201~IB870. ANU RECORDED ON AUCUST 2B, 2010 QI DOCUYENT N0. 20I0216BB0, OFFICIAL RECORD9 OF ALAYEDA COUNTY i CITY OF DUBLIN ALAMEDA COUNTY, CALIFORNIA RUGGERI-JENSEN-AZAR & ASSOCIATES CIVIL ENGINEERS, PLANNERS, SURVEYORS~ ~PIEA9ANIVN, CALIFORNIA YAY 2011 ~ !OB N0. 031006 SFIEET 9 DF 13 SHE6f9 ~ ~ ATTACHMENT / d - ~ ~~~ ~ RESOLUTION NO. -11 A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF DUBLIN *********~~*~**~*~********************~* APPROVING THE FORMATION OF THE FALLON CROSSINGS G.EOLOGIC HAZARD ABATEMENT DISTRICT, APPROVING THE PLAN OF CONTROL, AND APPOINTING THE DUBLIN CITY COUNCIL AS THE BOARD OF DIRECTORS WHEREAS, on June 21, 2005, pursuant to the provisions of section 26550 of the Public Resources Code, this City Council adopted Resolution No. 139-05, declaring the City Council to be subject to the provision of Division 17 (§§ 26500-26654) of said Code, and forwarded a copy of said Resolution to the State Controller; and WHEREAS, pursuant to the provisions of Division 17 of the Public Resources Code, a Petition ("Petition"), including a Plan of Control, was filed with the City Clerk, dated February 28, 2011, for the formation of the Fallon Crossings Geologic Hazard Abatement District ("GHAD" or "District"); and WHEREAS, on July 19, 2011, this City adopted Resolution No. 115-11 accepting the Petition and setting a hearing on the filed Petition on August 16, 2011, at 7:00 pm; and WHEREAS, notice of the hearing was given pursuant to the provisions of Public Resources Code sections 26561 through 26563; and WHEREAS, a public hearing before the City Council on the formation of the GHAD was held on August 16, 2011, at 7:00 p.m., pursuant to the requirements of section 26557 of the Public Resources Code; and WHEREAS, at the time set for the hearing, no owner of real property within the proposed GHAD had made a written objection to its formation in accordance with the provision of Public Resources Code sections 26564 through 26566; and WHEREAS, at the hearing, the owners of more than 50 percent of the assessed valuation of the GHAD did not object to the formation thereof, and the Board closed the hearing; and WHEREAS, the formation of the GHAD is exempt from the provisions of the California Environmental Quality Act (Public Resources Code §§ 21000 et seq.) in accordance with Public Resources Code sections 21080(b)(4) and 26559; NOW, THEREFORE, BE IT RESOLVED THAT: Section 1. Pursuant to Public Resources Code section 26567, the City Council hereby orders the formation of the GHAD, as described in the Petition, and approves the Plan of ControL _ - - --- - --- - ATTACHMENT ~ 0 ~ /~ d ~ Section 2. Pursuant to Public Resources Code section 26567, the City Council hereby appoints itself as the Board of Directors of the Fallon Village Geologic Hazard Abatement District (GHAD Board). Section 3. This resolution shall become effective immediately upon its passage and adoption. The GHAD shall become operational only after the parcels within the boundaries of the GHAD have been successfully assessed in accordance with Public Resources Code section 26650 and Article XIII(D) of the California Constitution. The GHAD Board intends to adopt separate resolutions to initiate the establishment and authorization of an assessment on the real property included in the GHAD. PASSED, APPROVED AND ADOPTED on this 16th day of August, 2011. AYES: NOES: ABSTAIN: ABSENT: Mayor ATTEST: City Clerk 1685576.1 2 G~~.~ OF DUB~~ ///~~~ ~\ 19 (~i= _J,~),SZ ~~. ~~,~/l ~~LIFpR~1~ ~ ~W ~ STAFF REPORT . DUBLIN CITY COUNCIL CITY CLERK F~ie # ^L~~~-~~ DATE: July 19, 2011 TO: Honorable Mayor and City Councilmembers FROM: Joni Pattillo, City Manager SUBJEC : Resolution Setting a Public Hearing on the - Geologic Hazard Abatement District Prepared By: Mark Lander, City Engineer EXECUTIVE SUMMARY: ~p~i~~~A~1Nf~,f~'~ ,± l_~ L. ~:~ ~~~~ ~ ~' 1 ~~ •_ ~, ~~~~~~~ ~~~~~~~ Formation of the Fallon Crossings The developer of the Fallon Crossings Development. (Tract 7617), in accordance with the conditions of approval for the project, has submitted a petition to create the~allon Crossings Geologic Hazard Abatement District (GHAD), encompassing the property within the development. This item is the first step in the process of the GHAD formation. State law requires that fhe City Council adopt a resolution setting a public hearing to . consider the formation and that the City notify the property'owners within the territory to be included in the GHAD. FINANCIAL IMPACT: There is no immediate fiscal impact. Once the Fallon Crossings Geologic Hazard Abatement District ("Fallon Crossings GHAD") has , been formed and a funding mechanism has been approved by the Board of Directors and affected property owners, costs associated with the operation of the Fallon Crossings GHAD will be offset by assessments paid by property owners within the District. RECOMMENDATION: Staff recommends that the City Council adopt the Resolution Setting a Public Hearing on the Formation of the Fallon Crossings Geologic Hazard Abatement District. ~, Reviewed By Appr ved y Public Warks Director Assistant--' "~~~~~----- -- ------ - - ~~ ATTACHMENT3 - ~ ~____ ,. Page 1 of 3 _ ~~ V 5 ATTACHMENTS: 1. Location Map 2. Resolution Setting a Public Hearing on the Formation of the Fallon Crossings Geologic Hazard Abatement District, together with Exhibit A(Petition for District Formation) and Exhibit B (Notice of Public Hearing). G:\GHAD\Fallon Crossings GHAD\Staff Report, Fallon Crossings - Setting Hearing on Formation, 7-19-11.DOC Paae 3 of 3 '~ ~ PETITION FOR FORMATION OF THE FALLON CROSSING GEOLOGIC HAZARD ABATEMENT DISTRICT ~ PURSUANT TO DIVISION 17 OF THE PUBLIC RESOURCES CODE OF THE STATE OFCALIFORNIA TO: The City Clerk for the City of Dublin: ) The undersigned owne"rs of land within the boundaries of the territory proposed to be included in the Fallon Crossing Geologic Hazard Abatement District ("District") hereby request that the City Council of the City of Dublin initiate proceedings for formation of the District to include the territory described in Exhibit B("Legat Description") and Exhibit C("Boundary Map"), attached hereto, pursuant to the provisions of Division 17 of the Public Resources Code sections 26500 et seq. Said owners are the owners of all the territory proposed for inclusion in the District. (a) This petition is made pursuant to Division 17 of the Public Resources Code with particular reference to Article 3(commencing with Section 26550) and Article 4(commencing with Section 26561). (b) Opposite the signature of each petitioner is an indication of the lot, tract and map number or other legal description sufficient to identify the signature of the petitioner as that of an owner of land within the ` territory proposed to be included in the District. (c) Opposite the signature of each petitioner is an indication of the date on which said petitioner's signature was affixed to this petition. ATTACHMENT l~~ (d) The following documents are attached to this petition and are incorporated herein by reference as if set forth in full in the petition: i. A.Plan of Control prepared by an engineering geologist certified pursuant to Section 7822 of the California Business and Professions Code, which describes in detail geologic hazards, their location and the areas affected thereby, and a plan for the prevention, mitigation, abatement and control thereof (Exhibit A). _ ii. A legal description of the boundaries of the territory , proposed to be included in the District (Exhibit B); and iii. A map of the boundaries of the territory proposed to be Z. Z~ ~~ Date 2 Z~ l~ Date ~ z~ ~o Date ~avc~Q~ ~ ~escription of Property CAv ~ ~" ~ ~escription of Property ~~~ 3 Description of Property Signature of Petitioner ! _~ ~ 1 BERLOGAR STEVENS & ASSOCIATES SOIL ENGINEERS ENGINEERING GEOLOGISTS ~ ll~a ` ^ ~ ~ ~ ~ ! ~ ' , ~ ' ~ ' ~ ~ ~ ~ ~ ~ ~ PLAN OF CONTROL FALLON CROSSINC GHAD TASSAJARA ROAD DIJBLIN, CALIFORNIA FOR STANDARD PACIFIC HOMES May 25, 2011 BERLOGAR STEVENS & CisSOCIATES ~(Q~ Job No. 3058.000 ~ ' Via Hand Delivery May 25, 2011 I Job No. 3058.000 , Mr. Aaron Ross-Swain , Standard Pacific Homes 3825 Hopyard Road, Suite 275 Pleasanton, California 94588 ~ Subject: Plan of Control Fallon Crossing GHAD ~ Tassajara Road Dublin, California BERLOGAR IQ ~D ~ STEVENS & ASSOCIATES , Dear Mr. Ross-Swain: We are pleased to present herein Volume 1 of the Plan of Control for the Fallon Crossing ~ Geologic Hazard Abatement District (GHAD) in Dublin, California. Volume 2 will include record drawings and as-built documents to be created at the completion of site development. This Plan of Control has been prepared to satisfy Condition of Approval #26 for the Fallon , Crossing residential development and in accordance with California Public Resources Code, Division 17, sections 26500 et seq. ' Should you have any questions regarding this document, please do not hesitate to contact us. Respectfully submitted, ~ BERLOG ST e~~ ~ ~ ichael Clar F ~ CEG .1264 ~9 ~ ~ ~ ~ MC/FB:jmb TES Copies: Addressee (2) Ruggeri-Jensen-Azar & Associates (1) Attention: Mr. Mark Falgout 3058.000/21439.doc ~ ~ :~~~~ ftS5l0~,~c' .~ ~'~~~ `~~` g E ~~ ~G ~~G~ ~~ ~Q ~o. G.E 142 9~ ~` ~M ~ rank Ber ~ ;,,~'p - ~ ~; ~~~ \GP~ GE 142 ~ ~ J,~,~ `~TFC~~N `~~P ry `~ dF CA~.1F0~ ~ SOIL ENGINEERS ENGINEERING GEOLOGISTS 5587 SUNOL BOULEVARD PLEASANTON, CA 94566 (925) 484-0220 FAX: (925) 846-9645 G~ lC~~ 1 TABLE OF CONTENTS ' GLOSSARY OF TERMS ................................... ......................................................................... ... iii I. AUTHORITY AND SCOPE ......................................................................................................................... .. 1 ' II. PROPERTY IDENTIFICATION ................................................................................................................. .. 1 III. BACKGROUND ............................................................................................................................................ .. 1 ~ Permitting .....................................................................:........................................................................... General Site Location And Existing Conditions ....................................................................................... .. 1 .. 1 Proposed Site Development ...................................................................................................................... .. 2 ~ IV. Open Space ............................................................................................................................................... SITE GEOLOGY .........................................:................................................................................................. .. 3 .. 4 Regional Geology And Seismicity ............................................................................................................ .. 4 ~ Site Geologic Units ................................................................................................................................... Artificial Fill ...................................................................................................................................... .. 5 .. 5 Residual Soils And Colluvial Deposits .............................................................................................. .. 6 ~ Alluvial Deposits ............................................................................................................................... .. 6 Landslide Deposits ............................................................................................................................ .. 6 Bedrock .............................................................................................................................................. .. 6 ~ V. GEOLOGIC HAZARDS ................................................................................................................................. 7 Slope Instability ........................................................................................................................................ .. 7 ~ Soil Creep ................................................................................................................................................. Erosion And Sedimentation ...................................................................................................................... .. 8 .. 9 Seismic Ground Shaking ............................................................................................................................ 9 ~ Creek Bank Instability And Erosion ........................................................................................................... 9 Shrink/Swell Of Expansive Earth ............................................................................................................... 9 Compressible Soils .................................................................................................................................... . 9 Dispersive Soils ........................................................................................................................................ 10 ' VI. FUNDING AND ACCEPTANCE OF RESPONSIBILITY BY GHAD .................................................... 10 Property Owner Assessments ................................................................................................................... 10 1 Transfer Of Responsibility To The District .............................................................................................. 10 VII. AREAS OF GHAD RESPONSIBILITY ...................................................................................................... 10 ~ Prevention, Mitigation, Abatement And/Or Control Of Geologic Hazards .............................................. Exceptions ................................................................................................................................................ 10 11 Isolated Or Remote Slope Instability ................................................................................................. 11 ~ Single Property .................................................................................................................................. Geologic Hazard That Requires Expenditure In Amount Exceeding The Value Of The 1'hreatened 11 Or Damaged Improvement ......................................................................................................... 11 ~ GHAD Funding Or Reimbursement For Damaged Or Destroyed Structures Or Site Improvements Earthquake Insurance ........................................................................................................................ 12 12 No Reimbursement Without Written Agreement .............................................................................. 12 ' Properiy Not Located Within GHAD Boundaries ............................................................................. Protected Habitat Under Conservation Easement ......................:....................................................... 12 13 Geologic Hazards In Open Space And Maintenance Of Open Space Areas ............................................ 13 , VIIL GEOTECHNICAL TECHNIQUES FOR MITIGATING LANDSLIDE AND EROSION HAZARDSI4 IX. BIOTECHNICAL RECOMMENDATIONS FOR PREVENTING AND MTTIGATING EXISTING OR POTENTIAL EROSION HAZARDS ................................................................................................... 15 ~ 1 1 BERLOGAR STEVENS & ASSOCIATES ~ ~ ~`~° ~ TABLE OF CONTENTS (continued) ~ X. PRIORITY FOR GHAD-FUNDED REPAIRS ........................................................................................... 15 I XI. RESERVE FUNDS ......................................................................................................................... ............... 16 XII. MAINTENANCE AND MONITORING SCHEDULE ................................:.............................. ............... 16 XIII. LIMITATIONS ............................................................................................................................... ...............18 1 Attachments: References Plate 1 - Vicinity Map ~ Plate 2- Pre-Development Geologic Map Plate 3- Remedial Grading Plan ~ Exhibit A- Open Space Ownership arid Maintenance Responsibilities Exhibit Exhibit B- Legal Descriptions of GHAD Boundaries and Maintenance Easement Exhibit C- Plats of GHAD Boundaries and Maintenance Easement Exhibit D- Deed Restriction Exhibit ' Appendix A- Detention/Water Quality Basin Operations and Maintenance Manual Appendix B- Fire Hazard Mitigation and Defensible Space Vegetation Management Plan Appendix C- Riparian Mitigation & Monitoring Plan ~ ~ ~ ~ ~ ~ C~ i [~ 1 ~~ BERLOGAR STEVENS & ASSOCIATES ~ ~~ ~~~ ! GLOSSARY OF TERMS ' Board of Directors - The governing body of the Geologic Hazard Abatement District. For the , Fallon Crossing GHAD, the initial Board of Directors is the Dublin City Council. Fallon Crossing Site or The Site - The roughly 68-acre parcel of land including both the , development area of Tract 7617 and the undeveloped open space. Refer to Plate 1. Geologic Hazard Abatement District (GHAD) - A district formed under California Public ~ Resources Code 26500-26601 that is intended to handle long-term abatement and control of real property threatened by earth movement. ~ Geologic Hazard - An actual or threatened landslide, land subsidence, soil erosion, earthquake, fault movement, or any other natural or unnatural movement of land or earth. 1 GHAD Boundaries - The limits of GHAD responsibilities as shown on Exhibit A. GHAD Maintenance Area - The area of GHAD maintenance responsibilities including Parcels A and H as well as the maintenance easement as shown on Exhibit A. GHAD Maintained Facilities - Facilities to be maintained by the GHAD, including concrete V 1 ditches, drainage facilities, subdrain outfalls, ponds and basins. GHAD Ownership Areas - The areas that the GHAD will have ownership over shown as ~ Parcels A and H on Exhibit A. Preserve - For the purposes of this document the preserve includes those areas within the Open ~ Space parcel "Parcel A" and the Riparian Corridor located within Parcel H, except for the areas referred to as Water Quality and Detention Basin. ~ , , ~ ~ ~ 1 GHAD Manager - The person in charge of overseeing GHAD related activities including budgeting, evaluation of assessments, contracting maintenance work, contracting technical consultant, and reporting to the Board of Directors. Plan of Control - A report prepared by an engineering geologist certified.pursuant to Section 7822 of the Business and Professional Code or a firm of engineering geologists which describes in detail a geologic hazard, its location and the area affected thereby, and a plan for the prevention, mitigation, abatement, or control thereof. , BERLOGAR STEVENS & ASSOCIATES iii May 25, 2011 /~ , Job No. 3058.000 ~~~ Page 1 ~ TRACT 7617 - FALLON CROSSING ~ PLAN OF CONTROL , I. AUTHORITY AND SCOPE ~ Formation of the Fallon Crossing Geologic Hazard Abatement District (GHAD) is proposed under authority of the California Public Resources Code, Division 17, sections 26500 et seq. ~ As required by Public Resources Code section 26509, an engineering geologist certified pursuant to section 7822 of the Business and Professions Code has prepared this Plan of Control which describes the potential geologic hazards within the Fallon Crossing GHAD boundaries. It also ' provides a plan for the prevention, mitigation, abatement, and control thereof. As used in this Plan of Control and as provided in Public Resources Code section 26507, "geologic hazard" means an actual or threatened landslide, land subsidence, soil erosion, earthquake, fault ~ movement or any other natural or unnatural movement of land or earth. , II. PROPERTY IDENTIFICATION The GHAD boundaries, shown in E~chibits B and C to this Plan of Control, include 47 acres of ' land within the Fallon Crossing site (The Site). Exhibit A is a plan entitled Open Space Ownership and Maintenance Responsibilities E~chibit, Tract 7617 - Fallon Crossing, prepared by Ruggeri-Jensen-Azar (RJA), dated October 2007. The plan shows the areas of the site that will ~ be owned and maintained by the GHAD and a 0.22-acre maintenance easement between the - Fallon Crossing development and the adjacent Silvera Ranch development. The GHAD will have maintenance responsibilities over, but will not own the easement. The legal descriptions 1 and Plats of the land within the Fallon Crossing GHAD are contained in Exhibits B and C, respectively. 1 III. BACKGROUND ' PERMITTING ~ Construction for Fallon Crossings will be carried out under permits issued by the City of Dublin, California Department of Fish and Game, National Fish and Wildlife Service, United States Army Corps of Engineers, and the Regional Water Quality Control Board. Certain conditions of 1 these permits may survive construction and may apply to ongoing GHAD management activities. , GENERAL SITE LOCATION AND EXISTING CONDITIONS The site is an irregularly shaped parcel including about 68 acres of land located on the northeast ~ side of Tassajara Road, about 2'/4 miles north of Interstate Highway 580. Tassajara Road and Moller Creek, a tributary of Tassajara Creek, border the western and northwestern limits of the ~ BERLOGAR STEVENS & ASSOCIATES ~ May 25, 2011 /~ I ~ Job No. 3058.000 ~ J ~p Page 2 ' site. MoIler Creek flows to the south-southwest into a culvert crossing under Tassajara Road. Grading for the Silvera Ranch residential development has been performed on the south and ~ southwest sides of the site. Open land borders the remainder of the site to the north and east. The site location is shown on the Vicinity Map, Plate l. ~ When this Plan of Control was prepared, the site was vacant and used for cattle grazing. A pond (labeled as "Lower Pond" on Exhibit A) is located adjacent to Moller Creek in the northwest corner of the site. Another intermittent pond (labeled as "Upper Pond" on Exhibit A) was ~ created by a man-made artificial fill berm placed in a drainage swale, upslope of the development. Additionally, there is an existing conservation easement at the site that includes the "Lower Pond" and a 200-foot wide. radius around the pond. ~ A ridge roughly 200 feet high trends east-west and dominates the northern portion of the site. This ridge slopes down to the development area at gradients as steep as about 2 horizontal to 1 , vertical (2H:1 V) near the top, but generally slopes between 2'/ZH:1 V to 3H:1 V or less steep as shown on the Pre-Development Geologic Map, Plate 2. A shallow drainage course drains westerly along the toe of the ridge and into Moller Creek. A man-made berm is located across 1 the drainage in the northeast portion of the site to form the "Upper Pond" about 450 feet east of the development area. Two smaller west-east trending ridge spurs separated by a small drainage swale extend into the southern portion of the site from the east. The ridge spurs are between ~ about 80 to 100 feet high with side slopes as steep as 2%ZH:1 V along the northern slope of the northern spur and 3H:1 V or less steep elsewhere. The spurs slope down to a relatively level plane east of Moller Creek. The plane ranges from about 100 to 300 feet wide. ' Site to o raphy ranges in elevation from 450 feet above mean lea level in Moller Creek in the Pg southwestern portion of the site near Tassajara Road to about 705 feet on the top of the northern , ridge. On-site vegetation consists of seasonal grasses on the slopes and in the valleys, and dense bushes and trees concentrated near the tributary creek. The site generally drains to the west. ~ PROPOSED SITE DEVELOPMENT The Fallon Crossing residential development is shown on the project grading plans prepared by ~ RJA, dated May 2, 2008. The grading plans show that the site will be developed into 106 single- family residences. Grading will be limited to about the western half of the site and extending , beyond the property line into partially graded ground within the adjacent Silvera Ranch development to the southeast and tying into an existing engineered fill slope of the Silvera Ranch development to the south. The roadways will include a main loop road that will connect to , Tassajara Road on the southwest side of the development and loop around the development in a clockwise direction to connect to Cydonia Road to the southeast. Three cul-de-sacs will extend to the southeast from the western stretch of the loop. Site grading will steepen the lower portion ~ of the slope in the eastern portion of the development. The spur ridges in the southern portion of the site will be modified by a combination of cuts and engineered f lls. A water quality pond and two detention basins are planned next to Moller Creek. We understand that future development 1 of adjacent properties (Moller Ranch) will include rerouting Moller Creek to the south into a culvert to pass beneath Tassajara Road. The design of the creek realignment and culvert should be provided to the Fallon Crossing GHAD for review and acceptance. ~ ~ BERLOGAR STEVENS & ASSOCIATES May 25, 2011 `~ // b ~ Job No. 3058.000 ~EJ ~ Page 3 , OPEN SPACE 1 Exhibit A of this Plan of Control shows the area of Fallon Crossing GHAD ownership as Parcels A and H collectively referred to as the Open Space. Parcel A is located upslope of the development area on the north and northeast sides. Parcel A consists mainly of undeveloped ~ open space and is bound by the Fallon Crossing and Silvera Ranch developments to the south, Parcel H to the west, and open graze land to the north and east. Parcel H is located in the northwest portion of the Fallon Crossing GHAD-owned open space and,is located along Moller ~ Creek that is northwest of the development area. The GHAD will maintain a 15-foot wide maintenance easement that is owned by the TR 7450 Home Owners Association (HOA). The maintenance easement is located in open space between the southeast side of the Fallon Crossing ~ development and the upslope Silvera Ranch development. The maintenance easement will be transferred to the GHAD upon the turnover of Parcel A& H to the GHAD pursuant to Section VI of this document. ~ Parcels B, C, D, E, F, and G are HOA owned and maintained properties. Parcel B is a linear park located between the development area and Parcel H. There is a 15-foot wide access , easement at the south end of Parcel B. Parcel C is a landscaped area along Tassajara Road. Parcel D is an open space located in the interior of the development area. Parcel D will consist of a northwest-facing slope that is planned to be an irrigated vineyard. Parcel E is a , neighborhood park located at the eastern edge of the development area. There is a 15-foot-wide access easement through this parcel. Parcels F and G are landscaped areas. ' Open space within the Fallon Crossing GHAD boundaries (Parcels A and H and the maintenance easement) shall be managed under the terms of the agreements between the developer and City of Dublin, this Plan of Control and any subsequent updates or amendments, the existing ' conservation easement that was recorded on the property in 2001 to satisfy biological mitigation measures, and the Fallon Crossing Riparian Mitigation and Monitoring Plan. A deed restriction ~ will be recorded over Parcel A and a portion of Parcel H(excluding the detention basin and water quality pond) for the benefit of preserving the natural habitat; Exhibit D depicts the area covered by the deed restriction. The Deed Restriction will enable to the GHAD to conduct ~ GHAD activities to protect the habitat area in an appropriate manner without interaction with the regulatory agencies. , Within the areas owned and maintained by the GHAD (parcel A and H), the GHAD's responsibilities may consist of, but are not limited to, the following: ~ • Open Space maintenance ~ Slope stabilization (landslides and erosion hazards) ' • Creek bank stabilization, when needed • Maintenance of the detention and water quality ponds including but not limited to thinning/removal of vegetation and sediment ~ • Subdrain outfall inspection and maintenance • Concrete lined V ditch maintenance, and repair or replacement 1 • Sediment removal (from concrete structures) ' BERLOGAR STEVENS & ASSOCIATES May 25, 2011 /(f , Job No. 3058.000 ~ C~~ Page 4 ' ~ ~ ~ ~ ' ~ , ' ~ ~ ~ • GHAD monitoring program • Contracting technical consultants • Geotechnical instrument monitoring (if installed in the future) • Equipment maintenance and operation in GHAD-maintained areas • Upper and Lower Pond repairs and rehabilitation (as discussed in Appendix B) • Vegetation control including revegetation and fire break mowing (as discussed in Appendix C) RIPARIAN ENHANCEMENT As a part of the permitting process with the Regional Water Quality Control Board (RWQCB) and California Department of Fish and Game (CDFG), a small portion of Parcel H within the existing conservation easement (depicted in E~ibit D) will benefit from riparian enhancement. The general purpose of the proposed mitigation is to enhance and expand the width of the existing riparian corridor along Moller Creek and provide species access to the creek from an existing stock pond known to contain CRLF. The 0.17 acres (150-foot by 50-foot section of Moller Creek) of riparian habitat enhancement/restoration work will consist of tree/shrub planting and the installation of temporary irrigation. Because this is a permit requirement, there will be maintenance and monitoring requirements associated with this enhancement work. For years 1 through 10, the maintenance and monitoring activities and expenses will be the responsibility of Standard Pacific Homes. Upon acknowledgement from the Agencies that the mitigation has reached its success criteria, management responsibilities which consist of reduced maintenance and monitoring will be turned over to the GHAD. These additional management activities that the GHAD will inherit will be incorporated into the GHAD's Engineers Estimate to generate funds to cover these additional activities. For details regarding the riparian enhancement work and for all maintenance and monitoring requirements, reference the Mitigation and Monitoring Plan incorporated herein as Appendix C and Section XII of this document IV. SITE GEOLOGY , REGIONAL GEOLOGY AND SEISMICITY The site is located within the Coast Ranges geomorphic province of California. The Coast , Ranges province is characterized by a series of northwest trending, folded and faulted mountain ranges and valleys. In this part of the province, sedimentary bedrock units have been mapped as the Tassajara Formation by Dibblee (1980) and Crane (1988). Graymer et al, (1996) and ' Barlock (1988) include these rocks as part of the Livermore Gravels. These materials were deposited during the Pliocene to Pleistocene epochs of geologic time (approximately 0.01 to 5.3 million years before present). The low-lying area at the site includes a Pleistocene alluvial ' terrace that has been incised by Moller Creek that crosses the northern portion of the site. ~ ~ BERLOGAR STEVENS & ASSOCIATES May 25, 2011 Q / Job No. 3058.000 v llQ ~ ' ~ Page 5 ' The region has been folded and faulted during the past few million years due to oblique strike- slip relative motions between the Pacific Plate and North American Plate. The site does not lie ~ within an earthquake fault zone for active faults as defined by the State of California (Bryant and Hart, 2007; Davis 1982). Major active faults in the region that influence the seismicity of the site include, but are not limited to, the Greenville fault located about 7 miles to the northeast, and , the Calaveras, Hayward and San Andreas faults located about 4, 11 and 30 miles to the southwest, respectively. The projected surface interception of the (blind) Mount Diablo Thrust fault is located about 2,000 feet south of the site. I SITE GEOLOGIC UNITS , Artificial Fill Existin~ Non-engineered Fills. There are two areas of non-engineered fill present at the site, as ' shown by the symbol "Qaf' on the Pre-Development Geologic Map. The non-engineered fills consist of a stockpile in the northeastern portion of the planned development area and a berm forming the dam of the "Upper Pond". The existing stockpile of non-engineered fill located ~ within the development area will be removed during mass grading of the site. The non- engineered fill berm at the "Upper Pond" is planned to remain. , ' ~ ~ ~ , , ' ' i ~ Off-Site Existin~~ineered Fill. Grading for the Silvera Ranch development has altered the ground surface of the adjacent property to the south. Engeo Incorporated prepared two reports in 2005 and 2006 that documented the results of Engeo's observation and testing services during grading of the adjacent Silvera Ranch residential development. The Engeo reports discuss the location of landslide remediation, subdrain installation, and engineered fill placement. As a result of the Silvera Ranch grading, engineered fill has been placed against the southern limit and upslope of the southeastern limit of the site. These fills are outside the GHAD-maintained open space area and it is not expected that these off-site fills will require attention by the Fallon Crossing GHAD. Future Engineered Fill. To grade for the planned residential development at the site, the swale areas are to be filled and spur ridges truncated by cuts. Engineered fill at the site will be constructed up to about 38 feet thick and will be placed on a properly prepared and geotechnically approved base. The geotechnical reports prepared by Berlogar Geotechnical Consultants (BGC) in 2001 and 2003 include the recommendation that an engineering geologist map future cut slopes for the Fallon Crossing project during construction. Based on such observations, there is the potential that the engineering geologist will recommend reconstructing selected portions of cut slopes with engineered fill. The limits of such future slope rebuilds cannot be predicted at the_ time of preparation of this Plan of Control; therefore, the project Remedial Grading Plan is provided as Plate 3. It is anticipated that the engineering geologist will document such locations of slope rebuilds, if