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PLANNING COMMISSION STAFF REPORT 5*1 TO: Chair and Planning Commission March 12, 2024 SUBJECT: Resolution No. 2024-04, adopting a Mitigated Negative Declaration of Environmental Significance and approving Major Subdivision SD 9264 and Tree Removal request TR24-0007 allowing for the subdivision of a combined 8.49-acre site into seven single-family lots and the removal of one Town -protected tree. The sites are located at 2449 & 2451 Tassajara Lane. (APN: 207-061-008 & 207-061-009) DESCRIPTION This application is a request to subdivide an 8.49-acre site, including two existing parcels, into seven single-family residential lots. The application includes a request to remove one 60-inch Town -protected Oak tree. Specific architecture is not proposed at this time, however, design guidelines to guide the future design of the residences were submitted and were reviewed and approved by the Design Review Board. The proposed project is located on a hillside on the south side of Tassajara Lane, a private street. Land uses to the west and north of the subject site include Braddock and Logari s Tassajara Lane and Rockhaven residential projects and one vacant parcel of land adjacent to the west. BACKGROUND The Towri s General Plan designates the Tassajara Lane/Sherburne Hills area as a Special Concern Area, which recognizes the need to coordinate remaining development to ensure full provision of services to this area. In addition, there are several General Plan policies that apply to this area. In summary, they state that the remaining vacant land should be developed to maintain the character of the area, conserve steeper slopes as open space, and minimize grading and vegetation removal. The General Plan also seeks to coordinate the development in the area to ensure the provision of necessary shared public and private improvements in the area. EVALUATION/ DISCUSSION Conformance with General Plan and Zoning District The site has a General Plan Land Use Designation of Residential - Country Estates, Minimum One acre Lot Size. The parcel is zoned P-1; Planned Unit Development District. The subject P-1; Planned Unit Development zoning district applies the Towri s R-40; Single Family Residential District standards. The proposed lots comply with all the minimum requirements of the zoning district, including net lot sizes, dimensions, and structural setbacks. Tree Removal One existing 60" Oak tree located on proposed Lot #2 would be removed to allow for the development. Required mitigation would require the planting of 30 - 15 gallon trees, or the planting of 15 - 24 gallon trees, or payment of an off -site planting mitigation fee of $7,500. C.3. Stormwater Pollution Control In compliance with the Towri s Stormwater Management and Discharge Control Ordinance, the development would be subject to compliance with the Towri s C.3 stormwater pollution control requirements as found in the Stormwater Control Plan. One dual -staged stormwater treatment facility is proposed for all nine lots. The stormwater treatment facility would then drain into a public storm system. The treatment facility would be maintained by the homeowners through a maintenance agreement. Parcel Development There is no architecture proposed for this development at this time. Future architecture for this development will require a separate Development Plan application and would be subject to review and approval by the Design Review Board. Future architecture would be required to be consistent with the Design Standards and Guidelines prepared by Francis Garcia Architect (see Attachment D). Access and Circulation Access to the site is Tassajara Lane, a private street south of the Tassajara Lane Bridge. Conditions of approval require that the seven new lots be included in the shared maintenance of the private street and bridge. GEOTECHNICAL REVIEW The applicant submitted a Geotechnical Report, prepared by ENGEO Geotechnical (see Attachment E). Based on off -site explorations and analysis as well as a review of available published maps and reports for the site, the main geotechnical concerns for the proposed development are critically expansive site soil and bedrock, extensive existing landslide deposits, existing undocumented fill, and the fact that landslide deposits identified on 2449 & 2451 Tassajara Lane 2 March 12, 2024 the site cross property boundaries where corrective grading excavations will be required include off -site areas which will require cooperation from the adjoining property owner to correct. Landslides can be effectively mitigated during site grading by removing the landslides and replacing the slide debris with engineered fill or buttressing the landslides and providing debris catchment areas. ENVIRONMENTAL REVIEW The project has been found to have less than significant environmental impacts by incorporating mitigation measures consistent with the requirements of the California Environmental Quality Act (CEQA). As a result, a Draft Mitigated Negative Declaration of Environmental Significance has been prepared for this project (Attachment C). PUBLIC CONTACT Public notice of the March 12, 2024, hearing was mailed to property owners within 750 feet and posted online. A total of 80 notices were mailed to surrounding property owners. RECOMMENDATION Adopt the Mitigated Negative Declaration of Environmental Significance and approve Major Subdivision SD 9264 and Tree Removal Permit TR24-0007 allowing the subdivision of a combined 8.49-acre site into seven single family lots and the removal of one Town - protected tree. The sites are located at 2449 & 2451 Tassajara Lane. (APN: 207-061-008 & 207-061-009) Prepared by: Fred Korbmacher Project Planner Attachments: A - Resolution No. 2024-04 B - Public Notification & Notification List C - Draft Mitigated Negative Declaration of Environmental Significance D - Project Design Guidelines E - Geotechnical Report - ENGEO F - Tentative Map 2449 & 2451 Tassajara Lane 3 March 12, 2024 RESOLUTION NO. 2024-04 ADOPTING A MITIGATED NEGATIVE DECLARATION OF ENVIRONMENTAL SIGNIFICANCE AND APPROVING MAJOR SUBDIVISION REQUEST SD 9264 AND TREE REMOVAL PERMIT TR24-0007 ALLOWING FOR THE SUBDIVISION OF A COMBINED 8.49-ACRE PARCELS INTO SEVEN SINGLE-FAMILY LOTS AND THE REMOVAL OF ONE TOWN -PROTECTED TREE. THE SITES ARE LOCATED AT 2449 & 2451 TASSAJARA LANE (APN: 207-061-008 & 207-061-009) WHEREAS, TASSAJARA HOLDINGS, LLC AND E. GREG & BEVERLY KENT have requested approval of Subdivision application (SD 9264) to subdivide a combined 8.49- acre site into seven single-family residential lots; and WHEREAS, the subject site is located at 2449 & 2451 Tassajara Lane and further identified as Assessor's Parcel Number 207-061-008 & 207-061-009; and WHEREAS, the Town of Danville Subdivision Ordinance requires Planning Commission approval of a tentative parcel map prior to the recordation of a final map; and WHEREAS, a Tree Removal permit is required to allow for the removal of one 60" Town - protected Oak tree; and WHEREAS, pursuant to the requirements of the California Environmental Quality Act (CEQA), a draft Mitigated Negative Declaration of Environmental Significance has been prepared for the project indicating that, as modified through project revisions and/or recommended mitigation measures which are included as project conditions of approval, no significant adverse environmental impacts are expected to be associated with the project; and WHEREAS, the Planning Commission did review the project at a noticed public hearing on March 12, 2024; and WHEREAS, the public notice of this action was given in all respects as required by law; and WHEREAS, the Planning Commission did hear and consider all reports, recommendations, and testimony submitted in writing and presented at the hearing concerning the project; now, therefore, be it RESOLVED that the Planning Commission approves the Mitigated Negative Declaration of Environmental Significance, approved Subdivision SD 9264, and approves the Tree Removal permit TR24-0007 subject to the conditions contained herein, and make the ATTACHMENT A following findings in support of these actions: FINDINGS OF APPROVAL Major Subdivision: 1. The proposed subdivision is in substantial conformance with the goals and policies in Sub Area 7, "Sycamore Valley" of the 2030 General Plan and the site's Residential - Single Family - Country Estates (1-acre lot minimum) land use designation. 2. The design of the proposed subdivision is in substantial conformance with the applicable zoning regulations as established under the Towri s R-40; Single Family Residential District Ordinance. 3. The design of the subdivision and the type of associated improvements will not likely cause serious public health problems because water and sanitary facility services will be available to the new parcels. 4. The design of the proposed subdivision and improvements are not likely to cause substantial environmental damage or subsequently injure fish or wildlife or their habitat since this property is in an area where residential development has previously occurred. 5. The design of the proposed subdivision and proposed improvements will not conflict with easements, acquired by the public at large, for access through or use of property within the proposed subdivision. 6. The density of the subdivision is physically suitable for the subject site and surrounding neighborhood because the proposed development is similar in size and density to the residential developments adjacent to and vicinity of the site. Tree Removal Permit 1. Necessity. The primary reason for the removal of the 1 - 60" Oak tree is that its location would prohibit the repair of an existing landslide and future pad development. 2. Erosion/surface water flow. Removal of the 1 tree would not cause significant soil erosion or cause a significant diversion or increase in the flow of surface water. 3. Removal of the 1 tree would not significantly affect off -site shade or adversely affect privacy between properties due to the site's topography. PAGE 2 OF RESOLUTION NO.2024-04 CONDITIONS OF APPROVAL Conditions of approval with an asterisk ("') in the left-hand column are standard project conditions of approval. Conditions of approval typed in italicized text are mitigation measures derived from the Mitigated Negative Declaration of Environmental Significance prepared for the project. Unless otherwise specified, the following conditions shall be complied with prior to the approval of the final map or issuance of grading or building permits for the project. Each item is subject to review and approval by the Planning Division unless otherwise specified. A. GENERAL 1. This approval is for Major Subdivision application SD 9264 and Tree Removal permit TR24-0007 allowing the subdivision of a 8.49-acre site located 2449 & 2451 Tassajara Lane into seven single family residential lots. The Tree Removal permit allows for the removal of one 60" Town -protected Oak tree. Development shall be substantially as shown on the project drawings as follows, except as may be modified by conditions contained herein; a. Vesting Tentative Map SD 9264 titled "Kent & Van Dam Properties," as prepared by Milani Associates, consisting of 21 sheets, dated January 25, 2024. b. Tatum Lane Design Standards and Landscape prepared by Francis Garcia, prepared December 22, 2023 c. Geotechnical Report, prepared by ENGEO Incorporated, dated February 10, 2022. 2. All Town and other related fees that the property may be subject to shall be paid by the applicant. These fees shall be based on the current fee schedule in effect at the time the relevant permits are secured and shall be paid prior to issuance of said permit and prior to any Town Council final approval action. The following fees are due at final map approval for the above -mentioned project and are subject to annual increases: PAGE 3 OF RESOLUTION NO.2024-04 1. Map Check Fee .........................................................$ 4,320.00 2. Base Map Revision Fee ...............................................