any, during construction. It is anticipated such construction-record documents will be available to professionals assisting the Fallon Crossing GHAD. BERLOGAR STEVENS & ASSOCIATES ~ May 25, 2011 /9 1i ,~ ~ Job No. 3058.000 ~ l JU/`•~ Page 6 ~ Residual Soils and Colluvial Deposits , Residual soils, derived by in-place weathering of the underlying parent bedrock, are located , along ridgelines and spur ridges. The residual soils at the site consist of dark gray and dark gray- brown silty clay (CL-CH). Typically the thickness of residual soils ranges from about 2 to 4 ' feet. The residual soils have a moderate to high plasticity and are considered highly expansive (BGC, 2003). Colluvial. deposits, generated by the downslope creeping of residual soils andlor their transportation by erosion, are located near the toes of slopes, in swales and near the , upstream end of valleys. Areas underlain by deposits of colluvium are delineated by the map symbol "Qc" on the Pre-Development Geologic Map. The colluvial deposits at the site consist of yellow-brown to dark brown silty clay (CH), have a high plasticity and are considered highly ~ expansive (BGC, 2003). Desiccation cracks up to about 3 inches wide and about 2 to 3 feet deep have been observed at the site in the summer months demonstrating the expansive nature of these residual and colluvial soils. ~ ~ Alluvial Deposits ~ Alluvium is material that has been transported and deposited by flowing water. Alluvial deposits were noted within and adjacent to Mollar Creek and its tributaries. The alluvial soils at the site generally consist of stiff to very stiff sandy clay and silty clay (CL-CH), medium stiff to stiff , clayey silt (ML), medium dense sandy silt (ML), clayey sand (5C) and silty sand (SM) (BGC, 2003). The alluvial deposits are delineated by the symbols "Qoa" (older alluvium) and "Qal" on the Pre-Development Geologic Map. The clayey portion of the alluvial soils have moderate to , high plasticity and are considered highly expansive (BGC, 2003). Landslide Deposits ~ A landslide is a mass of rock and/or soil that has because of the force of ravit broken free ~ g Y~ from intact earth along some discrete surface and has moved downslope. Landslides have a ~ variety of shapes, sizes, modes of movement, and material properties. They can consist of debris flows, earth flows, rotational slumps, or rock glides; there are also other less common types. The ~ landslides at the Fallon Crossing site appear to be a combination of soil slips, slumps and earthflows. Regional landslide maps prepared by the California Division of Mines and Geology (Ma~mundar, 1991) and the U.S. Geological Survey (Nilsen, 1973 and 1975) show several ~ suspected landslides within the site boundaries. The project's geotechnical reports (BGC, 2001 and 2003) have identified two landslides, designated as Landslides A and B that impact the development area. These two landslides will be completely removed and replaced with , engineered fill during site grading as shown on the Remedial Grading Plan for the site. There are additional suspected landslide deposits elsewhere on the site, but these are well outside (north and east) of the development area. The landslides identified at the site are delineated by the map 1 symbol "Qls" along with their letter designation (A through H) on the Pre-Development Geologic Map. ' Bedrock ~ Bedrock units of the Plio-Pleistocene aged (roughly 0.01 to 5.3 million years before present) ' Tassajara Formation underlie the site. In general; the Tassajara formation includes layers of sandstone, siltstone; claystone and conglomerate. These rocks are generally moderately to ~ ~ May 25, 2011 ao ~~~ Job No. 3058.000 Page 7 , highly weathered, friable, and moderately to highly fractured. Commonly, the claystone beds and some of the clayey siltstone beds are moderately to highly expansive. The areas underlain , by the Tassajara formation near the ground surface are delineated by the symbol "QTt" on the Pre-Development Geologic Map. i V. GEOLOGIC HAZARDS ' Geologic hazards identified at the site consist of potential slope instability, soil creep, erosion and sedimentation, seismic (earthquake) ground shaking, creek bank erosion, shrink and swell of expansive earth materials, compressible soils and dispersive soils. The grading for the planned , development is not expected to entirely eliminate the geologic hazards from the site. The geotechnical reports prepared by BGC (2001 and 2003) have identified the geologic hazards that impact the planned development. The Remedial Grading Plan shows the planned treatment of ~ the geologic hazards and other geotechnical factors identified within the development area that pose a direct impact to planned lots and site improvements. It is anticipated that field-verified geologic mapping will be undertaken during site grading operations. The record documents ~ showing subdrain locations and outfall elevations, bedrock structure, springs (if encountered), • and landslide/unstable soil areas limits and repairs shall be provided to the Fallon Crossing GHAD when available as Volume 2 of this Plan of Control. A brief description of the geologic 1 hazards within the Fallon Crossing GHAD boundaries is included below. ~ SLOPE INSTABILITY Slope instability is common in the San Francisco Bay Area and is not umque to the site. In , general, the stabilization of landslide masses and unsuitable materials on the slopes of the GHAD ownership and maintenance area will be performed during site grading only for slopes that could directly threaten improvements within the development area. It is considered neither practical ~ nor desirable to remove all landslide deposits and/or unstable soil areas from the surrounding hillsides during site grading. In addition to areas of slope instability identified during geotechnical explorations, geologic reconnaissance performed before site development, and ~ geologic observations made during site grading, areas of slope instability and/or landsliding could become apparent during the life of the development. Since earth instability is the GHAD's primary geotechnical concern, this section describes several types of slope instability that are the ~ GHAD's responsibility. See also Section VIII below under the heading Geotechnical Techniques for Mitigating Landslide and Erosion Hazards. ~ Landslides located within open space are natural landforms that typically do not require mitigation. Where they do merit mitigation, it is where they could affect man-made improvements. GHAD maintenance will be important to provide and maintain adequate ~ protection for the site improvements. See Section XII below under the heading Maintenance and Monitoring Schedule. Rainwater and artificial watering can raise pore pressures between earth particles and reduce the frictional forces holding the earth material together. Thus, water tends to reduce the strength of the earth material. For this reason, slope stability is lower and landslides occur more frequently ~ in the winter, which is the rainy season in California. Intensive tunneling by burrowing animals can provide pathways for surface water to permeate into the ground, sometimes leading to ~ BERLOGAR STEVENS & ASSOCIATES ~ ~ ' ~ ' i ' ~ ~ ' ~ ~ ~ May 25, 2011 ~ l I j„ ~ Job No. 3058.000 r~~~ ~ ~~~ Page 8 saturation of slopes and soil slips. Seismic ground shaking imposes forces on a slope that lowers slope stability and may increase landslide movements. The following table lists the areas of slope instability, their impacts to site improvements and the potential GHAD maintenance responsibilities. SLOPE INSTABILITY AND GHAD MAINTENANCE TABLE Location Potential Impact to Potential GHAD Site Im rovements Maintenance Res onsibilities Slopes above development If instabilities Slope monitoring required. Future area develop in the future, instabilities, should they develop, they could threaten would likely require removal of the homes and site unstable mass and replacement with improvements engineered fill. Mitigation to be determined by technical consultant and based on site-s ecific characteristics. Slopes located in Open Potential to block Slope monitoring required. Impact to Space and not within drainage. be evaluated by technical consultants develo ment area Landslides A and B None after site Monitor reconstructed slopes. development. Landslide C Potential to block Monitoring required. Future landslide drainage. movement may require removal of soil and/or slo e re-contouring Landslides D, E and F Future landslide Slope monitoring required. Removal of movement could materials at the toe may be needed to block the flow of allow for drainage. Tectinical water resulting in consultants to determine extent of increased erosion and removal so that remaining upslope sedimentation in the mass is not destabilized. "U er Pond". Landslides G and H None Future landslide movement not expected to result in GHAD maintenance. Future grading of the off-site portions of these landslides shall be reviewed by the GHAD for potential impacts to the Fallon Crossing GHAD. ~ SOIL CREEP ~ Soil creep is the gradual, diffuse downslope movement of surficial soil under the influence of gravity. Soil creep differs from landsliding in that creep does not involve a separation of earth material across any distinct surface. Creep moves at a speed imperceptible to the eye, on the ' order of a few inches per decade. Typically creep occurs in colluvial soil, though it can also occur in engineered fill, alluvium, and bedrock. ~ Soil creep has been observed at the site in the areas shown on the Pre-Development Geologic Map and is generally outside the area of site improvements. The potential GHAD maintenance responsibilities of soil creep to the Fallon Crossing GHAD are low. , , BERLOGAR STEVENS & ASSOCIATES May 25, 2011 I,, ~ ~ Job No. 3058.000 ~ I w Page 9 1 , ~ ~ ~ ' EROSION AND SEDIMENTATION Erosion is the movement of soil particles down a slope or channel by the flow of running water as sheetwash or rivulets. The soil particles are suspended or otherwise entrained in the water, as shown by the water's turbidity or cloudiness. Water usually does not flow in just a sheetwash mode for long and soon begins forming rivulets. Rills, which are tiny gullies, and then gullies are the result of concentrated water flow that remove soil on a slope. Where the slope gradient decreases or the water otherwise meets a barrier, the water slows and the soil particles settle out. The deposition of these soil particles is termed sedimentation. Vegetation can slow erosion, which will in turn reduce sedimentation. Conversely, a lack of vegetation can speed erosion and lead to down-gradient sedimentation. Slope height and concentration of water, natural or artificial, are also factors that contribute to erosion and sedimentation. Sedimentation could impact drainage facilities and the ponds and basins at the site. Sediment removal and erosion control will be needed. SEISMIC GROUND SHAKING ~ Future earthquakes of moderate to high magnitude are expected to occur in the region during the design life of the development. Strong ground shaking is expected to occur at the site as a result. To mitigate the shaking effects, structures will be designed under current building code ' requirements and using sound engineering judgment. Slope stability is also lowered under seismic-shaking conditions. ~ CREEK BANK INSTABILITY AND EROSION The channel of Moller Creek crosses the northern portion of the proposed GHAD boundary. The ~ creek banks may be locally over-steepened and be susceptible to instability and erosion. Observation of creek bank conditions, as ot~tlined in Section XII under the heading Monitoring and Maintenance Schedule, will be performed by the Fallon Crossing GHAD periodically. ' SHWNK/SWELL OF EXPANSIVE EARTH ~ Residual soils, colluvium, clayey alluvial soils, engineered fill, and some bedrock layers at the site could have a potential to shrink and swell with changes in moisture content. Such ~ movements potentially would cause heaving and cracking of slabs-on-grade, pavements, and structures founded on shallow foundations. It is anticipated that design and remedial grading under engineermg control and the use of structural slab foundations will mrtrgate the potential for ~ shrink and swell and reduce the potential hazard to low. COMPRESSIBLE SOILS ~ Colluvial deposits and alluvial soils are types of material that could be potentially compressible. Compression potentially would cause lowering and cracking of slabs-on-grade, pavements, and ~ structures founded on shallow foundations, and sags in gravity controlled utility pipelines (storm and sewer). It is anticipated that some settlement of the thicker engineered fills will occur with site development but that those settlements will be within tolerable limits of the site ~ improvements. It is anticipated that design and remedial grading under engineering control will mitigate the potential for soil compression and reduce the potential hazard to low. ~ BERLOGAR STEVENS & ASSOCIATES May 25, 2011 ' ~~ , Job No. 3058.000 Page 10 i ~ DISPERSIVE SOILS ~ The northwest portion of the site located adjacent to Moller Creek appears to be underlain by dispersive soils. The soils may contain dispersed clay particles that go into suspension in ' flowing water (both surface and subsurface) and potentially contain soluble salt minerals. As a result, the areas underlain by the dispersive soils are highly erodible and sometimes form sinkholes. It is anticipated that design and remedial grading under engineering control will , reduce the hazard of dispersive soils at the site to low. , VI. FUNDING AND ACCEPTANCE OF RESPONSIBILITY BY GHAD PROPERTY OWNER ASSESSMENTS ~ The Fallon Crossing GHAD is funded in perpetuity by assessments that are paid by the residences. Subject to applicable law, an annual assessment must be promptly implemented on , all residential parcels in the GHAD boundaries. The assessment will be levied by the Fallon Crossing GHAD on each individual residential parcel beginning the first fiscal year after the City issues a building permit for that parcel. Annual assessments will be based on the projected costs ~ that are incurred from the implementation of the geotechnical scope outlined in this document. The actual assessments will be calculated in the Engineers Report that will be developed subsequent to the approval of this document by the City Council. ~ TRANSFER OF RESPONSIBILITY TO THE DISTRICT ' The party that, on the date that the City records the Final Map within the boundaries of the Fallon Crossing GHAD, owns the developable parcels shown on that Final Map has the , responsibility to perform all the activities of the Fallon Crossing GHAD on property within that Final Map. Such responsibility shall automatically transfer to the Fallon Crossing GHAD at 9:00 a.m. on the day exactly three years after the first residential building permit is issued by the City. ~ This transfer date may be extended at the sole discretion of the project developer provided that the assessments continue to be levied during the extension period and that notice of such extension is delivered to the GHAD manager at least 30 days before the transfer date. The ' petitioners for formation of the Fallon Crossing GHAD intend that the approximately three-year period between the levying of the GHAD assessment and the Fallon Crossing GHAD becoming responsible to perform activities on property within the Final Map will allow the District to ~ accumulate reserve funds without incurring significant expenses. Such reserve funds are needed to address periodic major events that cannot be funded from annual revenues. ~ VII. AREAS OF GHAD RESPONSIBILITY ' PREVENTION, MITIGATION, ABATEMENT AND/OR CONTROL OF GEOLOGIC HAZARDS Subject to the following exceptions, the primary mission of the Fallon Crossing GHAD shall be ~ the prevention, mitigation, abatement, and/or control of geologic hazards within its boundaries that have damaged or that pose a significant threat of damage to site improvements within the ~ BERLOGAR STEVENS & ASSOCIATES May 25, 2011 ~ ~~ I /„ ~ , Job No. 3058.000 ~ U~ Page 11 ' ' ~ development areas of the site. As used herein, the term "site improvements" means buildings and outbuildings, roads, sidewalks, paths, utilities, improved trails, swimming pools, tennis courts, gazebos, cabanas, basins, geologic stabilization features, drainage features, or similar improvements. The exclusions and limitations set forth herein do not apply to geologic liazards existing on open-space property owned by any homeowner's associations except for the maintenance easement from the upslope Silvera Ranch development, since these areas are not part of the responsibility of the Fallon Crossing GHAD. , The secondary mission of the Fallon Crossing GHAD is to maintain the biological values of the open space by adhering to the conditions and restrictions set forth in the Resource Management Plan and the deed restriction. I EXCEPTIONS ~ The Fallon Crossing GHAD is not responsible for open space tasks that will be provided by the City of Dublin or the homeowners association as set forth in Exhibit A or in any future memoranda or agreements. The Fallon Crossing GHAD's role is limited to overseeing and 1 supervising the City's general physical maintenance of the open-space areas as may be required to prevent, mitigate, control, or abate erosion, sedimentation, and potential landslide hazards. ' The Fallon Crossing GHAD may decline to prevent, mitigate, abate, or control geologic hazards under the following circumstances: ' Isolated or Remote Slope Instability The Fallon Crossing GHAD will not have responsibility or may place a low priority on its ' responsibility to monitor, abate, mitigate, or control slope instability that does not involve damage, or pose a significant threat of damage, to site improvements, including residences. ~ Single Property The Fallon Crossing GHAD will not prevent, mitigate, abate, or control geologic hazards that are ' limited in area to a single parcel of property unless the geologic hazard has damaged, or poses a significant threat of damage, to site improvements located on other property within the GHAD boundaries. The GHAD maintenance area (Parcels A and H on Exhibit A) shall not be ' considered a"single parcel of property" for the purpose of this limitation, regardless of whether it may actually comprise a single legal parcel. ~ Geologic Hazard That Requires Expenditure in Amount Exceeding the Value of the Threatened or Damaged Improvement ~ The Fallon Crossing GHAD will not prevent, mitigate, abate, or control a geologic hazard where, in the GHAD manager's sole discretion, the anticipated expenditure required to be funded by the ~ Fallon Crossing GHAD to prevent, mitigate, abate, or control the geologic hazard will exceed the value of the structure(s) and site improvement(s) threatened with damage or loss. ' BERLOGAR STEVENS & ASSOCIATES ' ' May 25, 2011 ~~ I / ~ Job No. 3058.000 ~ ~Q Page 12 ' ' ~ LJ ~ ' ~ ~ ~ ~ ' ~ ' ~ GHAD Funding or Reimbursement for Damaged or Destroyed Structures or Site Improvements In the event a residence or any other private structure, site improvement, or landscape feature is damaged or destroyed as a result of a geologic hazard, the Fallon Crossing GHAD may fund or reimburse the property owner for the expenses necessary to repair or replace the damaged or destroyed structure, site improvements, or landscaping, with the exceptions noted above. Unless otherwise authorized by the board of directors, the dollar amount of the Fallon Crossing GHAD funding or reimbursement may not exceed ten percent (10%) of the costs incurred by the Fallon Crossing GHAD in preventing, mitigating, abating, or controlling the geologic hazard causing the damage. In the event the geologic hazard damaged or destroyed a structure, site improvement or landscaping that violated any provision of the City of Dublin Building Code or City of Dublin Municipal Code applicable at the time of its installation or improvement, the Fallon Crossing GHAD may decline to provide any funding or reimbursement to the property owner for repair or replacement of the damaged structure, improvement, or landscaping. Earthquake Insurance The Fallon Crossing GHAD is not intended to serve or provide "in-lieu" earthquake insurance for private property owners. Obtaining the adequate level of earthquake insurance is the sole responsibility of the individual property owners within the Fallon Crossing development. No Reimbursement without Written Agreement The Fallon Crossing GHAD will not be obligated to reimburse a property owner for expenses incurred by the property owner fo"r the prevention, mitigation, abatement, or control of a geologic hazard absent a written agreement between the property owner and the Fallon Crossing GHAD to that effect, executed before the property owner incurs said expenses, and following an investigation conducted by the Fallon Crossing GHAD. Property Not Located Within GHAD Boundaries Except as herein provided, the Fallon Crossing GHAD shall not prevent, mitigate, abate, or control geologic hazards located on property that is not located within the GHAD boundaries. In the event, however, that all or any portion of a geologic hazard existing on property located outside the GHAD boundaries has damaged or poses a significant risk of damage or site or other physical improvements located on property within the GHAD boundaries, the Fallon Crossing GHAD may prevent, mitigate, abate, or control the geologic hazard. Any work conducted on property located outside of the GHAD boundaries shall be strictly ' limited to that necessary to prevent, mitigate, or control the damage, or threat of damage, to property located within the boundaries of the Fallon Crossing GHAD. Should the Fallon Crossing GHAD be required to respond to a geologic hazard outside the GHAD boundaries, the ' Fallon Crossing GHAD may take such actions as may be appropriate to recover costs incurred as a result of preventing, mitigating, abating, or controlling such geologic hazards from the responsible party, if any. , ~ BERLOGAR STEVENS & ASSOCIATES ~ May 25, 2011 a I~ ~ Job No. 3058.000 Page 13 ' Protected Habitat under I)eed Restriction ' Geologic Hazards that occur within the Open Space that do not damage or threaten improvements, homes, or biological features (including the upper and lower stock ponds), will not be mitigated for. ~ GEOLOGIC HAZARDS IN OPEN SPACE AND MAINTENANCE OF OPEN SPACE AREAS ~ The Fallon Crossing GHAD may prevent, mitigate, abate, or control the geologic hazards in open space axeas and other unimproved areas within the GHAD boundaries if the geologic hazards have damaged or have the potential to damage site improvements located on properties 1 within the GHAD boundaries or result in a major adverse biological impact if not corrected or rehabilitated. All such prevention, mitigation, abatement, and control shall be done in a manner consistent with the Detention/Water Quality Basin Operations and Maintenance Manual and the ~ Resource Management Plan. Due to the sensitive biological nature of the open space within the Fallon Crossing GHAD ownership and maintenance areas, procedures for mitigating geologic hazards are set forth in the Detention/Water Quality Basin Operations Manual and Resource 1 Management Plan are provided in Appendices A and B hereto. No management activities can be performed within the deed restricted areas which result in the loss of habitat or impacts to any special-status species without required agency permits. , The Fallon Crossing GHAD will be responsible for slope stabilization, including major landslide events that meet the criteria for repair listed above for the potential to impact site improvements. ' This also includes repair of minor landslides and debris flows which have the potential to affect both the upper and lower ponds. ~ The Fallon Crossing GHAD is also authorized to monitor erosion and sedimentation in open space areas that affect developed lots andlor improvements. In addition, the Fallon Crossing GHAD is authorized to repair erosion gullies, etc. in open space areas if they pose an immediate i threat to improvements, or wildlife habitat. Repair activities conducted within the Preserve will be coordinated with the California Department of Fish and Game and/or US Fish and Wildlife ~ Service. The Fallon Crossing GHAD is responsible for sediment and debris removal from concrete V ~ ditches and open space catch basins. The Fallon Crossing GHAD is further authorized to maintain surface and subsurface drainage facilities and improvements located in the GHAD mamtenance area, either by ownership or easement, including, but not necessarily limited to, ~ concrete V ditches, storm drain inlets and outlets in open space and drainage corridors and subdrain outlets. Occasionally, portions of V ditches may require repair or replacement due to cracking caused by expansive soils, and this will be the responsibility of the Fallon Crossing ' GHAD. The GHAD's creek channel maintenance responsibilities are limited to repairing substantial bank ~ failures that directly damage or threaten actual site improvements (buildings, roads, utilities, trails, basins, etc.). Landslides that block the flow~of water resulting in flooding of the site improvements may require immediate treatment. Downstream sedimentation resulting from ' creek bank erosion is considered a natural geologic process and is not the responsibility of the Fallon Crossing GHAD. Drainage channel improvement projects armoring channels with rock 1 BERLOGAR STEVENS & ASSOCIATES May 25, 2011 ~~ '/ ~ , Job No. 3058.000 «~ Page 14 ~ , ' ~ ~ or other materials may be undertaken by the Fallon Crossing GHAD as required. Creek repairs will be required to obtain agency authorizations prior to undertaking such activity. The Fallon Crossing GHAD is responsible for routine clearing of the firebreak anci general maintenance of Parcels A and H(other than geologic hazard abatement). The Fire Hazard Mitigation and Defensible Space Vegetation Management Plan discusses the procedures for firebreak mowing and is included herein as Appendix C. The Fallon Crossing GHAD should review such activities for their potential to damage or interfere with the operation of any GHAD- maintained improvements, to cause an increase in erosion and/or sedimentation, or in any manner aggravate or increase the potential of a landslide. Equipment maintenance and operations includes items of equipment related to geotechnical stabilization within the open space areas could include items such as sump pumps. ~ GHAD operations will include monitoring of geotechnical instruments (e.g., piezometers, inclinometers, settlement monuments, etc., if any) within the GHAD boundaries, including open space area as required. ~ ~ ~ ~J ~ ~ ~ ~ i ' ~ ' ~ The Fallon Crossing GHAD may review and has the right to approve or disapprove physical construction, maintenance, or repair activities proposed within the GHAD maintenance area that, at the discretion of the GHAD manager, could increase erosion or sedimentation or otherwise impact or affect the geologic stability of the area. Furthermore, no management activities can be performed within the deed restricted areas which result in the loss of habitat or impacts to any special-status species without required agency permits. Should the Fallon Crossing GHAD be required to perform maintenance activities that are the responsibilities of others, the Fallon Crossing GHAD shall take such actions against the responsible party as may be required to recover costs incurred as a result of such activities. VIII. GEOTECHNICAL TECHNIQUES FOR MITIGATING LANDSLIDE AND EROSION HAZARDS Techniques the Fallon Crossing GHAD may employ to prevent, mitigate, or abate landslide or adverse erosion damage include, but are not limited to, the following: 1. Agency authorization, if applicable. 2. Removal of the unstable earth mass. 3. Stabilization by either partial or total removal of the landslide, and safely stockpiling of material near the excavation and replacement with engineered fill provided with subdrainage. 4. Construction of structures to retain or divert landslide material or sediment. 5. Construction of erosion-control devices or materials such as gabions, rip-rap, geotextiles, or lined ditches. 6. Placement of drained engineered buttress fills. 7. Placement of subsurface drainage devices, e.g., subdrains or horizontal drilled drains. BERLOGAR STEVENS & A.SSOCIATES May 25, 2011 ~ I/„ ~ , Job No. 3058.000 ~ «J Page 15 , , 8. Slope correction such as gradient change, biotechnical stabilization, and slope trimming or contouring. 9. Construction of additional surface ditches and/or detention basins, silt fences, sediment traps, or backfill of erosion channels. ~ ~ 10. Re-vegetation of slopes by planting or hydro-seeding. Potential landslide and erosion hazards can best be mitigated by controlling soil saturation and ~ water runoff and by maintaining surface and subsurface drainage systems. The Fallon Crossing GHAD should use techniques to mitigate individual events of slope instability or erosion that are based on the recommendations of licensed professional technical consultants contracted by the ~ Fallon Crossing GHAD. Maintenance shall be provided for lined surface drainage ditches and benches and drop inlets. ~ IX. BIOTECHNICAL RECOMMENDATIONS FOR PREVENTING AND MITIGATING EXISTING OR POTENTIAL EROSION HAZARDS , Fill and cut slopes within the GHAD boundaries are expected to be erodible. Therefore, the maintenance of vegetative cover is especially important. Vegetation provides a protective , function on soil and exposed rock. Vegetation absorbs the impacts of raindrops, reduces velocity of runoff, and retards erosion. ' ~ In many instances, adequate erosion protection for slopes can be accomplished with carefully selected and placed biological elements (plants) without the use of structures (e.g., brush layering and willow wadding). ~ In other areas, biotechnical slope protection may involve the use of inechanical elements or structures in combination with biological elements to provide erosion control and help prevent ~ small-scale slope failures. Locally, crib walls, welded-wire walls, gabion walls, rock walls, rip- rap, and reinforced earth walls used in combination with carefully selected and planted 1 vegetation can provide high-quality slope protection. The vegetation may be planted on the slope above a low retaining structure or toe wall, or the interstices of the structure can be planted. , X. PRIORITY FOR GHAD-FUNDED REPAIRS ~ Emergency response and scheduled repair expenditures are to be prioritized by the GHAD manager, at his or her discretian, based on available funds, a prudent reserve, and the approved operating budget. ' Should available funds not be sufficient to undertake all of the identified remedial and preventive stabilization measures; the expenditures shall be prioritized as follows in descending order of , priority: 1. The preyention, mitigation, abatement, or control of geologic hazards that have either ' damaged or pose a significant threat of damage to critical structures, residences, critical underground utilities, basins or paved streets. , BERLOGAR STEVENS & ASSOCIATES May 25, 2011 p ' Job No. 3058.000 ~ I ~ Page 16 ' 2. The prevention, mitigation, abatement, or control of geologic hazards that have either damaged or pose a significant threat of damage to community buildings. / 3. The prevention, mitigation, abatement, or control of geologic hazards that have either damaged or pose a significant threat of damage to private or community recreation facilities (e.g., park structures, pools, spas, tennis courts, etc.). ' 4. The prevention, mitigation, abatement, or control of geologic hazards that have either damaged or pose a significant threat of damage to loss of landscaping or other similar , nonessential amenities. 5. The prevention, mitigation, abatement, or control of geologic hazards located entirely on open-space property and which have neither damaged nor pose a significant threat of ~ damage to any site improvements. 