$ 714.00 3. Improvement Plan Check Fee ...............3% of cost estimate 4. Engineering Inspection Fee ...................5% of cost estimate 5. Grading Plan Check, Inspection and Permit.................TBD 6. Excavation Mitigation Fee (Flood Control) ..........$ 7,483.00 7. Park Land in Lieu Fee (7 Lots) .............................$ 92,120.00 The following fees are due at building permit issuance for the above mentioned project (credit for existing house): 1. Child Care Facilities Fee ...................................... $ 335/ unit 2. Finish Grading Fee ................................................. $ 86/ unit 3. Stormwater Pollution Program Fee ..................... $ 56/ unit 4. SCC Regional Fee ............................................... $ 1,676/unit 5. SCC Sub -Regional Fee ......................................$ 4,624/unit 6. Residential TIP Fee ............................................ $ 2,000/ unit 7. Tri-Valley Transportation Fee .......................... $ 6,946/unit 3. Prior to recordation of the final map the applicant shall reimburse the Town for notifying surrounding residents. The fee shall be $392.80 ($130 plus 80 notices x $0.83 per notice x two notices). * 4. Prior to the issuance of grading or building permits, the applicant shall submit written documentation that all requirements of the San Ramon Valley Fire Protection District (SRVFPD) and the San Ramon Valley Unified School District (SRVUSD) have been, or will be, met to the satisfaction of these respective agencies. * 5. In the event that subsurface archeological remains are discovered during any construction or pre -construction activities on the site, all land alteration work within 100 feet of the find shall be halted, the Town Planning Division notified, and a professional archeologist, certified by the Society of California Archeology and/or the Society of Professional Archeology, shall be notified. Site work in this area shall not occur until the archeologist has had an opportunity to evaluate the significance of the find and to outline appropriate mitigation measures if they are deemed necessary. If prehistoric archaeological deposits are discovered during development of the site, local Native American organizations shall be consulted and involved in making resource management decisions. PAGE 4 OF RESOLUTION NO.2024-04 6. Construction activity shall be restricted to the period between the weekday hours of 7:30 a.m. to 5:30 p.m. (Monday through Friday), unless otherwise approved in writing by the City Engineer for general construction activity and the Chief Building Official for building construction activity. Prior to any construction work on the site, including grading, the property owner shall install a minimum 3' x 3' sign at the project entry which specifies the allowable construction workdays and hours, and lists the name and contact person for the overall project manager and all contractors and sub -contractors working on the job. * 7. The applicant shall provide security fencing, to the satisfaction of the City Engineer and/or the Chief Building Official, around the site during construction of the project. 8. The applicant shall require their contractors and subcontractors to fit all internal combustion engines with mufflers which are in good condition, and to locate stationary noise -generating equipment as far away from existing residences as feasible. * 9. A watering program which incorporates the use of a dust suppressant, and which complies with Regulation 2 of the Bay Area Air Quality Management District shall be established and implemented for all on and off -site construction activities. Equipment and human resources for watering all exposed or disturbed soil surfaces shall be supplied on weekends and holidays as well as workdays. Dust -producing activities shall be discontinued during high wind periods. * 10. As part of the initial submittal for the final map, plan check review process, the applicant shall submit a written Compliance Report detailing how the conditions of approval for this project has been complied with. This report shall list each condition of approval followed by a description of what the property owner has provided as evidence of compliance with that condition. The report must be signed by the applicant. The report is subject to review and approval by the City Engineer and/or Chief of Planning and/or Chief Building Official and may be rejected by the Town if it is not comprehensive with respect to the applicable conditions of approval. * 11. Planning Division sign -off is required prior to final Building Inspection sign -off. 12. Prior to the issuance of grading permits, the applicant shall retain a specialist to assess rodent control impacts anticipated to be associated with grading activity and installation of subdivision improvements. As deemed PAGE 5 OF RESOLUTION NO.2024-04 necessary, following the Planning Division's review of the specialist's assessment, the applicant shall develop and implement a rodent control plan to reduce impacts to surrounding properties to the extent reasonably possible for the time periods of heavy construction activity. The report shall include a schedule for regular rodent inspections and mitigation in conjunction with the developer and the Town based on the development schedule for the project. This report shall be subject to review and approval by the Planning Division. 13. The applicant shall be responsible for washing the exterior of abutting residences, and cleaning pools, patios, etc. at the completion of mass grading activities. The residences to receive cleaning, the extent of the cleaning efforts to be performed and the timing (and frequency) of such cleaning shall be subject to review and approval by the Planning Division. B. SITE PLANNING * 1. All lighting shall be installed in such a manner that lighting is generally down directed and glare is directed away from surrounding properties and rights -of -way. 2. Any on -site wells and septic systems shall be destroyed in accordance with Contra Costa County Health Services Department - Environmental Health Division regulations. Environmental Health Division permits and inspections for this work shall be obtained. The maintenance of existing on - site wells shall be allowed for landscape irrigation purposes subject to review and approval by the Contra Costa County Health Services Department - Environmental Health Division. 3. The development and use of the lots created by this subdivision shall comply with all requirements of the Towri s R-40; Single Family Residential District Ordinance. C. LANDSCAPING 1. Landscape plans shall be submitted for review and approval as part of Development Plan applications for the development of each lot. 2. All plant material shall be served by an automatic underground irrigation system and maintained in a healthy growing condition. The irrigation system shall comply with East Bay Municipal Utility District's Section 31 Water Efficiency requirements, including use of a weather -based controller with soil moisture probe and rain -shutoff switch. PAGE 6 OF RESOLUTION NO.2024-04 3. The applicant shall mitigate the removal of one (1) 60" Oak tree by planting 30,15-gallon or 15, 24-gallon trees onsite or payment of an off -site planting mitigation fee of $7,500. D. ARCHITECTURE 1. All ducts, meters, air conditioning and/or any other mechanical equipment whether on the structure or on the ground shall be effectively screened from view with landscaping or materials architecturally compatible with the main structures. 2. The street numbers for each structure in the project shall be posted to be easily seen from the street at all times, day and night. 3. Development of the lots in this subdivision shall be subject to individual or collective Development Plan applications and subject to review and approval by the Towri s Design Review Board. Architecture and landscaping shall be consistent with "Tatum Lane" Design Standard and Guidelines prepared for the project. E. GRADING 1. Development shall be completed in compliance with a detailed soils report and the construction grading plans prepared for this project. The engineering recommendations outlined in the project specific soils report shall be incorporated into the design of this project. The report shall include specific recommendations for foundation design of the proposed buildings and shall be subject to review and approval by the Towri s Engineering and Planning Divisions. 2. Where soils or geologic conditions encountered in grading operations are different from that anticipated in the soil report, a revised soils report shall be submitted for review and approval by the City Engineer. It shall be accompanied by an engineering and geological opinion as to the safety of the site from settlement and seismic activity. 3. All development shall take place in compliance with the Town Erosion Control Ordinance (Ord19-4). Restrictions include limiting construction primarily to the dry months of the year (May through October) and, if construction does occur during the rainy season, the developer shall submit an Erosion Control Plan to the City Engineer for review and approval. This PAGE 7 OF RESOLUTION NO.2024-04 plan shall incorporate erosion control devices such as, the use of sediment traps, silt fencing, pad berming and other techniques to minimize erosion. * 4. All new development shall be consistent with modern design for resistance to seismic forces. All new development shall be in accordance with the Uniform Building Code and Town of Danville Ordinances. * 5. Stockpiles of debris, soil, sand or other materials that can be blown by the wind shall be covered. * 6. If toxic or contaminated soil is encountered during construction, all construction activity in that area shall cease until the appropriate action is determined and implemented. The concentrations, extent of the contamination and mitigation shall be determined by the Contra Costa County Health Department. Suitable disposal and/or treatment of any contaminated soil shall meet all federal state and local regulations. If deemed appropriate by the Health Department, the property owner shall make provisions for immediate containment of the materials. * 7. Runoff from any contaminated soil shall not be allowed to enter any drainage facility, inlet or creek. * 8. All grading activity shall address National Pollutant Discharge Elimination system (NPDES) concerns. Specific measures to control sediment runoff, construction pollution and other potential construction contamination shall be addressed through the Erosion control Plan (ECP) and Storm Water Pollution Prevention Plan (SWPPP). The SWPPP shall supplement the Erosion Control Plan and project improvement plans. These documents shall also be kept on -site while the project is under construction. A NPDES construction permit may be required, as determined by the City Engineer. 9. The applicant shall create a construction staging plan that addresses the ingress and egress location for all construction vehicles, parking and material storage area. All staging of construction materials and equipment shall occur on -site. This plan shall be subject to review and approval by the Town prior to the issuance of a grading permit. 10. Landslide areas as depicted in Section 4.2.3 of the ENGEO Incorporated report, shall include field inspections and shall make final recommendations for adjusting the depth and extent of soil removal and repair based on revealed conditions. 11. Erosion Control is outlined in Section 4.8 in the ENGEO Incorporated report. The PAGE 8 OF RESOLUTION NO.2024-04 applicant shall be required to follow the recommendations to include revegetation of graded slopes with organic -rich stripping's and spreading these materials in a thin layer (approximately 6 inched thick) on graded slopes prior to winter rains and following rough grading. All landscape slopes shall be maintained in a vegetated state after project completion. The use of drought -tolerant vegetation requiring infrequent drip irrigation during summer is recommended. No pressurized irrigation lines should be placed on or near the tops of graded slopes. 