6. As part of the standard GHAD budgeting practices, funds shall be allocated annually for , the purpose of routine maintenance and management over the detention and water quality basins to ensure that they are operating as designed. ~ In performing any of the duties described above, the Fallon Crossing GHAD may seek reimbursements from public and private entities including, but not limited to, FEMA, City and County agencies, insurance companies, etc. , XI. RESERVE FUNDS ' ~ ~ ~ ~ , ~ ~ , Based on the Engineers Report as well as subsequent Engineers Reports, the GHAD manager will evaluate the appropriate amount of funds to be reserved for emergency and long-term capital replacement projects that have costs in excess of the annual maintenance and repair budget. The reserve funds may be evaluated annually based on the most recent costs of GHAD projects at the site. XII. MAINTENANCE AND MONITORING SCHEDULE Geologic features and GHAD-maintained facilities shall be inspected on a regular basis and as necessary. Inspections shall be scheduled to occur a minimum of three times per year in normal years and four or more times per year in years of heavy rainfall as determined by the GHAD manager. The inspections shall be scheduled to take place prior to the middle of October before the first significant rainfall, midwinter as appropriate during heavy rainfall years, and in April at about the end of the rainy season. The operations and maintenance of the basins shall be conducted pursuant to Operations and Maintenance Manual (Exhibit D, Appendix A). The frequency of the inspections shall be increased in years of higher-than-average rainfall intensity and/or occurrence. The following table summarizes the inspection schedule recommended herein. ' BERLOGAR STEVENS & ASSOCIATES II ~ , 1 ' ~ ~ 1 , May 25, 2011 .i ' / ~ Job No. 3058.000 `~ ~P Page 17 ITEM SUGGESTED TIMING OF INSPECTIONS Fall Winter S rin Site Slopes Annual for first 5 years post Annual development Creek Banks Annual After si nificant rainfall events Annual Basins Annual After si nificant rainfall events U er Pond Annual Concrete Annual After significant rainfall events Structures Drainage Annual After significant rainfall events Facilities The Fallon Crossing GHAD shall review its inspection schedule annually and assess the effectiveness of its preventive maintenance program on a regular basis. GHAD staff shall prepare an annual report to the board of directors with recommendations for maintenance and/or repair projects. If necessary, consultants will be retained to undertake the needed studies. The district geotechnical engineer and/or engineering geologist retained by the Fallon Crossing GHAD shall prepare an annual inspection report for presentation to the GHAD board of directors. Slopes• Site slopes shall be observed during scheduled site visits by a State of California , certified geotechnical engineer (GE) or certified engineering geologist (CEG) for indications of slope instability, seeps, or unusual erosion. The schedule shall be two times per year for the first five years post-development and annually thereafter or as determined by the GHAD manager. ' Creek Banks. A GE or CEG shall inspect the banks of the tributary creek on a regular schedule. The inspections would check for indications of potential instability and significant erosion. The ~ inspections shall be performed prior to winter and during or shortly following significant rainfall events budget permitting. ~ Upper Pond. The GHAD Manager shall inspect the pond annually. The inspections would check for indications of potential instability, significant erosion, sediment deposition, vegetation accumulation, signs of trespass and human disturbance. The pond shall undergo sediment ~ removal once every fifteen years or on an as needed basis as determined by the GHAD manager. Basins. A GE or CEG shall inspect the detention and water quality basins for over vegetation or , sedimentation that would decrease the geotechnical functions intended. Maintenance may include thinning of vegetation and sediment removal. If maintenance is required, such methods shall adhere to the Detention/Water Quality Basin Operations and Maintenance Manual in ~ Appendix A. The operations and maintenance of the basins shall be conducted pursuant to Operations and Maintenance Manual (Exhibit D, Appendix A). ~ Concrete Structures. A GE or CEG shall inspect the surfaces of concrete-lined drainage ditches within the GHAD boundaries on a regular schedule. Inspections will be scheduled twice each year. One inspection should be in the fall before the onset of winter rains. The professional ~ should check for sedimentation, cracking or shifting of the concrete-lined ditches. Repairs and maintenance should be performed on a regular schedule. Excess silt or sediment in ditches shall ~ be removed and cracked or broken ditches should be patched or repaired as required before the beginning of the next rainy season. , BERLOGAR STEVENS & ASSOCIATES , May 25, 2011 %~j~ I~ b Job No. 3058.000 ~ Page 18 ~ Draina~e facilities. Culverts, storm drain inlets, outfalls or trash racks, if used, must be kept free , of debris and spillways maintained. Attention should be given to plantings or other obstructions that could interfere with access by mechanized equipment. Subsurface drain outlets shall be inspected on a regular schedule. Water flowing from these ~ outlets should be measured and documented during each inspection. Inspections shall be scheduled twice each year, preferably in the fall and spring. Suspicious interruption of flow should signal a need to unplug or clean by flushing the affected drain. ~ It is anticipated the project professionals observing the installation of subsurface drains and geotechnical instrumentation (if any) will document their locations and provide such documents , to the Fallon Crossing GHAD for use in their maintenance and monitoring tasks. ~ , ~~ II II u ~J ~ ~ ~ , ~ LJ I ~ u Instrumentation. Although no geotechnical instrumentation, such as piezometers, inclinometer casings, and settlement monitoring devices, are planried in the Fallon Crossing development, they could be installed depending on future recommendations made by project professionals. If installed, the Fallon Crossing GHAD shall monitor such instruments on a regular schedule. BIOLOGICAL RESPONSIBILITY TABLE Fallon Crossin - Parcel's A& H Annual Pre- Monitoring / Acceptable Annual Acceptable Construction Annual Inspect(on Monitoring Maintenance Maintenance Survey Agency Pertnit Report Area Parcel Re uirement Methods Activities Methods Re uirement Noti£cadon Re uirement Re uirement Additional Infortnation Identified as Assumed to occur The GHAD musl apply tor lhe Stock Pond Upper pond; NA NA once every 15 TBD None Yes Yes NO appropriate agency permits prior located wfin years. Or on an as- to conducting the sedimenl Parcel A needed basis. removal from the pond. Mnual maintenance may No - However, , include maintenance Yes - QuaAerly. clearing/maintenan Hand labor & must be Insped outlet ce of Inlet and wheelbarrows conducted in strudures, access Outlet Structures, within the accordancs road, basin banks, access road basin, with the p,~l Maintenance adivities to Delention fencing. ~uarterly Visual repairs, basin mechanized ~ Operations remove vegelation and/or Basin gasin Area Monitoring Report Inspection embankment equipment yes No and No . sediment shall be pertormed template can be repairs, fencing positioned Maintenance behveen August 1 and found in the 0&M repairs, desitting of from the Manual September 30. Manual attached basins, and maintenance prepared by hereto as an exhibit. mosquito rd. RJA, attached abatement. See hereto as an O&M Manual for exhibit. more detail. Yes; Quarterly for years 1-3, with Vandalism Portion of reduced levels for inspections, weed Parcel H; years 4 and on. control, plant and Riparian within Detailed breakdown Visual irrigation Hand labor No No No Yes Corridor existing of maintenance and Inspection mainlenance, ~itter conservation monitoring removal, and Easement obligations can be erosion control found in the MMP maintenance. (Appendix C). BERLOGAR STEVENS & ASSOCIATES ~ ~~ , XIII. LIMITATIONS May 25, 2011 ~~ I~~ Job No. 3058.000 Page 19 ' The conclusions and recommendations presented in this document are based on information provided to us regarding the proposed improvements and other aspects of site development, the results of the geotechnical investigations at the site, available published regional geologic data ~ and professional judgment. This document has been prepared in accordance with current standards of the engineering geology profession. No warranty is expressed or implied. ~ 3058.000/21439.doc ' ~ , ~ ~ ~ ~ ~ ~ l~ ~ ~ r ~ BERLOGAR STEVENS & ASSOCIATES r ~ 33 ~C~o ~ REFERENCES ' Barlock, V.E.; 1988; Geologic map of the Livermore Gravels, Alameda County, California: U.S. ' Geological Survey, Open File Report 88-516. Berlogar Geotechnical Consultants; September 19, 2003; Design level geotechnical ~ investigation, Mission Peak property, Tassajara Road, Alameda County, Galifornia. Berlogar Geotechnical Consultants; September 13, 2001; Report, feasibility-level geotechnical ~ investigation, Mission Peak property, Tassajara Road, Alameda County, California. Bryant, W.A. and Hart, E.W.; 2007 (Interim Revision); Fault-rupture hazard zones in California, ~ Alquist-Priolo Earthquake Fault Zoning Act with index to Earthquake Fault Zones maps: California Geological Survey Special Publication 42. ~ Dublin, City of; 2007; Approving a site development review and Vesting Tentative Map 7617 within existing PD-Planned development district known as "Fallon Crossing" at the northeast intersection of Tassajara Road and Fallon Road, PA 04-016, APN 985-00021-001: Planning ~ Commission Resolution No. 07-59. Davis, J.; 1982; State of California Special Studies Zones, Livermore, Official Map; California , Division of Mines and Geology. Dibblee, T.W.; 1980; Preliminary geologic map of the Livermore Quadrangle, Alameda and ~ Contra Costa Counties, California; U.S. Geological Survey, Open File Report 80-533B. Engeo Incorporated; September 28, 2006; Final report, observation and testing services during , grading, Silvera Ranch, Tract 7441, Dublin, California. Engeo Incorporated; May 2001; Preliminary Geologic Map, SilveralHaight Property, Dublin, ~ California. Graymer, R.W., Jones, D.L. and Brabb, E.E.; 1996; Preliminary geologic map emphasizing , bedrock formations in Alameda County, California: a digital database: U.S. Geological Survey, Open-File Report 96-252. ~ Nilsen, T.H.; 1975; Preliminary photointerpretation map of landslide and other surficial deposits of the Livermore 7%z' Quadrangle, Alameda County, California: U.S. Geological Survey, ~ Open File Map 75-277-26. Nilsen, T.H.; 1973; Preliminary photointerpretation map of landslide and other surficial deposits ~ of the Livermore and part of the Hayward 15-Minute Quadrangles, Alameda and Contra Costa counties, California: U.S. Geological Survey, Miscellaneous Field Studies Map MF- 519. ~ Majmundar, H.H.; 1991; Landslide hazard in the Livermore Valley and Vicinity, Alameda and Contra Costa Counties, California, Landslide Hazard Identification Map No. 21: California ~ Division of Mines and Geology, Open File Report 91-2. ~ BERLOGAR STEVENS & ASSOCIATES 3`~ Il~n ' REFERENCES (continued) t Ruggeri-Jensen-Azar; May 2, 2008; Grading Plans Tract 7617 - Fallon Crossing, City of Dublin, Alameda County, California. , State of California; February 27, 2008; Seismic hazard zones, Livermore Quadrangle, Preliminary Map: California Geological Survey. , r ~ ~ ~ ~ ~ ~ M ~ ~ ~ ~ ~ ~ BERLOGAR STEVENS & ASSOCIATES r 1 1 ' U U } m ' ~ 0 ao ~ ~ ' LLI H Q 0 ~ O O O ~ ~ ' O M ~ W m ~ ~ ~ Z m O ' ~ , 0 2000 , 1 "=2000' , ' VICINITY MAP , FALLON CROSSING TASSAJARA ROAD DUBLIN, CALIFORNIA , FOR STANDARD PACIFIC HOMES ~ ~ ~ BASE: PORTION OF U.S.G.S. 7.5 MINUTE TOPOGRAPHIC QUADR,4NGLE, DUBLIN, CALIFORNIA, PHOTOREVISED 1983, AT A SCALE OF 124,000. 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",:~ . , ./I '~' ~..•~~-~ , ~ ... ~ .. ~ .. . . ~ ' ~ ~ ~ . . ."- " /~22FOOTLONGGeOGftID.TVPICAL ' ' '161NCHESMINIM M 181NCHESMINIMUM I ~ ' - ~' ~ .. I - ~ . .. ?\ \ ' ~~ -I1 10 FOOT LONG GEOGRIO, ~ ~~ / ~/ N . - . I ~ -. --~ ~ ~ ~~ ', ' - ~~ ~ TYPICAL ~ _CLA552FERMEABLE _ ' ~ ~ . .'~ . ~, . ---L '_ \___ ___"__ ~~ MATERIAL(NOTEI) ' ~ " ~/ ,i _ ---- '---- -_ . REMOVEANO 9FEET ~ -' ~~ n['. /~.~ / ~ ' -\ \ ` \ . N ~-' __ _ ~-_----- -~\~/ COMPACT MINIMUM ~ € ~ PERFORATEO PIPE INOTE 2) ~ ~ MINIMUM ~__. , . .'~ . . c\~ : '. ~~MIF A ~ti .', , ;I ~ - ~ . ._' _ \- .-QI5\ . .~ -~_ -REfAININGWALL ~~/ / %':/%///// - \ / ' ~~ . ~ .'~ -~ :;~~I ~•i /- .; ..~~ ..- ~ \\ __ ' ///- . . \) BINCHES ~KE AVASAPPftOVE~. ~~~BIN~ ~ ~:"/ I I ' _ ~ ~_ ~ . ~ _ - ~ / ~ ~~ ~~ BY HESOILENGINEER . ~- n~ /G~ /" /~ ' ~, -~ .-. ~- - _c ~. ~ QC / . ~ ' - . REMOVEANO NOTES: ~ .. !~ // ~• ~ : Tt'~ ; UPPEft 5119ORAIN TO EXTEND FROM qT ~~ ` , ' r GOMPqCT ~- CIT55 2 PERMEA ~E MATERIAL,SECTION BB- 1 O15, STATE OF '~.._ ~;' ~ ~ ~_/ I I ~~-~-~~~--~, ' LEASTIFEETBELOWiQ2FEETABOVE- -~ ~" \ : CALIFORNIASTA AR~SPECIFICATIONS,JULY,200BEDiTION. TNE6EOROC SOICCONTACT~-' ' \.~ '2. PERfORPTEDPiP PLACEDPERFORATIONSDOWN,PVCPIPEtMTHA ~ ~ . ~"'- - ~ , ~ QT4 ~~ MINIMUM~IAMET ROF51X(6)INCHES,CONFORMINGTOASTMD3034 ~ r l' '~ 'D~j ' ~ ~ '/ . '~.. -_ " - ~ ~ , . ~ S~R35,FORDE~ HSLESSTHrW30FEEf,AN~5~R2].5FOftDEP~HS ~~ ' ' ~ ~ ~.-. ~ . ' . ..,. '. ~' .~ ' ...- •... ~ . p . . GREATERTHAN FEET: N TE ~, ~~/ ~ I ; . ~ . '/ ~ ~ _ .. . ~ ~ OG S C EEfVE CALLY START , j ~ : ... . . . lOAND]OFOOTGE RID PA EDSF Rrl , 1 AT - `,;; ~ ._.. (' ,~ ~ ~ . ~*, ~ ' ' .\ • ~ , ~ BOl70M WITH ]a FOOT LENGTH. THEN ALTERWITE LENGTHS. ' \ ~ ~. 21T4 ~, / . 1 . ,. ,, ; ~-.. . .. _ ---- . . . . '~ . ~ ' I, '1. ~ . ExISTIN LT09E. ~ .. ~ ~Tt '~"- ~ ' ' ~ . GEOGRIO REINFORCED SLOP,ES DETAIL' i PICAL SUBURAIN DETAIL ~- ~ ' / ~ ~/ I I ' ~` ~ OVEU ~ / / UPPER LIMITOF LANDSLIOE ~ ~" ' ~ ~ ' ~ l5 TOFCOLLWIUM ~ ~ ~ O,_ % B VATION ~ ~ ~ OVEREXCAVATION TO BE EVPLUATEOIN q q C C ~ ~ 0 ~ - ~ ~ ~ '~ - , - THE FlELD 9Y A GEOLOGIST WRiNG. - ~(~,~ ~ ~ y : u~ -~ REMOVAL,AOOITIONAL'IIPSLOPE / s _ e \ / ~ ~ j ~01~~~ /~ O ~ ~ ~~ '~ , ~~REXCAVATIONMAY.6ENEE~EO I ' _ _ BERMtOPREVENTSURFACE ~'~ ~, $' BASEDON.EXPOSEDCONOITO ~.... . / ': ~ I 5., '!~ ~ ~ ~~~5. ' - '. ~ . ~ N5._.. ~ I ~ - ~ ' WATER ON SLOPE . \ - :~~ ~ ` ~y {~ e; ~ ~6ANDRSLiDE . . ~ . " ` .,_ __ .. 1 5 = ,-z . ~ - .,...,..... ^^^^^~. \~ . , 1 ~-~ .f~ PNOt C6E%I@TI . ~~/ ' ~ ~ ~ ~V ORIGINAL . '~ ~ P WE~t POLE3 `. .~~ •^~ x° ~~' -~ .. BENCMES/ ~- GRADE , / : ~ ... 1 re4 I ~ ~ ~ ~ ~ . . ~°~ ~„ _.. . . . soo sao soo . . 5 (NOTE 1) '.,~ ^ I I ~ ~~~ Qoa ~ J ~ ~~ `rfa~3 i ~i ~ .. ~x ~ _. . roasoa. ouwiu~~~~~~~"~ ~ ~ ~ ~~ .' ~4 ~iP~. ' . .. ~~ <FEEf ~ ~/iQal i ~~ - / ~~ ,~ . . .~ . ~ ~ /~ . oasu~~oeoais 1 i_ . _,~ ~ ~~~/ hk ~ ' ' .; . .. ~ .~ . ' d ~ .... ` ~~ . .. e B' SUBDRAI~~ MINIMt1M , \ J%. J ` ~ , ~ ~, , ~ / '~.., . e 50 '(NO E2) 15FEETMIN. :. ~ - ' V ! .~! I _,~~ ' ~' ' .6BS e..~ ~F ...'. . z ' -" " ~ ' KEYWAV .. ~' ~~1~~ ~ < f ..~.' :. /4ANOSLIUE I ~ " w - - ~ .1 ~ /(/ l q . '.'. . . ~ Y ~: C ' _ " . (NOTE:1) ~ AL RNATIV~ _ . / . , '~ rln .: .,~' \ ~ 9 - 00 ~ ~ l ~'' 1'~t IL ~ .. a ~ ~l ~ I .. ~ NOTES: ~ / (~ ~ _ J _. K AY ~ /' ..... ~ / l:• . ' RGF ~ . ~ . . ~..5". ~ . . : ~R ~ . I ~ ~ - "" t .SU~ RAIN / ~/~ I ~i ~~ ~i ~. ., l ~.: -y. ^ - / /\^ __ 1. _ HIMOST1FFSOIL ~ TI~AN ~ J ~9 ~ ~ ~ ~ ~/ ~ ~41a I -- -- ' ORBEOROCKASI ETERMINEOBY60L NGINEERFNC : . . . ~1 ~ '..: : - _ ' _ ' „=' N : somHmi ~~ ~ ; ~ ~: ~ ~~~~ .•:• ,:R '~ _ ~ ~. rwt D 5 . ~ , T, ~ ,- ..., : .,~ i , ~ 4, sa ~uru . 5w ~ • :: TNISKE AY\. ~ ~ :'ll k~ ~~ ~ 1 . ~ ~: .'~. ~ ' ,~' "~+! y~, ~'~~~QTt -.... '" '~ ~I .-------+-. 3. KEY4VAYPSHOULqIXTENATLEA5T4FEETEMO5T1O501LOR~ ~TOE%T~.---~ Ij,/ -~'^"s~ ~.G.' '~y ~~~~~~ ' .' ' ~ _.,BUTRESSFILLCUTSIOPET09~/' , BE~ROCHASDEYERMINE~BVTHESOILENGINEER.KEYWAVWIDTH ~ ~~"" ~ ~~~ • ~ ~~yJ ~ ~4~~. ~•~~ ' ~ MNPPEDBYGEOLOGIST_... ~ SHOULDBEAMI IMUMOFI5FEEfOR1/20FTHEFILLSLOPEHEIGFR, . MINIMII 9 ~ /J ~ ~ ~ ~ ~ . " , ~ '~' V ~" ~ oING S G FEETBEL ~~' ,~ ~ ~~ ~~. ~ . -~- . ~ ~ICHEVERI TER. FUTUR~k/ , l ~~ ~ ~. , BEL .:. ~<. ~' '~ ..° ,.--D~ G~ .. s~ E%PLANATION ~ sao ' i / ~ CREEK~A , .'' = ` ~/' GRqOING, ~ /, ~ ,~ : ~ F-:.. - . f .-.. ~ -. " Exisirvc~ '-' ~v FILLSLOPEDETAIL ~ ~ - ~,j../ I 1. ." , f , ~ {& 1~ '- __ / ~ ~~ ( ~ ~ ..~'~. ~ ~ ~ ~ ~ ~ c\ k i ~~ - r i1`~ -_ i Eca F ii TIESUO~Ni~ ~ ` _ ..\ ' ~ ~. _"__'- PaO~as[ocawE osioEev so[wE.mM . INTO t ~ /~(A ~ . - TR ~T~,~1~1 ~ a" C~NNELTTOEl~9TIN0~ iEUivawwvencxan v~v~nc£~cwAFS~cw ~ . ~ F ': SUMH NI0~.1~. ' .L. } - ' t. ._ SUBORAIN WITH SOLID B N ~ , I '" ~ ,r ~ I~ /, ~ i , ~ > ~ -- ~~~ INCN SEPARATE LINE T0. ~ aeau u'n , . ~ .~ / ~~y/7 . t,~ . . ~~ ~ ~ GftAVITYDISCHARCE ~.' ~ -.. ' :I Q~. . " E m ~ ti~ ~ ~o '. _~, ~ THROUGN PARCEL'B' ~ NORTH EAST 9UTRE55 FILL CIITSLOPE SECTIONS ' 1 '~.. .'~. ~ '~. ~ J t, ~ 'e =' i QafO~. - _ NGBUB MIN ~ 1"=50' ' p S ~ ~^ ~~~~ /l ~ f r Ks ,,,/ ~n STUB D E%PLANATII N ~o ~ 1 \ Q ; y Q" ../ ~ ., ~r / ~ ~.r - , f ~ ~ % . . ~~~. : ~ . , \?~ ~2 ~ ~ - --SUBDIVISIONBOUNDARV ~rr7F~'l WATER OU~tRYPOND l ~' I ~' 4 ~(`I(' / ~~ j ~ g ~j ~' ~ SILVERARANCH, . ' . ._. . ~ f ,. `•~i~%:'~ FEETTALL,REMOVEAN~REPLACE . ~~ ~~, h ' I ~~ ~~i~~l ~~I r /~ ~//~ ' "~ . DEVEL~PMEPIT ~~- , ! *',~ LANOSLIDEREMOVEAN~ CUTSLOPESNAiHGEOGRD10 ~' I YI ~ '~ . ' fIl~ I ~~~ I ~ ~~I ~ ~ ~ 1~~~ - /uao~ ~ ~ - , ~ I ,,,;j REPIACE REINFORCE~SOIL.USETENSAR p I µ , ~ 9 I~/ ~,7 ~~1, ~ _ , , U%1400OREQUIVALENT.NO / r/l : ~~ C - ~i~~~ II~ t i ~ ° ~ Y ~ ' " . ' ~ . OVERII~PNEEOE~SIOE9YSIDE. -y --~4 `~ 3 6 ~~ ~ SUBDRA N TO BE PLALEO AT LEAST 10 (SEE OETAIU / I~ I.I I . ~~•~~ ) IT/ ~I ~ ~~ FEETBELOWFINI3HPADGRAOE~ANDAT ~ .':~ RESI~UALSOILAND ~ . ~'~ ~ I~~ ye. . 1//ti '~~IIIII I 1~~~~~¢ -"~ ~ -. / :'LEAST9FEETUTiIOI ESUTURE9TREET . .. . . .. . , . ~ --~-~ SOU~FJ(CPVATIONALONG --'-'- EXISTINGSUBOR/UNONSILVFAA ~ / / ! ~ y))_,~,`- t\ . CUi/FILLTRr1NSITIONLINE - RANCHPROPEftTV ` p '~ - ~I ~ 1 (10 FEET BELOW PAD ~` ~ ~ ~ . - GRADE) PftOPOSE~SUBDRAINFORFALLON ~~. ~ i ~~ / / • / ~ ~ k~. •°~ \ ~ .. '_ ` ~ _ . CROSSING ~ ~ ~~ ' i ~ I1I ('Ii~~j~ i/Jr/~ ~ - \ ~ G0095ERVEOVERE%CAVAl10NNLONG ~ .. • _____ CUT/FlILTRAN51T10NlJNE(PRE (~~~ Y ` THEPROPERTYeOUNDARYTO _. ~-~;J CUTIFILLPPD , REMEOIALC>RADING) • -~'~ , ~a < ~ ~ ~" ' - - DETERMINETME~E%TENTOFREMOVALOF ~ ( Y_,-,:~ SlIBEXCAVATION(JFEEf ' ~. \\ THE COLLUV~AL SOILS OOWN TO BELOW PM 6RA0~ ' .. \.. b • `\ ~ . ~ ~. . . . . . ~ / ~ , BEDROCK . ~ - • ~ . .• . .. COLLUVIUM ~ ~ ~ SUBDRAINAS-BUILTS ~`~y.v~ 5ueoccnvnnoNTO ' _ ~\ '. ~~' , ' ~ . "- SIIBDRAINILOCATIONS~NOOUTFALLSTOBESURVEYEDINTHE BE~ROCK ` ~~ . \` , -~ .~ '~ ~ ~ ~ . ~ _ ~ FIELO DUR NG GONSTRUCTION L~E -k F.'~ !i_H \ ~ '., ~ . ~ _ , ~ . . . . . ~ .. ' . A_~ ~_.~ , .. , . -.. SELECTFILLREaUIREMENTS KEVwqY~tirvimUMaFEEr '~ ' - ' SELECTFILLREFERSTOSOILSBLENOE~VViiHBEDROCNCUTAT e 9 ,,.,iosT~FFSO~~oR - REMEDIAL GRADING PLAN GK f°°°:`°° 9EOROCK, ANO MINIMUM 15 F~errnaoaw~n ALLON OSSIN ~~•.-\ ~~ . :: . .. . ~ ' ~ , rneovacnnouawruwuvnEru~nu+oEwrxESUVEVhspN r. .. .. . ... WnOBACKFlLLT5IRED~FORKEYVJAYSAN~MSERETNMrv 4m•L~ ~ICHEVERISGREATER . F OUBL C~AI RNW G . SELECT FILL REDU G FILL SLOPE HEIGHi TAS0.1 ROA~ IFO . . . .. . s s oa~ . ..__.__. _ .. IN•FOR . , vnwun n ' ' ' ' cEZla __ . . ~~ ~ ~ - ~ , ' _.. _ I i:! BENGHKEV. MINIIAUM 15 STANOARO PAGIFIC HOMES ~.-, , .-' ~ . ~' ;., ..~ ' . "~ ....~- . ' -~ '--._ _..._. . I 'r.,;t . . ea~loearGewacM1ncaiCmsultervs . . . " . ~ . ' .. ~ . ~ `._._ . 4EET VNDE en9EVpnNLEDBYPWtEmJExscNATMn iFb.2E6~vEONI.EMNLP4lEO11t]-lo ' ~ - I ~ PW~ 1 1 1 1 ~ i ' , 1 ' ' , ~ _' ' ' EXHIBIT A OPEN SPACE OWNERSHIP AND MAINTENANCE RESPONSIBILITIES EXHIBIT ' BERLOGAR STEVENS & ASSOCIATES 37~/~~ •;., , ~ ~t f~~'~i• . + ~ ~ J~ Y ~ \ ~ . ~k N\ ~ ~.. AYN sHEY/H~UMER BS Op1-001 ~ , S rT:... . . ;i S ~ J ~ ~ ~r ~~i:. . . $? ~ n o ~ ~ , \ ' ~l ~ r a„ o 8 ~YARWS { ^a; . APN~ BB -0004-0OY-D ~ $ . ~ wi ~ ~~ ~ - F~~y~~ e' a i. ~ ~ ~ r t` °'a ~n„'r . t _ E~ ~~~~ 0 j ~~ ~ ~ ili.; c~` ~ . ~~~Y P ~ T ~l U"'i - _ _ " ' i„ wY 6~~ICH 1 •~ b. AeNi s d C ~ ~ °I~ . 3 ~Rby ~~ . .` -voz-o . ? 4 S 7\ e . ~1 4' ~ ' . r~ 3 .l .. ~ . ~ „ y , . . .. ~ ~r+~ . ~ , .` , ~ . ~4V". ~ ',. . @`°' lr`~ ~ . c reo~ ro naol 4" . tk~ i f y ~ , • ~ y1 ~ Il ~ . . ~ ~ . ~'~° a~. .~ ~~r~.ti~ ~ `^"* -0 : .. ~•~.x~`i ~~~' ~'~:;~" ~ i ~ ~ ~ EG ND: / g /'S~.ti' `r ~,~,t /~~~'j'~ ~{~ YY' i . ~ ~ . 1, ~aae~' ~i~ ff . ~ . oMm er m ~sw xa, ww ~lntn a~auo . ~ 3 ,~'~ ~ ~~~E ~ ~'~ 4 d,w~, ~qz y ~p ~f ~?i ~~ ' i ~ _ ~ ^ ~~ 5 PFA ~ ~ ~G~ r f/ T ] o , ' aw~~ ~~,wm er m ~ r on aaaN l~, g ,y,tr'.. j ~~"''~9 e~,y f 1 d 6 4~'~~'~ "~ "~ .Lt'~°.' fl~ ~ ~S" ir ~ ~ n.wu.wG r:merna~owms.~am~nm i , , ~ ~.~ . 0 ~ ~.~;~~+at ~~~~h ~~,rr~Hn ~' ~ ' ~ ~.," . ~ ,~,~a.a.,~~~~, ~ s. ~r~ w ~^ ~xa f ~`}? a r >r~~~ ~ '~ ,~+ ouo ~.~ '~ ~rF ~~ -W-sa~W~li. 3~ .'v~b ~ h,~~'u'X}j'~~i ~~ ~pPy 5• / ~ l ~` l z ' '? ' ~ v~~E w w~ ~ s P ~ , t ; ~'F~' 9~ ~e ~`~~r~ ` ~~' '? ~ ~ u I ~ rw ~ m r - orxoe ~ Cl~rt4~ ~(AY . r 9~O~Y . 3 ~~ ~ . 4 ~ NMSfM'-uwi~N~Der NMalY.~eran ~ Y y C!]MI • V ~~y~~~':~'. €'aJ~ ~ ~ r~~ x . -N-. ~ ~ ;:: onmcxe,csm¢. ~f< A ~, , 7 ~, . q,,„ : f~ , ny~4y ~ . . fi (~~ 4. ~~.' :. t vc/ $' r ~ "____ r~.a~nvrur[ "" "`~n°"`" '~ 3g ~ ~ OPEN SPACE OWNERSHIP AND " ` ~ r ~ MAINTENANCE RESPONSIBILITIES EXHIBIT °"""`°` ~`"'~ " "- Rvss~" ens e n ~ ~ TRACT 7617 - FALLON CROSSING ='- ~ Aza. d nssodaus ~ ~ ~ ~ ~6p~ ~ arv oF oue~w. uu.ao~ couNn. cu~owa.~ ~ Y ~ g~ r ~w - u.,e r¢«u.n.. mn : ona oe 7m ' ~ ' ' '~I ~~ , 1 , , ' ~ ~ ~ ~ ' t , ' EXHIBIT B LEGAL DESCRIPTIONS OF GHAD BOUNDARY AND MAINTENANCE EASEMENT BERLOGAR STEVENS & ASSOCIATES ' /~ ~V ~ 1 Standard Pacific Cotporation City of Dubliij ~ County of Alameda Exhibit "B" L~gal Description ' ~H~~1I~ ~Parcel 1 Real property situate in the City of Dublin, County of Alameda, State of Califor~~ia, ' described as follows: Being a portion of the Parcel described i~l flle deed recorded on April 14,.2005 to ' Standard Pacific Corporation in Document No. 200514(i527, Official Records of the County of Alameda, State of Galifornia, dcscribed as follows: ' Beginning at the. northeastert~ corne~• oi'saicl Parcel; tl~ence along the eastern line of said Parcel, South O1 °04'38"West, 1264:53 feet to the southern line of said Parcel;. thence South 60°Y9'O1"West, 133.52 feet; thence.North 83°40'S9"West, 135.30 feet; thence , North 64°10'S9"Wesfi, 528.U0 feet; thence :N'orth 87°10'S9"West, 473.88 feet; thence, South 34°49'O l"West,. 576.18 feef; thencc Norti~ 89°25'S9"West, 725.18 feet to a non- tangent curve to the right having a radial which bears South 69°08'38" West, a radius of 1066.00 £eet, a delta of 17°39'41 "; thence leaving said southern line, northwesterly along ' said curve an arc length of328,59 feet; tllence North 03°11'41"West, 121.68; thence Nortli 33°23'O1 "~asi, 83.52; thence NoiKl~ 13"U2'00"West, 227.15 feet to the northwestei7i line of said parcel; thence a(oirg said na.rthwestern line, North 31 °O1'01" ' East, 953.44 feet to tl~e northwest coriler of said Parcel; thence along the northein line of said Parcel, South 89°20.'13"East, 186(i.04 feet to.the Point of Beginning. ' Cot~taining C6.4 Acres t ' ' ~ ' ~ ~ ~ ' ~ ~i~~~~ Charles Sellman L.S. 518C o ~1~23-~DOa Date Na. 5186 Exp. 06-30•09 'F CP Created on 6/12/?008 4:11 PM G:\AdminUobs-03\031006\Survey\New 1.)eeds\GI-tAD A & H.doc l~~ 1 ~ ' , ~ ~ ' ' ~ ' Pfeiffer.Rancll Investors 1I Inc City ofpublin County of Alameda Exhibit `°B" Legal Description GHAD ]?arcel 2 Real property situate in tl~e City of Dublin; CotYnty of Alameda, State of California, described as follows: y~ ~~~ ~ Being a portion of Lot "A3" as shown ou the inap e~ititled "Tract 7441" filed:in Book,279 of Maps at Page 68, Records of thc County of Alamecia, State of Califorriia, described as follows: Beginning at an angle.point o~i the northern line of said Lot,.said point being the southwestern ternlinus. of the course shown as "N34°49'O1 "E 576.18"'; thence, South 44°22'OS"West, 50.43 feef to a non-tangei~t curve to the right having a radial which bears South 32°49'S2" West, a.radius of 25.00 feet; a delta of 11°32'13"; thence, northwesterly along said curve an arc len~th of 5.~3 feet; thcnce North 45°37'S5"West, 48.12 feet to said notthern line; thence along said northein l.ine, South 89°25'S9"East, 73:b0 to the Yoint of Beginning. Coiltaining .03 Acres t ~ ' C'' " - Charles Sellman L. . 5186 ' D~i-Z3 ;200~ Date , ~~5 SF~, "''~ ~ iJo. 5186 Exp. 06-30•~9 C ' , ~ , ~ Crcatcd on 9/23/2008 2:03 PM G:~dminVobs-03\03100GCSurvey\New Deeds\GH~11~ parcel2.doc ' 1 ' ' ' , ' ' ' , ' 1 ' , , ' ' ' , ' ~a I(~~ ~ Pfeiffer Ranch I~ivestors .Ii inc City of Dublin County of Alameda I;xhibit "B" Lega.1.TJ~scription G .NAD Parcel 3 Real property siittate in the City of D~~blin, Coui.ity of Alameda, State of California, described as follows: Being Lot "A4" as shown on the mlp.entitled "Tract.7441" filed in Book 279 of Maps at Page 68, Recoz•ds of tbe Cou~~ty of Al~r~ileda, State of California, described as follows: Containing .0.1. A.cres t r!~.--,~''~ ~~-"" \ Clzarles Sellman L.S. 518G ~~-~.S~-~ob Date %~S SF~\rC ~ ~4v No. 5186 Exp.06•30•09 , Created on 9/23/2008 2:45 PM G:1AdminUobs-031U31006\Survey\Neyv .Deecis\GIIAD parcel3.doc 1 1 1 1 1 ' ' ' 1 ' 1 ' ' ~ ~ ' ' ' EXHIBIT C PLATS OF GHAD BOUNDARY AND MAINTENANCE EASEMENT BERLOGAR STEVENS & ASSOCIATES ' ~ i~o 1 , ' 1 ' , ' , , ' , ' ' ' , ' ' ~ ' L1N L2 ,s) i 3 0 300 600 LEGEND P.O.B. POINT OF BEGINNIN6 (nz~r) 1 iaoh = 300 tt EXHIBIT C ~~~°'~~~^T~.~9 9,~,~ IDCBq3 AM PDT PLAT TO ACCOMPANY LEGAL DESCRIPTION 1 1 FOR RUGGERI-JENSEN-AZAR ENCtNEERS • PLANNERS • SURVEYORS GHAD ~9 PHONE~ (925 227 ~9100~ PA% (925)TI27 9300 ~ SCALE: DATE: JOB NO.: C179! OF DUHI~1, At~1~:DA CCUNTY. CALffO&NiA i°=300' 9-23-08 031006 ~(~o / ' ~ ~ ~ ~ ~ _~ '~ ~ 1 1 1 1 ' ' , ' 1 ' ' ' ' ~ , , , ' ' ,b ~ '~~ _N_ ~I ~ ~ I ~ ~ 0 100 200 4 { n~t ~gr } q4 1 inch = ioa r~. v~ N44 22'05"E 50.43' S32 49'52"W(R) R=25.00' d=41'35'35" L=18.15'- 4~U~~~~ 44'~'`~~t'~ II ~,~ 44~~~`~ ~ Q ~y I ~,,4 ~ ~ ~~~q. ~O ,4,4 ~ ~S44~2'05°W 42.19' N08'45'4.3"WlR) P.0.6: S8770'59"£ 17. 69' ~ MA/NIFNAIVCE EASEMENT REQUIRED FROM TRACT 7540 AREA = 9, 437 SQ. FT. ~ .' h,~~' ~ ~;~ ~ , ,~g6~ ~~, _, 0 ~~ ~ ~0~ ;~~p~~ ~' LO 7 ' A 3 ' 7 R A C 7 7 4 4 ~ LEGEND P.D.B. POINT OF BEGINNING SQ. FT. SQUARE FEET EXHIBIT C I ~'w~03\031D06\HAPPINfi\PLATSVIAINTENMICE ESMTdrg 7/31/2008 8~3692 AM POT i' PLAT TO ACCOMPANY LEGAL DESCRIPTION ~; ~ 1 FOR ~; RUGGERI-JENSEN-AZAR i ENOINEERS ~ PIANNERS • SURVEYORS MAINTENANCE EASEMENT ', 4640 CHABOT DRIVE. ~~,~ z~ PIEA$ANTON, CA 94588 PHONE: (92S) 227-910~ FAX: {925) 227-9300 '~ SCALE: . DATE: JOB NO.: C1TSt OF DtJBLW. AI~-I~DA COVNTY. CALtFOxxIA ; 1"=100' 7-31-08 031 Q06 1 ~~~ ~ 1 !~ [~ ~ 1 '' ~ ~ ~I 1 ~ EXHIBIT D 1 ~ . I DEED RESTRICTION EXHIBIT ~ I I ' I II ' ' I~ , ' ' ~ ' ' , LJ ~' ~(~~ ~ ' BERLOGAR STEVENS & ASSOCIATES ~ € JOB N0. 031006 FALLON CROS3ING ( n~ ~'~' > i inch = 200 it. ~N' ~~~ DATE: FEBRUARY 15, 2011 ~ ~9 I a Co ! 1 , 1 1 ' APPENDIX A , DETENTION/WATER QUALITY BASIN OPERATIONS AND MAINTENANCE MANUAL ' Prepared By: ' Ruggeri-Jensen-Azar and Associates ' . ' , ' , ~ 1 ' ' BERLOGAR STEVENS & ASSOCIATES ' r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ' , ~ ~ ' ~ ' ' 5~~f(~ GHAD Management DetentionlWater Quality Basin Operations and Maintenance Manual Tract 7617 Fallon Crossing Dublin, Alameda County, California Prepared by: 1'~ 11 RUGGERI•JENSEN•AZAR [NCINCCRS • ~lqNNlll£ • SU~1VlYON6 4690 Chabot Drive, Suite 200 Pleasanton, CA 94588 (925) 227-9100 February 15, 2011 Updated April 13, 2011 :'~„'``~~~p P R OF~S+`S/ , ,.-~ . ., v~c' .•~~ '• ~y9 ~ _,.r~ < ~v~ -'G~P$W(~ : ; , . ' ~-- : ti ~Mark Andrew Falgout : , •, No.0566 .' '• ;s~; •.. .-'P~. . ~~~'j WA -TER p~v . . i 1 ~ ~ ' ' ~ ~ 1 ' i ~ ~ ~~ ~(~o ~ FOREWORD The purpose of this document is to provide a manual for the management and maintenance of the Fapon Crossing Detention/Water Qualify Basin. The Fallon Crossing praject is located at the intersection of Tassajara Road and Fallon Road in the City af Dublin. The two Water Quality Ponds are in the western portion of the site and treat runoff from the entire site. Stvrmwafer runoff from the northern and eastern portian of the development is collected and treated by filtration though 18 inches of sandy loam in the Upper Water Quality Pond before outlef#ing to the detention basin through a storm drain. The southern and western portion of the site drains to the Lower Water Quality Pond where it is also filtered through 18 inches of sandy loam, then outletted to the detention basin. The water quality ponds are located along Tassajara Creek and are within an area which has been recognized as habitat for bath the federally protected California red-legged frog and California tiger salamander. All maintenance activities are to be performed in a manner which does not result in the "take" or harm to either of these species. Maintenance activities will be performed in a manner which avoids, to the maximum extent practicable, impacts to these species. Maintenance of the Water Quality Pands and Detention Basin will initially be performed by Standard Pacific Homes and will remain thei~ responsibility until the Geologic Hazard Abatement District (GHAD) assumes the maintenance duties. The Basin Operations and Maintenance Manual provides policies, responsibilities, authorities, and procedural guidance for management and maintenance of the Water Quality and Detention Basins. The GHAD Manager will provide to regulatory agencies requesting them, annual reports on maintenance activities and will comply with all applicable State of California and federal laws and requirements governing the maintenance activities. Maintenance activities may generally be summarized as foliows: GHAD Mana ement Taslc O en S ace Maintenance DetentionNVater Quali Basin O eration and Maintenance Erosion Re airs Reve etation Sediment Removal from Ponds Access Road Maintenance ! Basin Oqerations and Maintenance The basin maintenance responsibilities inclucle monitoring and maintenance so that Detention and Water ' Quality Basins function within the intended purpose. The Basin Operations and Maintenance Manual may be modified from time to time at the discretion of the GHAD Manager, subject to applicable laws and rules. ~ ~ i ~ Page 1 ' ' BASIN OPERATIONS AND MAINTENANCE MAIVUAL 1 ~ t ~ ~ ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ Procedures and Guidance for Implementation ofi Policies ~ ~~~1~ ~ 1 \ 53~ ll~~ ' OVERVIEW The procedures in #he following chapters are appiicable to the identified organizational elements. ' Chapter 1 presents Procedures for General Basin Maintenance. Chapter 2 presents procedures for Maintenance of Basin Water Height and Facilities. ' Refinemenf of the O&M Program shoufd be expected based on the recammendation and agreement of , Sediment accumulation measurements will occur quarterly, with the exception of monitoring during the wet seasan, the rate of sedimenta#ion in the Detention/Water Quality Basins and identify the need for removal. Some sedimentation is expec#ed within the basin; removal is pfanned only ta the extent necessary to maintain proper basin function and performed in a manner which reduces impacts ta ! wildlife. the GHAD Manager, GHAD, the Regionaf Water Quality Control Board and other applicab{e public agencies. ~ General Main#enance and Monitorinq The DetentionNVater Quafity Basins wifl be monitored to assure that they are self-draining with a ' residence time that does not signi~can#ly exceed the design criteria. Quarterly monitoring during January, April, July and October is planned with additional monitoring within two working days after significant storm events, i.e., one inch of rainfall in a 12-hour period. The Detention/Water Quality Basins ' should drain within five days. All inlet structures will be monitored to ensure proper function. Remedial procedures for the inlets should be taken immediately if the water level overtops an emergency overtlow structure. Overtopping of the basin, or a drain time in excess of five days would be indicative of silt built- ' up or an inoperable basin outlet structure that should be maintainedlrepaired to prepare for subsequent storm events. ~ ~ ~ 1 ~ , ~ ~ ~ As the Detention/Water Quality Basins fill, the rate of discharge from the basin should increase with increased water depth. The basin outlet. structure should be monitored for proper funcfion during significant storm events. Vegetation that does not preclude the proposed function of the Detention/Water Quaiity Basins should be allowed on the floor of the basins to aid in the trapping of sediment. Herbicides will not be used in the Fallon Crossing Detention/Water Quaiity Basins unless absolutely necessary. Pesticide use will be limited and only used if absolutely necessary for mosquito control, with input from Alameda County Mosquito Abatement District, and in conformance with all applicable rules and regulations. All herbicideslpesticides used in the management of fhe FaHon Crossing Detention/Water Quality Basins will be selected from a California Department of Fish and Game (COFG) approved list. Policy Implementation GHAD Manager maintenance and monitoring procedures will include: . Inspection and repair of inlet and outlet structures. • Stabilization and/or repair of eroded areas or faiiures of the embankment surrounding the DetentionlWater Quality Basins. • Pruning/cutting of the vegetation within and surrounding the Detention/Water Quality Basins. • Maintenance of all access roadways. • Monitoring any perimeter fencing far public safety, if present. • Measurement of Detention/Water Quality Basin water ievels. • Mosquito abatement. Page 1 1 1 ' , ' ~ ' ' ~ ~I 5~ lC~v Technicians retained by the GHAD Manager will carry out the quarterly site inspections and utilize the Monitoring Report Form included at the back of this manual. The GHAD Manager will ultimately be responsible for determining the need for more frequent monitoring. Personnel and subcontractors involved in Detention/ Water Quality Basin management will be trained on reading the staff gage, proper running/cutting techniques, and inspection measures by the GHAD Manager. A sample Inspection Report is inciuded at the end of this manual. An annual review shall be made .by the GHAD Manager to assess the effectiveness of the maintenance program and to make recommendations as to which measures should be undertaken in fhe next fiscal year. The GHAD Manager should submit an annual Program Review report to the GHAD verifying that O&M Program pertormance goals are being attained. Any appropriate site-specific study or request for remedia! repair sha11 be determined at that time. Consultants, if necessary, wili be retained to undertake the needed studies/repairs. Emerqencv Response and Scheduled Remed#ai Re~air Emergency respanse and scheduied repair expenditures are to be prioritized at the discre#ion of the GHAD Manager, based upon available funds and the approved operating budget. When available funds are not sufficient to undertake all of the identifisd remedial and preventive stabilization measures, the expenditures are fo be prioritized as follows in descending order or priority: A. Prevention, mitigation, abatement or con#rol of hazards thaf have either damaged or pose a signi~cant threat of damage ta the Detentian/Water Quaiity Basin levees or overflow structures. B. Prevention, mitigation, abatement or control of hazards which have either damaged or pose a significant threai of damage to ancillary structures, including but not limited to the ir+let and outlet pipes. C. Prevention, mitigation, abatement or control of geologic hazards which have either damaged or pose a significant threat of damage fo the Detention/Wat~r Quality Basins. ~ The techniques which may be employed by the GHAD Manager to prevent, mitigate, abate, or control hazards include, but are not (imited to, the following: ~ ~ ' ~ ~~ ~ 1. Repair, maintenance or repfacement of inlet or outlet control valves structures. 2. Stabilization (either partial or total) of levee embankments by removal and replacement with compacted, drained fili. 3. Construction of erosion control measures. Whenever, #easible, bioengineering techniques will be utilized and are preferred over hard armor. 4. Placement of subsurface drainage devices (e.g., underdrains, or horizontal drilled drains). 