12. Removals for general subexcavation, existing fill, and landslide removals shall be as outlined in Section 4.2 of the ENGEO Incorporated report. 13. Stormwater and surface water runoff shall be directed into the property's storm drain system. The applicant shall be required to pay the Excavation Mitigation Fee to Contra Costa County Flood Control. F. STREETS * 1. The applicant shall obtain an encroachment permit from the Engineering Division prior to commencing any construction activities within any public right-of-way or easement. * 2. All mud or dirt carried off the construction site onto adjacent streets shall be swept each day. Water flushing of site debris or sediment or concrete washing is expressly prohibited. * 3. All improvements within the public right-of-way, including driveways, paving and utilities, shall be constructed in accordance with approved standards and/or plans and shall comply with the standard plans and specifications of the Development Services Department and Chapters XII and XXXI of the Town Code. At the time project improvement plans are submitted, the applicant shall supply to the City Engineer an up-to-date title report for the subject property. 4. A satisfactory private storm drain maintenance agreement for the C.3 retention basin shall be submitted for review and approval by the Town prior to recordation of the final map. 4. Prior to the acceptance of the private improvements, the applicant shall repair any damaged pavement of Tassajara Lane to the satisfaction of the City Engineer. 5. Each parcel created by this subdivision shall participate in the Tassajara Lane private road maintenance agreement including their fair share of PAGE 9 OF RESOLUTION NO.2024-04 Tassajara Lane bridge maintenance. G. INFRASTRUCTURE * 1. The new and existing residences shall be required to connect to public water and sewer facilities, subject to all permitting requirements and conditions imposed by EBMUD and CCCSD. * 2. Drainage facilities and easements shall be provided to the satisfaction of the City Engineer and/or the Chief Engineer of the Contra Costa County Flood Control & Water Conservation District (CCCFC & WCD). 3. All runoff from impervious surfaces shall be intercepted at the project boundary and shall be collected and conducted via an approved drainage method through the project to an approved storm drainage facility, as determined by the City Engineer. * 4. Roof drainage from structures shall be collected via a closed pipe and conveyed to an approved storm drainage facility in the street curb. No concentrated drainage shall be permitted to surface flow across sidewalks. * 5. If a storm drain must cross a lot, or be in an easement between lots, the easement shall be equal to or at least double the depth of the storm drain. * 6. The applicant shall furnish proof to the City Engineer of the acquisition of all necessary rights of entry, permits and/or easements for the construction of off -site temporary or permanent road and drainage improvements. * 7. Electrical, gas, telephone, and cable TV services, shall be provided underground in accordance with the Town policies and existing ordinances. All utilities shall be located and provided within public utility easements, sited to meet utility company standards, or in public streets. * 8. All new utilities required to serve the development shall be installed underground. * 9. All street, drainage or grading improvement plans shall be prepared by a licensed civil engineer. H. MISCELLANEOUS * 1. The project shall be constructed as approved. Minor modifications in the design, but not the use, may be approved by staff. Any other change will PAGE 10 OF RESOLUTION NO.2024-04 require Planning Commission approval through the subdivision review process. * 2. Pursuant to Government Code section 66474.9, the applicant (including the applicant or any agent thereof) shall defend, indemnify, and hold harmless the Town of Danville and its agents, officers, and employees from any claim, action, or proceeding against the Town or its agents, officers, or employees to attack, set aside, void, or annul, the Town's approval concerning this Subdivision application, which action is brought within the time period provided for in Section 66499.37. The Town will promptly notify the applicant of any such claim, action, or proceeding and cooperate fully in the defense. * 3. Use of a private gated entrance for more than one parcel is expressly prohibited. * 4. The proposed project shall conform to the Towri s Stormwater Management and Discharge Control Ordinance (Ord. No. 2004-06) and all applicable construction Best Management Practices (BMPs) for the site. For example, construction BMPs may include, but are not limited to: the storage and handling of construction materials, street cleaning, proper disposal of wastes and debris, painting, concrete operations, dewatering operations, pavement operations, vehicle/equipment cleaning, maintenance and fueling and stabilization of construction entrances. Training of contractors on BMPs for construction activities is a requirement of this permit. At the discretion of the City Engineer, a Storm Water Pollution Prevention Plan (SWPPP) may be required for projects under five acres. * 5. The project shall conform to the Regional Water Quality Control Board post -construction C.3 regulations which shall be designed and engineered to integrate into the project's overall site, architectural, landscaping and improvement plans. These requirements are contained in the project's Stormwater Control Plan and are to be implemented as follows: • Prior to issuance of permits for building, site improvements, or landscaping, the permit application shall be consistent with the applicant's approved Stormwater Control Plan and shall include drawings and specifications necessary to implement all measures in the approved plan. The permit application shall include a completed Stormwater Control Plan for a Small Land Development Project as published by the Contra Costa Clean Water Program. PAGE 11 OF RESOLUTION NO.2024-04 APPROVED by the Danville Planning Commission at a regular meeting on March 12, 2024, by the following vote: AYES: NOES: ABSTAINED: ABSENT: CHAIR APPROVED AS TO FORM: ATTEST: CITY ATTORNEY CHIEF OF PLANNING PAGE 12 OF RESOLUTION NO.2024-04 NOTICE TO SURROUNDING PROPWNERS MAILED BY v- NOTICE OF A PUBLIC HEARING, A PUBLIC REVIEW PERIOD, AND INTENT TO ADOPT A NEGATIVE DECLARATION OF ENVIRONMENTAL SIGNIFICANCE Danville Planning Commission Meeting Tuesday, March 12, 2024, at 5:00 p.m. I Town Meeting Hall, 201 Front Street Project: SD 9264 - Tatum Lane Location: 2449 & 2451 Tassajara Lane Description: The subdivision of 8.49 combined acres into seven Single -Family residential lots Environmental The project has been found to have no significant environmental impacts under the Review: California Environmental Quality Act (CEQA). As a result, a Draft Negative Declaration of Environmental Significance has been prepared for this project. Copies of the Draft Negative Declaration and Initial Study of Environmental Significance that were prepared for the project are available at the Town of Danville Town Offices located at 500 La Gonda Way and on the Town Talks website which may be accessed by scanning the QR code below. The review period for a proposed Negative Declaration shall not be less than 20 days. Staff Contact: Fred Korbmacher, Project Planner Phone: (925) 314-3317 Email: I k-orl inache:-<«idanviIIexa - ov All interested persons are encouraged to attend and be heard at the scheduled public hearing at 5:00 p.m. on Tuesday, March 12, 2024, at the Town Meeting Hall at 201 Front Street, Danville, CA. NOTE: If you challenge the Town's decision on this matter in court, you may be limited to raising only those issues you or someone else raised at the public hearing described in this notice, or in written correspondence delivered to the Town at, or prior, to the public hearing. ATTACHMENT B In compliance with the Americans with Disabilities Act, the Town of Danville will provide special assistance for disabled citizens. If you need special assistance to participate in this meeting, please contact the City Clerk (925) 314-3388. Notification 48 hours prior to the meeting will enable the Town to make reasonable arrangements to ensure accessibility to this meeting. [28CFR 35.102-35.104 ADA Title II] To view the plans for the proposed project, please visit our Development Activity Map, which is available on our website or by scanning the QR code below. mall ■■a ■ INN ■alra !ai �!!r! r ■ Ei ■■ i!■ a ■aE■E a■ ■ a ■ Booms oil rri�RlNa a ■■■■is r r■ a ! is a a MkaaE a ■ ■ ■ ■ Ea■! NEa ■m r w r■a r ■ ■ ■ i ■■■■!ar a■a a!!aa r rr ! a! a aaaar a■ E■■ r■■■ai■ii r IN litre a rii10■!!ia No ■i 11[ ! aE ■11■ aE is ■aa as ■!E! !a maim a■ !a■! 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GROSS BARRY R & BARBARA S TRE GROSS BARRY R & BARBARA S TRE PATELCIIIRAG FIASFIMUKI-I TRC ACOSTA TERESA R TIRE TASSAJARA LANE HOA TASSAJARA LANE OWNERS ASS TASSAJARA HOLDINGS LLC COCCIMIGLIO RON & JUDI IF TRE ROSSI DONALD & KATHE TIRE ROBINSON AN1 HONY C TRE ROBINSON ELENA M TIRE 31.8 MONTOYA WAY 32 SHERBURNE HILLS HE) 32.7 MONTOYA WAY 329 MON10YA WAY 3500 CAMINO TASSAJARA 36 SHERBURNE HILLS RD 37 MCNEIL LN 4 CORTE LA RADO 4 CORTE LA RA DO 4 CROSS BRIDGE PL 40 SARAH CT 4155 BLACKHAWK PL47-A CIR 4201 4155 BLACKHAWK PLAZA CIR 4201 6033 LAURCLSPUR LOOP 68 SHERBURNE. HILLS RD 71 SHERBURNE HII-I.S R❑ 810 BOLIVAR PI. 9 SHERBURNE HILLS RD DANVILLE CA DANVILLE CA DANVIILE C.A DANVILLE CA ❑ANVIELI CA DANVILI.0 CA DANVILI.[ [:A MORAGA CA MORAGA CA DANVILLE CA DANVILLE CA DANVILLE CA DANVILLE CA SAN RAMON CA DANVILLE CA DANVILLE CA SAN RAMON CA DANVILLE CA 94526 94526 94526 94526 94506 94526 94526 94556 94556 9457.E 94526 94505 94506 94582 94526 94526 94583 94526 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 "Small Town Atmosphere Outstanding Quality of Life' DRAFT MITIGATED NEGATIVE DECLARATION OF ENVIRONMENTAL SIGNIFICANCE LEAD AGENCY: Town of Danville -- (Fred Korbmacher) NAME OF PROJECT: SUB22-0006 (SD 9264) - TR22-0060 PROJECT DESCRIPTION: The subdivision of an existing 8.49-acre parcel into seven single family residential lots where there is one (1) Town -protected tree on the subject property affected by this proposal ENVIRONMENTAL EFFECTS/MITIGATION MEASURES: 1. GEOLOGY AND SOILS: Will the Project: a) Expose people or structzlres to potential substantial adverse effects, inclucli the risk, of loss, injury, or Death involving: ii) Landslides? Less Than Significant Impact with mitigations Incorporated. Existing landslide on the subject properties could be subject to seismically induced deformation and will require corrective grading to improve slope stability as discussed in the report prepared by ENGEO Incorporated. MITIGATION MEASURE 1: Landslides removals are depicted in Section 4.2.3 in the ENGEO Incorporated report, znhich mill require field inspections to make recommendations for adjusting the depth and extents of removals based on revealed conditions. b) Result in substantial soil erosion or the loss of topsoil? Less than Significant Impact with mitigations Incorporated. Per the report prepared by ENGEO Incorporated, recommend additional sulfated testing at the completion of finished grading. MITIGATION MEASURE 2: Erosion Control is outlined in Section 4.8 in the ENGEO Incorporated report. The applicant shall be required to folloza the recommendations to include revegetation of graded slopes zaith organic -rich stripping's and spreading these materials in a thin layer (approximately 6 inched thick) on graded slopes prior to zvinter rains and follozving rough 510 LA GONDA WAY, DANVILLE, CALIFORNIA 94526 Administration Building Engineering & Planning Transportation Maintenance Police Parks and Recreation (925) 314-3388 (925) 314-3330 (925) 314-3310 (925) 314-3310 (925) 314-3450 (925) 314-3410 (925) 314-3400 ATTACHMENT C February 16, 2024 Page 2 grading. All landscape slopes shall be maintained in a vegetated state after project completion. The use of drought -tolerant vegetation requiring infrequent drip irrigation during summer os recommended. No pressurized irrigation lines should be placed on or near the tops of graded slopes. c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off -site landslide, lateral spreading, subsidence, liLluefaction or collapse? Less than Significant Impact with mitigation Incorporated. According to the Geotechnical report prepared by ENGEO Incorporated, it is recommending to design improvements to mitigate these concerns. MITIGATION MEASURE 3: Removals for General Subexcavation, Existing Fill, Landslide Removals are outlined in Section 4.2 of the ENGEO Incorporated report. d) Be located on expansive Soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property? Less than Significant Impact with mitigations Incorporated. Landslides and expansive soil hazards exist throughout the Danville area. Expansive soil can be mitigated by proper foundation design and grading measures. These mitigation measures are detailed in the report prepared by ENGEO Incorporated. MITIGATION MEASURE 4: The applicant Shall follozo the recommendations of the soils report prepared by ENGEO Incorporated Section 5.0 FOUNDATION RECOMMENDATIONS. 