5. Siope correction (e.g., gradient change, slope trimming or contouring). 6. Construction of additional surFace ditches, sediment traps, or backfill of eroded channels. Page 2 . ~~ l~o i , CHAPTER 1 PROCEDURES FQR GENERAI. BASIN MAtNTENANCE ' II-1-1 Procedures. The GHAD Manager provides technical guidance for the O&M Program process and promotes management practices with standards and guidelines. The GHAD Manager is responsible for providing effective and efficient use of staff and subcontractors. Procedures far ~ the following maintenance items are presented in the following sections of this chapter: • inlet and outlet structures • Maintenance of access roads ' • DetentionlWater Quality Basin Embankments • Fencing repair • Desilting and clearing of basin ' • Mosquito abatement . Vegetation control ~ II-1-2 Inlet and Outlet Structures. Maintenance of inlet and outlet structures will involve the clearing of debris and repair of the trash rack structure, as required to allow passage of storm flows. The outlet structure in fhe Upper Water Quality Pond is a 48-inch-diameter riser pipe with 2-inch- ~ diameter holes as shown on the Fallon Crossing Storm Water Treatment Plan. The outlet sfructure in #he Detenfion Basin is also a 48-inch-diameter riser pipe with 3-inch and 4-inch diameter holes. The inlet and outlet structures should be visually inspected during or immediately after large storm events to avoid prolonged blockage. The holes on the outlet structure should be i clear of debris and observed during each maintenance check. Any obsenred damage or apparent inoperability of the structures will be reported to the GHAD Manager immediately. ' In the evenf thaf the primary DetentionNllafer Quaiity Basin outlet is rendered inoperable during a major storm event, the emergency overflow structure should be allowed #o operate as designed #o pass the storm ffows. Emergency maintenance of the inoperable outlet structure should be ~ underfaken at such time and with the equipment that the GHAD Manager deems.appropriate. II-1-3 Maintenanc~ of Access Road. Maintenance of access roads, as shown on the attached ~ improvement plans, will invalve repair of excessive bumps, cracks and depressions such that maintenance vehicles can easily naviga#e the roads. The roadways wi11 be inspected on a quarterly basis and repaired as needed. Any damage to or failures of #he embankments near the road will be reported to the GHAD Manager immediately. Pavement repairs should be perFormed , in accardance with the general repair practices of the City of Dublin's Public Works/Maintenance Department. , I1-1-4 Detentias~NVater Quality Basin Embankments. Maintenance of the Detention/Water Quality Basin embankments shall invoive visual inspection of the Detention/Water Quality Basin embankments and slapes. Observations should occur on a quarterly basis in conjunction with the inlet and , outlet structure inspectivns. The Detentian/Water Quality Basin slopes should be inspected for obviaus signs of vertical and/or horizontal displacements. Embankment sides should be free of erosion, rills, slumps or landslides. Any observed slope displacement should be reported to the ' GHAD Manager immediately. II-1-5 ~encinq Ftepair. Fencing installation on the eastern side of the DetentionNUater Quality Basin will ~ occur with the development af Fallon Crossing. Maintenance of fencing involves repair of all gaps, tears, sags and breaics such that public safety is provided. All perimeter fencing will be monitored quarterly and maintained in good condition without breaks or damage. L Page 1 ~ 1 1 ' ~ ' LJ !_J ~ ~ ' , LJ , ~ ~ ' ~ ~ ~ ~~~~~ 1i-1-6 Desiltinq and Clearinqof Basin. Detention/Water Quality Basin floors should be regularly cleared of excess sediment and excess vegetation to enabie proper flow characteristics. Failure to do so can create flood hazards; however, a vegetative growth af less than 5 feet in height contributes to sediment trapping within tMe basin. Although vegetative growth is generally encouraged, excess vege#ation (defined as shrub and tree grow#h in excess of 5 feet in height) should be removed from the basin floor by pruning. Aggressive, non-native species such as bamboo may need total removal with shovels. The floor of the Detention/Water Quality Basin should be monitored by GHAD Manager on a quarterly basis. If sediment in excess of 18 inches or 10 percent of the storage capacity, whichever is greater, has accumulated abave design grades, the sediment should be removed. Vegetation in excess of 5 feet in height and grass exceeding 4-inches in height will require removal. Sediment accumulation will be measured with installed staff gages. Vegetation accumulafion will be measured with a tape measure in at least four locatians within the basin floor. Vegetation removal would be restricted to the period of August 1 through September 30. Prior to sediment removal or vegetation pruning, the procedure should be reviewed and authorized by the GHAD Manager. If sediment in excess of 18 inches or 10 percent of the storage capacity, whichever is greater, has accumulated above design grades during a quarterly sediment monito~ing event, sediment removal shall be undertaken before the next wet season. Sediment removal shall be restricted to the period of August 1 th~ough September 30. Sediment removal for routine maintenance will be with hand labar, lawn mowers and wheelbarrows as much as possible within the pond and mechanized equipment working from the maintenance road for heavier work to maintain compliance with regulatory agency requirements. Emergency repairs may require use of larger equipment including, but not limited to, excavators and dump trucks. Sediment will be removed in small sections, with as little disturbance to existing vegetation as possible. No heavy equipment will be used within the Detention/Water Quality Basin without permission from the GHAD Manager. Prior to any mechanized removal of silt or vegetation, a pre-canstruction survey shall be performed by a biolagist having direct knowledge of local flora and fauna to remove wildlife species and assure that al! special-status species including but not limited to the California red- legged frog {CRLF) are not impacted by the maintenance activity. Standing wa#er should not remain in the Water Quality Ponds for more than five days. If water is visible in the Water Quality Ponds for longer periods with no evidence of sediment an the su~face, the sandy loam should be removed and replaced with a soil mixture meeting the Alameda Countywide Clean Water Pragram soil specifications included in appendix G of the Stormwater Management Plan. The sediment shalf be off-hauled to a landfllf or other suitabie disposal site with no biological rest~aints. a. Vegetation maintenance will be accomplished by hand pruning, unless aggressive, non-native speciss become a problem, in which case other methods of removal can be inifiated at the discretion of the GHAD Manager. Qruning will only involve the cutting and removing of vegetation above the ground, e.g., mowing, rotary cutting, and chain-sawing, where the activity neither substantially disturbs the root system nor invalves mechanized pushing, dragging, or other similar activities. No heavy equipment will be used within the Detention/Water Quality Basins for rou#ine maintenance. Pruning debris will 8e removed from the basin in burlap or canvas bundles and trucked to an authorized dumpsite reviewed and approved by the GHAD Manager. Vegetafion removed or destroyed during maintenance wi{I be allowed to re-establish naturally without replanting. Page 2 ~ ~~ 11~0 ~ ~ b. The sides of the Detenfion/Water Quality Basins are to be monitored on a quarterly basis. Plantings and other vegetation are to be inspected for health and vigor. All embankment ' sides should be free of erosion, riils, slumps or landslides. Embankment slape irregularifies should be reported to the GHAD Manager in the monitoring report. Irrigation sys#ems, if present, are to be monitored for proper function. Leaking or malfunctioning irrigation systems ' will be repaired within two days of inspection. lI-1-7 Mosq,uito Abatement. As part of DetentionNVater Quality Basin maintenance, the GHAD ' Manager will coordinate wi#h Alameda County Mosquito Abatement Distric# to monitor for the potentiai presence of mosquita vectors as necessary. Shoufd mosquito populations be detected in the basin, the GHAD Manager will coorclinate with Alameda County Mosquito Abaternent 1 District to employ techniques to contral mosquito produc#ion that are acceptable to the applicable regulatory agencies. ~ ~ ~ LJ ~ ~ , ~ ~ ~ ~ ~ ' Page 3 1 1 ' ~g 1~~ ~ CHAPER 2 MAINTENANCE OF BASIN FACILiTIES II-2-1 Procedures. Prvicedures for the following maintenance items are outiined in the subsequent chapter sections. , • Manitoring stormwater height in the DetentionNVater Quality Basin. • Cleaning of all debris racks. • Maintenance of basin outflow structures. , • Repair tasks. • Embankment stabilization. ~ II-2-2 Monitorinp Sformwater Heiqht 8 C(eaning Debris Racks a. The Detention/Water Quality Basin inlets will be inspected quar#erly and maintained in good condition without obstructions. It is of ufmost impo~tance that the inlet functions properly, ~ substantially free of debris or other obstructions. Special attention should be given to whether erosian is occurring around the edges of th~ inlet structures as well as at or immediately downstream from the discharge point into the basin. Litter and obstruction removal should be undertaken during routine maintenance visits. ~ b. The DetentionNVater Qualit Basin outlets and the eme~gency overflow structure will be Y inspected quarterly and after all storm events generating more than 1.0 inch of rainfall in.any ~ 12-hour period. The overtiow structure should be additionally inspected after any event that causes flow over the overflow structure. Any debris accumulating an trash racks is ta be removed. All trash racks and the emergency overflow structure will be maintained and , repaired as necessary to allow proper function. c. The basin shauld drain within 72 hours of significant precipitation. The water level should not ~ be significantly higher than the maximum elevatian of the outlet control structure, or less than one fee# below the level of the emergency overflow structure. ~ 11-2-3 Maintenance Discharqes. Water removed from the Defention/Water Quaiity Basin facilities for maintenance will be directly released into the 24-inch storm drains. 1 Maintenance discharges are limited to those approved by the GHAD Manager. Before approving the remavai of water or sediment from the Detention/Water Quality Basins, the GHAD Manager will consider the following factors: 1 • The size and age of the facility. • The construction quality of the facility. • The maintenance history. ~ • Whether the facility has been functioning at capacity and for how long. • Present vs. original stormwater cantrol needs. ~ Whether sensitive/unique functio~s and values may be adversely affected. 1 II-2-4 Repair Tasks. In determining the need far repairs to the De#ention/Water Quali~y Basin's embankments, overflow structures, inlets ar autlets, the GHAD Manager will consider the ~ following factors: • Any original mitigation required. ~ ~ The current environmental setting. • Any adverse effects of the repair project including #hose to wildlife species utilizing the basin. ' Page 4 r ~~/~6 ~ ' The GHAD Manager will immediately undertake maintenance for completion of any basin repairs, provided that the GHAD Manager established a schedule for the identification, approval, development, construction and completion of the required repair in accordance with City policy. ~ II-2-5 Embankment Stabilization. The embankment of the basins should be maintained in a stable condition and are designed to remain stable throughout the life of the projecf; however, if areas of weakness are noted during the monitoring process, stabilization should be undertaken in a timely , fashion. The fol{owing guidelines are appiied to ali grading accampllshed for non-emergency construction of stabilixation measures: • Both an Engineering Geologist and Civil Engineer should be consulted on significant I embankment repairs. • Soi( removal/placement should be limited to the minimum needed for erosion/fload protection. • No material shouid be placed in any special aquatic site, including wetlands, without proper , resource agency permitting. ~ Preference will be given to soft armor and bioengineering techniques whenever passibfe. • No material should be placed in any location, or in any manner, so as to impair surface water ~ flow into or out of any wetland area without proper resource agency permit#ing. • No material shouid be placed within a surrounding open space area withouf the consen# of ~ the GHAD. • No ma#erial should be placed in a manner #hat wili be eroded by normal or expected high flows. ' C~ 1 I 1 I 1 1 i 1 Page 5 r ~ ' ' ~ ~ , , , ' , ~ ~ r 1 r ~ ~ i ~a~i~ M~NITORiNG REPORT Fallon Crossing , Alameda County, California Fallon Crossing Detention/Water Quality Basin Operations and Maintenance Site~ Monitoring and Maintenance Report Form (to be completed quarterly in January, April, July and October and as necessary during heavy rainfall, and submitted in the semi-annuai sediment accumulatfon and hydrologic function reports in February and August, and in the Stormwater Maintenance and Monitoring Report by December 31 of each year) (nspector: Wea#her Conditions: Date: Days since last rainfall: Dry season? We# season? Basin Water Level: Sediment Accumulated since Last Monitoring Event: MONITORED YES NO N1A COMMENTS! 5UGGEST~D MAINTENANCE CONTROL 9. Are inlet and outlet structures functioning properly, allowing the basin to drain and are they in satisfactory condition? 2. Are all holes on the outlet structure ciear of debris and allowed to function ro erl ? 3. Are access roads in satisfacto condition? 4. Is all perimeter fencing (if present) in good condition without breaks, a s or dama e? 5. Have the debris racks been cleaned and are the in ood candition? 6 Are embankments surrounding the basin in good condition without rills or failure7 7. Is fhe vegetatfon 4ess than 5 feet in hei ht? 8. Are embankment slopes profected with mulch or ve etation? 9. Has water removal been undertaken in the last 3 months7 If so, describe rocedure? 1 i , ' ' ~ ~ ~ , ~l /C~o ~ MONITORED YES NO NlA COMMENTS! SUGGfSTED MAINTENANCE CONTROL 10. Has sediment removal been undertaken in the last 3 months? 11. Do any basin devices require maintenance to provide more effective function? 12. Are there any signs of leaking irrigation s stems? 9 3. A~e there any signs of vandalism? 14. Are mosquitoes evident? 15. Has mosquito abatement been undertaken since the last monitoring event? 16. Are there remedial/repair tasks that should be undertaken in the near #uture? 17. Is there evidence or information received in the last 3 months to indicate a lengthy drain time~ ~ "No" answers to Items 1-9 or "Yes" answers to Items 10-17 require a corrective action. , ~ ~ ~ ~ , ' ~ , ! ~a l c~.o ~ ' FALLON CROSSING DETENTIONNVATER QUALITY BASIN OPERATIONS AND MAINTENANCE ' SITE MONITORING AND MAINTENANCE REPORT FORM {CONTINUED) , CORRECTIVE ACTIONS UNDERTAKEN {if none required, enter date and "none") ' ' , ~ 1 ~ ~ ~ ~ , 1 1 ' 1 OATE I ACTION REQUIRED ~ CORRECTIVE ACTION TAKEN ' ! 1 , ~ ~ ~ ~ ~ ~ ~ ~ ~J ~ ~ ~ r r ~ ~ ~(~o ~ DAT~ I ACTIQN REQUIRED ~ CORRECTIVE ACTiON TAKEN ~ 1 1 1 ' ' ` ~ , ~_J , ' ~ ' ~ ~ ~ ~ ~ ~~ APPENDIX RUGGERI-JENSEN-AZAf7 & ASSOCIATES Falion Crossing Stormwater Treatment Ptan Alameda County, California ~~ L(eo ~ ' ! ! 1 , ' ~ ~ , , ~ ' ~ , ~ ~ ' ~ ~ ' Stormwater Management Plan Fallon Crossing - Tract 7617 Dublin, Alameda County, California Prepared for: Standard Pacific Homes Prepared by; 1~~11 I~UGC~ER1-JENSEN -AZAI~ ENGI NEERS ~ PLANNE-iS • SURVEYORS Project No. 031006Il' September 19, 2008 Updated July 30, 2009 Updated April 13, 2011 ~~' l~o ~ ~~ i Table of Contents l~ I~,o ~ ~ Int~•oduction ......................................................................................................................... 1 Purpose and Scope . 1 Water Oualitv ...................................................................................................................... 2 ' Wate~- Quantity ...............................................................................................................•.... 3 Site Location and Description. 3 Soils Conditions ...................................................... ....................................................... 3 ~ Climate .....:...:.................................................................................................................. Ground Wate~• and Surface Watex. . 4 4 Pro~ect Description .............................................................................................................. ~4 ~ Drainage Management Areas ............................................................. ............................ Detention Design Guidelines . 5 5 Additional Source Controls ............................................................................................. 5 ~ Maintenance :....................................................................................................................... References . 5 6 Appendix ............................................................................................................................ A ~ Vicinity Map ....................................................................................................................... Storm Water Treatment Plan . B C Water Quality Sizing Calculations ...................................................................................... D ~ Pond Volume Calculations ................................................................................................. BAHM Report ..................................................................................................................... E F Alameda Countywide Clean Water Program Soil Specifications ....................................... G ~ ~ ' ~ i ~ L~ ~ C~ 1 1 i 1 ' ~ ~~ ~ ~ ~ ~ ~ ' ~ , i (~~ I(~o ~ Introduction The Fallon Crossing Residential project (P~-oject) is a planned development in the City of Dublin, Alameda County, California. The stormwater runoff gen.erated by the Project site is subject to Provision C.3 of the NPDBS permit issued to the local municipality by the California Regional Water Quality Control Board (RWQCB) for the San Francisco Bay Region. The regulations require treatment of the post construction runoff from new developments and significant redevelopments before the runoff is discharged to the municipal stonn drains to the Maximurz~ Extent Practicable {MEP). In addition, many projects must also control the rates and dw•ations of runoff flows to match p~-e- development levels for a particular range of storm events. RWQCB staff monitors each municipality's implementation of permit requirements. Each municipality musf report on its development review proeess, number and type of projects reviewed and what Integrated Management Practices (IMP) were utilized in projects. Development and redevelopment activities can degrade water quality during construction with erosion and sedimentation as weli discharge of other pollutants. Since 1999, a Storm Water Pollution Prevention Plan (SWPPP) has been a standard part of grading plans to be used to winterize jobs wllere the hardscape and landscaping has not been coinpleted prior to the a•ainy season. in addition to these short term source pollutants, long term pollutant sources can degrade the water quality being discharged to receiving streams, lakes, estuaries and bays. While stormwater runoff is a natural part of the hydt•ologic process, urbanization and agricultural Iand uses have altered the natu~-al drainage paftezns and added pollutants to receiving waters. Project applicants are required to incorporate IMPs into the site to offset the negative impacts of u~•banization. This plan addresses both water quaiity and flow control measures at the planning level of detail to show complian.ce with the post-construction, long teim requirements of P2•ovision C.3. A SWPPP will be prepared as a sepax~ate document to control short term, construction related discharge pollutants as required by the California State Water Resources Control Board Order No. 99-08-DWQ. ' Purpose and Scope The purpose and scope of this plan is: I. Determ~ne the existing hydrologte, topographic, soils, and drainage featu~-es of the ~ site. 2. Identify site constraints and opportunities for selection of treatment and flow control facilities. ~ 3. Utilize these features to design water quality treatment facilities for removal of pollutants. 4. Utilize existing site features desci7bed above and proposed site featu~•es to design hydrograph modification facilities, if needed, using the Bay Area Hydrograph ~ Model {BAHM). , G:V+dminUolx•01~031 WGlSiomnvnicr Mnnagcmcm Plan.doc A. Acheckzai ~ ~ 1~~~ l(~d ~ 5. Document design decisions within this report to quantify the benefits achieved by the site design. ' This Sto~mwater Management Plan (SMP) has been develaped using guidelines provided by the Alameda Countywide Clea.n Water Program (ACCCWP) C.3 Stormwater Technical Gui~'ance, the California Stotmwater Quality Association (CASQA) ' Stormwater Best Management Practice Handbook, the Bay Area Stoi-mwater Management Agencies Association (BASMAA) Using Site Design Techniques to Meet Development Standards for Stormwater Quality and past expe~-ience in the design of , storniwater quality facilities. ~ Water ualitX Impervious surfaces in developed areas such as roofs, roads, parking lots and sidewaIks ' prevent stormwater fi-om infiltrating into the soil. Most of t~e rainfall ~-emains on the surface which is designed to drain as quickly and efficientiy as possible. The surface flow washes debris, dirt, oil and other vehicle fluids, chemicals and other pollutants into ~ the storm drain system which eventually outlets into receiving waters such as streams, i7vers or bays. Approximately 80% of annual rainfall occurs in more frequen,t, low intensity stoz~ms that , produce less ~•unoff. The goal of the SMP is to remove pol(utants from the stormwater runoff dui7ng these low intensity storm events while still providing flood protection for the infrequent high intensity events. ' CASQA lists th~ follor~ving pollutants of concern and their impacts on water quality in their 2003 handbook; • Sediment - nutrient transpoi~t and interferes with aquatic life ~ • Nutrients - excessive or accelera.ted growth of algae • Bacteria and Viruses - health conceins for humans at recreational facilities ' • Oil and Grease - toxic to ayuatic organisms at iow concentrations ~ Metals - toxic to aquat~c organisms, bioaccumulation and drinking water contamination • Organics - synthetic organic compounds are environmentaliy harmful to water ' quality • Pesticides - environmental, wildlife and human health concerns through ~ bioaccumulation • Gross Pollutants - includes trash, debris and floatables that creates an ey~sore in waterways , • Vector Production - mosquitoes, flies and rodents are attracted to areas of standing water and can spread disease , ~ ~ 2 A. Acl~eckzai G:1AdminWUs-01W310DGlSlt~nnvatcr M~wgcn~ent Plan.doc ~ 1 1 ' ' ' ' ~ ' , ~ ~ ~ ~ , ~ 1 ~ , G~ ~c~~ Water QuantitY Hydrograph modification is the change in timing and volume of stoi-mwater runoff when a site is developed. In August 2006, Pz'ovision C.3.f in the stormwater National Pollutant Discharge Elimination System (NPDES) permit reyuires municipatities to manage increases in peak runoff flow and volume from all projects that create or replace an acre or moae of impervious area (Group 1 Project} where the increase in flow or volunne ~s likely to cause increased erosion in creek beds and banks, generate silt pollution or otherwise impact beneficiai uses of water bodies. Larger volum.es and faster flow rates in unprotected creeks or channels in.crease erosion. As the channei enlarges due to erosion, damage to habitat, water quality and property occurs. Traditional detention designs have not adequately addressed this problem in the past due to the fact that relativeiy low flows can cause erosive damage. For this reason, ACCWP re,qnires continuous simulation using record rainfall data to evaluate Hydragraph Modification for the s~orm event range of 14% of the 2 year storm to the 10 yea~~ storn~. ACCWP has pa~~ticipated, along with San Mateo County, Santa Clara County and Clear Creek Solutians, Inc. in developing a computer model fo~ this pu~pose. The Bay Area Hydrograph Model {BAHM) is the result of this collaboration and is used in this plan to evaluate Hydi•ograph Modification for the site. Projects are subject to Pi•ovision C.3.f unless they can show that the project will not cause erosion or other significant effects to beneficial uses in the receiving waters. Site Location and Description The Project site is a 67~ acre undeveloped pa~•ccl located at the intersection of Tassajara Road and Fallon Road in the City of Dublin as shown on the vicinity map (Figure 1). The Project is situated on a city block that does not yet have fully developed streets. Bordering on the north is an undeveloped parcel owned by Charles Richey and Charles Hunter. The westei~n boundary is Tassajara Road, which connects Alameda County and Contra Costa County. To the south and east borders Silvec•a Ranch, a recently developed residential development. Soils Canditions Based on the design level geotechnical investigation report by Berlogar Geotechnical Consultants, residuai soils, colluviai deposits, and alluvial deposits wex~e encountered in boring Iogs performed. The residual soils encounte~•ed consisted of dark gray and dark gray-bz•own silty clay (CL-CH). Colluvial deposits were also found to consist of dark gray to dark gray-brown to dark bz-own silty clay (CH}. Alluvial deposits were located within and adjacent to Tassajara Creek. The alluvial soils consisted of stiff to very stiff sandy clay and silty clay (CL-CH), medium stiff to stiff clayey silt (ML), medium dense sandy silt (ML}, clayed sand (SC) and silty sand {SM). 3 A. AcheckzAi G:V~dminVobs-03193100615tomiwalcr r9anagcnunt Plan.doc t ~ ~ ~ I (eo ' Cliznate Dublin has a climate characterized by wet winters and dry summers receiving a mean t annual precipitation of 16 inches (ACCWP, Attachement-6). The typical wet season is from October to April with occasional, uncharacteristic rainfall during the other months. ~ Ground Water and Surface Water Groundwater conditions at the site a~•e expected to vary signi~cantly depending on weather conditions during the time of year, water ievel in the creek, and in•~gation practices. Tt is not anticipated that groundwater will interfere with stormwater facilities on ' this site. Surface runoff begins when the soils reach thei;• saturation level and additional rainfall ' begins overland flow. The surface water begins as ovex•lan:d flow down the hillside eventually makes its way to Tassajara Creek. ~ Project Descri tp ion 1 The Project is planned to be composed of 10G single family homes. The development consists of 3 private driveways, 3 cul-de-sacs, and one stree~ which i-uns th~•augh tlle entire site. A 3~ acre trail/landscaping area is planned to be centrally located and 1 landscaping areas are planned to maximize the green areas of the site. 100% of storm water runoff vvill be treated in the proposed Upper and Lower Water Quality Ponds vvhich will have 18" of sandy loam rrzeeting the ACCW~' soil specifications (Appendix G) on ' the bottom su~•face to ~~ter stormwatex• prior to discharge to a detention basin des~gned using BAHM to meet the hydromodification standard. The detention basin discharges into the Tassajara Creek thi•ough a storm drain pipe and energy dissipater. ' The property fronts on existing Tassajara Road which is cun•ently nat tx-eated for stormwatea• yuality. The project will construct curb, gulter and sidewalk on the existing ' road and replace existing pavement with the ultimate road section. The portion of the existing street that drains toward the new curb, gutter and sidewalk will be t~•eated in two ~ , 6 fe~t by 10 feet Filterra units. The total area conri•ibuting to these Fillerra units is 0.74 acres (Areas 4 and S in the table below). The number and size of the Fziterra units has been designed to treat double the contributing ai•ea. , . ~ ' ' ~ 4 A. Acheckzai G: VldminUobs-03103 f ODG151omavatcr Myu~gement PL~n.doc ' r i ' ' LJ ' ~ ' ' , ' ' ~ , ~ ~ ' ~ ~~ I~a Drainage Manag;ement Areas For the purpose of this report, the project l~as been divided into Drainage Management Areas (DMA) as shown in Figure 2. The table below describes the treatment method used for each DMA. Impervious Required Volume Area Surface Area (SF) BMP Used Votume Provided ID Treatect Ac-f't Ac-ft Area 1 Roof/I'aving/SWK/DWY 186,250 U er Water Qualit Pond* 0.18 0.25 Area 2 Roof/Pavin /SWK/DWY 226,347 Lower Water ualit Pond* 0.2G 0.30 Area 3 O en S ace 0 Self Treatin - - Area 4 Pavin~/SWK offsite 23,565 FIIh'1fiOt1 U131t - - Area 5 Pavin SWK offsite 8,837 Filtratio~~ Unit - - --_. _ *Water quality pond sized using 80% capture method described in Alameda Countywide Clean Water Program (see append'rx) Detention Design Guidelines Flow control for this site is ptanned to be addressed prior to connection t~ the existing City sto~~m drain system. The BAHM model described earliex• in this report was used to determine the amount of storage requircd and the outlet stivcture needed to meet the HMP standard (see appendix). Additional Source Controls Tn addition to tlie watcr quality pond, education is an impoz-tan.t factor to water quality. Education includes printed material available from ACCW P that should be provided to all buyei-s and tenants as they move in. The printed materials have infoi~rnation regarding the damaging effects of spilled oil, car washing, paint products and many more cammon sources of pollution from developments and how to minimize or eliminate them. In addition to this, stenciling "NQ DUMPING, DR.ATNS TO CREEK" on all storm water inlets is anothe~• way of informing the public. The use of drought tolerant planting will reduce irrigation requirements thereby reducing the potential for polluted runoff. Maintena.nce Maintenance of the ponds will be the responsibility of the owner until it is delegated to the Geological Hazard Abatement Distt•ict (GHAD). The focus of the maintenance is to keep the ponds in the condition to provide the sec~vices i•equired to meet water quality and flow control standards. Primary maintenance af detentian basins and water quality ponds should include managing vegetation annually during the summer, trimming vegetation at the beginning and end of the wet season and inspecting on a month to month basis to prevent establishment of woody vegetation and fox• aesthetic and mosquito control reasons. The , A. Acheckzai ' G:V~dminVoln•0310310QGLSIOmiwalcr Managcmcnt 1'lan.doc t ~ f(~~ ' basins and ponds should be regraded every ten years or when the accumulated sediment volume exceeds ten percent of the basin volume. ~ t A separate and more detailed Qperations and Maintenance has been prepared for the ponds. , The Filten~a units will be maintained by Filiei~ra for the first year, then by Standard Pacific Homes until such time as the City of Dublin accepts the right of way dedicafion. Once the dedication is accepted, maintenance will be perfoa-med by the City or its ' designec. ' Filtezxa will provide an Operations and Maintenance manual for these units. References ~ 1. Alameda Countywide Clean Water Program, C.3 Stormwater Technical Guidance: A handbook foz- developers, builders and project applieants, August 31, 2Q0G. ' 2. Alameda Countywide Clean Water Prog~•am, C.3 Stormvvater Technical Guidance: A handbook for developers, builders and praject applicants, October 19, 2010. ~ 3. Bay Area Stormwater Management Agencies Association, Using Site Design Techniques to Meet Development Standu•ds for Stormwater Quality, May 2003. 4. California State Water Resources Conh•ol Board, August 19, 1999, General , Permit No. CASO40002, State Board Order No. 99-08-DWQ, WDID No. 2075313525. 5. Califo~•nia Sto~-mwater Quality Association, Stoz•mwater Best Management ' Practice Handbook, January 2003. 6. Contra Costa County Clean Watcr Progz~am, Stormwater C.3 Guidebook, 3r~ Edition, October 200d. ' 7. United States Department of,Ag~•iculture, Urban Hydcology for Small Watersheds: Technical Release 55, June i986. ' 8. United States Department of Agriculture, Web Soils Survey, http://websoilsurve nres d / / . .us a.gov . app ' 1 ~ ' 1 ~ A. Acheckzai G:~AdminUoln•OJ10310061Swrnnvatcr M:uugenxnl Plan.doc ' ~ ~ Appendix ' ~ ~ ' , ' , ' 1 r ~ ~ ~ ~ ~ A ' ~ ~~ ~~ ~ ~ ~ ~ ~ ~ ' ' ~ ~ ' ' ~ ' ' ' ~ , ' ~~n ~~«R .~A cost ~"n ;;`'~ ~ ~;~':. PROJECT oK c ~;;;. ~ .~.,~,.N,. ~ ~,pAE~QA ,;~}~;fiY~~N.G~;.~i.,:: :_; -~sj~ ~~=~k ~ SITE ux ;~~,~':~` "'~ ~ SIL VfRA RANCH LIN LIN _ N __ c, 4 ~ ~ ~ ~~Y q A~ ~ ~ ~ ~ a~ASav oRr~ ~ ~p PKWY DU9U L INIERSTA~ 580 oA° ~'°~ ~`~~~ ~° ~,p~'~ ~~P ~3 a ~~ 5P d VICINITY MAP NOT 1t? SCAL£ ^ ~ ..~ ~~ ~~ ' ' ' ' i 1 ' ' ' ' ' ' ' t ' 1 ' ' ' --~\\~ ~ ` ~ I ~ V ~ 1 \ 1 I N o ia ao ~oo I ~_~~~ crmr) IW~.IODM1 LIN I / // / ~~ A MA~DEV0.0PNiNT YlFFYpIK AAG ~ IIA141 0.f. 0. POlT OEYEIOPAETIf M61YqU! AA611 L RDADMAY Q~LU0110 COIMOM DAIYEMAYII ~ tp.NN A.f. ! 1100F/ ~ tlll6Tf /f, !, 1pEN'µ~( ~ azae+ af. TOTAI POlT OkYNOPYflR raraue uiu ~ u~,~n ~ e.F. BTOAAI ~AfE xed n A 1 M'A } A 1RE~TAENf CAlW wr~a 1 AIN' IY A A111r , i1T lA7qNB: ~°~"f ~~ N6 71 7 __ ewure MIA M~RQIUff 1^ ra~r ~MC Io-R K-R ~arr novo K-I OR /%I J M Ki 0 AU AGI A711 IAMC y: }lOfS R~RM4~I ' A9A1 ... _ iA1KG~._____ 4 1lRA0.M4~I ' _ WS ~ pG pMp1YMq MO ttWC III WMIf MKO M70MI0 K aum aurmrt dnw wx~ nkoea •-~aaf ~i-~-~s ~ f ~~~f~.~ r...._. - - -s~ia~f ~# ~f~~~s ~ ~~~~- 1 ~ ~ ~ A3 ~ ~ ~~, •~~ ~ ~ . ~~ ~ ~~ 1 „ ~~ M N ' U ~/ y, IS \ a a ~ a ~ u ~ ~ a _ ~~ ~ J a ~.____ n ` e ~~ \\ w ~~ ~ ~-~ ~ .~ ,~ ~~ b ,, ~~ ~ , N r~~~•____,. ~ w ~ I v ~ ~,~ µ .1 .4:...:..~:~\~ ~•.•.,-~, I ~~ \ I ., - , _._.~ .~~, ..i~~ ,.~.::% ...