2, NOISE: Would the project result in: d) A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? Less than Significant Impact with Mitigation Incorporated. Noise levels would temporarily be increased due to noise associated with the construction of the project. The noise impact will be less than significant given required standard conditions of approval which define and limit hours of construction. MITIGATION MEASURE 5: The applicant shall require their contractors and subcontractors to the period between the weekday hours of 7:30 a.m. to 5:30 p.m. (Mondays through Fridays), unless otherwise approved in writing by the City Engineer for general construction activity and the Chief Building Official for building construction activity. Prior to any construction work on the site, including grading, the applicant shall install a minimum 3' x 3' sign at the project entry February 16, 2024 Page 3 zoleich specifies the allowable construction workdays and hours, and lists the name and contact person for the overall project manager and all contractors and sub -contractors ulorking on the job. 3. UTILITIES AND SERVICE SYSTEMS: Would the project result in: c) Require or result in the construction of new storm water drainake facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? Less Than Significant with Mitigation Incorporated. The project will be required to comply with all stormwater quality requirements. The project proposes self -retaining pervious areas and a bio-retention basin. Calculations were computed on the Contra Costa Clean Water Program's IMP calculator to determine C3 compliance. MITIGATION MEASURE 6: Stormwater and surface water runoff shall be directed into the property's public storm drain system. The applicant shall be required to pap the Excavation Mitigation Fee to Contra Costa County Flood Control. DETERMINATION: Based upon the above identified mitigation measures, no significant environmental impacts are anticipated to be associated with the subject project. A Draft Mitigated Negative Declaration of Environmental Significance has been prepared. The Initial Study was prepared by the Planning Department, Town of Danville. Copies of the Initial Study may be obtained at the Town offices located at 500 La Gonda Way, Danville, California 94526. ATTEST: Fred Korbmacher Development Service Coordinator 4pw A. OBJECTIVES............................................................................................................................................................................................................................... 1 B. COMPLIANCE WITH REGULATIONS................................................................................................................................................................................................. 1 C. DESIGN REVIEW PROCEDURES....................................................................................................................................................................................................... 1 A. BUILDING MASSING AND ARTICULATION......................................................................................................................................................................................... 2 1. Front Elevations.................................................................................................................................................................................................................. 2 2. Side and Rear facing Elevations......................................................................................................................................................................................... 3 3. Garages.............................................................................................................................................................................................................................. 3 4. Roofs...................................................................................................................................................................................................................................4 B. EXTERIOR MATERIALS.................................................................................................................................................................................................................. 4 1. Facades...............................................................................................................................................................................................................................4 2. Roofs................................................................................................................................................................................................................................... S C. EXTERIOR TRIM.......................................................................................................................................................................................................................... 5 D. EXTERIOR COLORS...................................................................................................................................................................................................................... 6 E. WINDOWS................................................................................................................................................................................................................................ 7 F. ENTRIES....................................................................................................................................................................................................................................7 G. DOORS..................................................................................................................................................................................................................................... S H. FIREPLACES & CHIMNEYS............................................................................................................................................................................................................. S I. GUTTERS AND DOWNSPOUTS........................................................................................................................................................................................................ S J. COLUMNS.................................................................................................................................................................................................................................9 K. BALCONIES................................................................................................................................................................................................................................9 L. BAYS/UINDOWS..........................................................................................................................................................................................................................9 M. DORMERS.................................................................................................................................................................................................................................9 N. EXTERIOR DECKS AND TRELLISES....................................................................................................................................................................................................9 O. SKYLIGHTS...............................................................................................................................................................................................................................10 P. SOLAR PANELS......................................................................................................................................................................................................................... 10 Q. ANTENNAS.............................................................................................................................................................................................................................. 10 R. EXTERIOR BUILDING LIGHTING.................................................................................................................................................................................................... 11 S. MECHANICAL EQUIPMENT.......................................................................................................................................................................................................... 12 T. GAME AREAS, PLAYHOUSES & AUXILIARY STRUCTURES.................................................................................................................................................................... 12 Tatum Lane Design Guidelines TOC 1 A. INTRODUCTION ........................................................................................................................................................................................................................ l3 B. TRANSITION ZONES ................................................................................................................................................................................................................... l3 C. GRADING ................................................................................................................................................................................................................................ l3 D. WALLS AND FENCES .................................................................................................................................................................................................................. l4 1 Retaining Walls .---------------------------------------------------------------------.14 I Free-standing Walls .-------------------------------------------------------------------15 IFences ............................................................................................................................................................................................................................... 15 4 Gates and Vehicular Entry Gates ...................................................................................................................................................................................... 