~ I 11 ~ ~ ~ 91L ENA RAN H ~ _ - - A ' ' ~__ _ 7 ~ _f ~ __ ~ - 7 _~. ~ SipE[f 'B' m~ auxln-1 warow 1Af ~ 11. I~IP POND BECTION .OlA RNf ~~s ~ u~~ara ou~a~ W - y ~ ~_YL i~zs ~.aror -" .' ,.n. --- .mw ,~ ~ • Yrpnpt ~.~ N'Mr-. ~~n+wrac ~-- ~ ~Tiw N~yur~ini~ ~ ,i '------------~'--- --------- -'"~- -- LOIIER PqP ItlSER ~ vr ~ 11~ q'w Oqf (!17 ~ uar m~oroo N~ 'E`~~' ~~ ~ ~ ( ~p IMl i~i~ N'Np10r y~y N'MrM1tMIAMfN ~ bMWInN W,4 !Mp ~f~ IR(/iYIf~O ~Y~r/aWYO ~ 1 W/p0 IW~MWOIYIOUtlp ~p, pnOralaD rmeawrin~ " ~°1/P~ YIATER DUAUTY POND BEGTION Gar ~•ianr ersrow ~UBDRNN DETAIL ''fPLO"`"` AWqfOtl( (nGMNK ~ ~ ~~Ya OUTLET WORKB DE~ l~,Q W.L~ +w A rwr 1\i'L ~ RUa~ERI•JENSEN•AZAR STORM WATER TREATMEIdT PLAN - FALLON CROSSING ~°°~»~~~~.,"~•~~,.,°~°~~~~, N10 MNOI pIM. WR 7Ep RfA3IM14( µ N!N -- mom~ pnl m-nm !AY (IH~ lT.II00 CIT1' OF DI~IM, COUNTY OF AUWEDA, CALIFORNIA ~ I~O ~ ~ ~ ~ ~ ' ' ' ~ , 1 ' ' ' ~ ~ ' ~ ' , 1 , ~~ -~~ FALLON CR~SSING Water Quality Sizing Calculations - 80% Capture Method (ACCWP) Total Drainage Area(WQP1)= 7.91 AC (UPPER) 7otal Drainage Area(WQP2)= 12.77 AC {LOWER) Averas~e Typical Pervious Flows ta Lot No. Lot Area Roof Area* D area Total DCIA % DCIA Area LOWER WQP 1 4,790 1,760 234 1,994 42% 2,796 LOWER WQP 2 4,651 1,907 283 2,190 47% 2,461 LOWER WQP 3 9,266 2,140 288 2,42$ 26% 6,838 LOW~R WQP 4 8,643 1,919 276 2,195 25% 6,448 LOWER WQP 5 4,159 1,760 243 2,003 48% 2,156 LOWER WQP 6 4,361 1,760 190 1,950 45% 2,411 LOWER WQP 7 5,210 1,907 410 2,317 44% 2,893 LOWER WQP 8 5,633 1,527 614 2,141 38% 3,492 LOWER WQP 9 5,603 1,760 . 304 2,064 37% 3,539 LOWER WQP 10 7,183 1,907 357 2,264 32% 4,919 LOWER WQP 11 5,431 2,134 277 2,411 44% 3,024 LOWER WQP 12 4,277 1,501 589 2,090 49% 2,187 LOWER WQP 13 5,229 2,134 325 2,459 47% 2,770 LOWER WQP 14 4,62'I 1,9~7 398 2,305 50°/a 2,316 LOWER WQP 15 5,637 1,501 592 2,Q93 37°!0 3,544 LOWER WQP 16 5,378 1,919 359 2,278 42% 3,100 LOWER WQP 17 5,119 2,127 333 2,460 48% 2,659 LOWER WQP 18 4,762 1,907 357 2,264 48% 2,498 ~OWER WQP 19 2,950 857 175 1,032 35% 1,918 L.OWER WQP 20 2,493. 543 215 758 30% 1,735 LOWER WQP 21 4,000 1,919 357 2,276 57% 1,724 LOWER WQP 22 3,8$9 1,502 579 2,081 54% 1,808 LOWER WQP 23 4,837 1,760 252 2,012 42% 2,825 LOWER WQP 24 4,318 2,134 256 2,390 55% 1,928 LOWER WQP 25 4,211 1,502 575 2,077 49% 2,134 LOWER WQP 26 5,966 1,919 312 2,231 37% 3,735 LOWER WQP 27 5,937 2,127 240 2,367 40% 3,570 LOWER WQP 28 5,244 1,907 463 2,370 45% 2,874 LOWER WQP 29 4,763 1,501 594 2,095 44% 2,668 LOWER WQP 30 5,000 1,907 357 2,264 45% 2,736 LOWER WQP 31 5,334 1,760 304 2,064 39% 3,270 LOWER WQP 32 6,381 2,140 371 2,511 39% 3,870 LOWER WQP 33 2,633 8A3 214 1,057 40% 1,576 LOW ER WQP 34 2,465 887 175 1,062 43% 1,403 LOWER WQP 35 3,800 1,527 589 2,116 56% 1,684 LOWER WQP 36 4,OQ0 2,127 288 2,415 60% 1,585 ~OWER WQP 37 4,00~ 1,919 357 2,276 57% 1,724 LOWER WQP 38 3,939 1,501 596 2,097 53% 1,842 LOWER WQP 39 4,161 1,760 316 2,076 50% 2,085 LOWER WQP 40 4,926 1,907 359 . 2,266 46% 2,660 LOWER WQP 41 4,476 2,134 2S3 2,387 53% 2,089 LOWER WQP 42 5,598 1,527 663 2,190 39% 3,408 LOWER WG1P 43 4,125 1,760 279 2,039 ~ 49% 2,086 ---- ~ ..., ~ ~ , 1 ' , ~ ' ' ' , ~ , , ' , , ' ' ~~ i ~~ ~ Avera~te Tvqical Pervious Flows to Lot No. Lot Area Roof Area* Dw area Total OCIA % DCIA Area LOWER WQP 44 4,587 1,907 331 2,238 49% 2,349 LOWER WQP 45 4,417 1,760 249 2,009 45% 2,408 LOWER WQP 46 4,498 1,502 580 2,082 46% 2,416 LOWER WQP 47 4,427 2,140 288 2,428 55% 1,999 LOWER WQP 48 4,299 1,501 589 2,090 49% 2,209 LOWER WQP 49 4,726 1,9Q7 387 2,294 49% 2,432 LOWER WQP 50 5,202 2,134 354 2,488 48% 2,714 LOWER WQP ~ 51 4,533 1,502 571 2,073 46% 2,460 LOW ER 1NQP 52 3,238 857 161 1,018 31 % 2,220 L.OW ER WQP 53 2,083 843 201 1,044 50% 1,039 streets ~ ~ u, ~ b;c ~r Totals 246,619 89,140 9 9,045 108,185 C(Ala Co. Ciean 0.7 NA 0.75 0.8 , NA Water Program) Open Space 199,940 SF Weighted C* 0.39 Correction Factor= 1.11111111 Unit Basin Stor 0.22 in Corr UBS= 0.24 in WQv= 0.26 Ac-ft At 3.5' max WQ depth, need area= 0.48 ac 92% 138,434 NA 0.1 Avera e Tvpical Pervious Flows to Lot No. Lot Area Roof Area* D area Total DCIA % DCIA Area UPPER WQP 54 3,992 1,760 304 2,064 52% 1,928 UPPER WQP 55 4,115 1,919 356 2,275 55% 1,840 UF'PER WC1P 56 4,OS2 1,542 579 2,081 51 % 1,971 UPPER WQP 57 3,909 1,760 255 2,015 52% 1,894 UPPER WQP 58 4,025 1,90? 387 2,294 57% 1,731 UPPER WQP 59 3,825 1,501 589 2,090 55% 1,735 UPPER WQP 60 4,075 1,907 357 2,264 56% 1,811 UPPER WQP 61 4,107 1,760 311 2,071 50% 2,036 UPPER WQP 62 4,217 2,134 310 2,444 58% 1,773 UPPER WQP 63 3,227 889 231 1,120 35% 2,107 UPPER WQP 64 2,791 843 271 1,114 40% 1,677 UPPER WQP 65 3,871 1,760 324 2,084 54% 1,787 UPPER WQP 66 3,982 1,501 604 2,105 53% 1,877 UPPER WQP 67 4,307 1,907 409 2,316 54% 1,991 UPPER WQP 68 4,082 1,502 570 2,072 51% 2,410 UPPER WQP 69 4,242 2,127 265 2,392 56% 1,850 UPPER WQP 70 4,263 1,919 334 2,253 53% 2,010 UPPER WQP 71 3,953 1,527 574 2,101 53% 1,852 UPPER WQP 72 4,013 1,501 354 1,855 46% 2,158 UPPER WQP 73 3,872 1,501 610 2,111 55% 1,761 UPPER WQP 74 4,187 1,907 425 2,332 56% 1,855 URPER WQP 75 4,226 2,134 337 2,471 58% 1,755 UPPER WQP 76 4,054 1,501 614 2,115 52% 1,939 UPPER WQP 77 3,927 1,760 257 2,017 51% 1,910 UPPER WQP 78 5,505 1,919 407 2,326 42% 3,179 UPPER WG1P 79 6,410 2,127 476 2,603 41% 3,807 ' , ' ~ ~ ' ' 1 , ~ ' ~ ' , ' 1 ' ~ ' ~ I~~ l Averaste 7 ical Pervious Flows to Lot No. Lot Area Roof Area* Dw area Total DCIA % DCIA Area UPPER WQP 80 5,440 1,527 574 2,1U1 39% 3,339 UPPER WQP 81 5,919 1,907 338 2,245 3$% 3,674 UPPER WQP 82 5,805 1,502 565 2,067 36% 3,7$$ UPPER WQP 83 5,950 1,760 241 2,001 34% 3,949 UPPER WQP 84 6,219 1,919 384 2,303 37% 3,916 UPPER WQP 85 5,999 2,134 344 2,47$ 41% 3,521 UPPER WQP 86 5,761 1,907 434 2,341 41% 3,420 UPPER WQP 87 5,252 1,501 619 2,120 40% 3,132 UPPER WQP 88 5,276 1,907 380 2,287 43% 2,989 UPPER WQP 89 4,984 1,527 582 2,109 42% 2,875 UPPER WQP 90 5,086 1,760 29fi 2,056 40% 3,030 UPPER WQP 91 5,474 1,919 341 2,260 41% 3,214 UPPER WQP 92 5,347 2,140 274 2,414 45% 2,933 UPPER WQP 93 4,115 2,127 342 2,469 60% 1,646 UPPER WQP 94 3,84$ 1,527 559 2,086 54% 1,762 UPPER WQP 95 4,036 1,907 387 2,294 57% 1,742 UPPER WQP 96 3,951 1,501 589 2,090 53% 1,861 UPPER WQP 97 3,907 1,760 257 2,017 52% 1,890 UPPER WQP 98 4,058 1,919 357 2,276 58% 1,782 UPPER WQP 99 3,800 1,760 304 2,064 54% 1,736 UPPER WQP 100 3,800 1,502 579 2,081 55% 1,719 UPPER WQP 101 3,900 1,760 307 2,067 53% 1,833 UPPER WQP 102 4,132 1,907 361 2,268 55% 1,864 UPPER WQP 103 3,975 1,527 593 2,120 53% 1,855 UPPER WQP 104 4,004 1,907 360 2,267 57% 1,737 UPPER WQP 105 3,852 1,501 592 2,093 54% 1,759 UPPER WQP 106 4,065 2,127 316 2,443 60% 1,622 Streets 7~s4s 5t- Totals 235,184 92,617 21,785 114,402 C(Ala Co. Ciean 0.7 NA 0.75 0.8 NA Water Program) Open space 31258 Weighted C* 0.45 Correction Factor= 1.11111911 Unit Basin Stor 0.25 in Corr UBS= 0.28 in WQv= 0.18 Ac-ft At 3.5' max WQ depth, need area= 0.05 ac 79% 120,782 NA 0.1 0 ~ ~ ' , ~ , ~ i r ' ~ ' ' , 1 , 1 ~ , Fallon Crossing Pond Volume Calculations Lower WQ Pond Contour Area s Volume (cfl Voiume (Ac-Ft) 472.7 0.0 597.8 0.01 473.2 2391.0 2318.8 0.05 474.0 3406.0 8728.0 0.20 476.0 5322.0 1081.7 0.02 476.2 5495.0 TOTAL 0.29 Upper WQ Pond Contour Area s Volume (cfl Volume (Ac-Ft} 477.5 0,0 369.5 0.01 478.0 1478.0 4038.0 0.09 480.0 2560.0 4560.0 0.10 481.5 3520.0 TOTAL 0.21 _... ~~. ~ ~~~a ~ 1 1 ' ' ' , ' ' ~ ' ' ~ ~ ~ ~ ' ' , ' Bay Area Hydrology Model PROJSCT REPQRT ProjecY. Name: Site Address: City : lteport Da~e : aage . nata Start : ~ata ~nd : Precip Saale: HAHM Version~ Fall.on Crossing 'Cassajara/Fallon Rd Dublin 9/~9/2008 ~rIVERNIORE i9s9/zo/o~ 2004/09/30 1.07 PREDEVBLOPED LAND U3E Name . Pre-Developed Bypaas: No GroundWaGer: No Pervi.ous Land U~e ACrea C D,(~rass,Vary(>20~) 103.5 Impervious Land Us~ Acres Element Flowa To: Surface Intexflow Name : Lower Development Bypasg~ No c3roundwaters No Pervioutt Land Use Acrett C D,Urban,FlattO-5~) 3.18 C D,Urban,Very(>20~) 4.39 Impervious I,a~ld Use Acres Roads,Flatco-s~> ~..2 Mad(5-L0~) 1.51 Roof Area 2.~5 DSod(5-10~) 0.44 Groundwa~er Element Flowe mo: SLiz'taCe IAtertlOw r• ~ ^ Gsoundwater ~o I(.~o 1 i ~ ' , i ' ~ ~ ' ~ ~ ~ ~ i ~ ~ ~ ~ LQW~R WQP, LOWER WQP, Name : Upper nevelopment Bypaess No GroundWa~er: No Pervious I,and Use Acras C A,Urban,~'lat(0-5~) 2•77 C D,Urban,V'ery(>20~} .86 ~mpervious Laad Vee Acres Roads,Fia~(0-5~) 0.5 D2od(5-108s~ 1.15 Roof Area a.13 Mod(5-10~) 0.5 El.ement Flows xo: Surface Intez~flow - UPPER WQP , UPPEEi WQP , Name : LOWER WQP Bottom Y,ength: 63f~. Hotieom Wi,dth: 4of~. Depth : 5ft. Volume at riser head : 0.30?8tt. Side slope 1: 3 Tq 1 Side slope 2: 3 20 1 Side glope 3: 3 To 1 Side s].opa 4 t 3 To 1 Discharge Structure Ai.ser Heigh~: 3.5 ft. Rieer Diameter: 198 in. Ori.fice 1 Diameter: 2 in. Elevation: 0 ft. Blement Flowg To: Outlet 7. Outlet 2 Deten~ion Pond, Groundwatier Pond Hydraulia Table Staae(ft) Area(acr) Volwne(acs-£C) Dschrg(cfs~ InEl.lt(cfsZ_ 0.0•00 0.058 0.000 0.000 0.000 0.056 0.059 0.003 0.025 0.000 0.111 0.059 0.047 0.035 0.000 0.167 0.060 0.07.0 0.043 O.U00 0.222 0.061 0.013 0.050 0.000 0.278 0.062 0.0~.7 0.055 0.000 ~~~ 81~~(ea ~ ~ ~ ' ~ i , ~ ~ ~ ~ ' ' ~ ' ' ~ ' i, 0.333 0.0&3 0.02Q 0.061 O.Q04 0.389 0.063 0.024 0.066 0.000 0,444 0.064 0.027 0.070 0.000 0.500 4,065 0.031 0.0')4 0.000 0.556 0.066 Q.03~ 0.078 0.000 0.611 0.067 0.038 0.082 0.000 0.667 0.068 0.042 0.086 4.000 0.722 0.069 O.OSk6 0.069 0.000 0.778 O.U69 0.049 0.093 0.000 0.833 0.070 0.053 0.096 0.000 0.$89 0.071 0.057 Q.099 0.000 0.944 0.072 0.061 0.102 0.000 1.000 0,073 0.065 0.105 0.000 1.056 O.Q74 0.069 0.10$ 0.000 i.i~.i o.o~s o.073 o.sii o.ooo 1.7.67 0.076 Q.078 0.113 0.400 1.222 0.076 0.082 0.7.~6 0.000 1.276 0.077 0.08~ o.li9 0.000 1.333 0.078 O.Q90 0.~21 0.000 1.389 0.079 0.095 0.124 0.000 1.9~39 0.060 0.099 0.126 O.Q04 1.500 0.081 0.104 0.129 0.000 1.556 0.082 0.108 0.131 0.000 ~.611 0.083 0.113 D.133 ~.000 1.667 0.084 0.117 0.136 0.000 1.722 0.~85 0.122 0.138 0.000 1.778 0.086 0.127 0.7.40 0.000 1.633 0.087 0.132 0.142 0.000 ].. 889 0.088 0. ~.36 0. 144 0. 000 1.944 0.089 0.19:J. 0.146 0.000 2.004 0.090 0.1~k6 0.149 0.000 2.056 0.091 0.151 0.151 0.000 2.111 0.091 Q.156 0.153 0.000 2.167 0.092 0.161 0.155 O.QQO 2.222 0.093 0.7.67 0.157 0.000 2.278 0.099 0.7.~2 0.159 0.000 2.333 0.095 0.177 0.160 0.000 2.389 0.096 0.182 0.162 0.000 2.444 0.097 0.168 0.164 0.000 2.500 0.098 0.193 0.166 0.000 2.556 0.100 0.199 0.168 0.000 2.611 0.101 Q.204 0.170 0.000 2.667 0.102 0.210 0.172 0.000 2.722 0.103 0.216 0.7.73 0.000 2.7'18 0.104 0.22~. 0.175 0.000 2.833 0.105 0.227 0.177 0.000 2.869 0.106 0.233 0.179 0.000 2.944 0.107 0.239 0.184 0.000 3.000 0.108 0.245 0.182 0.000 3.056 0.109 0.251 0.184 0.000 3.11.1 0.110 0.257 6.185 0.000 3.167 0.111 0.263 0.187 0.000 3.222 0.112 0.269 0.189 0.000 3.278 0.1].~ 0.276 0.190 0.000 3.333 0.7.14 0.282 0.192 0.000 3.389 0.115 0.288 0.193 0.000 3.444 0.117 0.295 0.195 0.000 ~. ~~ ~~ '~ v ~ ~ f ~ ~ 1 1 , i ' ' ' ' ~ ~ ~ 3.500 0.118 0.301 0.197 0.000 3.SS6 0.119 0.30£3 2.302 0.000 3.611 0.120 0.3~4 6.151 0.000 3.657 0.121 4.321 1,1.13 O.OOQ 3.722 0.122 4.328 17.04 0.000 3.'7'78 0.123 0.335 23.73 0.000 3.833 0.129 0.3A2 31.13 0.000 3.889 0.126 0.398 39.18 0.000 3.944 0.~27 0.355 47.82 0.000 4.000 0.128 0.363 57.02 0.000 4.056 0.129 0.370 66.75 0.000 4.11I 0.230 0.377 76.98 0.000 9;.167 0.131 0.3fl4 8~.58 0.000 4,222 0,132 0.391 98.84 ~.000 9.278 0.134 0.399 110.4 0.000 ~.333 o.z35 0.406 ia2.5 0.000 4.389 0.136 0.47.4 139.9 0.000 4.444 0.137 0.421 147.7 0.000 4.500 0.136 0.429 160.9 0.000 9.556 0.140 0.937 174.5 O.Q00 4.611 0.141 0.445 188.4 O.OQO 4.667 0.142 0.452 202.7 0.000 4.722 O.a43 0.~60 2~7.4 0.000 4.77a 4.195 o.~l68 232.3 0.000 4.t333 0.196 0.476 247.6 0.000 4.889 0.147 0.485 263.3 0.000 4.944 0.148 0.493 2?9.2 0.0~0 5.000 0.~.49 0.501 295.4 0.000 5.056 0.151 0.509 33.2.0 0.000 IJ~ne t tJPPLR WQP Bottom Length: 60ft. sottom widths 25f~. Depth : 5.5ft. Volume at riser head :- 0.2079ft. 8ide slope 1: 3 To 1 Side e~.ope 2: 3 To 1 S~.de elope 3: 3 To 1 Side ~lope Ar 3 To 1 Afgcharge Stzucture Risez Heighti 3.5 ft. Rises Diame~er: 48 in. Ori~~.ae 1 Diametex: 2 in. Elevation: 0 f~. Elsment Flowa To: Outlet ]. Outlet 2 17etentiion Pond, POnd HydrauliC Table 8kaae(ft) Axeatacr) Volume(act-£t ) Dachrg(c£a) Infilt{cEsl ' 0.000 0.034 0.000 0.000 0.000 0.061 d.a35 0.002 0.026 0.000 A.122 0.036 0.00~ 0.037 ~.000 ' ~ ~c~o ~ ~ ~ ~• w 1 1 1 ~ ~ 1 ~ ~ u ' ~ ~~ 1 ~ ~ ~ ~ i 0.183 Q.037 0.007 0.045 0.000 0.244 0.037 0.009 0,052 0.000 0.306 0.038 0.011 O.OSB ~.000 0.367 0.039 0.013 0.069: 0.000 0.428 4.040 0.016 0.069 0.000 0.~89 0.040 0.018 0.073 0.000 0.550 0.041 0.021 0.070 0.000 0.611 0.042 0.023 0.082 0.000 0.672 0.0~13 0.026 0.086 0.400 0.733 0.093 0.029 0.090 0.000 0.794 0.044 0.031 0.099 0.000 0.856 0.045 0.034 0.097 O.OOQ 0.917 0.046 0.037 0.101 0.000 0.978 0.047 0.040 0.104 4.000 1.039 0.~~17 O.Oh2 0.107 0.000 1.100 0.048 0.045 0.110 0.000 1.161 0.049 0.048 0.113 0.000 ]„222 0.050 0.051 0.116 0.000 1. 283 O.OS7. 0. 054 0. ]..19 0. 000 1.344 0.052 0.058 0.122 0.000 1.406 0.053 0.061 0.125 0.000 1.467 0.053 O.Ob4 0.127 0.000 1.528 0.054 0.067 0.130 0.000 1.5f39 0.055 0.071 0.132 0.000 1.650 ~.056 0.0'74 0.135 0.000 1.71J. 0.057 0.077 0.~37 0.000 1.772 0.05£3 0.081 0.140 O.U00 1.833 0.059 4.065 4.142 0.000 1,894 0.060 0.088 0.145 0.000 1.956 0.060 0.092 0.].9? 0.000 2.01'7 0.061 0.096 0.149 0.000 2.078 0.062 0.099 0.].51 0.000 2.139 0.063 O.J.03 0.154 0.000 2.200 0.064 a.107 0.156 0.000 2.261 0.065 0.111 0.158 0.000 2.322 0.066 0.115 4.160 0.000 2.383 0.067 0.119 0.162 0.000 2.444 0. Ob8 0. 123 0. ]:6.4 0. 000 2.506 0.069 0.127 0.166 0.000 2.567 0.070 0.).32 0.168 0.000 2.62£i 0.071 0.~36 0.170 D.000 2.689 0.072 0.140 0.172 0.000 2.750 0.093 0.145 0.174 0.000 2.811 0.074 0.149 0.176 0.000 2.8'72 0.075 0.154 0.178 0.400 2.933 0.076 0.158 0.180 0.000 2.994 0.077 0.163 0.182 0.000 3.056 0.078 0.168 0.184 U.U00 3.117 0.079 0.173 0.185 0.000 3.178 0.080 0.177 0.187 0.000 3.239 0.081 Q.182 0.1f39 U.000 3.300 0.082 O.1.87 0.191 0.000 3.361 0.083 0.192 0.193 0.000 3.922 0.084 0.197 0.194 0.000 3.483 0.085 0.203 0.196 0.040 3.544 0.086 0.208 0.563 Q.00~ 3.606 0.087 0.213 1.535 U.000 __ ~. ~. ~~~~~ ~] 1 3.667 0.088 0.219 2.B52 0.000 3.728 O.U90 0.224 4.438 0.000 ~ 3.789 0.091 0.229 6.253 0.000 3.850 a.092 0.235 8.272 0.000 3.911 0.093 0.241 10.48 0.000 3.972 0.094 0.246 12.85 0.000 ~ 4.033 0.095 0.252 ~5.38 0.000 4.094 0.096 0.258 18.07 0.000 4.156 0.097 0.264 20.89 0.000 4.217 0.098 0.270 23.85 0.000 ~ 4.278 0.100 0.276 26.94 0.040 4.339 0.10~, 0.282 30.15 0.000 4.400 0.102 0.288 33.48 0.000 ' 4.461 0.103 0.295 36.93 0.000 4.522 0.104 0.301 90.49 0.000 A.583 0.105 0.307 ~4.1.5 0.000 4.644 0.107 0.314 97.92 0.~00 ~ 4.706 0.108 0.324 51.79 0.000 4.767 0.109 0.327 55.76 0.000 4.828 0.110 0.334 59.83 0.000 4.689 0.111 0.340 64.00 0.000 ' 4.950 0.113 0.347 66.28 0.000 5.O7.J. 0.114 0.354 72.60 0.000 5.072 0.115 0.361 77.03 0.000 5.133 0.116 0.36£f F31.56 0.000 1 5.194 0.118 0.375 86.16 0.000 5.256 0.119 0.383 90.86 0.000 5.317 0.120 0.390 95.63 0.000 ' 5.37£3 0.~21 0.39? 100.5 0.000 5.439 0.123 0.405 105.4 0.000 5.500 0.124 0.4~2 1J.O.A 0.000 ~ 5.561 0.125 0.420 115.5 0,000 Name . Aetention Pand Bottom Length: 172ft . ~ sottom wa.dth: 2~:Et. Depth : 7.7ft. volume at riaer head : ~.0826ft. ~ Side slope 1: 3 To 1 Sida slope 2s 3 To 1 3ide slope 3r 2 To 1 ' . side slope 4: ].1 mo pischarge 5tzucture 1 Riser Heigh~: 6 ft. Rieer Diamet~r: 4~ i.n . NotchType : Rectan gular ~ Notch Wid~h : 2.000 ft. Notah Heigh~: 1.Q00 ft. Ori.~iae 1 Di.ameter: 3 a.n. 8lavations 0 ft. Oxifice ~ A3.ametex~: 4 in. Elavation: 1~r. ' Oritice 1 Diameter: 18 in. Elevatioa: 3 ft. ~ ' ~ Element Flowa To: Outlet 1 Out].et 2 .• ~i .~- ~S~II~v 1 ~ 1 ~ ~ ' ~ ~ L ~ ~ 1~ ' ~ , ~ , ~ Po~nd H~-draulic Table Stage(Pb) Area(acs) Volume(acr-ft) Dsahrg(cfe) Infllt(cfe)_ 970.0 0.079 0.000 0.000 0.000 470.X 0.081 0.007 0.069 0.000 470.2 0.083 0.07.4 0.09£3 0.000 470.3 0.086 0.021 0.120 0.000 470.3 0.088 0.029 0.7.38 0.400 470.4 0.090 0.036 0.155 0.900 470.5 0.093 0.044 0.169 0.000 470.6 0.095 0.052 0.1~3 0.000 470.7 0.098 0.060 0.196 0.000 470.F3 0.100 0.069 0.207 0.000 470.9 0.103 0.077 0.219 0.000 470.9 0.105 0.086 0.229 0.000 471.0 0.108 0.095 0.308 O.OUO 471.1 0.110 0:105 0.390 0.000 471.2 0.113 0.114 0.446 0.000 471.3 O.liS 0.124 0.491 0.000 Q71.4 0.7.1$ 0.134 0.532 0.000 471.5 0.120 0.144 0.568 0.000 477. , 5 0. J.23 0.155 0. 602 0. 000 471.6 0.126 0.165 0.634 0.006 971.7 0.128 0.176 0.664 0.000 471.8 0.131 0.187 0.692 0.000 471.9 0.134 0.199 0.719 0.000 472.0 0.137 0.210 0.7A5 0.000 472.1 0.139 0.222 0.770 0.000 472.1 0.142 0.23A 0.794 0.000 472.2 0.145 0.246 0.87.8 0.000 4~2.3 0.14£3 0.259 0.640 0.000 472.4 0.151 0.272 0.852 0.000 472.5 0.154 0.2£38 0.884 0.000 472.6 0.157 0.298 0.905 0.000 472.7 0.~,60 0.311 0.925 0.000 472.7 0.163 0.325 0.945 0.000 472.8 0.166 0.339 0.965 0.000 472.9 0.169 0.354 0.984 O.U00 973.0 0.172 0.36F3 1.002 0.000 473.1 d.7.75 0.383 3.428 0.000 473.2 0.~78 0.398 4.507. 0.000 473.3 0.181 0.413 5.321 0.000 473.3 0.7.89 0.429 6.012 0.000 473.4 0.187 0.445 6.621 0.000 473.5 0.191 0.461 7.172 0.000 973.6 0.194 0.47£i 7.68d 0.000 473.7 0.197 0.494 8.153 4.000 4'73.8 0.200 0.5X1 8.597 0.000 473.9 0.204 O.S29 9.019 0.000 473.9 0.207 0.546 9.420 O.OQO 474.0 0.210 0.569 9.603 0.000 474.1 4.214 0.582 10.~,'~ 0.000 9:7A.2 0.217 0.601 10.53 0.000 479.3 0.220 0.619 10.87 0.000 474.4 0.224 0.638 11.20 0.000 ~174.4 0.227 0.658 11.52 0.000 ..... ~• --. g~~~l~a t t ~ ~ ~ ' ~ i ' ~ ~ ~ ~ ~ ~ ~ 474.5 0.231 O.S77 11.83 0.000 4"14.6 0.234 0.697 12,~.4 0.000 474.7 0.238 0.717 12.93 0.000 4'74.8 0.241 0.736 12.72 0.000 474.9 0.295 0.75B 13.01 0.000 475.0 0.248 0.7f30 13.28 0.000 975.0 4.252 4.841 13.62 0.000 475.1 0.256 0.823 7.4.13 O.OOQ 475.2 0.259 0.845 .1~k~73 0.000 475.3 0.263 0.867 15.38 0,000 4'75.4 0.26? 0.890 16.08 0.000 475.5 0.270 0.913 16.81 0.000 475.6 0.274 0.936 17.56 0.000 475.6 0.278 0.960 18.33 0.000 975.7 0.2E32 0.984 19.11 0.000 ~%5.8 0.286 1..008 19.9~ 0.000 475.9 0.289 1.03~ 26.69 0.000 476_0 0.293 1.057 21.48 0.040 476.~. 0.297 1.083 22.57 0.000 476.2 0.301 1.7.08 24.49 0.400 A76.2 0.305 1.134 26.95 O.ObO 476.3 0.309 1.160 29.85 0.000 476.4 0.3J.3 1,.7.f37 33.11 O.QOQ 47b.5 0.317 1.214 36•71 0.000 q7g,6 0.32J. 1.241 40.60 0.000 476.7 0.325 1.269 44.77 0.000 476.8 0.329 1.297 49.20 0.000 476.8 0.333 1.325 53.88 0.000 476.9 0.338 J..354 58.76 0.000 477.0 0.342 1.383 63.91 0.000 ~77.1 0.3~#6 1.412 69-24 0.000 4~~,2 0.350 1.442 74.78 0.000 477.3 0.359 1.472 80.57. 0.046 477.9 0.359 1.503 86.43 0.000 977.4 0.363 1.534 92.53 0.000 477.5 0.367 1.565 96.80 0.000 q77.6 0.371 1.597 .145.3 0.000 477.7 0.376 1.62$ 111.9 0.000 Name s Self treating area Bypase: Yes GraundWater: No Pervious Land Vae Acres C D,Gzass,Very(>20~} 82.82 Impervious Land Use Acreg SlemO~t FlOwB TO: Surfaae Inter~low azpundwa~ex ~~~~ ~7~ ~~-~ 1 1 ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ , [~~ ~ ~~ MIT~GATED LAND USE 1~NAY,YSIS RE8ULT8 Flow Frequency Return Periode for PredevBloped. pOC #1 Return Period k'low(cEs) 2 year 22.46II2 5 year 38.689691 10 y~aar 51.572878 25 year 58.506461 E'low b'requency Reburn periods for Ma.tigated. POC #1 Return Period Flow(cE~) 2 year 19.7~32 5 year 35.535061 10 year 96.202422 25 y'ear 53.526743 Xearly Peaka Eor Qredevelopec~ and Mitigated. POC #1 Xear Pxedeveloped Ma.tigated 1961 19,1.06 15.672 1962 11.523 9.304 196 3 24 . 5'71 19 . 713 1964 27.930 26.662 ~.965 6.526 9.684 19b6 10.543 14.884 196'% X6.321 13.156 196F3 90.595 80.928 1969 22.45$ 22.015 1970 34.124 32.459 7,g71 30.374 24.734 ].972 29.421 23.402 7.973 0.185 0.775 1974 55.450 50.9I7 1975 37.786 30.9?7 ~.976 19.376 ]5.665 1977 0.009 0.338 1978 0.021 0.300 1979 33.759 27.511 1980 36.187 29.512 1961 2~.023 21.994 1982 6.999 ~.~0$ 1983 51.821 45.619 1984 38.941 36.390 1985 20.796 16.922 ~.986 10.587 8.853 1987 52.343 48.169 1988 14.~2'I 13.922 1989 1.261 1.143 1990 3.635 3.133 1991 13.391 12.390 19g2 18.223 1b.61'l 1993 21.669 17.606 ~~~ g~~ I~~ ~ 1 ~ i ' r ~ 1 ~ ~ i ~ ~ , ~ ~ ~ , r 1999 24.365 23.361 1995 10.582 6.654 1996 42.572 41.953 1997 51.491 45.925 1998 ?.7.877 26.500 1999 47.043 39.975 2000 2?.1S4 22.002 2001 17.061 16.229 2002 3.115 2.532 2003 10.946 8.956 2004 29.769 27.763 2005 47.27fl 4b.722 Ranked Yearly Peake Por Predeveloped ar~d Mitigated. POC #1 Rank PredeveLoped Mitigated 1 90.5951 80.9280 2 55.450A 50.9171 3~ 52.3432 48.1688 9 51.8209 46.7224 5 51.4406 45.9251 6 47.2739 45.6185 7 47.0434 41.952$ 8 42.5719 39.9799 9 38.9408 36.3898 10 37.7657 32.4580 11 36.1866 30.9768 12 34.1237 29.5121 13 33.7592 27.7634 19 30.3793 ?.7.5114 15 29.7692 26.6622 J.6 29.4212 26.5000 1.7 27.9299 24.7336 14 27.8772 23.9019 19 27.1544 23.36~.4 ' 20 24.5705 22.0753 21 24.3646 22.0022 22 24.0229 21.9936 23 22.4682 19.7132 29 21.6691 1.'7.6057 25 20.7964 16.9222 26 19.3761 16.6167 27 19.7,056 16.2291 28 18.5430 15.8649 29 18.2231 15.6718 30 7.7 . 0614 14. f3841 31 16.3206 13.9221 32 14.1269 13.1556 33 13.3908 12.3895 34 1.1.5229 9.6848 35 10.9964 9.3b37 36 10.5866 8.9559 37 10.5823 8.8535 38 6.9988 8.6545 39 6.5259 6.4083 40 3.8352 3.1326 47. 3.1155 2.5323 .~~_ ~ ~ ~~~ 1 ~o ~~a ~ 1 ~}2 1.2611 1.1430 ' 43 44 0.1851 0.07.09 0.7752 0.3382 45 0.0093 0.3000 ~ POC #1 The Faci].i.ty PASSED ~ The Faci].iCy PASS ~D. Flow(CFS) Prede~v Dev Percoln~age pae~/Fail 2.2468 1522 1513 99 Pass ~ 2.7451 1353 1312 96 PasB 3.2433 1212 1157 95 Pass 3.7415 1107 ~033 93 Paes ~ 4.2398 4.7380 1017 931 928 847 91 90 Pass Pasc y.2363 850 755 88 Pass 5.7345 777 685 88 ~ Pass 6.2328 701 623 88 Pass ~ 6.7310 651 566 86 Pass 7.2293 598 529 88 Pass 7.72i5 554 488 8a Pass g.2257 514 99:2 85 Pass I a.7240 48'7 396 41 Pass 9.2222 450 367 81 Pass 9.7205 4].0 341 £33 Pass , 10.21n7 3a1 310 81 Pass 10.7170 354 281 79 Pass 11.2152 334 258 77 Pass 11.7134 308 23f3 77 PasB ~ 12.2117 290 212 73 Pass 12.~099 272 201 73 Pass 13.2082 2S3 187 73 Pass 13.7064 23A 173 73 Pass 1 14.2097 218 162 74 Pass ~.4.7029 202 152 75 Pass 15.2011 189 142 75 Pass ~ 15.6994 177 130 73 Qass 16.1976 166 119 72 Pasa 16.6959 154 106 68 Pass ~ 17.1941 17.6924 1.45 133 100 94 68 70 Pass Pasa 18.1906 1,26 88 69 Pasa 18.6888 7.~7 83 70 Pass 19.1871 109 77 70 Pass ~ 19.6853 97 75 77 P~ss 20.1836 94 65 69 Pass 20.6818 90 64 71 Pass 21.1601 86 64 74 Pass ' 21.6783 79 61 77 Pass 22.1765 77 55 71 Paas 22.674a 72 54 75 PasR 1 23 .~.730 65 53 81 Pass 23.6713 62 52 83 Pass 24.1fi95 60 50 83 Pasa ~ ~ ~~ ' 1 1 1 ~ ~ , ~ 1 ~ 1 ' ~ , ~ ~ ' ~ ' , 24.6678 53 46 86 Pass 25.1660 52 45 86 Pass 25.6642 52 42 80 Pass 26.1625 48 37 77 Pass 26.6607 45 34 75 Pass 27.1590 45 33 73 Pass 27.6572 39 32 82 Pass 28.1555 37 28 75 Pass 28.6537 34 28 82 Pass 29.1.57.9 34 28 82 Pas~ 29.6502 33 27 82 Pasa 30 .].484 31 27 67 Pasa 30.6467 30 25 83 Pass 31.1949 30 24 80 P~ss 31.6432 30 23 76 Pass 32.1414 28 22 78 Pdsg 32.6396 28 20 77. Pass 33.1379 2£3 20 7J. Pass 33.636~. 28 19 67 Pass 34.1344 25 19 76 Pass 34.6326 24 19 79 Pasa 35.1309 22 17 77 Pass 35.6291 2Q 17 t35 Pass 36.1273 19 17 89 Pas~ 36.6256 18 14 77 Pass 37.1238 18 14 77 Pass 37.6221 18 14 '7') Pass 38.1203 17 14 82 Paes 38.6186 1,7 ~.4 82 Pass 39.11G6 7.5 ~4 93 Paas 39.67.50 1A 13 92 Pass 40.1133 12 12 100 Pass ~l0.617.5 12 10 83 Pass 41.1096 12 10 83 Pass 41.b080 12 10 83 Pass 42.1Q63 10 8 80 Pass 42.6045 9 8 88 Pass A3.1027 9 8 88 Pass 43.6010 9 8 88 Paes 44.0992 9 8 86 Pass 44.5975 9 7 77 Pasa 45.0957 8 7 87 Pasa 45.5990 8 7 $~ Pass 46.0922 7 5 71 Pass 46.5904 7 5 71 Pass 47.08$7 6 4 66 Pass 47.5869 5 4 80 pass 98.0852 5 4 80 Pass 48.5834 5 3 60 Pass 49.0817 5 3 60 Paptt 49.5799 5 2 40 Pass 50.078~. 5 2 40 Pass 50.5764 5 2 40 Pass 51.0746 5 1 20 Pass 51.5729 9 ]. 25 Pass ..~, ~- W.,.. ~~~ I ~e~ 1 ~ , -ie' without Narranty oi aey id d ' as s Thie program and accompanying documsatation are prov kind. Ths entire risk reqarding the periormanae and resulte of thia proQrata i~ eeaumed by Bnd Ueer. Clear Creek eolutiona inc. and the govercmiental licensee or eubliaeneeea dieclaim all varraatiee, either expressad or implied, inoludiny buE not limited to ~ implisd ~-arranties of progrem and aacompsnyiag docwnentatioa. in ao eveat ehnll Clear Creek 8oiutions inc, Applied idarine 8oiencee Incorporatsd, the Alameda Cow~ty Ylood Control and i~atsr Coneervstion District, E01- Iaoorporatad, a~embsr agenoiee o! the 111ameda CountynriQe Clesn watsr Proyram, member agenciee oi Ehe San Mateo Countynvide 1Pater membes agencisa oE tbe Snnta Clars Valley Urban RunolL m P i ~ , rogra on Poilubion erevent Poilutioa prevention Prograa- or any other LOU Partioinante or subhosissd r~ps~oentativea of LOO Pnrticinants be liable for any Qamagee Mhatsoever (inaluding without limitallon to damaQss ior losa o! buainees yrolits, losa oY business 1aEormaCion, busiasas inCerruptioa, anQ Che like) ariaing out oE Ghe use o!, or inabiliEy to use tt~ie program ~ even i! Ciear Creek BoluEioos Inc., 1lppiied Marine 8aienaes 2noorporatsa, the Alameda County piood Control and WaEer Coaservation Distriat, Q011 inaorporated or any member agenaiso oP the IAU Partiaipanta or their auehori:ed r~prsseuE~tivsa have bssn advised oi tbe poasibility oP suoh damagee. Bote~-are CopyrighC ~ by Cl~ar Creek Solutioae, ino. ~ ]005-1007i All RighEe Reeervsd. ~ n ~ ~ v ' v J 1 ~ ~ , ! j i r ~ P~ro~~t Time~ Exoa~di~~ 100 ~a~(~~ ~ .-~-. `' 10E•4 10E•3 10E•2 10E•1 1 10 ~ 1 ' ~ ~ ' ~ ~ ~ 93 ~~b ~ , ; ~>> ~~~~~ j Alameda Countywide ~/~~ Clean Water Program ~ A Consortium of Local Agencies ~ ~i~ SOIL SPECIFICATIONS FOR STORMWATER TREATMENT MEASURES The Alameda Countywide Clean Water Prog~am's New Development Subcommittee is providing these specifications to its member agencies for use in non-proprietary, landscaped-based stormwater treatment measures. The purpose of these specifications is to help applicants specify soils that will provide suitable growing conditions for appropriate plantings and meet the percolation requirements identified in Chapter 6 of ACCWP's C.3 Stormwater Technical Guidance for the specific types of landscape-based treatment measure proposed in their projects. Some requirements may vary from one jurisdiction to another. Project applicants should check with the jurisdiction having authority over the project regarding applicabie local requirements. The specifications refer specifically to treatment measures for which technical guidance is included in the Alameda Countywide Clean Water Program's C.3 _ Stormwater Technical Guidance (August 2006). The specifications identify planting soils to be used (Section I), requirements for compost amendments in the planting soils (Section II), and a top dressing layer of mulch (Section III). ~ I. PLANTING SOIL , Planting soil is to be placed for the purpose of providing a soil for plants to be established in the treatment measure. ACCWP previously provided specifications for dewatering soils for use in vegetated swales. The dewatering soil option has been removed, howe~er, in preparation to implement the requirements of the Municipal 1 Regional Stormwater Permit's (MRP) Provision C.3.c.i(2)(b)(vi) requirements for biotrea#ment soils with a long-term infiltration rate of 5 to 10 inches, and a biotreatment measure surface loading area no small than what is required to 1 accommodate a 5 inches/hour surface loading rate. Project proponents may meet these requirements using the treatment soil mix specified below. , Treatment Soils (high percolation planting soils, such as loamy sands) shall be used for filtering of a volume of water in the treatment measures, such as flow-through planters and bioretention areas. These treatment measures shall treat runoff by , passing it through the surface layer of high percolation p(anting soil, then saturating a zone of crushed drain rock and finally in most cases, entering a perforated sub-drain. A. IMPORTED MATERIAL FOR TREATMENT (LOAMY SAND) ~ Planting soil material for treatment shall consist of high organics. soil (no gravel) with a high percolation rate, supplied from previously tested and.approved sources, and ~ shall conform to the following specifications and requirements: ~ F:NIOML91ItDS+AL9IAI WSI~oO+nfC./TaMolbiluuUpGYt0lAUpuAC(1VPPMIDMhIYSaI_6~i6uYens_NDS_~ppotd.Nry_e t007do[ Page 1 NDS Approved May 8, 2007 (Dewatering soil option removed Sept 2410) ~ ~ ~r 1 ' 1. Ail material shall be free of trash and debris, expansive clays or any other deleterious materials, and shail be subject to the approval and acceptance of ' the Authority Having Jurisdiction. 2. The contractor shall designate their proposed import sources in advance and shall provide source samples of material to the jurisdiction having authority. , 3. Material shall be free of seeds. 4. The treatment planting soil shall have documentation from the supplier 1 showing conformance to the foltowing gradation guidelines: Screen Information Percentaqe , a. Maximum particle size 2 millimeters (0.078 inch) b. Percent passing No. 10 screen (2mm) 10Q (coarse sand or ~ner) , c. Percent passing No. 200 screen (0.074mm) 10 to 15% d. The overall dry weight percentages shall be 85-90% sand, less than 5% ~ clay, and less than 5% si1t. The range of clay and silt and organics should be 10-15% of total volume. 5. The treatment planting soi! shall have 4 to 6% by dry weight organic compost , mixed in. Organic compost percentage may be lowered by the jurisdiction of authority for varying plant species in the treatment measure. Native in-situ loamy sand soils can be used, with 4 to 6% of organic compost mixed in. This , mixed soil must be certi#ied to meet the imported planting soil requirements. Organic compost shall meet the specifications stated in Section II - Organic Compost Amendment. The soil shall have a salt concentration less than 500 ' mg/L. The pH shall be between 5.5 and 7, unless directed otherwise by the jurisdiction of authority. , 6. One test shall be conducted by the supplier per each 500 cubic yards supplied. Testing shall be conducted for the above gradation requirements, salt contents and pH range. 7. Contractor shall demonstrate the in-situ percolation of each treatment 1 measure for design storm flows through the installed soil to the satisfaction of the Authority Having Jurisdiction. The material shall have an onsite tested percolation rate of 5 to 10 inch per hour. In-field percolation test shall consist , of a 1-foot diameter pipe, 2.5 feet long pipe, driven 1.5 feet deep into treatment soils. Pipe shall be ~Iled with 1 foot of water after the treatment measure has been wetted. The pipe should empty 1 foot of water above the , wetted soil layer in no fess than 1 hour and 12 minutes, and no longer than 2 hours and 24 minutes. Contractor shall pravide records of percolation tests to city inspector. ' 8. Soil shall be placed in lifts of 8-10 inches. 9. Standard compaction to a minimum of 85 percent shaN be used when placing the mixed material. The method to achieve 85°/a compaction shall be e approved by the local jurisdiction before the soil is placed in the treatment measure. , 97\OY'AL97 OI~ f N19 M1 tW1.Om Xpaitrcuion~~'lit~~pM'N\/aT_[ URM1elat{!' 17n'MicYliaOan~l'~G:sOYAy iM'~'nTtwllpulTd.Swl . : ~ . . . . Page 2 NDS Approved May 8, 2007 ' ~ (Dewaterin~ soil option removed Sept 2010) ~ ~~ l(~ 1 , ' ' 1 1 , ~ , ' ~ , LJ II. ORGANIC COMPOST AMENDMENT An organic amendment per Attachment 1 is to be mixed into the planting soil for the purpose of providing organic material to be utilized by plantings placed within the treatment measure. The following specifications are for amendments used in bioretention areas, flow through planters, vegetated buffer strips, vegetated swales, and extended detention basins only. A. COMPOST SPECIFICATIONS Organic compost shall meet the requirements of the Alameda County Bay Friendly Landscape program. Provide a lab analysis of proposed material performed by either: (1) a certified US Composting Council Compost Analysis Program (CAP) laboratory or (2) a laboratory approved by the local jurisdiction, using approved Test Methods for the Evaluation of Composting and Compost (TMECC). Verifying current participation in CAP can be achieved by visiting www.compostinpcouncil.orp. The TMECC methods are explained at www.tmecc.or4/tmecc. Check with local jurisdiction for a list of approved laboratories. See the attached Bay-Friendly Landscaping (BFL) Soil Preparation Specifications, Part 2.1.6.1, Section 02920: Soil Preparation for approved testing ranges of attributes for compost amendments. Organic content may be lowered by the jurisdiction having authority for varying plant species in the treatment measure. This mixed soil must be certified by the laboratory to meet the imported planting soil requirements. III. TOP DRESSING MULCH A three-inch thick layer of top dressing mulch shall be placed in all designated planting areas for the purpose of retaining moisture, preventing erosion and minimizing weed growth. Keep top dressing six inches away from tree trunks for tree health except where approVed by the jurisdiction having authority. The following specifications are for top dressing soils used in bioretention areas, flow through planters, vegetated buffer strips, vegetated swales, and extended detention basins only. A. MULCH SPECIFICATIONS ~ ~ ~ , ' ~ Any of the following materials may be used as top dressing for any of the treatment measures listed above, subject to the jurisdiction of authority's approval. Options for top dressing material include: Arbor Mulch: Arbor Mulch shall be wood waste from tree trimming and not contain eucalyptus. Local tree companies may have material available free of charge. Submit a minimum one-quart sample of proposed material to be used, to jurisdiction with authority. Wood Chip Mulch: Wood Chip Mulch shall be a coarse wood mulch made from salvaged kiln dried lumber and be color enhanced with mineral pigments that have a I:UMaNL %~U9AU7.01 NDS habnt'CJ TKV's~IO~M~a~e UpA~M1 A~ps AttlYf Mal DRNTL 6ei1_Sy~si4rmf_NDS_~¢w~d}Yry_t 7001dx Page 3 NDS Approved May 8, 2007 (Dewatering soil option removed Sept 2410) .~ C~ .-~ b `Q~ 1 i ~ ' L~ ' demonstrated color longevity of one year. Mulch material shall pass a two inch screen. Organic Compost: Organic Compost may be used as mulch as determined by the jurisdiction having authority. Organic compost shall meet the specifications stated above in Section II - Organic Compost Amendment. The foilowing are specifications for the above dressing materials: 1. The top dressing soil material shall not float when three inches or more of wafer has ponded in the treatment measure. 2. Natural compaction is adequate for top dressing layer soil. 3. The 3 inches o# top dressing mulch shall be placed in a single lift. ~ LJ ~ ~ ~ ~ ~ ~ ~ ' ~ , , IV. SOURCES/DOCUMENT PREPARERS These specifications were prepared under the guidance of the New Development Subcommittee. BKF Engineers prepared the specifica#ions with substantial input from Design, Community and Environment. Organic compost amendment specifications in Section II were based on Bay-Friendly Landscaping specifications prepared by Stopwaste.org. As the permit compliance consultant, EOA, Inc. coordinated work group meetings, reviews of draft specifications, and subcontracts with the consulting engineer and landscape architect. V. DEFINITIONS 1. Lift - Depth of soil placed before compacfion is necessary 2. Expansive clay soi(s -- are in-situ clay soils. These soils must be amended to be used in the treatmen# measures. 3. Stormwater treatment measure - Any engineered system designed to remove poliutants from stormwater by simple gravity settling of particle pollutants, filtration, biological uptake, media adsorption or any other physical, biological, or chemical process. Sometimes called a treatment control, treatment control measure, treatment best management practice (BMP), or treatment facility. 4. Wetted soil - soil that has been irrigated unti! the water has penetrated soil to a minimum of 4 inches. f:U19~U~.91 \IxCtA1.97.U1 \IN h~1.t1~l:.) 7a~•I~ifJ (~w~~Ke I:rlaliN Mr~p~t A('<:NT 11eJ OPMI`.1.6ei1 %pntf ~nal~. \pl,amrmn1.11ar.1 300).0> Page 4 NDS Approved M~y 8, 2007 (Dewatecing soil option removed Sept 2010) ~.,..., ~.~-~ .~--. ~ 1~~ ~ ~ ~ Attachment 1 ~ BFL Soil Prcparation Spccifications Part 2.1.B.1 Sectior~ 02920: Soil Preparation , 1. Organic Asnendment Compost shall be a we11 decomposed, stable, weed free organic matter soucce. 'The product shall be cerrified throu~h the US Com~osting Counci]'s (USCC) Seal of 1'esting Assurance Pro~xaGn (S'1'A) ~ Progratn (1 compost tesdn~ and in£ormation distlosure ptogram). It shall Ue derived from agricultur.al or food waste or yard trimmin~s. The prod~~ct shall contain no substances toaic to ~~lants, sha11 possess no oUjectionable odors and shall not resemble the Eeedstock (the original materials from ' which it was derived. I3e£ore delivery of the com~ost, the supplier shall submit a copy o£ lab ana[ysis perfnrmed by a laborato~.y thar. is enrolled in the US Composting Council's CAP and usin~ the approved '1'est ~ Methods for the ]:valuadon of Compostin~ and Compost ~l'MECC~.'I'he 1aU repoct sl~all verify: A. I~eedstock Mater.ials shall be specified and include one or inore oE the following: ~ landscape/yard trimmin~s, gcass clippings, food scraps, and agricultural crap cesidues. 13. Ur~anic ]Ylatter Content: 50% - 60% by dry wt. prefereed, 35-70% acceptable w l bil i d f ' . ty an at east sta C. Clrbon and Nitr.ogen Ratio: C:N < 25:1 plus at least one measur.e o c>ne measure of toxiciry. , ll. Maturity/Stability: shall have a dark br.own color 1nd a soil-like odor. Compost exhiUiting a sour or putr.id stnell, containin~ zecognizable ~rass or leaves, or is hot (1201~ upon delivery or rewettin~ is not acceptable. In addidon any one of the following is required to ~ indicate stability a. Oxygen 'Test < 1.3 02 / unit TS / hr b. Specific oxy. '1 est < 1.5 Oz / unit B I~S / hr ~ c. Respitarion test < 8 C/ trnit VS / day d. llewar. test < 20 Temp. t'!se (oC) ~ e. Solvita~ > S lndex value ~'s. '1"o~:icity: any one of the following measures is sufficient to indicate non-toxicity. a. NHa- : N03-N < 3 ~ b. Ammonium < 500 ppm, dry basis c. Seed Ger~nination > 80 % of control d. Plant Trials > 80% of control ~ e. Solvita~ > 5lndex value , I;. Nutrient Contene: provide analysis detailin~; nutrient content including N-P-I{, Ca, Na, VI'g, S, and 13. a. 'i'otal Nitrogen content 0.9% or above preferred. ' b.l3oron: '1'otal shall be <80 i~pm; Soluble shall be <2.5 ppm U. Salinity: Must be r.e~~or.ted; may vary but < 4.0 mmhos/cm preferred. Soil should alsc~ be tested: <2.5 mmhos/cm is preFec•red for soil/com~ose blend but may vary with plant ~ species. H. pH: pH shall be between 6.5 and 8. May eaiy with plant species. r 1':`AN~Vd.v1\lA'.~I.7).OI~U5M1n7rn~1'.71xYwalf.~rrl:MalMAKn:AfMT1Yro17fRAlTJ.SNI.iM f ne+~_\IK.~ryorv.l.af~)'.t 10Dl.da Pa~;e 5 NDS Approved May 8, 2007 (Dewatering soil option removed Sept 2010) r ~ ~~~ !~ 1 ~ I. 1'ar.ricle size: 95% passin~ a 1/2" scr.cen. ~ ~. I3ulk density: shall be between 500 and 1100 dry Ibs/cubic }~ard I{. MoisCUre (:ontent shaIl be benveen 35°/n - 55% c~f dry solids. ~ I.. Incrts: e<~m~~ose sh111 be relativelp free of inerl ingredients, including ~lass, plastic and paper., < 1% Uy weight or volume.~ ~ Vf. Weed seed/pathogen destrucdon: l~rovide pcoof of pr.ocess to further r.ecluce pathogens (l~I'RP}. T^or example, tucned windrows inust reach min. 55C for 15 days ~vith at least 5 turnin~s dur.ing ti~at pe:riod. , N. Select l~atho~;ens: 5almoneJla <3 M1.'N/4grams of'1'S, oi Coliform 13acteria <1Q000 MPN/gram. ~ O. 'i race Cot~taminants Nletals (I.ead, Mer~ury, rtc.)1'roduct must meet US FI'A, 40 CFR 503 regulations. ' 2. Additaonal amendinents and/or fertilizer.s as r.equired in the soils r.cport. 1.11dditiot~al amendmenes and fer.tilizers thal are approved for use by thc Or~,~nics Marer.ials Reseacch Institute (UMRI) for use in crop productinn ar.e approved for use. See ~ w~vw.omri.ocg. rertilizers that are not approved or are rc:stricted for. use b}~ UMRl sha11 be appliecl only after ceview and written app~oval by the C)wner. , ~~~~5: 1) Snlvita is a~~egistercd tradem~ric test. PIease see http://solvita.com/ 2) 'i'S is Total Solids,13V5 'ss liic~logieal Volatile Solids, VS is Volatile Solicls, MPN J~r.am is Most ~ I'robable Number per gram, ~~pm is parts per million. ~ ~ , ~ ' ~ ' The 2007 version of tbis specificAtion indic~ted a<0. I% threshold for allowable inerts. In September 2010, this was chanbed to <1% for consistency with the US Cotnposting Council's Seal of Testin~ ~ Assurance Program. I:~N+h`AI.9/ rqi`.~1.91.0f ~D~ h.yhni f.17n'hreMGuii+nt~• t:Atr,c(4 Avryu n1Y'n'f f~wllblMT1. b~il..Yye'fv Wu~~ \'D5 i~p~nd_?IaY_k,10117AS: Page 6 NDS Approved May $, 200? {Dewatering soil option removed Sept 2010) ' ,~... ~ - l~~ ~ ~~c~~ s , ~ ~ ~ , APPENDIX B ~ FIRE HAZARD MITIGATION AND DEFENSIBLE SPACE VEGETATION MANAGEMENT PLAN ~ Prepared By: ~ Ralph J. Alexander & Associates ~ ~ ' ' ' ' ~ ' ~ BERLOGAR STEVENS & ASSOCIATES ~ 1 ~ 1 1 ~ ~ ` 1 1 i ~ ~ ~ ' ' , ~ , ~ FIRE HAZARD MITIGATION AND DEFENSIBLE SPACE VEGETATION MANAGEMENT PLAN FALLON CROSSING Prepared for: Standard Pacific Homes 3825 Hopyard Road, Suite 195 Pleasanton, CA 94588 Prepared by: Ralph J. Alexander 8~ Associates 1020 Railroad Avenue, Suite C Novato, CA 94945 (415) 898-8722 May 29, 2007 l~~ ~l~a ~~'~[~-~ ~ TABLE OF CONTENTS ' PAGE ' LIST OF FIGURES iii EXECUTIVE SUMMARY iv ~ EXISTING SITE DESCRIPTION 1 ' VEGETATION RESTORATION AND MANAGEMENT CONCEPT 1 RECOMMENDED METHODS OF VEGETATION MANAGEMENT 1 , DEFENSIBLE SPACE ZONES 3 0-3' CRITICAL ZONE 3 Ground Covers 3 ~ Perennials 4 Maintenance Standards 4 ~ 4'-14' 8~ 4'-24" DEFENSIBLE SPACE ZONE 4 Ground Covers 4 Perennials 5 ~ Shrubs ~ 5 Trees 6 ~ Maintenance Standards 15'-30' 8~ 25'-55' DEFENSIBLE SPACE ZONE 6 7 Ground Covers 7 Shrubs 8 ' Trees 8 Maintenance Standards 8 ~ 55'-100' DEFENSIBLE SPACE ZONE 9 Grasses and Wiidflowers 10 Trees 10 ~ Maintenance Standards 10 ' DESCRIPTIONS OF MAINTENANCE PROCEDURES GRASS MOWING 1 1 1 1 SHRUB MANAGEMENT 12 , PRUNING OF OAK SAVANNA / WOODLANDS 13 SUMMARY OF FREQUENCY OF RECOMMENDED MANAGEMENT 14 ~ ACTIONS TO BE TAKEN DURING HIGH FIRE DANGER 14 ' , u 1 ~ LIST OF FIGURES ' Drawing F-1. Fire Hazard Mitigation and Defensible Space Vegetation ' Management Plan - 1 "=50' - 0" , CJ ' 1 ' ' , ' ~ ' ' ~ ' ~ ~6a 1~~ i 1 ' EXECUTIVE SUMMARY i~ ~~ ~~ ~ The City of Dublin requires the preparation and submittal of a Wildfire Management Plan prior to any development approval. The Plan includes both a text description of the management concepts, defensible space zones and ' maintenance procedures, and a graphic plan delineation of the Defensible Space Zones. The graphic plan, Drawing F-1, is attached to this report. ~ This Pfan lays out the criteria for design, management and maintenance of the landscape to achieve a fire-safe landscape installation that will achieve the ' proper gaps and spacing of landscaping to prevent the spread of fires to the development areas. Trees and vegetation with a high fire risk, including pyrophytic species, such as California Bay and Eucalyptus, are prohibited within ' the 0'-30' zone surrounding all project buildings. The existing trees of other species to remain must be limbed up, cleaned up and cleared underneath, as specified in this report. No new trees of these species shall be planted. ' This plan describes the Vegetation Restoration and Management Concepts; the Defensib{e Space Zones, which include the 0-3' Critical Zone, and the 4'-14', 4'- t 24', 15'-30', 25'-55', and 55'-100' Defensible Space Zones; the Maintenance Procedures for Grass Mowing, Shrub Management and Pruning of Oak Savanna/Woodlands; the Frequency of Recommended Management; and ' Actions to be Taken During High Fire Danger. A map is included that delineates each of the above zones. The criteria for which zones are applicable are: ~ upslope - to 30', sideslope - to 30' and downslope - to 30' or 100'. In addition, all grass must be mown to a 2" height within 10' of any road or driveway. ' The areas shown on the Plan will be planted and irrigated, using plant materials specified in this report. The private yards will be planted and irrigated by the homeowners purchasing the affected houses. The CC8~R's will specify that the ' installation will be complete within 6 months of occupancy of the home, and that maintenance must be carried out as specified in this plan. , References used in the preparation of this plan include "Pyrophytic vs. Fire Resistant Plants" by Ray Moritz and Pavel Svihra, obtained from the Marin County ~ Fire Department, and "~ire-Safe Plant Selections, Landscape Restoration in Inverness Park" by Ray Moritz, and "Fire-Safe Landscape Database" by UCFPL. , ~ ' , iv ~ ~ ~ ' ~ ' I~ ~ ' EXISTING SITE DESCRIPTION c~~ ~ ~ Fallon Crossing is a 66.9 acre site consisting of both flat and hillside topography, at the intersection of Fallon and Tassajara Roads. There are no existing structures on the site, and it is currently used for grazing. The existing vegetation consists of primarily introduced and native grasses. There are no trees within the developmenfi area. The only trees occur within the creek area, and consist of native, riparian trees. VEGETATION RESTORATION AND MANAGEMENT CONCEPT There will be four zones delineated in the Defensible Space Vegetation Management plan, as required by the City of Dublin. 0-3' Critical Zone 4'-14' & 4'-24' Defensible Space Zone 15'-30' 8~ 25'-55' Defensible Space Zone 55'-100' Defensible Space Zone The subject property requires the following Fire Hazard Mitigation and Defensible Space Zones. Up Slope to 30' , Cross Slope to 30' Down Slope to 30' or 100' ~ ' ' , ~ ~ ' Recommended Methods of Vegetation Management Several methods of vegetation management are feasible. In fact, there are environmental benefits to occasionally changing the method used. The maintenance actions in the vegetation management guidelines can be categorized by vegetation types. Grass must be mowed, shrubs will be pruned of dead material, shortened or removed altogether. Trees and tree-like shrubs will not be removed, but pruned of lower branches when grasses under them are not mowed. Fire resistant, water conserving, landscaping will be installed near the structure, in the Defensible Zones, and along roads. All newly installed landscaping will be irrigated. ALL NEW LANDSCAPED AREAS SHOULD BE MULCHED, BUT THE USE OF "MONKEY HAIR "OR "SHREDDED REDWOOD BARK" IS PROHIBITED. Cut material may be left on the site only if it has been mechanically chipped. , 1 1 ' , ' ~ ~ ~ ~ ' ' ~ ' ~ ~ , ~05~ ~ c~~ Removal of brush and dead shrubs will take place throughout the site before construction begins, as construction itself can be an additional risk of ignition. Shrubs which will remain after the entire project has been compieted will be identified in the field, marked and preserved. Other shrubs will be removed before construction begins. Pruning of any existing trees fio be retained throughout the site is advisable, as is mowing the grass where pruning to a height higher than three times the unmowed grass height is undesirable. Understory shrubs will need to be removed and shrub clusters formed in open shrubby vegetation. There are several advantages to fuel treatment before construction begins. The cost of fuel modification in a wildland setting is many times less expensive than when improvements are even partly in place. The desired vegetation will have at least one season to re-grow and become visually appealing. Lastly, the chance of a damaging fire caused by construction itself is reduced. The frequency of vegetation management is linked to the vegetation type, and is described in this plan. Grass will need to be mowed annually when 30% of the grass cover has cured (any time from April 15-June 1). The grass will be cut within the week when 30% of the grass cover is determined to be cured, and no later than June 1. This may require re-mowing if late season rains promote grass growth after the first cutting. This will apply during construction and prior to occupancy, as all of the Defensible Space Zon`es will be irrigated, and not contain native grasses. The expected frequency of treatment of shrubs should be as necessary to meet the requirements of this plan, but in no case less than five years. Shrubs may need to be pruned of dead wood, shortened, shrub groupings minimized in size, or new shrubs removed under tree canopies. Shrub removal or pruning may be done any time of year. Application of a herbicide to prevent re-sprouting may be more effective in the spring, but will follow recommendations. , Because trees typically grow from the top ends of branches, subsequent pruning needs to occur only every five years or so, depending on the rate of growth, and significant events which may cause dead wood to develop or breakage to occur. Pruning of oaks, other trees and tree-like shrubs can be done at any time of the year, depending on recommendations from a professional arborist. Trees and large tree-form shrubs shall be pruned to provide clearance of three , times the height of the understory plant material, or 8 feet, whichever is higher. - Limbs which are smaller than 3 inches in diameter are to be pruned up to 8 feet ' off the ground, and in young trees, the lower one-third of the height of the tree. Thus, if a tree is 10 feet tall, the lower 3-4 feet will be pruned up and understory 1 2 ~ ~~~ cc~ ~ plant material kept to less than 6 inches in height. Then as it grows to 24 feet in height, the 8-foot distance from ground can be achieved, and the understory ~ plant material is allowed to reach 2.5 feet in height. The tree canopy will not be disturbed or thinned, since this promotes growth of more flammable vegetation. , Removal of a litter layer which is deeper than the guidelines allow is expected to be necessary only once every ten years. , Creation of "ladder fuel situation" (where a fire can climb from one vegetation layer to the next) will be avoided. Thus shrubs may be near, but not under, trees. ~ Individual plants or shrubs masses will create "shrub islands" with adequate horizontal spacing. Shrub islands are distinct groupings of shrubs designed to help control the spread of fire. Islands will be small enough to provide adequate ' horizontal separation between groupings and to ensure proper maintenance; shrub islands will be no wider than two times the shrub height, or 120 square feet ' in area. The space between islands would be greater than three times the height of the shrub or a 12 foot minimum. Emerging trees will have a spacing of 12 feet cleared from the edge of the canopy. As an alternative to "shrub ~ islands", shrubs may be placed in sinuous single rows of varying length, but not more than 7 feet in width, and with spacing of at least 12 feet to other rows and/or "islands" of shrubs. ' ' ~ ~ ' ' ' I ~ ' Trees may be planted singly or in clusters, but the crowns should be separated by at least 10 feet. This does not apply to trees within clusters, but does apply to crowns between clusters. The crowns should also be separated at least 10 feet from any flammable structures. An additional 5 feet shall be added to the above spacings for every 10 (10%) percent increase in slope. DEFENSIBLE SPACE ZONES 0-3' Critical Zone The zone 0-3' around the buildings is either hardscape, or irrigated and landscaped with plant material that is low growing and nonflammable, as well as deer resistant. Limited trees are proposed in this zone. Groundcovers: Arctostaphylos ' Hookeri' Ceanothus gloriosus Coprosma kirkii Festuca longifolia Liriope gigantea Monardella purpurea Monterey Carpet Pt. Reyes Ceanothus Creeping Coprosma Hard Fescue Giant Turf Lily Coyote Mint 3 1 ~ ~ 1 ~ ' ' ~ ' ' , ~ ~ ' ~ ~ ~ ~ ~ , 1~~ I~~ ~ Myoporum parvifolium Myoporum Salvia sohomensis Creeping Sage Trachelospermum jasminoides Star Jasmine Perennials: Coreopsis species Dietes bicolor Hemerocallis hybrids Iris douglasii Lantana montevidensis Lavandula species Polystichum munitum Tulbaghia violacea Coreopsis African Iris Daylily Douglas Iris Lantana Lavender Sword Fern Society Garlic Maintenance Standards: The following standards will be used as guidance for maintenance as it applies to the zone between 0-3' from buildings. All dead plants and combustible materials shall be removed to establish and maintain a defensible space. Removal of combustible materials includes keeping the ground, roofs, decking and balconies free of dead leaves, needles or other plant debris, and removing dead material that drapes over ground cover yearly, before June l: This includes leaves, bark, and branches. 4'-14' or 4'-24' Defensible Space Zone The zone 4'-14' or 24' around the buildings will be irrigated and planted with a variety of low and medium growing groundcovers and herbaceous shrubs that are fire-resistant, and deer resistant. Individual plants or shrub masses will create "shrub islands" with adequate horizontal spacing. Some clusters of trees are being proposed for screening. All landscaping will be irrigated. Groundcovers: Ajuga reptans Arctostaphylos `Hookeri' Armeria maritime Ceanothus gforiosus Cerastium tomentosum Cistus salvifolius Coprosma kirkii Cotoneaster spp. Carpet Bugle Monterey Carpet Common Thrift Pt. Reyes Ceanothus Snow-in-Summer Sageleaf Rockrose Creeping Coprosma Cotoneaster 4 ! 1 ~ , ~ ~ Epilobium canum Festuca longifolia Fragaria chiloensis Liriope gigantea Monardella purpurea Myoporum parvifolium Osteospermum fruticosum Salvia sonomensis Teucrium chamaedys Thymus praecox articus Verbena peruviana California Fuchsia Hard Fescue Beach Strawberry Giant Tur.f Lily Coyote Mint Myoporum Trailing African Daisy Creeping Sage Prostrate Germander Creeping Thyme Perennial Verbena Perennials: ~ 1 1 ~ ' , Shrubs: r ~ , 1 i , ~ Achillea species Yarrow Coreopsis species Coreopsis Dietes bicolor African Iris Erysimum linifolium Wallflower Hemerocallis hybrids Daylily Iris douglasii Douglas Iris Lantana montevidensis Lantana Lavandula species Lavender Limonium percil Sea Lavender Lupinus species Lupine Polystichum munitum Sword Fern . Sidalcea hickmanii Marin Checkerbloom Tulbaghia violacea Society Garlic Zauschneria.californica California Fuchsia Ceanothus 'Dark Star' Ceanothus Cistus spp. Rockrose Correa 'Carmine Bells' Australian Fuschia Corylus cornuta 'Californica' California Hazelnut Elaeagnus pungens Silverberry Eriophyllum lanatum Wooly Sunflower Garrya elliptica Silktassel Heteromeles arbutifolia Toyon Lonicera involucrata Twinberry Mimulus aurantiacus Sticky Monkey Flower Myrica california Wax Myrtle Polystichum munitum Sword Fern Prunus ilicifolia Holly-Leafed Cherry Rhamnus californica 'Eve Case' Coffeeberry 5 ~08 ~~~a ~ ~ , Ribes sanguineum Red-Flowering Current `~ C 6 ~ ~ Salvia greggii Autumn Sage ~ Solanum xantii Chaparral Nightshade Trees: I Aesculus californica California Bucke e y ~ Alnus rhombifolia Arbutus unedo White Alder Strawberry Tree Cercis occidentalis Western Redbud Crataegus phaenopyrum Washington Thorn , Pistachia chinensis Chinese Pistache Quercus coccinea Coast Liv~ Oak ' Quercus ilex Holly Oak Quercus lobata Valley Oak Quercus rubra Black Oak ~ Quercus suber Cork Oak Schinus molle California Pepper ' Maintenance Standards: The following proposed set of maintenance standards will be used as guidance ' for work performance for maintenance as it applies to the zone between 0-30' from buildings. ' l. All dead plants and dry vegetation shall be removed to establish and maintain a defensible space. The following actions will provide ~ the equivalent level of fire safety as removing all combustible material. ~ a. Cut grass and weeds to less than 2 inches yearly when 30% of the grasses have cured. The grass will be cut within the week ~ when 30% of the grass cover is determined to be cured, and no later than June l. This may require re-mowing if late season rains promote grass growth after the first cutting. All , cut grass shall be raked and removed from the site. This will apply during construction and prior to occupancy, as all of the Defensible Space Zones will be irrigated, and not contain ' native grasses. b. Keep the ground, roofs, decking and balconies free of dead ' leaves or other plant debris. 1 ~ 6 i 1 ~ , ~ ~ ~ ~ ' ' , ' ~ 1 ~ ~ 1 , ' , ~ ll~ I~~ c. Leaves, bark and humus will be cleared every year under trees and shrubs. At no time will a buildup of leaves and humus exceed 1 inch in depth anywhere in a landscaped area. However, bare earth will not be exposed in over SO% of the site. d. Dead material that drapes over ground cover will need to be removed yearly, before June l. This includes leaves, bark, and branches. e. Remove all dead branches from within live ground covers, vines and shrubs, immature and landscape trees. 2. Mechanically chipped materials can remain on the site provided the mulch layer is no greater than 2 inches in depth. 3. Creation of "ladder fuel situation" (where a fire can climb from one vegetation layer to the next) will be avoided. Thus shrubs may be near but not under trees. If there is a choice, place trees downhill and shrubs uphill where the structure is above the open space. 4. No stacked wood piles will be located in this zone. 15'-30' or 25'-55' Defensible Space Zone A portion of the zone 15'-55' from the buildings will provide additional defensible space. Most of this area will be irrigated, and will be landscaped with groupings of low and medium height, fire resistant plant material, and will be aggressively maintained. There will be a few random tree groupings for screening. Groundcovers: Arctostophylos ' Hookeri' Ceanothus gloriosus Cistus salvifolius Coprosma kirkii Cotoneaster spp. Epilobium canum Festuca longifolia Monardella purpurea Myoporum parvifolium Salvia sonomensis Manzanita Pt. Reyes Ceanothus Sageleaf Rockrose Creeping Coprosma Cotoneaster California Fuschia Hard Fescue Coyote Mint Myoporum Creeping Sage 7 , , Shrubs: , Ceanothus 'Dark Star' Ceanothus Cistus spp. Rockrose Correa 'Carmine Belis' Australian Fuschia , Corylus cornuta 'Californica' California Hazelnut Elaeagnus pungens Silverberry Garrya elliptica Silktassel ~ Heteromeles arbutifolia Toyon Mimulus aurantiacus Sticky Monkey Flower Myrica california Wax Myrtle ~ Prunus ilicifolia Holly-Leafed Cherry Rhamnus californica 'Eve Case' Coffeeberry ~ Ribes sanguineum Red-Flowering Current Salvia greggii Autumn Sage , Trees: Aesculus californica Buckeye ~ Alnus rhombifolia White Alder Arbutus menziesii Madrone ' Cercis occidentalis Pistache chinensis Western Redbud Chinese Pistache Quercus coccinea Coast Live Oak Quercus Ilex Holly Oak ' Quercus lobata Valley Oak Quercus rubra Black Oak ~ Quercus suber Cork Oak Schinus molle California Pepper ' Maintenance Standards: ~ 1~ `(~~ ~ , The following proposed set of maintenance standards will be used as guidance for work performance for maintenance as it applies to the zone between 15'-55' from the home. , 1. All dead plants and dry vegetation shall be removed to establish and maintain a defensible space. The following actions will provide the , equivalent level of fire safety as removing all combustible material. a. Cut grass and weeds to less than 2 inches yearly when 30% of the ' grasses have cured. The grass will be cut within the week when 30% of the grass cover is determined to be cured, and no later than ' June 1. This may require re-mowing if late season rains promote grass growth after the first cutting. All cut grass shall be raked and ~ $ r t , , ' ' ~~a ~ ~ ~ ~ removed from the site. This will apply during construction and prior to occupancy, as all of the Defensible Space Zones will be irrigated, and not contain native grasses. b. Leaves, bark and humus will be cleared every year under trees and shrubs. At no time will a buildup of leaves and humus exceed 1 inch in depth anywhere in a landscaped area. However, bare earth will not be exposed in over 50~ of the site. c. Dead material that drapes over ground cover will need to be removed yearly, before June l. This includes leaves, bark, and branches. , d. Remove from mature trees all vines, loose papery bark, dead branches and live branches smaller than 3 inches in diameter; to 8 feet above ground. ' , ' , ~ e. Remove all dead branches from within live ground covers, vines and shrubs, immature and landscape trees. 2. Remove and safely dispose of all cut vegetation and hazardous refuse. 3. Mechanically chipped materials can remain on the site provided the mulch layer is no greater than 2 inches in depth. 4. Creation of "ladder fuel situation" (where a fire can climb from one vegetation layer to the next) will be avoided. Thus shrubs may be near but not under trees. If there is a choice, place trees downhill and shrubs uphill where the structure is above the open space. ' 5. No stacked wood piles will be located in this zone. , 55'-100' Defensible Space Zone ~ A portion of the zone 55'-100' from the buildings will provide additional downslope defensible space. Some, but not all of this area will be irrigated, and will be encouraged to revert to a natural landscape fabric. Landscaping will ' consist of hydroseeded annual grasses and wild flowers with strong slope stabilization qualities and low fuel volume. Some random tree clusters will be created for screening and aesthetic appeal, and reforestation. All vegetation ~ will be aggressively maintained. ~ ~ 9 ~ i ' , ' , Grasses and Wildflowers: 113~ ( (~ ~ Seed Mix % by weiqht Botanical Name Common Name 25% Festuca rubera cv. Molate Red Fescue 25% Hordeum brachyantherum Meadow Barley 15% Melica imperfecta Coast Range Melic 15% Nassela pulchra (Stipa) Purple Needlegrass 7% Mimulus aurantiacus Monkeyflower 6% Artemisia californica California Sage 3% Lupinus succulentus Succulent Lupine 2.50% Eschscholzia californica California Poppy .75% Layia platyglossa Tidy Tips .50% Clarkia amoena ssp. Godetia .25% Achillea millefolium ~ Yarrow Trees: ~ ' , ' ' ' , ~ , ~ ' ~ Aesculus californica Alnus cordata Alnus rhombifolia Cercis occidentalis Heteromeles arbutifolia Prunus ilicifolia Quercus coccinea Quercus lobata Quercus rubra Quercus suber Maintenance Standards: Buckeye ~ Italian Alder White Alder Western Redbud Toyon Holly-Leafed Cherry Coast Live Oak Valley Oak Black Oak ' Cork Oak The following proposed set of maintenance standards will be used as guidance for work performance for maintenance as it applies to the zone between 55'- 100' from buildings. Creation of "ladder fuel situations" (where a fire can climb from one vegetation layer to the next) will be avoided. In openings between trees, shrubs may remain. Maintain individual plants or shrub masses to create "shrub islands" with adequate horizontal spacing. The crown cover of shrubs will not exceed 30% shrub, with remaining vegetation ideally comprising 50% grass and 20% other herbaceous plants. The maximum dead-to-live ratio would be 20% in the fuel modification zones. Those shrubs which readily reseed (poison oak and coyote bush) will be preferentially cut before those shrubs which depend upon seeding for replacement. ~ 10 ~ i ' ' ~ ~ , ~ C~ ~ ~ 1 ~ C_J ' 11~~ ~~ I All dead plants and combustible materials shall be removed within 100 feet of the structure to establish and maintain a defensible space. The following actions will provide the equivalent level of fire safety as removing all combustible material. a. Cut grass and weeds to less than 4 inches in height under short trees (trees under 24 feet in height) to preclude excessive pruning. This will be done yearly before May 1. Cutting of native grass and wildflowers may be delayed under after seed set provided they do not form a means of rapidly transmitting fire to any structures. b. Remove from mature trees all vines, loose papery bark, dead branches and live branches smaller than 3 inches in diameter, to 8 feet above ground. c. Remove all dead branches from within live ground covers, vines and shrubs, immature and landscape trees. 2. Trees and large tree-form shrubs shall be pruned to provide clearance of three times the height of the understory plant material or 8 feet, whichever is higher. 3. Mechanically chipped materials can remain on the site provided the mulch layer is no greater than 2 inches in depth. 4. Remove and safely dispose of all cut vegetation and hazardous refuse. DESCRIPTIONS OF MAINTENANCE PROCEDURES Grass Mowing Grass will be mowed with a nylon cord weed whipper or grazed with goats. The control that is afforded by manual or goat herds, as compared to mechanical equipment, is advantageous to avoid harming new and existing oak seedlings, as well as damaging rock formations. Weeds will be removed with manual labor using a weed whipper or applying herbicides on a spot basis. Weeds, grass and removal of any oak leaf litter or other dead material in the ' critical zone will similarly need to be done manually, possible with a rake. This will apply during construction and prior to occupancy, as all of the , Defensible Space Zones, except for the 55'-100' zone, will be irrigated, and not contain native grasses. ~ ~ ! Il~ f ~~ ~ , Shrub Management ' Shrubs that need to be removed will be cut with weed whips that have a cutting blade attached, or grazed with a goat herd. Branches which are larger than can be handled by the weed whip, or consumed by goats will be cut with a ' chainsaw. When manual labor is used, special precautions will be needed in poison oak. To avoid re-cutting or otherwise re-treating undesired shrubs, spot application of a Category 3 or 4 herbicide will .be applied to the foliage or ~ stump, depending on the recommendation provided by a licensed Pest Control Advisor (PCA). ~ If goat grazing were used, dead material which was not broken up or consumed will need to be cut manually with loppers and saws. Oak seedlings ~ and small oaks will need to be protected from goat grazing, as the animals will browse and girdle the trees. Protection may take the form of "cages" made from fencing or temporarily wrapping the tree trunk. If manual labor is used, ' dead material will need to be cut with loppers and/or saws. Pruning and shortening shrub height will need to be accomplished with the same method. ! The debris of the shrubs can be cut and hauled away, or mechanically chipped and left in place. i Following the initial treatment, manual labor or a goat herd will be used to remove incipient shrubs in the grasslands before they flower. While the plants ' need not be removed the first year they appear (since the shrubs would provide some improved deer browse), they will be cut or grazed before they are old enough to set seed and spread (this is approximately three years). , While the initial treatment is likely to be substantial, subsequent maintenance will require significantly less effort. Application of herbicides to undesired shrubs will ' further diminish subsequent maintenance requirements, as it will prevent re- sprouting. ! In addition to reduction of fire hazards, hand crews will be used for the removal of undesirable and hazardous plants such as poison oak, artichoke thistle, purple ' and yellow star thistle, and Russian thistle. These species will be removed with a combination of repeated manual cutting, spot application of a Category 3 or 4 herbicide, and mowing at the time of flowering. The open space will need to , be monitored through the year, every year, in order to eradicate these weeds before they become dominant and constitute a significant fire hazard. ~ , r-; ~ , 12 , ~ ' ~ ~ ~ ~ ~ ~ ' i ~ i ! 1 ~ ! 1 ' ~~~~ ~~~ Pruning of Oak Savanna/Woodlands Pruning of lower branches of oaks, other trees and tree-like shrubs wherever they occur will need to be performed by hand crews, using loppers, hand saws, chain saws and chain saws on poles under supervision of an arborist. Similarly, dead material in the tree crowns will need to be accomplished in the same manner. . Where leaf litter has accumulated to a depth which triggers management action, hand crews with rakes will need to be used to remove the material. Debris of the pruning operation can be hauled away, or mechanically chipped and left in place. 