15 E. MAILBOXES ............................................................................................................................................................................................................................. l6 F. PAVING .................................................................................................................................................................................................................................. l6 G. LIGHTING ................................................................................................................................................................................................................................ l7 H. PLANTING ............................................................................................................................................................................................................................... l7 1 Street Trees ....................................................................................................................................................................................................................... 18 IFront Planting ................................................................................................................................................................................................................... 19 IRear Planting .................................................................................................................................................................................................................... 19 Tatum Lane Design Guidelines TOC 2 The Tatum Lane development consists of seven lots located on the eastern hills off Tassajara Road in the Town of Danville, California. These guidelines are written to give developers, designers and home owners design flexibility to allow them to reflect individuality in design, while also encouraging development that results in: ■ high -quality design that projects a simple elegance and harmony within each property; ■ is visually cohesive, particularly along public frontages; ■ embraces modern and contemporary aesthetics that reflect the architectural and landscape styles of the region; and ■ respects and harmonizes with the surrounding open spaces. These guidelines also serve to assist Town of Danville Design Review Board members and staff in approving the development of the lots in the Tatum Lane neighborhood. All projects must adhere to the development requirements set by the Town of Danville. In cases of conflict with these guidelines, the Town's requirements will take precedence. Every project will undergo a review by the Town of Danville Design Review Board and must adhere to their specific submittal requirements. Tatum Lane Design Guidelines Page 1 Generally, overall volumes of the residence should be kept simple and harmonious with enough articulation to break up massing. Excessive changes and disparities in volume, massing, rooflines, and materials are discouraged. Street -facing elevations should offer variations in structure depth, aesthetically pleasing projections, and diversity in foundation, wall, and rooflines. Main entrances should be highlighted through massing, rooflines and/or materials. Avoid long, unadorned exterior walls. Strive for consistent window styles and detailing on these elevations. f�! Tatum Lane Design Guidelines Page 2 Rear facing elevations should complement front elevations, but can vary to address the more private spaces. Ensure maximum privacy for neighbors on side and rear -facing elevations through careful window placement and room orientations. Strive for consistent window styles and detailing on these elevations. Pay careful attention to garage design, minimizing their visibility from public streets. Side -loading garages with doors perpendicular to the street and facing away from Tassajara Lane, or setback to clearly subordinate it from main facade, are preferred. Utilize offsets in foundation, wall, and roof to reduce the impact of street -facing garage entries. Maintain consistency in window styles and detailing with main house. Tatum Lane Design Guidelines Page 3 The roof form is primary in providing clarity to the overall building form. The roof form should express a clear hierarchy appropriate to the style. The roof is one of the most significant elements of the building and should be simply shaped and uncomplicated. Roof forms should be well organized and demonstrate the same character on all sides of the residence. The pitch of the roof shall be consistent with the style of the dwelling. All metal valleys, flashings, vents and skylight curbs shall be painted to match roofing material or copper. Plumbing vents are to be combined wherever possible to reduce the number of roof penetrations as the plumbing/mechanical code allows. Plumbing and attic vents shall be placed behind street -facing ridge lines unless prohibited by code. Limit the number of exterior materials used on any wall. Locate material changes at interior corners or other logical terminations and not at external corners such that individual volumes, instead of facades, are highlighted. The same care in placing and designing the shape of windows and doors in the exterior elevation should be observed when designing the shape of the area of the different siding materials. The shape of the different materials should look pleasing on their own as the doors and windows do. This concept is referred to as "negative space" in art and photography. The use of contemporary materials is encouraged. Suitable materials include concrete, stone, stucco, metal, or wood siding. Only high -quality imitation stone, brick, tile or fiber cement, and porcelain panels and veneers are permitted. Samples must be submitted to the Danville Design Review Board for approval. Stucco finishes should be smooth and must be applied in a 3-coat application with integral color or approved acrylic finish. Sand finish is allowed when appropriate to the architectural style. Special attention should be paid to the trim on ganged windows. Where masonry is specified, preference is given to real masonry, but high -quality manufactured masonry is allowed. Detail manufactured masonry carefully, focusing on window openings, caps, and base. Maintain the appearance of structural stone walls for stone, and use earth -toned bricks. Provide grout color and tooling specifications, and ensure openings are well -detailed. Highly textured finishes are to be avoided unless appropriate to the style of the home. Small slivers of exterior materials between windows or between windows and building corners should be avoided. Vinyl, Masonite, plain concrete block, or plain T-111 plywood siding are prohibited. Tatum Lane Design Guidelines Page 4 Roof material shall be appropriate to the style of the residence. Acceptable roofing materials are: slate, clay tile, concrete tile, wood, or standing seamed metal, either copper or factory painted steel and TPO membrane for low slope roofs. Architectural grade composition (40-year high definition without abstract shingle patterns) is acceptable, but not encouraged. Colors should be appropriate for the style of the home although bold colors should be avoided. TPO membranes should be overlaid with neutral toned gravel or pebbles. Provide small samples of actual material proposed in full color range. Ensure exterior trim matches the architectural style of the home, employing sleek and clean detailing around doors and windows. Maintain consistency in detailing on all elevations, articulating openings through the use of modern elements. Tatum Lane Design Guidelines Page 5 All exterior colors and their locations must be approved by the Design Review Board. Coordinate house colors with modern materials and roofing options. Use a contemporary color palette, emphasizing neutrality and modern tones. Red, orange or terracotta color ceramic and concrete tile or roofs of other materials are prohibited. Bronze, brown, gray, charcoal and black and other colors are acceptable upon approval of the Design Review Board. Bright white siding and stucco is prohibited. Off-white colors are allowed. Light Reflectance Value (LRV) of siding and stucco should be a maximum of 75. Low slope roofs that are visible from the lots at a higher elevation shall be a color that complements the colors of the wall materials. Tatum Lane Design Guidelines Page 6 The Design Review Board must approve all exterior colors and their corresponding locations. Care should be taken to match the house colors with the masonry and roofing materials. Trim and accent colors shall be carefully coordinated with the body colors. Colors for all exterior materials should be appropriate for the selected building style. Color selections may be denied if they contrast with adjacent homes or match too closely to other homes in the immediate area. Choose a harmonious color palette that complements each other, instead of a disjointed mix of conflicting colors. The style of the window chosen should match the style of the building. Windows on street -facing elevations should be consistent in style. Maintain uniform window material and operation on all sides however, side and rear elevations may deviate from street elevations at appropriate transition points such as facades or volume changes (See Side and Rear Facing Elevations Section above). Side and rear elevation windows overlooking adjacent homes and impacting either existing or future privacy should be carefully evaluated. Skylights, where possible, should be placed behind street facing ridgelines and the glass shall be either clear or bronze in color. Glazing shall be clear or gray tinted only. Reflective glazing of any type is not allowed. The architect or designer is encouraged to use windows and doors made of wood, aluminum clad wood or fiberglass. Snap -in grids or imitation divided lights installed solely within dual pane glass are not allowed. Vinyl windows are allowed, but extra care shall be taken in detailing. Windows should be square or rectangular in shape, with a vertical to horizontal ratio of at least 3 to 2, except in instances where they are compatible with the architectural style or used as transoms. Arch -top windows are to be discouraged. Design of arched windows is to be carefully considered along with the architectural style of the home. Careful attention is to be paid to the walls on all sides of arched windows to achieve visual balance. Do not use horizontal window panes or vary window panes dramatically within a building. The proportion and size of window panes should be kept consistent as much as possible. Horizontal sliding windows are prohibited, unless at the side or rear where a projecting casement window would become a safety concern or where used for a pass -through. The main entrance may have a sense of prominence, but must not be over -scaled or excessively or overly ornamented. The main entrance should contain more detail than other openings but be consistent in styling and simplicity with the residence. Tatum Lane Design Guidelines Page 7 Care should be taken in roof and wall design to provide adequate weather protection. Care should be taken in design and placement of fireplaces. Exterior fireplaces and chimneys contribute greatly towards the mass and visual permanence of a structure. The architect or designer must veneer all fireplaces with steel, masonry or stucco. All gutters shall be drained in a solid pipe system through curbs onto bio-treatment basins. All gutters and downspouts shall be painted unless copper. No plastic gutters are allowed. Refer to federal, state and local ordinances regarding restrictions on the use of copper. Tatum Lane Design Guidelines Page 8 Design or specify columns in harmony with the architectural style, ensuring the use of robust materials. Accurately depict columns to scale on the elevations, providing comprehensive installation details, including base and cap connections. Also, ensure proper detailing of beams or entablature atop the columns. Pay particular attention to proportionate design in areas with multiple columns, aligning them with the chosen style. Carefully detail balconies where visible to the street. "Heavy" materials, such as cast concrete balustrades are to be avoided, unless detailed appropriately. Railings should have top and bottom rails. Visually support projecting balconies. Bay