13 ~ ' ~ SUMMARY OF FREQUENCY OF RECOMMENDED MANAGEMENT ~ Annval Management ' ' ' ' Il~~ f (~~ ~ • mow, graze grass near structures and under trees and shrubs during construction, prior to occupancy and along roads and driveways • hand crew cut shrubs and weeds in grasslands • monitor site for weed and shrub encroachment • inspect trees for deadwood, vertical clearances • re-establish vertical clearance in Landscape Zone • remove weeds, all dead material in Landscape Zone Management That Will Occur Every 5 Years, Or More Frequently As Necessary To Meet The Plan • thin shrubs into groupings ' • remove new understory shrubs • prune trees of lower branches to re-establish vertical clearance ~ ACTIONS TO BE TAKEN DURING HIGH FIRE DANGER ' In times of very high fire danger, extra precautionary procedures should be instituted by the facility. ~ 1 , ~ , ' ' ' ' 14 , ~ i ~ i APPENDIX C ' ' , ~ , ' ' , , ' ~ ' RIPARIAN MITIGATION & MONITORING PLAN ~1~~ ~c~~ , BERLOGAR STEVENS & ASSOCIATES ~ 1 1 ~ ~ ' ~ , ' 1 ' ~ ' , 1 1 ~ ' ' < < ~ ~~~ ~ REVISED RIPARIAN MITIGATION AND MONITORING PLAN FOR THE FALLON CROSSING DEVELOPMENT PROJECT ALAMEDA COUNTY, CALIFORNIA Prepared for: STANDARD PACIFIC HOMES 3825 Hopyard Road, Suite 275 Pleasanton, California 94588 Prepared by: OLBERDING ENVIRONMENTAL, INC. Wetland Regulatory Consultants 3170 Crow Canyon Place, Suite 260 San Ramon, Califomia 94583 Phone: (925) 866-2111 ~ FAX (925) 866-2126 Contact: Jeff Olberding MAY 2011 1 '~~ 1 ' ' i ~~~ ~ TABLE OF CONTENTS 1.0 PROJECT DESCRIPTION FOR WHICH MITIGATION IS REQUIRED ........................1 1.1 Brief Summary of Overall Project ...........................................................................1 1.2 Location of Project ...................................................................................................2 1.3 Responsible Parties ..................................................................................................2 1.4 Habitat Types and Functions of the Jurisdictional Areas Impacted ........................3 , 2.0 GOAL OF RESTORATION AND MITIGATION PLAN ................................................3 ' 3.0 IMPLEMENTATION PLAN ..............................................................................................4 3.1 Plan and Permit Check .............................................................................................4 3.2 Install Protective Flagging for Preservation and Pond Construction Areas ............4 3.3 Installation of Exclusion Fencing ............................................................................ 5 ' ~ ' 3.4 3.5 3.6 3.7 3.8 Site Grading ............................................................................................................. Weed Control ........................................................................................................... Augering of Holes for Trees and Shrubs ................................................................. Planting .................................................................................................................... Installation of Irrigation ........................................................................................... 5 5 5 5 7 ' 3.9 Complete Erosion Control Measures .......................................................................7 3.10 Prepare As-Built Drawings and Construction Report ..............................................7 4.0 MAINTENANCE DURING MONITORING PERIOD ..................................................... 7 , 4.1 Maintenance Activities .......................................................................................... ..8 ' 4.1.1 Vandalism .................................................................................................. ..8 , 4.1.2 Weed Control ............................................................................................. 4.1.3 Plant Maintenance ..................................................................................... ..8 11 ' 4.1.4 Irrigation Maintenance and Monitoring .................................................... 11 , 4.1. S Litter Removal ............................................................................................ 4.1.6 Erosion Control ......................................................................................... l 1 1 l ` 4.1. 7 Maintenance Records ................................................................................. 12 ' 4.2 4.3 Responsible Parties ................................................................................................ Schedule ..... ......................................................................................................... 12 12 4.4 Long-term Maintenance ......................................................................................... 13 , 5.0 FINAL SUCCESS CRITERIA ..........................................................................................14 5.1 Overall Mitigation Objectives ................................................................................14 5.2 Conditions Proposed for the Site that Will Insure Success ....................................14 ' S.3 Quantitative Mitigation Success Criteria ...............................................................15 6.0 MONITORING PLAN ......................................................................................................15 ' 6.1 Performance Criteria ..............................................................................................16 = 6.1.1 Number Remaining from Original Planting ..............................................16 ~' i , , 1 1 ~ ' ~ ' r , i ' ~ ' ~ ' , ' ~ ' ~ ' ' r ~ { ' ~ ~ ' ~ ' , ' I ' l~l~ (~~ 6.1.2 Site Maintenance ........................................................................................16 6.1.3 Plant Vigor and Health/Abundance and Diversiry ....................................16 6.2 Monitoring Methods and Schedule ........................................................................17 6.2.1 Number Remaining from Original Planting .............................................. 17 6.2.2 Site Maintenance ........................................................................................ 17 6.2.3 Plant Vigor and Health/Abundance and Diversity .................................... 17 6.2.4. Photo-Documentation ................................................................................ 18 6.3 Data Analysis ......................................................................................................... 18 6.3.1 Number Remaining from Original Planting .............................................. 18 6.3.2 Site Maintenance ........................................................................................ 18 6.3.3 Plant Vigor and Health/Abundance and Diversity .................................... 18 6.4 Annual Reports ...................................................................................................... 19 6.5 Schedule ................................................................................................................. 19 7.0 CONIPLETION OF RESTORATION ...............................................................................20 7.1 Notification of Completion ....................................................................................20 7.2 Confirmation ..........................................................................................................20 8.0 CONTINGENCY MEASURES ........................................................................................20 8.1 Initiating Procedures ..............................................................................................20 List of Tables Table 1 Sequence of Habitat Construction Tasks .......................................................................4 Table 2 Proposed Riparian Plants and Estimated Number Required .........................................6 Table 3 Maintenance Activities by Year ...................................................................................12 Table 4 Long-term Maintenance Activity Beyond Year 10 .....................................................13 Table 5 Plant Vigor and Health Ratings ...................................................................................17 11 1 1 1~ ' , ' , ' 1 1 , ' ' ' ' ' ' , ~' , i~~~~~ ATTACHMENTS ATTACHMENT 1 FIGURES Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Regional Map Vicinity Map USGS Quadrangle Map for Livermore Aerial Photograph Fallon Crossing Development Site Plan Mitigation Area Map Riparian Planting Plan Deed Restriction Area Map This report should be cited as: Olberding Environmental, Inc. May 2011. Revised Riparian Mitigation and Monitoring Plan for the Fallon Crossing Development Project, Alameda Counry, California. Prepared for Standard Pacific Homes, Pleasanton, California. iii i . ~ ~ ' ~ ' , 1 1 ~ ' ' ~ ' ' ' ~I ' ' 1 ;~ ~~3 c~~ ~ 1.0 PROJECT DESCRIPTION FOR WHICH MITIGATION IS REQUIRED 1.1 Brief Summary of Overall Project The Fallon Crossing Property (Property) consists of 66.9 acres of gently rolling hills primarily vegetated with non-native annual grassland habitat (Attachment l, Figures 1-4). A segment of a degraded incised creek channel (Moller Creek) flows across the northern portion of the Property. Proposed development of approximately 106 single family residential units, interior streets, utilities, a storm water detention basin and two water quality basins will result in permanent impacts to 21 acres of the Property (Attachment 1, Figure 5). An additiona19.8 acres (6.1 acres located on-site and 3.7 acres located on an adjacent property) will be temporarily impacted by grading in order to stabilize the hillsides above the development Project. All areas temporarily impacted for geotechnical rehabilitation purposes will be restored back to grassland habitat upon completion. The Development Project will involve the construction of an outfall structure within Moller Creek with impacts to the bank of Moller Creek above and below the ordinary high water (OHV~ line. The outfall will consist of a 9x20x12 foot concrete structure (180 square feet) or 0.004 acres of impact along a degraded creek embankment. Sheet pilings will be installed just above the OHW line to provide a footing for the outfall. Three concrete chambers have been designed to dissipate water velocity from storm water discharges. Work includes placement of 1/4 ton rock rip rap to slow water flow as it enters the creek. The rock rip rap protection apron and coir fabric will be positioned at the base of the outfall. The bank protection material will be installed over a 15-foot wide length of channel and extend 5 feet below the OHW line. The dimensions of the rock rip rap are 15x5x3 feet for a total of (75 square feet). Permanent impacts within the creek total 255 square feet (0.006 acres). Additionally, a detention basin and the two storm water quality basins (water quality ponds) will be constructed to treat water that will flow from the development site into Moller Creek. The detention and water quality basins will be located between the development and Moller Creek and managed for water quality purposes. The outfall will discharge stormwater which collects within the detention basin and two water quality ponds. These facilities will be maintained by the Geologic Hazard Abatement District (GHAD) as described in the Stormwater Management Plan which has been submitted under separate cover. Additional work in Moller Creek consists of the placement of the discharge culvert from the water treatment basin within an excavated trench through the bank of Moller Creek. This activity includes the excavation of a trench 15x4 feet from the edge of the riparian dripline to the outfall structure for a total of 60 square feet. Finally, an additional 18-inch storm drain line will be installed along Tassajara Road. The storm drain will tie into the existing culvert located under the Tassajara Road Bridge. T'his activity involves the excavation of a trench 47x5 feet along the edge of the creek bank with a portion of the trench located in the riparian dripline for a total of 235 square feet of impact. In both cases, the utility trench accommodating the storm drain lines will be backfilled and restored. Temporary impacts within the creek tota1295 square feet (0.007 acres). , ,' 1 1 ' , , , ~ , i ~ ' la y ~~~ ~ A total of 550 square feet (0.013 acres) of impact (255 sqft permanent and 295sqft temporary) would occur along a combined total of 33 linear feet of the Moller Creek channel and embankment, to install an outfall structure and riprap and allow for trenching work to accommodate storm drain lines. The outfall structure is positioned between a break in the willow riparian vegetation, but construction may require the trimming of trees to accommodate equipment access to the work area. Native material will be removed for the placement of the storm drain lines, gravel will be installed in the trenches, and native soils will be replaced. The on-site mitigation area proposed for project related impacts to Moller Creek and associated riparian habitat is approximately 150 feet long by 50 feet wide, 7,500 square feet (0.17 acres) and occurs between Pond 2(lower pond) and Moller Creek (Attachment l, Figure 6). The mitigation calls for the installation of 82 native riparian trees and shrubs that will provide additional cover for CRLF. The expansion of riparian habitat will enhance the existing setback buffer between planned residential development, the Creek and the lower pond. 1.2 Location of Project The 66.9-acre Property is located on the east side of Tassajara Road, northeast of the city of Dublin. The Property is found approximately 2.5 miles north of the Highway 580 and Tassajara Road interchange. The Property is situated at the first bend in the roadway where it curves east to cross over Moller Creek in Alameda County, just south of the Contra Costa/Alameda County line. Moller Creek forms the northwestern boundary of the site, Tassajara Road forms the western border, Pinn Brothers Silvera Development is located along the southern boundary and fence lines and undeveloped lands form all other boundaries. Attachment 1, Figure 2 illustrates the vicinity of the Property in relationship to the City of Dublin. Attachment 1, Figure 3 identifies the location of the Property on the USGS 7.5 Quadrangle Map for Livermore. An aerial photograph of the Property is contained in Attachment 1, Figure 4. The development Project is depicted in Attachment 1, Figure 5. ~ 1.3 Responsible Parties ~ , ' ' ' , The applicant for this project is: Standard Pacific Homes 3825 Hopyard Road, Suite 275 Pleasanton, California 94558 Contact: Mr. Aaron Ross-Swain Telephone: (925)-730-1375 Fax: (949) 789-9601 E-mail: arossswain@stanpac.com T'his riparian mitigation plan is being prepared by: Olberding Environmental, Inc. 1370 Crow Canyon Place, Suite 260 San Ramon, California 994583 Contact: Mr. Jeff Olberding Telephone: (916)-985-1188 Fax: (916) 985-2288 E-mail: jeff@olberdingenv.com ~ ~ ~ ' ' , ' r ~ ~~~ ~~~ ~ 1.4 Habitat Types and Functions of the Jurisdictional Areas Impacted Moller Creek is defined by a very deeply incised bed and bank. Approximately 1,460 linear feet of the channel occur along the northwestern property line. The active channel averages approximately five feet wide and lies approximately 20 feet below the top of the bank. A narrow flood terrace is also located along portions of the Creek adding an average of nine additional feet to the channel. The slopes of the banks approach vertical, however, a few locations occur that are less steep allowing access to the channel. Scour is ongoing along the banks of the channel and there is a lack of channel vegetation. The portion of the channel in the property area and directly downstream appears to suffer from a very high erosion rate. Arroyo willow (Salix lasiolepis) and valley oak (Quercus lobata) are found along the active portion of the channel and up to the top of the bank. Elderberry (Sambucus mexicana) and coyote brush (Baccharis pilularis) were also observed as secondary species in the corridor and were the only understory components along the channel. Several mature blue gum (Eucalyptus globulus) occur on the top of the east bank and within the channel. Fine gravel material and silt are found in the bed of the Creek. Where Tassajara Road crosses the Creek, a large corrugated metal culvert transports flows beneath the roadway. Approximately 1,200 feet southwest from the property, Moller Creek joins the main channel of Tassajara Creek. ' A stock pond is located along the east bank of Moller Creek in the northwestern corner of the property. This pond was restored in the spring of 2001 and planted with freshwater marsh and riparian species such as cattails (Typha latifolia), three square (Scirpus americanus), arroyo ' willow, western sycamore (Platanus racemosa), and cottonwood (Populus fremontii). The pond is approximately 9,280 square feet (58 feet by 160 feet) in size. Pond depths range from several ~ inches along the edge of the pond to 13 feet deep near the center. ' Both the pond and the creek channel provide habitat for the California red-legged frog (Rana draytonii (CRLF). ' 2.0 GOAL OF RESTORATION AND MITIGATION PLAN ' The goal of this document is to set forth a riparian planting plan to enhancelrestore 0.17 acres of ' riparian habitat along a 150-foot by 50-foot section of Moller Creek fully mitigating impacts to ' 0.013 acres of non-vegetated creek bank associated with outfall construction and utility trenching. The general purpose of the proposed mitigation is to enhance and expand the width of ~ the existing riparian corridor along Moller Creek and provide species access to the creek from an existing stock pond known to contain CRLF. , - I~ ~ ~, 3 i ~: ,+ i ~ f ' ! ' ~ ' ~ ' f ~ ~ ' ~ ~ ~ ' , , r ' I~~~ ~~~ 3.0 IMPLEMENTATION PLAN The general sequence of construction tasks is shown in Table 1 below. 1. Plan and permit check 2. Install protective flagging for preservation areas (riparian comdor and oak trees). 3. Installation of exclusion fencing. 4. Site grading. 5. Weed control. 6. Augering of holes for trees and shrubs. 7. Planting. 8. Installation of imgation. 9. Erosion control measures. 10. Prepare as-built drawings and construction report. All tasks will be overseen by an Ecological Monitor (EM), a qualified ecologist with experience in the areas of habitat development, hired by the applicant. Vehicular access to the restoration area will be restricted to restoration construction and later to emergency and maintenance purposes (estimated to occur twice per year or less). 3.1 Plan and Permit Check Plan check requires an on-the-ground survey of all work detailed in the restoration plan. Pernvt checks require ensuring that all work complies with State, and local permits. The EM must identify in the field the preserve, weed control zones, access routes and materials and equipment storage. a ~ 3.2 Install Protective Flagging for Preservation and Pond Construction Areas ~ Prior to any site modification, all existing habitats within the general work area that will be ' protected (the riparian vegetation along the creek and preserved valley oaks) shall be staked and flagged by the EM. Flagging will consist of four-foot red or orange construction fencing and be i replaced as necessary to be continuously in place during construction activities. Flagging shall ~' extend around the protected area perimeters or along their entire lengths to prevent any wanted intrusions and/or damage. ~' Accidentally damaged plants or areas will be replaced or repaired and the damage and corrective act~on reported in the first morutonng report. If flagging proves an insufficient barrier to ~ protected areas, fencing will be required. Fencing and flagging will be removed at the end of ' construction work. Garbage, including old barbed wire fences, on the restoration site or discovered during initial mobilization shall be removed to an approved disposal site. ~' 4 ' ! 1 ~ ~ ~ ~ ~~~ ~ ~~ ~ 3.3 Installation of Exclusion Fencing A split rail or similar type of fence, to be field located by the landscape architect, will be permanently installed between the riparian mitigation area and the development. The location of the fence will roughly correspond to the outer edge of the 100-foot riparian setback buffer and the 200 foot setback around the constructed pond feature at the north boundary of the mitigation site. 3.4 Site Grading ' No grading is anticipated within the riparian mitigation area. A truck mounted augur will be used in the establishment of tree and shrub planting. Shallow watering basins will also be placed around each of the new plants. , 3.5 Weed Control ' Invasive non-native plants within the mitigation area will be removed prior to any revegetation work. Treatment involves the mowing, disking, or removal of the primary plant, all roots, and any seed that could contammate the site. These opportunistic species are known to out-compete ~ California natives for light, water, nutrients and space. An aggressive eradication effort prior to revegetation will give the natives a much-needed competitive edge and significantly reduce future maintenance efforts. ' Areas of noxious weeds shall be disked, watered to encourage seed growth, and disked again. The cycle may be repeated until weed growth is extremely sparse. Areas with little or no grading will require at least a thorough mowing so that debris will not hamper construction. A flail-type , mower should be used, and all debris thoroughly mulched. . 3.6 Auguring of Holes for Trees and Shrubs ' Holes will be augured to a de th re uired for ro er installation of restoration stock. Tre w' P 9 P P es ill be excavated to a width of 24 inches greater than that of the root ball, and to the depth of the root ~ ball. Shrubs and vine will be excavated to a width of 12 inches greater than the width of the root ball, and to the depth of the root ball. Subgrade material in the holes shall be loosened to a depth of three inches. ~ 3.7 Planting ' A mix of riparian trees and shrubs is proposed to be planted to enhance the existing riparian corridor and to increase the area of the riparian habitat of the Moller Creek corridor. The species composition is detailed in Table 2 below. ~ ~ ~ ~ ~ ' 1 1 ' t ' ~ , ' 1~-~~ 1~~ , Common Name , , ~ ~~ a;hi'~ ~ .. '~`'~" ~yt'l ~ , ~ ~.~~ `~~~~`~. ~ .~ ~~~`:;~. California Bucke e _ Botanical Name .~ .~ [,. ~ . ta~.r •'C'N d w i . ' .TJ . ~.~~°,~ ~~ ~~ ~ '~REE Aesculus cali ornica Size * ~ , t* : S~.~ ~. .. ; :~ . . "~%~~:1~ 15 aUl al uanti ~ ~~~~~ j~~ u ~ ~ ~~ ~y ~~ ~~ .~_.. ~ y3 Western S camore Plantanus racemosa 15 aUl al ( Coast Live Oak uercus a ri olia 15 aUl al 3 California Ba . _ . ` , ,~., ~~~ 3 Co ote Brush Umbellularia cali ornica , '~ ~. ~ Baccharis ilularis 15 aUl al . : 1 al 3 r.. . _ ~,, ., ~ _ ..: ,~, _ ,. :~ ~ 4 10f Mule Fat Baccharis salici olia 1 al $ Blue Blossom Ceanothus s. 1 al 6 California Wild Rose Rosa cali ornica 1 al 14 California Blackbe Rubus ursinus 1 al 21 Mexican Elderbe Sambucus Mexicana 1 al 6 Snowbe S m horica os alblus 1 al 5 TOTAL ~~Y~ ~~~~.~,~. ~ w=~~~~~~ Y' "~`" `~ 82 * 15% of all trees shal] be 15 allon containers, remainin trees shall be 1 ailon containers. ' The species have been selected based upon presence near the site. Unless specifically noted • below, it is the goal of this program that all plant materials - container stock, seeds, and plugs ~ are to be planted from stock gathered in the immediate vicinity of the Project site. As a result, only genotypes of locally native species should be planted. Generally, plant material may be ~ installed as container stock, bare root seedlings, cuttings, canes, plugs or seed. Viability and ~ growth of different species varies by stock type, however, and the form chosen for this plan is based on the authors experience with these species. The trees specified for planting shall meet the following minimum standards. The form shall be ~ standard with the main scaffold branches established and properly distributed, preferably with a • full skirt of branches: For 15 gallon container size trees, the minimum trunk caliper at six inches in height should be between one and 1.25 inches. The minimum height should be seven to eight ' feet, and the minimum canopy spread should be between two and three feet. Prior to planting, all planting areas will be tilled to loosen soils to a minimum depth of eight ~ inches. Plant material shall be free from damage, disease, insects and weeds, not be rootbound, and identified correctly to genus and species. Plants shall be sufficiently rooted to the edge of the container to maintain the root ball when removed. The planting area should be free of weeds, ' trash and other debris. Plants will be placed according to the plans of the landscape architect, , using a triangulaz spacing method. The root collar will be placed at one inch above the surrounding grade. All holes shall be backfilled by the end of that same workday. Backfill ' material will include one part existing soil (or approved topsoil) and one part nitrolized fir shavings or nitrolized half-inch minus fir bark. Soils shall be completely saturated to promote ~ 6 t ~ 1 , , , ~ ~ ~ ' ' ' , ~ ~a ~~ l ~-~ settling of excavated soil. Slow-release fertilizer such as agriform or osmocote will be added to each planting hole prior to planting. After planting ammonium sulphate should be applied at a rate of five pounds per 1000 square feet to all planting areas. All areas with ground cover and shrubs shall have two-inch shredded bark mulch applied as well. All new plantings shall be watered deeply and thoroughly. All trees shall be staked, and trees and shrubs shall have watering basins. All plants will have deer protection such as screeriing for foliage and collars for the root structures if browsing is evident. All trees shall be guaranteed for a minimum of one full year from the date of final acceptance. Shrubs and ground cover plantings will be guaranteed for a minimum of 6 months from the date of final acceptance. The landscape contractor, to be named by the property owner, shall be responsible for maintaining the plantings for 60 days from the date of final acceptance. The EM will oversee maintenance during this interval. The trees and shrubs installed will eventually provide higher quality habitat and additional cover for CRLF than what currently exists on the site. It is estimated that it will take at least three to five years for the understory species and eight to ten years for tree species to provide habitat functions similar to those located along Moller Creek. It can be assumed that this habitat will provide food, cover, and nesting materials to a wide variety of riparian wildlife species once established. 3.8 Installation of Irrigation The contractor shall provide shop drawings of the irrigation system which shall be reviewed by the landscape architect prior to installation. Irrigation shall be temporary for the first three years. After three years the irrigation system will no longer be utilized. 3.9 Complete Erosion Control Measures All graded slopes will be revegetated and seeded as noted above, and the Project will be subject to State and local erosion control regulations. 3.10 Prepare As-Built Drawings and Construction Report ' Within six months of completion of the construction project, the EM shall sign a copy of the . construction log and as-builts for the Project. The as-builts will include Project topography and planting zones and shall be used in the future as the base map for the monitoring report. At that ' time, the applicant will send a copy of the signed as-builts to the City and request, in writing, . inspection of the Project. ' 4.0 MAINTENANCE DURING MONITORING PERIOD ~ Inspection and maintenance activities will be undertaken by a contractor hired by Standard Pacific Homes with oversight by the EM. Inspection and maintenance activities will be , 1 ' 13 I~ ~b 1 undertaken each year for a period of 10 years according to the schedule presented in Table 3 ' below. The monitoring schedule will be broken down into three categories: 1) Years 1-3 Plant Irrigation Period; 2) Years 4& 5 Plant Establishment Period; and 3) Years 6-10 Extended Monitoring Period. ' 4.1 Maintenance Activities ~ Most native plants such as those proposed for the restoration site are pre-adapted to their normal regional growing conditions and do not require substantial maintenance. "Pre-adapted to their growing conditions" means simply that they will occur only where conditions are relatively ~ optimal for their growth. However, the species to be planted pursuant to this plan will not have sprouted naturally. ~ Restoration is an artificial process undertaken in anticipation that a native plant community, one adapted to the site conditions, will develop. Maintenance activities will therefore be needed to • ensure that (1) the community develops as a native plant community without the mtroduction of harmful non-native species, (2) the community can naturally regenerate and sustain itself in 1 perpetuity, and (3) the development of this native community does not create potential hazards • for the adjacent neighborhoods. 1 At the same time, maintenance shall not require significant modifications to the site. The ~ guidance provided in this section describes maintenance activities that do not require further permitting actions. Mainteriance activities shall be guided by defined treatments and restrictions. ~ 4.1.1 Vandalism ~ Maintenance activities will be conducted quarterly during Years 1-5 and then annually during . Years 6-10. Site inspections shall be performed by the contractor for any evidence of vandalism. Given the proximity of the mitigation sites to a residential neighborhood, it is possible that ~ damage may occur from vandalism. The site will also be monitored for signs of excessive or . uncontrolled human disturbance such as off-road vehicle use, presence of brush and litter and human foot traffic. Presence of human disturbance will be recorded along with suggested ~ remedial action. 4.1.2 Weed Control ~ In most cases, careful design and pre-planting weed control procedures will reduce the burden of weed abatement. However, a freshly-graded construction site is a haven for weeds which may ' blow in from off-site. Additionally, misapplied cultural efforts (irrigation during the warm season in an area known to contain warm season weeds) may actually promote weed growth in the restoration area. The EM shall make a distinction between ruderal species that are part of ~ natural succession and those species that will impede development of the target vegetation association. This latter group, particularly non-native and aggressive species, can be controlled using manual or chemical methods, bearing in mind that simply removing the weed is no ~ guarantee that another will not replace it. , , ~ 1 ~31~ I~~ The EM must also ensure that the appropriate native species replace the weed species and the ~ conditions which resulted in weed growth will not re-occur. This step is best addressed prior to construction through development of a weed control program that emphasizes prevention followed by containment and elimination/reduction. ~ , ' ~ ~ ' , ~ ' ~ 1 r ' e ;~ ~ ~~ ~ ~ It is necessary to weed plant basins to control invasive non-native species that can reduce water or light availability. During the first one to two years after planting, it will be possible for weedy plants to grow as tall as or taller than the planted shrubs and to compete with the native species for water or nutrients. While some of these weeds will be native plants that might not compete with the planted species (they may simply appear due to the relatively high fertilization rates or presence of disturbed soils), few people aside from experienced horticulturalists or plant ecologists will recognize the difference between native plants which may be relatively benign and those weeds which can harm the restoration success. Consequently, this plan espouses manual and/or chemical removal of all weeds within the planting basins that compete with the planted species. A desirable objective is to remove all non-natives prior to planting. This gives the natives the competitive edge needed to capture the site. Freshly graded soil from site preparation provides a perfect seedbed for windblown seed from invasive non-native species. The success of initial eradication efforts may strongly influence maintenance requirements. Invading non-natives shall be removed before they are allowed to seed or become well- established on the site. Invasion of the restoration area by non-native species and weeds shall be noted in the monitoring reports and prescriptions for removal shall-be provided in the maintenance manual. Post-construction weed control must take into account the following steps: l. Identify and address the conditions which allowed or encouraged the exotic to become established. 2. Remove the exotic. 3. Replace the exotic with the appropriate native plant. 4. Maintain the site such that further opportunities for the exotic to become re- established are limited. Manual controls consist of either hand removal of the entire plant or cutting the plant above- ground. Hand removal of the entire weed is almost always possible but also labor-intensive and is best suited for woody plants. The advantage of hand removal is that the area of impact is usually quite small; less specific weed control activities can create the type of disturbance which results iri more weed growth. It is often much less expensive to cut the weed and then spot-spray the stump with an herbicide (see below for herbicide cautions). For conditions that militate against the use of chemical controls, an array of tools are available from suppliers that can be used to selectively remove even mid-sized trees without disturbing the adjacent land or plants. Cutting can include hand-pruning or chopping, weed "whips" or similar hand-held but gas- powered tools; and tractor-driven or floating mowers. Hand pruning or chopping is labor- 9 ~' ~~1 ~ ~ ~ ~ ~'~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ '13a ~ ~ ~-~ intensive and costly unless the weeders are volunteers. Prior to selecting this method, the ecologist shall personally weed a specific area for at least two hours and develop an estimate of the amount of person-hours then required, multiplying this by the cost of the labor. Where weeding will occur in dense growth or where only a few plants among many are to be eliminated, this method is the most productive. Weed whips and similar tools are very useful for clearing annual or soft perennial growth over large or small areas where tractors cannot be driven (slopes, marshes, etc.). These shall not be used near planted trees and shrubs or above-ground irrigation lines as even an experienced practitioner can inadvertently girdle a plant or chop up a poly line. Mechanical mowers are the most efficient means of cutting large areas of vegetation. They cannot run on steep slopes (although some have mowing "booms" which can reach out and cut limited areas) and to operate need a certain distance between trees and shrubs which are to remain uncut. It also is important to consider these issues during the design phase. An easily maintained project is generally subject to fewer disturbances and may prove to be more successful. Surveys for weed control needs shall start as soon after the construction as the growing season begins. Timing is often crucial in manually controlling weeds, especially annuals. Because cutting does not remove the root systems, it is generally important to cut the plant just prior to seed set to maximize the likelihood of complete control. Even this technique may not always work. Chemical controls are often the least expensive means of eradicating or reducing weed growth. Application of a herbicide to the lowest portion of the tree provided good control for trees under 18 inches in diameter at the base while cutting and application to the stump was required for larger trees. Few chemicals are licensed for use in wetlands and a licensed technician is often required by local regulations. Further, environmental conditions, e.g., wind speeds, must be carefully monitored to avoid damage outside the target area. Chemical controls include "pre-emergents" that are applied to the ground prior to the emergence of the weeds in the spring or "post- emergents" that kill or stunt plants during their active growth stages. Pre-emergent are most useful when applied adjacent to newly planted propagules as they limit the growth of competing weeds adjacent to the propagule. Post-emergent controls are most useful for broad areas completely dominated by weeds; areas where no plants are proposed (firebreaks, for example); or spot-spraying of individual weeds. On this site, spot spraying of a post -emergent broadleaf may be needed once to twice per year during the spring growing season with two additional applications latter in the summer. Tree and shrub basins should be maintained quarterly during the first five years and fhen annually in Years 6-10, removing weeds by hand pulling if possible to prevent overspray on the installed plants. The placement of mulch or wood chips within the planting basins will also reduce weed growth. Mulch should be checked on a quarterly basis during Years 1-5 and annually in Years 6-10. 10 ~ ~~ i 4.1.3 Plant Maintenance I 33 I~ ' All new tree and shrub plantings will be checked by the EM on a quarterly basis for deer browsing, proper functioning of irrigation, healthy rootball, application of fertilizer, repair of ~ water basins, and other pest damage during the first five years and annually thereafter up to Year 10. Irrigation shall be checked only for the first three years, after which plantings will no longer be irrigated. Hand clearing of weeds around the base of the installed plants will also be ~ conducted on a quarterly basis. Once trees have become well-established, and if deemed necessary, some pruning of trees may be conducted to compensate for irregular growth due to ~ excessive browsing or broken branches. Dead plants will be replaced annually in the late fall. , 4.1.4 Irrigation Maintenance and Monitoring ~ Irrigation will be used during the first three years to assist in plant establishment. The irrigation system shall be checked quarterly during the three year irrigation period and as much as weekly immediately following plant mstallation, for malfunction and vandalism. All drip lines and ~ filters shall be flushed as needed. Emitters must be checked regularly for malfunctions, position of emitter over root ball, and vandalism. Flushing end caps must also be checked regularly. , Irrigation for plantings is a temporary tool to help establish the constructed vegetation association. Water shall be decreased every year, and ideally shall not be needed after the third ~ year. Caution shall be exercised not to create lush plants, which would become dependent on ' regular watering. Deep watering, spaced at the longest time possible before plants show signs of stress, shall be used. This type of watering will encourage plant roots to travel downward into ~ the appropriate water zones m the soil. ~ 4.I.5 Litter Removal Litter can impede the growth of propagules or seedlings, and increase the cost of plant care ~ maintenance efforts. Therefore, it is recommended that each site be thoroughly policed, and all ~ litter and debris removed from the site at least quarterly during the first five years and annually in Years 6-10. Adjacent construction especially generates large numbers of small snack bags ~ which lodge among plants. Construction projects which are near or within residential areas generally collect the most trash. , 4.1.6 Erosion Control The site will be inspected for signs of erosion quarterly during the first five years and annually in ~ Years 6-10. Visual inspections of the restoration site will be conducted to ensure that there is not . erosion or downcutting from broken irrigation lines or surface hydrology. The EM will determine if woody. vegetation has become established. If it is determined that erosion is ' occurring, measures will be taken to divert or slow runoff prior to remedial actions. ~ t ~~ I ~ ~ ~ , ~' ~ ~ ' ~ ~ ~ , ~ ~ ' ~ ~ , ~3 ; ~(~~ 4.1.7 Mainte~:ance Records Documentation of all maintenance activities will be prepared by the applicant during the five- year monitoring period, then annually in Years 6-10. Photographs documenting the progress of the plantings will be taken at each visit. Photographic reference points will be pre-determined during the as-built survey. These points will include the outfall, riparian plantings, and the new swale feature. A record of maintenance activities by date will be submitted in a monitoring report. All monitoring reports will include information on type of activity, frequency and dates of maintenance activities and a summary of repairs and remedial actions and any other maintenance activities. 4.2 Responsible Parties Maintenance of the restoration area during the 10 year maintenance period will be the responsibility of the applicant with coordination from the EM. Maintenance, monitoring, and compliance reporting activities will be financed and carried out by the applicant through a contracted landscape maintenance company until mitigation has been determined to be successful by the EM and verified by the regulatory agencies. This mitigation plan is being designed so that restored riparian habitats are self-sustaining and will not require maintenance to assure continued viability. Maintenance may be required, however, to respond to disturbance by humans. For example, if unauthorized dumping were to occur within the restored area, maintenance would be required in order to properly dispose of the garbage or debris and clean up the site. 4.3 Schedule For the first one to two years, most projects will require a walk-through by an ecologist or maintenance technician every month. The variation in the number of visits depends on the size of the site, its proximity to disturbance and the time of year. Visits may reasonably be required every week for the first year and twice monthly for the next two years. Smaller sites, for example those less than ten acres, can reasonably be visited once every two weeks during the first year, and monthly in subsequent years. The maintenance schedule determined for the site is listed in table 3 below. 12 (I ~ ' ~ ' ' , ~ ~ ~ , , ' ~ ~ ~ ~ ar ~i e .;~ f' e I ` I~ ~ 4.4 Long-term Maintenance The EM would be responsible for the coordination of site maintenance with the applicant and monitoring of the restoration site for ten years or until success criteria have been met and the regulatory agencies have provided a letter of release. Following the ten years of monitoring and maintenance the property own will incorporate passive long-term maintenance to ensure that the restoration site is functioning according to design and that vegetation is maintaining with minimum competition from invasive exotic plants or disturbance from public access or trash build-up. Long-term maintenance will include regular inspections for exotic plant species, to be periodically eradicated, and removal of trash. 13 ' ~ ' , , ' ~ , ~ ' ' ~ , ' ' ' ~~ ~ ~`~ ~ 5.0 FINAL SUCCESS CRITERIA The final success criteria will be used to determine if the applicant has met the obligations outlined in this plan. Attainment of the final success criteria will indicate that the restoration site is well on its way toward meeting the long-term habitat goals of the site with. little chance of failure. Success criteria will be evaluated each year that monitoring is conducted with a final assessment performed the last -year for which monitoring is required. Results of the final evaluation will be compared to the established success criteria and described in table format in the final report. Restoration of the functions lost as a result of the impacts to riparian habitat is a primary goal of this plan. This will be measured through the successful establishment of riparian habitat on the restoration site. Attainment of final success will be determined by the regulatory agencies, which will verify success of the restoration site after being notified of attainment of the established criteria in the final report. Success criteria will be quantitatively evaluated by monitoring the restoration site annually during the 5-year monitoring period, then every other year until Year 10. 5.1 Overall Mitigation Objectives Proposed mitigation will have the following overall objectives for mitigation of permanent impacts: ^ To create 0.17 acres of self-sustaining riparian habitat; ^ To attain 70 percent survival of planted trees and 80 percent survival of planted shrubs, evaluated individually for each planted species. ; ^ Should the survival rate fall below 70 percent for tree species and 80 percent for shrub species at any point during the monitoring period (5 years for shrubs, and ten years for trees) until the success criteria in this plan are achieved, remedial planting shall be conducted and the monitoring period shall start anew. 5.2 Conditions Proposed for the Site that Will Insure Success ^ The restoration area will be maintained in as natural a state as possible. The riparian habitat will not be mowed, burned, grazed or otherwise maintained, except as part of a regulatory agency approved long-term plan should such a plan be prepared, to maintain or enhance the natural values of the established habitats. ^ No construction will occur in areas under regulatory agency jurisdiction outside the permitted mitigation project footprint; ~ Unless authorized by the regulatory agencies, no work will be conducted within the ;' restoration area that may modify the hydrologic regime of the riparian habitat once established; '~ 14 ;' ~~ ~1 137 ~~a ~ ^ No farming or farming activity will be allowed within the restoration area; ^ No grazing will be allowed within the restoration area; ^ No off-road vehicle use will be allowed within the restoration area. 5.3 Quantitative Mitigation Success Criteria The 0.17 acre mitigation area will be evaluated based on the following quantitative success criteria. Once the site has met these criteria and the circumstances on site have been confirmed by the regulatory agencies, the monitoring requirements will be considered satisfied and there will be no further obligation for this site. It is anticipated by the applicant's biological consultant that these criteria will likely be met within ten years. If the site has not rnet these criteria and ten years have past, monitoring and maintenance shall continue until the conditions a.re met or an alternate mitigation plan is approved by the regulatory agencies. Non-native plant species identified by the EM as "nuisance species" shall not be greater than 10% of the total vegetation cover (cumulative for all species of nuisance plants) within the riparian mitigation area; 2. The restoration area shall demonstrate natural hydrology. This shall be indicated by the lack of artificial irrigation for at least two years (with no loss of vegetation); and 3. Restoration tree stock will remain alive at the end of the annual five year growing season (and every other year until year 10) with 70 percent survival of all planted trees. Restoration shrub stock will remain alive at the end of the annual five year growing season with 80 percent survival of all planted shrubs. All trees and shrubs planted in the restoration areas shall exhibit medium to high health and vigor and demonstrate new vegetative growth on an annual basis. 6.0 MONITORING PLAN The restoration site will be monitored over a five-year (and ultimately ten-year) period to ~ ascertain whether the performance and success criteria are met. Vegetation monitoring will be a conducted annually for the first five years, then every other year until Year 10. By Year 5, the restoration site should be sufficiently well established to determine if it will reach the long-term '' goals, summarized below, with little chance of failure. The results of vegetative monitoring in ~~ Year 5 will be compared to the final success criteria to determine if these criteria have been met. If the final success criteria have not been met at the end of the monitoring period, monitoring will continue until they have been met. Additionally, creek monitoring will take place at the ; outfall location in order to evaluate any hydrogeomorphological changes associated with outfall construction. Three repeatable transect lines will be established across Moller Creek. One each i, up and downstream (50 feet) and the third at the outfall location. Measurements will be taken to ; demonstrate the location of top-of-bank, midpoint on the embankment, ordinary high water mark i~ ` 15 ~Lr' /~ ~(p b ~ ' ' ~ , , ' and thalweg or bottom of the channel. Data collection will follow the vegetative monitoring schedule. Photo points will also be established at each transect line location. 6.1 Performance Criteria This section contains the performance criteria for the restoration site. Monitoring of performance criteria will evaluate the extent to which original plantings remain so that the restoration site continues to meet the established final success criteria. The performance criteria are quantitative benchmarks against which the success of restoration will be tracked. 6.1.1 Number Remaining from Original Planting At no time during the monitoring period, should the number of riparian plant species remaining from the original planting be lower than 70 percent survival for trees during the ten year monitoring period and 80 percent survival for shrubs during the five year monitoring period. If fewer than 70 percent of the original tree plantings and 80 percent of the original shrub plantings remain, replanting shall be conducted so that the original plantings are replaced. Percent survival must be evaluated individually for each planted species. If these success criteria are not achieved, dead plants must be replaced in kind, unless the Applicant demonstrates that the site is not conducive to the survival of a specific plant species, in which case alternate native riparian plant species may be used. Replacement plantings must be made within one year of survival rates failing to meet the specified success criteria. Replacement shrubs shall be monitored for five years from the date of replanting. Replacement tress shall be monitored for ten years from the date of replanting. Replacement plants are subject to the same performance criteria as the initial plantings ~ Irrigation should only be conducted during the first three years unless replanting occurs. If replanting is needed irrigation shall be utilized for an additional3 years to allow establishment of the newly planted stock. 1 6.1.2 Site Maintenance i ~ ~ ~ ' ~ Site maintenance is included in the performance criteria because of the critical importance of proper maintenance during the plant establishment period. Site maintenance will be monitored to assess weed control, irrigation adequacy, trash removal, and vandalism. Site maintenance will be monitored during the ten-year monitoring period. 6.1.3 Plant Yigor and Health/Abundance and Diversity The health and vigor of each dominant native riparian species occurring in the restoration area will be qualitatively assessed. The following factors will be taken into consideration in this deternunation: plant color, seed development, new growth, herbivory, drought stress, fungal/insect infestation, and physical damage. Overall health and vigor of each dominant riparian species will be rated as high, medium, or low (Table 5). 16 ' r ~M 1 ~~~ C(~ ' 6.2 Monitoring Methods and Schedule ' The restoration area will be monitored using the sampling techniques described below until the . performance criteria described above have been met or exceeded, and it is demonstrated that the restored habitats have become self-maintaining. Permanent photo points that provide views of , the restoration area would be established during the construction of the riparian habitats. Monitoring will be conducted between February and June of each monitoring year. Monitoring ' reports will be prepared by the EM following data collection and will be submitted to the permitting agencies by December 31 of each monitoring year. , 6.2.1 Number Remaining from Original Planting The percentage of remaining plant species from the original planting at the restoration area will 1 be measured by counting the number of individuals of each species of tree and shrub remaining. , Sampling will be conducted at random locations throughout the restoration area site. I 6.2.2 Site Maintenance Site maintenance will be assessed during percent cover estimates and during general site ' monitoring as specified in the maintenance schedule. Pertinent information derived from visual observations, reports from site maintenance crews, or from other sources will be included in the . summary for site maintenance. , 6.2.3 Plant Vigor and HealthlAbundance and Diversity 4 1 A rating of plant vigor and health will be assigned to all dominant plant species observed in the restoration area. An explanation of each rating will be provided in the text giving details of the rational for each rating. The qualitative assessment will be conducted at each data point; then an ' assessment that characterizes the entire site will be determined based on the average rating of the species. , Abundance and diversity will be assessed by qualitatively analyzing the total number of plant species observed at the mitigation site. This information will be recorded on the data sheets by ` documenting each species encountered. ~ ~ 17 ' r ' , ~ , , ~ ~ , ~ ~ , ~ ' ~ ~ ' ' , I~O ~ ~~ ~ 6.2.4. Photo-Documentation Photo-documentation of the site will be conducted from fixed permanent locations along the creek channel. Photographs will also be taken to record any events that rnay have a significant effect on the success of restoration, such as flood, fire, or vandalism. Photos will be taken to document the success of plantings and erosion control measures. These locations will be predetermined during the as-built survey. Additional photos will be taken if it is determined that the initial photo points are not sufficient to track riparian plantings along Moller Creek. A minimum of four photo points would be established along the restoration area. 6.3 Data Anatysis The yearly monitoring results will be compared with results from previous years to evaluate site progress. 6.3.1 Number Remaining from Original Planting The number of remaining individuals of each species will be tabulated each year. Number of remaining species will be compared to the number at the time of the original planting. 6.3.2 Site Maintenance Success or failure of site maintenance will be analyzed and 'vncluded in the monitoring report. Any recommendations will be provided based on yearly findings. 6.3.3 Plant Vigor and Health/Abundance and Diversity Plant vigor and health will be reported as high, medium, or low for each dominant species. Health and vigor ratings will be compared between years. The vigor and health rating for each dominant species will be included for discussion in the report. The abundance and diversity of the site will be qualitatively discussed in reference to the dominant species. 6.4 Chanel Stability Monitoring Creek monitoring will be performed along three repeatable transect lines established across ~' stationary points on Moller Creek. Measurements will be taken to demonstrate the location of top-of-bank, midpoint on the embankment, ordinary high water mark and thalweg or bottom of the channel on each transect line. Information would be collected to assess the stability of the ~' channel and determine if the outfall has had an impact on the channel feature. Observation and ~ data comparisons will be used to document channel slumping, bank erosion, channel incision, undercutting of the banks and loss of vegetation due to increased scour or erosion. Data collection will follow the-vegetative monitoring schedule. Photo points will also be established at ~' each transect line location. ~' ~~ 18 ~ ' ~ ~~ I~ ~ ' 6.5 Annual Reports ' Annual reports will be completed and submitted by the EM that present vegetation and channel stability monitoring results for the year monitored. These reports will assess both attain.ment of ~ yeazly vegetation performance criteria and trend chazacteristics that demonstrate progress toward final success criteria. The reports will also include specific information collected from stationary/repeatable transect lines at the three locations across the channel to document channel ' stability characteristics. The report will include documentation of observed conditions, attainment of success criteria and an assessment of any identified changes. Data sheets and photo ' documentation developed from the monitoring effort would be combined with a compliance ~ report summarizing monitoring results. This information will be submitted on an annual basis in the form of a mitigation monitoring report during the month of December or until success is ' achieved by meeting the final success criteria listed above. ,~ As required, these reports will include a list of names, titles, and companies of persons preparing ' the report, as well as all participants in the monitoring activities; a copy of the Corps permit, ' Special Conditions, and subsequent Letters of Modification; analysis of quantitative monitoring data; prints of all included monitoring photographs; and maps identifying monitoring areas, ' transects, planting zones, etc. ~ Annual monitoring reports will be sent by December 31 of each monitoring year. Annual ' monitoring reports will include a brief description of the project, the methods used to collect and , analyze the data, the results of the data analysis, a discussion of the results, and conclusions regarding the present condition of the site. The report will also include a remedial action section ~ that will discuss any additional actions required to ensure that the site meets the success criteria. ' 6.6 Schedule t ~ Monitoring to determine the successful attairunent of the performance criteria shall be tied to the actual implementation date of the restoration effort rather than to predetermined years. It is a anticipated that mitigation will be completed m 2011. The proposed monitoring schedule is outlined below: ' 1. Conduct baseline ve etation and channel stabili monitorin in th f 8 ty g e all of 2011. ' 2. Conduct annual site vegetation and channel monitoring to determine restoration success and channel stability between February and June 2012-2016, then every other year until 2021. The ~ monitoring period will restart for any new plantings mstalled, should the survival rate fall below 70 percent for trees during the ten year monitoring period or 80 percent for shrubs during the ' initial five years of monitoring. ~ 3. Submit an annual compliance monitoring report which includes data sheets, photo ' documentation and a report summarizing monitoring results in 2012-2016, 2018, 2020, and 0 2021. ~ , ~ 19 ~ , ' ~ 7.0 COMPLETION OF RESTORA'TION , 7.1 Notification of Completion ~'~~ ~~b ' When the initial monitoring period is complete, and/or the applicant believes that the final success criteria have been met the applicant will notify the regulatory agencies when submitting the final annual report that documents this completion. ~ 7.2 Confirmation , Upon submission of the above-mentioned final report, the regulatory agencies will conduct a site inspection (if needed), and upon determining that mitigation success has been achieved will provide a letter of release from further mitigation momtonng requirements. ~ 8.0 CONTINGEN CY MEASURES ~ ~ ' ' ~ ~ ' , , ~ ' If the number of restoration plants fails to met the identified success criteria in a given year, additional planting will be require to bring the total number back to the original number planted with site monitoring starting over. If the identified success criteria are not achieved, dead plants must be replaced in kind, unless the Applicant demonstrates that the site is not conducive to the survival of a specific plant species, in which case alternate native riparian plant species may be used. These actions would be coordinated with the regulatory agencies. Channel stability characteristics will also be evaluated each year reporting is required. In the event that instability problems are observed within the channel during monitoring events, an assessment will be made as to the appropriate action to be taken. This will include consultation with a hydrologist experienced in geomorphology. Recommendations will be assessed and evaluated and the problem corrected. Corrective actions may require permitting and oversight from resource agencies in order to conducted work in the creek channel. 8.1 Initiating Procedures Subsequent to the first year's monitoring result of any subsequent years of the required ten-year monitoring period, corrective actions will be taken to correct unforeseen deficiencies in the establishment of riparian vegetative conditions. Analysis of the cause of site failures will be made and remedial actions will be recommended to correct the problem if a performance criterion or a final success criterion is not met. 20 ~i~ ~ ' ~ ~ ' ~ ~ ~ ~ ~ ~ ! ~ ~ ~ ~ ~ ~ ~ ~ /~ ~~ ~~ ATTACHMENTS ~ r ~ ~ ~ ~ ~ ~ ~ , ' ' ~ ' ' ' , ' , ' ' ~ ~ i c~~ ~ ~ ATTACHMENT 1 FIGURES Figure 1 Regional Map Figure 2 Vicinity Map Figure 3 USGS Quadrangle Map Figure 4 Aerial Photograph Figure 5 Fallon Crossing Development Site Plan Figure 6 Mitigation Area Map Figure 7 Riparian Planting Plan Figure 8 Deed Restriction Area Map , ~ ~ ~ , ~ ~ ~ ~ ~ i 1 1 1 1 1 ~ 1 V 1 I ~f(v ~ ~l~a sc...~ ana: usn~~ zoos . ~ . . Viqq-"yfslNOn - / •'. ~Blydc Landing f ~ ( `~ • , - ~ _ +~ t ~4ecmlr~o '. i~rf; . ~ ,~r '~ arN auna . ~'j I ~ 4,~r~. iwAa i ~~ ~ ~ ")a - ~ ~••:~oL.:w.. ~ . ~ '~ . 4sr6evJeJand •w ' i ~. . .. - ~ - -- - ---`-~.,~ ---:7_~ ~w.~aklMy f~,, - ~ ' '~_~ ` '~r(~ e • ~ S,/ Gncoid ~ r ~ ~ \ ~ ~wKnlgh~een ~ '~ PI•asont H~II "t ~ , . . _ ~ ~ : ow~H ~ ~ ~ ~ ~ ' ~ Claylon . ~ `•~ ; `. ~" '-^--' - ~ ~ .~ ~ Brsntwo~d --2•--- ,__ ; - y~ i - ' > MMa1nn1 2~ . ~ ~ . .__~ - ~ Ln}k - ~. ~ ~ ' ~ . • . P ~c . ~va aln ut HNphts . , * !- --- ---~r _ ~'iByron ~ ~ l amo ~ ~ "v ~ ~Mo~a a H Al~no • D f ~ ~ r.w L` ~a•' ' ~ ~ . p~~ ~ amdlla ~ ,~~~ ~ ~ d ~C" _ , _ \ ~, ~. + i~r '•il a ~ San Rsmon ~ 'ti ~-~' ;~ ~, _. - , ~ ~~.9ert ~:.. ~ f ` ~~, ' i ', ~ ~ , ~ fdasrrroif ~. • ~. Fallon'!~rossing Propert.~r ,~~ 1 '~pdf0 ~' ^~ . ~ ~? ~ ti , ~ ~ . ~Komandorsk~ VNlap~ ~ ~; ...-l ` > ~ Capi~ r « ~•'~•_,r..,._.~ ._:_ x ~ ~ 1a(~" ~ , . ~,.__ ,,,*~mon I , ,,~Hayward ,~s , .~ ~ . ~WK ton ~ ~ ~@ ~ uhREd~n I ~ 11 r~ Woodz I '~~• -.~7~~,~ ~ ~y~ ~ y~" ~ Unlon CMy r~ ol ~ ? \ Z ~" iG . ' Yo y , ~ ~ ° ~ '1<:- Fn~oat . _ I ~ ~ ~ ~•` ~ 2.~-U k \ `._ C ~~.• ~ ,` ~ / • st~aldAKo ~ , --•"-- -•-•-•-•-----•------- i -~ ~ Q 5 ~ ~ ~~N~. Of ' ~'ii'~ ,J~, i ~ 1 r oi 1 ~ vrk ; lo Arco sb d', ~ ~ ve-. `l-~1co : ~ ~ . +~.. . ~ 7 _ ~ ~ ... ~ w ~ii,,, J s ~L~ ~ s Atte s ~ ~f~lum Rook Yaneos w1s Y6 r . coperr.c~s Peeh fe,, RNd- ~kw of - • Monta ~ y Ino ~M~ dl ~ an o ~ Shrntl~ ~ Data use subject to license. ~ 2005 DeLorme. Street Atias USA~+12006. ' wwrr.delorme.com Olberding Environmental, Inc. ' 3170 Crow Canyon Place, Suite 260 San Ramon, California 94583 Phone:(925)866-2111 , This document is not intended for detail design work. 1 'I~,~ , ml ~ 0 2 4 6 8 10 MN (14.4• E) Data Zoom B-0 Figure 1 Regional Map of the Fallon Crossing Development Project Alameda Counry, Califomia i' I i ' ' ' , ~ ' E ' 4 ' a ~ ~ ' ~ , ~ ~ ~ i ~ 1 r 1 ~ 1 ~ 1 , 1 t ~ i~~~ -~~ sa..c~n~: usn~c~soa ~ __.- ~ ' . _ ' , _ , ,~ ,y~ ~ ' ~ Tas a~a Creek ~ . . . ~ ~ Fallon Crossing Property ~ ~ b vk 0 R~ ~ ~ N T ~ ~ a ~ ~~ I ~ ~_-~ ;I= _ -+~~5 ~ !,; ~ ~ I r- I ~?~R ~/; .~~~ {'~j~ ~ ~r~~ 1~__ ~ %"` ~~ ~, ~ ' MI C7 ~. ~N~ I ~~ ~ STILL~ CT T~~ ` ~ cP1do •r~ I ~~/ ~~~ •N I ~ tp1 I I ~ /i ~. - CN( 4l~~LN ~ U2L2 USB SUDJBC[ [O IICCIISG. ~ R ~ 2005 DeLorme. Street Atlas USN~1 2006. 0 400 B00 1200 1600 2000 www.delorme.com MN (14.4• E) Data Zoom 14-0 Olberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 San Ramon, California 94583 Figure 2 Phone: (925) 866-2111 Vicinity Map of the Fallon Crossing Development Project This document is not intended for detail design work. _ Alameda County, California , ~ ' ' ~ ' ' ~ , ~ ~ ~ , , ~ ' ~ ' ' ~ I , ~ , ~ 1 1 , , ~ 1 , , ~ ~ , C~ I~o ~~ 1~r~ , s?o : ,_ ~-~.-~. ~ ~ ~ ~ -.. o & , ~ ~' ~ N , ^ • ' 1 - ~.~ •~~ ~~ ~{ rr ~c• • ' f ~ ~ ` ~~~ ~(~r "`+ '~ ~ ~ ~~.~ ~" - 't. l~ `+ {f t '__ ~ ^~ ' , r, ' ~ ' i ~ ;~~ ~`. ;.""~ ~\ + / t r \O , ~ ~ >':~ 1 ~ \ ~~~ ;~ • '~ . t ~ .;__.~ , ~ ,~ (~---•-~ - r ~ f-.,~ ~. ~ , .- ~ . 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F ,=,;, , ; .F ' , ~. l .~ ~ ~ ~ , ~ ` ,_; y_ ~~ ~ ~ ~\ ~ ~t .` ! i • ~' ~-~' ' i , ~ ~ i~ '",, ~ t 6 .9 ~ , { i ` ~ ' `f1 P` h `, ~ .. u / \ ~~~ ~y i~ ~ ' (+ /Y ~±!j,~ / $' ', ~ ~ ~ ' ~ . t ~~ ~. ~ - / ! ~O ~.- ~`., ~~ "i- p ~ I~i j ~~1 ~~, ~, ~ ,,~ ,:~, ,, ~ ' ` ) 1'• • ~ ;' ~1 ~ ;~ ~ ~~ ~--._ << ~ ;~ . ~ ~ , ~ , . . .-- ` O ' - ~ ~ ' ~ '~ ~ ' ~ t , , i .,~ , ~ ~ _ . : ~ e wea w~.nw~. s~o r+-~w• a. a.~• ~.%..~am er s•n~.w~ .w..~.. ~ -- s -~ n1 r www.~Nl~nw~.~.w~ I/ ( wr~ Olberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 Figure 3 San Ramon, Califomia 94583 USGS Quadrangle M$p of the Fallon Crossing Phone: (925) 866-2111 Development Project Livermore Quadrangle This document is not intended for detail design work. Alameda Count , Califomia , ' ' ~ ~ ~ ~ 1 ~ 1 1 1 1 t 1 i~ 1 r ~ t ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ ~ ~ ~r ~ ~ Olberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 San Ramon, Califomia 94583 Phone:(925)866-2111 This document is not intended for detail desiQn work. ~ Figure 4 ~ Aerial Photo of the Fallon Crossing Development Project ~ Alameda County, California , ~ ~ ~ S ~ ~ ~ ~ ~ ' ' ~ r . ~ ~ ~ ~ ~ t ~ ~ ~ m~ °~ -~ -~ p~ -~r -~ -~ -r -~ -~ -r -~ -~ -+~^~ -r -~ -~ -~ .-..._. -. . _.. _ - ~~' .. .;`=- _ - = _ - ~ _ -- ~ --.:;. --.--~_.~ -- _ -._ = _ . , ~ l `'" ' ; , ' ~ .'~ . . WWRRA YIlYCY~ ~ r^ ~L r~CJr~~r .,~e I ( . , (; -„ti~su..__,~.~"y-~_ . ~ -- ~ ~!r1~ . ~' 'tL~_ ~`~ _ '. _ . . l~ ' 1 ~;;'~., .:.m.'~''~ • _"~. ~~~. / ~ ~'~? :J s= _ ;~; , :r . ~•. ~ ~.r ~ f ' ~~~.~ ~ ~}IOII.Ml1 ~~ Olberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 San Ramon, California 94583 Phone:(925)866-2111 This document is not intended for detail \ \~ r! ~~. ~• f ~/ Y f ~ . ~~ \r 1 •.r ~ ,, ~.~u. _ . ~`, ~ y r - . ~, ~^at~ ~ e ~.L ~.. - l ,, ti ~ • ~ I' y . ,'~ / ~ ~ 7 :~.ii ~~ r~mata3•/ 't~ ti ~~ . . I'ff illu~~ ~ • • . -~'~~ 'I~ ~~' • i r. ~~, rrr~~ . l ~~ :~ ' f~ ~'~ /,/ f : 1 •G~ ~ ~ : ~ i: f !~ r ~ ~ •~ ~ =_ +,.: . , • w_. :;~- ~~:K., .. ~~_i : . ,~. . , work. .y p . t . .,~ f j % ''~ j/ l ~ . 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I .~d, •+ ..i ~ ,ti1\~ . ~ ~ . ~ « ' ~~~~.r ~~ ' _ - . ~ / I " ~ ~ . . - -' . l '. ~ ~. -• ~ ~ ~r ~ - • ~ ,, - ~~ \'`'`~`~)'~. i ~°° ` `~I - ,~ ~ ~ ' ,~ ~ _ ~~` . . ~ =r . • ~ ' ~ ! : _ -a..,,.... a d ~ „ . -- - - S t' '. . - ' " 6 . ~ ' J ~ ,~1 ~ ti~ ! ~ ~ ~ ' .` ,~ ~ ~' r ~--' - ~ ~ ~ ~ . ; ~ ` _ vr ~~. ~. ~ ~,... ~ , ~ J~ t. ~ ~ , ~a : I 3 Y ~ ~ " { J I ~ . ~ ~ ..:~. ~; > ?~ i ~ ' r i ~ ~ ' .,:1 ----j ; ; . ~ ,~.; ~ ; , _ ~ ' _ , . .. -_ ,. . ~. - :.. ~ - . -~ ~ ,,,,~ ~ T o~ ~,~ - - --,...~...,lr1 _._.. ~,.~ _. __ i~ ,I nwa~f ~ N~~ G4~1~1 1 _~-4~~~~`~~ ` c t T 1j ..~_~.. ,y.~ .~ I L ..1~-~`'J- .:~~,~i ~ ~ ~~.7~9S~ALRY ~01f~_~ILA1 M~p-Nii/llt 0~-1~~11W M:e ~•.w 40t 171~7MI1- CATVO~ Oe r n~ r~~ ulww dT ~w FAL~ON CR09SINq - SITE PLAN EXHIBIT ~R ,~~e~„"_ r~re~'awrv. u~sew~~ rw~ w~uarn ~ioia wer~ ~ lAura Asaeel~le~ 1.1 ~~... .. ... _ _ e,d a~ ..~ , _ _. Figure 5 Site Plan of the Fallon Crossing Development Project Alameda Countv, California ~ ~ 1 ~ ~ ' r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~r ~r ~ ~ ~ ~ ~ ~ ~~^r ~ ~r ~ ~ ~^r ~ ~^~r Olberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 San Ramon, California 94583 Phone: (925) 866-2111 This document is not intended for detail desien work. Figure 6 v o~ Mitigation Area Map at the Fallon Crossing Development Project ~ Alameda Count , California ~ ~ ~ 1 ' , ~ ~ ~ 1 r ' ' e ' ~ 1 ' ' ~ ' a ~ s ~ ~ i r ~ ~ ~ ~ ~ ~ ~ ~ ar ~ ~ ~ ~ ~ ~ Glberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 San Ramon, California 94583 Figure 7 Phone: (925) 866-2111 Riparian PlanNng Plan at the Fallon Crossing Development Project This document is not intended for detail design work. Alameda County, California ' ~ ~ ' i ~ ! 1 1 1 1 i 1 ;1 1 1 1 ! w~ ~ ~ r ~ ~ ~r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Olberding Environmental, Inc. 3170 Crow Canyon Place, Suite 260 San Ramon, California 94583 Phone:(925)866-2111 This document is not intended for de '=-~~// ~'~~. ,-ZT/.~ ~~ ~ GRAPHIC 3CAT,.E ~ ~ 400 ( ~r ras+ ) i dn - soo R DEVELOPMENT AREA EXHIBIT FALLON CROS91N0 wnn oasew~~ Mo. Figure 8 Deed Restriction Area Map at the Fallon Crossing Development Project Alameda County, California ~