windows should be carried down to grade or express visual support at cantilevered conditions. When bay windows are stacked in a 2-story condition, the blank panel between all facets should be articulated. Bay roofs should be distinct from the primary roof. Dormers should be designed in keeping with the architectural style Dormers must be correctly located on the roof and not be too large or out of proportion. Dormer jamb materials should be a solid assembly with strong, substantial casing boards at the corners. Dormer roof trim should begin at the window head with no siding over the window. Properly proportion dormers so the window adequately fills the dormer face. Articulate the post between the windows on ganged dormer windows. Do not over- size the dormer roof or eaves. Stone or brick dormer faces should terminate with a parapet. Decks, balconies & trellises must be integrated into the house design and be compatible in color, texture and form. Second story decks must not intrude on the privacy of adjacent homes. Exterior stairways must be integrated into the house design. Raised deck supports should incorporate materials which relate to the residence, such as wood, brick, stucco or stone. If wood posts are used, they should be a minimum of 6" by 6" with base and capital detailing. Tatum Lane Design Guidelines Page 9 Skylights can detract from the roof-scape and therefore should be used sparingly. Skylights are to be flat panel with a thin profile and follow the pitch of the roof. Exposed curbs and flashing should be painted to match the color of the roof. Location of skylights should be carefully considered so as not to clutter the roof. Architecturally integrated lanterns or dormers should be considered in lieu of skylights. The location of all solar panels must receive approval from both the Design Review Board and the Town of Danville Planning Department. Solar panel systems should be planned to reduce any reflection and glare that may affect neighboring homes. Installing solar panels on elevations facing the street is not encouraged. It is important to integrate solar systems into the roof structure during the design process, rather than adding them as an afterthought. Satellite dishes and antennas shall not be visible from streets and must be screened from adjacent lots. No roof- top antennas are allowed. The Town of Danville Planning Department must approve antenna location and screening. Tatum Lane Design Guidelines Page 10 The approval of all exterior lighting fixtures is a requirement of the Design Review Board. Street -facing exterior lighting should primarily serve the purpose of highlighting architectural elements, illuminating walkways and doors. It is crucial to prevent any glare from the lighting onto streets and neighboring homes. Lighting in side and rear yards should be task -oriented, serving decks, patios, doorways, and landscaping. The light should be directed precisely to the intended areas without causing glare on adjacent properties. Security floodlights should not be put on timers unless mandated by code, and they should not remain in constant operation. In the case of decorative exterior lighting, the light source must be adequately shielded. Detailed fixture information, such as cut sheets, should be provided for review. Tatum Lane Design Guidelines Page 11 Electrical meters, gas meters, trash containers, air conditioning units, soft water tanks, pool and spa equipment, etc., shall be completely screened from view of neighboring houses and streets and shall not be located on the front elevation nor within the first one third of the side elevations. This may be accomplished by individual enclosures, fencing or landscaping. Equipment noise mitigation should be considered in screen design. Equipment should not be located in Transition Zones. Mechanical equipment should be screened using materials that complement site walls or fences. All detached structures require approval from both the Design Review Board and the Town of Danville Planning Department. The design of these external/detached structures should harmonize with the architectural style of the main residence. Construction of basketball hoops and playhouses on street -facing elevations is prohibited, and they should remain hidden from street view. The use of landscaping is encouraged to minimize the visual impact of these detached structures on neighboring properties. Site plans must include the location of any proposed accessory structures, encompassing pool houses, detached garages, guest houses, play structures, storage sheds, or any additional structures intended for the homesite. All design criteria applied to the main residence should also be adhered to for any proposed accessory structures. These structures' design, including material and color choices, should be in sync with the architecture of the primary dwelling. When developing the schematic design for the site plan and main house, it is advisable to incorporate a plan for a potential accessory dwelling unit. This ensures that if the owner decides to construct one in the future, there will be a designated area on the site plan that does not conflict with the primary residence. Tatum Lane Design Guidelines Page 12 These guidelines define a path for the design of the landscape that will work in concert with the architectural design of the individual homes while creating a cohesive, well -planned and compatible look between the properties where they address more public spaces. They emphasize creating appropriate transitions to the surrounding open spaces and natural areas so that the overall development respects and enhances it by mitigating its impact on the natural hillsides. Street frontages are also addressed to form a cohesive design for the development as a whole. The design of the landscape should complement the architectural style of the home through shape, form, materials and general planting palette. The overall design of the landscape should begin with an overall style, while taking care to address changes into the Transition Zones. Changes in materials, forms, volumes, massing should be cohesive and compatible and should be kept to a minimum. Mixing styles and incorporating too numerous materials, forms and styles should be avoided. Transition Zones are the portions of the landscape within the rear setback and any side yards that abut open spaces and natural areas. These zones serve to bridge the more manicured and active private landscape with natural areas and open spaces. Transition Zones should help define the boundaries and clarify the transition between the private outdoor space and the more public space. Transition Zones should be planted with low water use, native and Mediterranean plants. Any paths in these areas should be limited to gravel, stepping stones, flagstone or timber steps. Fully paved concrete or hardscape should be avoided in these areas. Landscape lighting is not allowed in these zones. Where walls are not proposed, grading should appear as natural as possible. Slopes should not exceed 2.5:1. Tatum Lane Design Guidelines Page 13 For retaining wall heights and regulations, see Town of Danville zoning ordinance. Walls should be softened with planting at both the base and top unless adjacent to a useable area. Wall materials should be of stone, stucco, concrete (natural or colored) or stained wood. Steel may be used if primed and painted or weathering -type steel designed to rust. Segmental block walls are to be discouraged, but if used, should match the existing site walls in material and color and be straight-faced. Tri-plane segmental block walls are prohibited. Tatum Lane Design Guidelines Page 14 Free -Standing Walls should be constructed of wood, stone, concrete, CMU or steel. Finishes may be wood, stucco, natural stone, or decorative board -formed or smooth concrete. Painted steel or Corten weathering steel panels may be used for walls up to 5' in height. Rear fencing in Transition Zones must be open style - either deer fencing using wire mesh panels or rolls, with wood or steel posts, or ornamental iron. If fences are ornamental iron, the design should be clean and simple without pointed pickets, circles or other details that distract from the open space. These fences must be at least 60% open. Chain -link fences and diagonal lattice are prohibited. Fences between properties and at transition to front yards may be solid wood, or steel or wood slats. Wood may be left natural or stained brown or gray tones. No tones of red, yellow or other rich colors are allowed. Planting should soften the change in plane along fences and walls. See also fence and wall requirements in Section of the Danville Gates should reflect the style and design of the home and landscape, and contribute to the aesthetics of the public street. Driveway entries should be set back a minimum of 15 feet to allow a vehicle to pull completely out of the roadway in front of the gate. Minimum width should be 14 feet. Circular driveways are discouraged. Tatum Lane Design Guidelines Page 15 Mailboxes should be designed as an integral part of the design taking into account both the landscape and architectural style of the property development. The mailbox may be an integral part of a wall or fence, or installed as a separate component. Mailbox locations and heights must meet USPS requirements. Hardscapes should utilize quality materials such as concrete, brick, stone, tile, wood decking or interlocking pavers. Materials can be combined to break up the amount of perceived paving and provide greater interest. Gravel and crushed rock can be used for lower impact walkable areas such as within Transition Zones. Stamped and/or glossy concrete is discouraged. Tatum Lane Design Guidelines Page 16 Exterior lighting shall be properly designed and maintained so as to preserve the views of the night sky. Fixture should be shielded to prevent glare and prevent direct site -lines to the bulb or light source. Minimizing up -lighting into trees is advised and should be avoided so as to not impact adjacent homes, public spaces and Transition Zones. Planting design must adhere to current MWELO (Model Water Efficient Landscape Ordinance) and take into account flammability and fire fuel loads. Trees and lower planting materials should help "ground" the building and mitigate its mass. Tatum Lane Design Guidelines Page 17 A minimum of 2 - 24" box size or larger street trees should be planted between 3' and 6' from the pavement edge, and placed a minimum of 30' apart, taking into account the layout of the lot and adjacent lots. Trees should be of standard single -trunk form and chosen from the following list: ■ Pistacia chinensis - Chinese Pistache ■ Lagerstroemia x `Natchez' - Natchez White Flowering Crape Myrtle ■ Platanus x acerifolia - London Plane Tree ■ Platanus racemosa - California Sycamore ■ Ulmus parvifolia - Chinese Elm • Quercus suber - Cork Oak Tatum Lane Design Guidelines Page 18 Front yards should speak to the region as well as the style of the house. Naturalistic forms are not required, but native and Mediterranean plants are recommended. The use of ornamental grasses is encouraged to reflect the regional landscape. Succulents and other emphatic plants may be used but should not dominate the plant palette. Front lawns are discouraged but if utilized, must not exceed 30% of the front area of the lot. Alternatives to front lawns that can exceed 30% include no -mow type sod and meadow plantings of ornamental grasses. Rear planting should work with the style of the house architecture. Planting in Transition Zones should "feather" the active spaces into the surrounding hillsides' natural landscaping with appropriate planting. See Section B. Transition Zones. Tatum Lane Design Guidelines Page 19 The following plants are prohibited from both front and backyards due to visual incompatibilities, invasiveness, fire hazard or other non -desirable qualities: ■ All palms growing to over 12' tall. Low multi -trunk palms are allowed. ■ Mexican Feather Grass - Stipa tenuissima ■ Running Bamboo species ■ Clumping bamboo species that grown over 15' tall. ■ Pine species growing over 12' tall. ■ Cypress - Italian, Arizona and Leyland Cypress ■ Juniper species except Shore Juniper and Juniperus horizontalis varieties ■ Cytisus, Genista, Spartium - Brooms ■ Cortaderia sellowiana - Pampas grass Tatum Lane Design Guidelines Page 20 KENT AND VANDAM PROPERTIES 2449 AND 2451 TASSAJARA LANE AP N 207-061-008 AND 207-061-009-8 DANVILLE, CALIFORNIA GEOTECHNICAL REPORT SUBMITTED TO Mr. Othmar Vandam 6033 Laurelspur Loop San Ramon, CA 94582 PREPARED BY ENGEO Incorporated February 10, 2022 PROJECT NO. 5393.000.000 GEO February 10, 2022 Mr. Othmar Vandam 6033 Laurelspur Loop San Ramon, CA 94582 Subject: Kent and Vandam Properties 2449 and 2451 Tassajara Lane Danville, California GEOTECHNICAL REPORT Dear Mr. Vandam: GEOTECHNICAL ENVIRONMENTAL WATER RESOURCES CONSTRUCTION SERVICES COASTAL/MARINE GEOTECHNICS Project No. 5393.000.000 With your authorization, we conducted a geotechnical exploration for the proposed residential development at the Kent and Vandam properties in Danville, California. The accompanying report presents the results of our site exploration and geotechnical conclusions and recommendations for the project. It is our opinion that the proposed development is feasible from a geotechnical standpoint provided that the geotechnical recommendations presented in this report are incorporated into design and implemented during construction. If you have any questions or comments regarding this report, please call and we will be glad to discuss them with you. Sincerely, ENGEO Incorporated Siobhan O'Reil sos/jjt/ps/dt G\VEERING \ ST UFG�FFo � l v 40 Phil Stuecheli, C / �P 9TF OF CA, � 2010 Crow Canyon Place, Suite 250 • San Ramon, CA 94583 • (925) 866-9000 • Fax (888) 279-2698 www.engeo.com TABLE OF CONTENTS LETTER OF TRANSMITTAL 1.0 INTRODUCTION.................................................................................................. 1 1.1 PURPOSE AND SCOPE.................................................................................................... 1 1.2 PROJECT LOCATION AND DESCRIPTION..................................................................... 1 1.3 PROPOSED DEVELOPMENT........................................................................................... 1 1.4 EXISTING GEOTECHNICAL DATA...................................................................................2 1.5 2019 FIELD EXPLORATION AND LABORATORY TESTING ........................................... 2 1.5.1 Borings................................................................................................................... 2 1.5.2 Test Pits................................................................................................................. 2 2.0 FINDINGS............................................................................................................ 3 2.1 SITE BACKGROUND......................................................................................................... 3 2.2 GEOLOGY.......................................................................................................................... 3 2.2.1 Regional Geology.................................................................................................. 3 2.2.2 Site Geology........................................................................................................... 3 2.3 GROUNDWATER CONDITIONS.......................................................................................4 2.4 SEISMICITY........................................................................................................................4 3.0 ANALYSIS AND CONCLUSIONS....................................................................... 5 3.1 SEISMIC HAZARDS........................................................................................................... 5 3.1.1 Ground Rupture..................................................................................................... 5 3.1.2 Ground Shaking..................................................................................................... 5 3.1.3 Liquefaction............................................................................................................6 3.1.4 Seismically -Induced Landslide Deformation..........................................................6 3.2 2019 CBC SEISMIC DESIGN PARAMETERS...................................................................6 3.3 LANDSLIDE HAZARDS......................................................................................................6 3.3.1 Landslides and Earthflows..................................................................................... 6 3.3.2 Off -site Landslides and Debris Flows.................................................................... 7 3.4 SLOPE STABILITY ANALYSIS.......................................................................................... 8 3.4.1 Geometry and Assumed Soil Parameters............................................................. 8 3.4.2 Method of Analysis................................................................................................. 8 3.4.3 Results of Slope Stability Analyses....................................................................... 8 3.5 SOIL CORROSION POTENTIAL........................................................................................ 9 3.6 EXPANSIVE SOIL............................................................................................................... 9 4.0 EARTHWORK RECOMMENDATIONS............................................................... 9 4.1 GENERAL SITE CLEARING.............................................................................................. 9 4.2 REMOVALS...................................................................................................................... 10 4.2.1 General Subexcavation........................................................................................ 10 4.2.2 Existing Fill........................................................................................................... 10 4.2.3 Landslide Removals............................................................................................. 10 4.3 SLOPE GRADING............................................................................................................ 10 4.3.1 Toe Keyways and Benching................................................................................ 10 4.3.2 Subsurface Drainage........................................................................................... 11 4.3.3 Cut Slopes............................................................................................................ 11 GEO TABLE OF CONTENTS (Continued) 4.4 REMEDIAL GRADING EVALUATION/ACCEPTANCE.................................................... 11 4.5 FILL PLACEMENT............................................................................................................ 11 4.6 SELECTION OF MATERIALS.......................................................................................... 12 4.7 UNDERGROUND UTILITY BACKFILL............................................................................. 12 4.8 EROSION CONTROL....................................................................................................... 13 4.9 STORMWATER BIORETENTION AREAS....................................................................... 13 5.0 FOUNDATION RECOMMENDATIONS............................................................. 14 5.1 PIER AND GRADE BEAM................................................................................................ 14 5.2 CRAWL SPACE MOISTURE CONTROL......................................................................... 15 5.3 PAD AND FOUNDATION DRAINAGE............................................................................. 16 5.4 EXTERIOR SLAB-ON-GRADE......................................................................................... 16 6.0 RETAINING WALL RECOMMENDATIONS...................................................... 17 6.1 SHORING/CATCHMENT WALL....................................................................................... 17 6.2 CONVENTIONAL RETAINING WALLS............................................................................ 17 6.2.1 Retaining Wall Surcharge.................................................................................... 18 6.3 MECHANICALLY STABILIZED EARTH (MSE) WALLS ................................................... 18 6.4 RETAINING WALL DRAINAGE AND BACKFILL............................................................. 19 7.1 CUT-OFF CURBS.............................................................................................................20 8.0 LIMITATIONS AND UNIFORMITY OF CONDITIONS ....................................... 20 PROJECT REFERENCES TECHNICAL REFERENCES FIGURES APPENDIX A— Exploration Logs APPENDIX B — Laboratory Test Data APPENDIX C — Previous Exploration Logs (ENGEO, 2005) APPENDIX D — Previous Exploration Logs (HJA, 2007) APPENDIX E — Previous Laboratory Test Data (ENGEO, 2004 - 2007) APPENDIX F — Slope Stability Analysis APPENDIX G — Geotechnical Contract Standards GEO 1.0 INTRODUCTION 1.1 PURPOSE AND SCOPE The purpose of this report is to develop geotechnical recommendations for the design and construction of the proposed project. Our scope of services included the items described below. • Review previous borings and laboratory data from adjacent projects. • Review previous reports by other consultants listed in the References, available literature, historic aerial images, and published geologic maps covering the study area. • Subsurface field exploration and laboratory testing. • Interpretation of subsurface field exploration data. • Evaluation of potential geotechnical concerns. • Data analysis and conclusions. • Prepare a report summarizing our conclusions and recommendations. This report was prepared for the exclusive use of our client and their consultants for design of this project. In the event that any changes are made in the character, design or layout of the development, we must be contacted to review the conclusions and recommendations contained in this report to evaluate whether modifications are recommended. 1.2 PROJECT LOCATION AND DESCRIPTION The proposed development includes the Kent and Vandam properties totaling approximately 8.5 acres, located in Danville, as shown on Figures 1 and 5. The 4.6-acre Kent property, designated as Assessor's Parcel Number (APN) 207-061-008, is bordered by Tassajara Lane on the northwest, the existing Subdivision 9014 on the north, private parcels on the east and south, and the Vandam property on the west. The 3.9-acre Vandam Property, designated as APN 207-061-009-8 is bordered on the north by Tassajara Lane and by private properties on the west and south. Elevations across the site vary from approximately 508 feet along the east property line on the Kent property to about 670 feet at the southwest corner of the Vandam property, as shown on Figure 5. Existing structures on the properties include a barn and outbuildings. The site topography has been modified by grading, including small cuts and fills on the Kent property. The eastern side of the Kent property was re -graded to create the existing east -facing slope in 2007 as part of the construction of Subdivision 9014. 1.3 PROPOSED DEVELOPMENT Based on preliminary grading plans prepared by Milani & Associates, Inc. dated March 2009, it is proposed to construct seven single-family residential lots on Kent and Vandam Properties as shown on Figure 5. Building pads will be created by making cuts of up to about 20 feet, generally around the southern and western portions of the site, and fills of up to about 15 feet on the northern portion of the site. It is proposed to construct a new 15-foot-high 3:1 (horizontal:vertical) slope along the north margin of the project. Tassajara Lane will be widened along the property's western boundary. The proposed building pads will be split-level, with 10-foot-high 2:1 slopes between the upper and lower level. The development of the subject site will also include construction of interior driveways and utilities to service the development. Structural loads and other details related to the proposed residential structures and site improvements have not been developed at this time. However, we understand that the proposed residential houses are anticipated to consist of one - and two-story wood -framed structures. 1.4 EXISTING GEOTECHNICAL DATA ENGEO completed a geotechnical exploration in 2005 on the adjacent Subdivision 9014 (formerly the Gates property), that included drilling three borings on the Gates property and two borings on the Kent property. Henry Justiniano & Associates (HJA) prepared a series of geotechnical reports for the Kent and Vandam properties in 2008 and 2009 (listed in the References). The HJA exploration included drilling eight borings, laboratory testing and preparation of geotechnical recommendations for the proposed seven -lot residential development depicted on Figure 5. Logs of the previous ENGEO borings and laboratory test results are contained in Appendix A. HJA boring and laboratory test results are presented in Appendix B. 1.5 2019 FIELD EXPLORATION AND LABORATORY TESTING Our field exploration included drilling 9 continuously cored borings and 21 test pits at the locations shown on Figure 6. An explanation of our field exploration methods and the exploration logs are presented in Appendix A. To measure shear strength, soil gradation, plasticity index, dry density, and moisture content, we tested samples recovered during drilling activities. Our laboratory test results are presented in Appendix B, and select test results are also presented on the boring logs in Appendix A. 1.5.1 Borings We drilled eight borings with a CME dry core sampling system to obtain relatively continuous soil profiles at each boring location. The cores were photographed and logged in the field by our engineering geologist. The recovered cores were returned to our lab for additional observation and testing. We used our field logs combined with examination of core photos and laboratory testing to develop the report logs in Appendix A. The logs depict subsurface conditions at the exploration locations for the date of exploration; however, subsurface conditions may vary with time. 1.5.2 Test Pits We excavated 21 test pits to a maximum depth of 14 feet. An ENGEO geologist observed the test pit excavation and logged the subsurface conditions at each location. We retained a backhoe to excavate the test pits using a 2-foot-wide bucket and logged the type, location, and uniformity of the underlying soil/rock. We obtained bulk soil samples from the test pits using hand -sampling techniques. The test pit logs present descriptions of the subsurface conditions encountered. We used the field logs to develop the report logs in Appendix A. The logs depict subsurface conditions at the exploration locations for the date of exploration; however, subsurface conditions may vary with time. GEO 2.0 FINDINGS 2.1 SITE BACKGROUND To characterize and understand the site use history and the geomorphology, we reviewed stereographic-paired aerial photographs dating to 1939 (References). The Kent property includes a barn and corrals and has previously been used for agricultural purposes. The Vandam property is open, undeveloped grassland. There have been several episodes of minor grading on the Kent property, occurring from the mid-1960s through the 1980s, resulting in placement of fill as described below in Section 2.2.2. 2.2 GEOLOGY 2.2.1 Regional Geology As shown on Figure 2, The Tassajara Valley is underlain by folded upper Miocene -age nonmarine sedimentary rocks generally referred to as the Green Valley/Tassajara Group (Tgvt) (Graymer, 1994). The Tgvt typically consists of interbedded claystone, clayey siltstone, sandstone and conglomerate. The Tgvt bedrock contains a high proportion of fine-grained and expansive clay. Similar folded Miocene/Pliocene-age rocks extend from the south edge of the Mount Diablo uplift to the Livermore Valley. Regional landslide mapping by Nilsen (1975) is depicted on Figure 3. Nilsen identified earthflows in the swale areas south and east of the Kent property, as well as on the western portion of the Vandam property. For this project, landslide mapping was refined based on detailed examination of aerial photographs and a geologic field reconnaissance. 2.2.2 Site Geology Artificial Fill (Qaf, Qef) — portions of the Kent and Vandam properties were previously graded in the 1960s through the 1980s to fill in old incised drainages and locally create more level areas. The older fill is considered undocumented and are labeled on Figure 6 as Qaf. Undocumented fill up to about 12 feet thick was encountered in borings along the north side of the Kent property. In 2007, Braddock & Logan Services constructed the adjacent Subdivision 9014. Part of the site grading included a buttress key that extended up to about 40 feet below the original ground surface. The southern edge of the buttress extended on to the Kent property, as shown on Figures 6 and 7. Grading on Subdivision 9014 was observed and tested by ENGEO, and the extent of corrective grading and exposed geologic conditions were documented in the ENGEO report of July 5, 2007. The limits of documented engineered fill are depicted on Figure 5. The engineered fill typically consisted of clay and rock fragments derived from buttress excavations and from fill imported from the nearby Tassajara Lane project. • Surficial Landslides (Qls) — most of the area of the Kent property and swale areas on the Vandam property are underlain by surficial landslides consisting of stiff, high plasticity clay. The surficial landslide deposits typically contain numerous internal slip surfaces and are generally bounded at the base by well-defined slip planes. A landslide on the west -central portion of the Vandam property has exhibited several recent episodes of activity, including as GEO recently as the winter of 2016-2017. This landslide extends off the property to the west on to the adjacent Subdivision 9014 property. Deep-seated Bedrock Landslides (Qls) — Borings completed by ENGEO for the current and previous projects encountered evidence of landslide slip planes within weathered bedrock underlying surficial landslide deposits at depths of about 25 to 45 feet as described in the boring logs and depicted on the Cross Sections, Figure 7. In addition, landslide slip planes in the upper portions of the bedrock were previously observed in the back cut of the existing buttress key at the north end of the Kent property. Dormant Landslide Lobe — The east side of the Kent property is bordered by an approximately 700-foot-long dormant landslide lobe that extends off the property to the east. Test pits excavated along the east property line encountered landslide deposits to the maximum depth explored, over 14 feet. Adjacent Borings 2-133 and 2-137 encountered landslide deposits to depths of about 30 to 40 feet. The geomorphology of the landslide lobe is subdued and it appears to be inactive. • Tassajara Green Valley Group Bedrock (Tgvt) — Bedrock deposits encountered in site explorations consist mainly of claystone and clayey siltstone with minor amounts of interbedded friable sandstone. The bedrock is weak, closely fractured and the claystone and siltstone are highly expansive. The bedrock strikes west-northwest and dips at steep inclinations generally between 40 and 60 degrees to the north. 2.3 GROUNDWATER CONDITIONS Groundwater was encountered in Boring 2-B-4 at 24 feet but was not encountered in any other previous borings or test pits completed for this study. During grading of the buttress key on the adjacent Subdivision 9014, the 40-foot deep excavation did not encounter significant free groundwater. 2.4 SEISMICITY Numerous small earthquakes occur every year in the San Francisco Bay Area and larger earthquakes have been recorded and can be expected to occur in the future. Figure 3 shows the approximate location of faults and epicenters of significant historic earthquakes recorded within the Greater Bay Area Region. We provide a list of active faults within 25 miles of the site and their estimated maximum earthquake magnitudes in the following table. The California Geological Survey defines an active fault as one that has had surface displacement within Holocene time (approximately the last 11,000 years) (Bryant and Hart, 2007). TABLE 2.4-1: Nearby Active Faults, Latitude: 37.80557 Longitude:-121.95365 Mount Diablo Thrust South 6.3 6.6 Calaveras 5.8 7.1 Mount Diablo Thrust North 2.3 7.2 Concord 11.2 6.6 Hayward 17.3 2.4 The United States Geologic Survey evaluated California seismicity through a study by the 2014 Working Group on California Earthquake Probabilities (WGCEP) (Field, 2014) which led to GEO development of Uniform California Rupture Forecast (Version 2) (UCERF3). The 2014 WGCEP evaluated the 30-year probability of Mw 6.7 or greater earthquake occurring on the known active fault systems in the San Francisco Bay Area, and the 2014 WGCEP estimated an overall probability of 72 percent for this area. The site is not located within a currently designated Alquist-Priolo Earthquake Fault Zone and no known surface expression of active faults is believed to exist within the site; therefore, fault rupture through the site is not anticipated. 3.0 ANALYSIS AND CONCLUSIONS It is our opinion that the proposed seven -lot subdivision is feasible from a geologic and geotechnical standpoint, provided the recommendations contained in this report are incorporated into the development plans. Based on our explorations and analysis as well as a review of available published maps and reports for the site, the main geotechnical concerns for the proposed development are critically expansive site soil and bedrock, the extensive existing landslide deposits, existing undocumented fill, and the fact that landslide deposits identified on the site cross property boundaries where corrective grading excavations will be required. Landslide and expansive soil hazards exist throughout the Danville area. Landslides can be effectively mitigated during site grading by removing the landslides and replacing the slide debris with engineered fill, or buttressing the landslides and providing debris catchment areas. Expansive soil can be mitigated by proper foundation design and grading measures. These items and other geotechnical issues are discussed in the following sections of this report. 3.1 SEISMIC HAZARDS Potential seismic hazards resulting from a nearby earthquake can generally be classified as primary and secondary. The primary effect is ground rupture, also called surface faulting. The common secondary seismic hazards include ground shaking, liquefaction, and seismically induces landslide deformation. The following sections present a discussion of these hazards as they apply to the site. Based on topographic and lithologic data, the risk of regional subsidence or uplift, tsunamis, flooding or seiches is considered low to negligible at the site. 3.1.1 Ground Rupture Since there are no known active faults crossing the property and the site is not located within an Earthquake Fault Special Study Zone, it is our opinion that ground rupture is unlikely at the subject property. 3.1.2 Ground Shaking An earthquake of moderate to high magnitude generated within the San Francisco Bay Area region could cause considerable ground shaking at the site, similar to that which has occurred in the past. To mitigate the shaking effects, structures should be designed using sound engineering judgment and the 2019 California Building Code (CBC) requirements, as a minimum. Seismic design provisions of current building codes generally prescribe minimum lateral forces, applied statically to the structure, combined with the gravity forces of dead -and -live loads. The code -prescribed lateral forces are generally considered to be substantially smaller than the GEO comparable forces that would be associated with a major earthquake. Therefore, structures should be able to: (1) resist minor earthquakes without damage, (2) resist moderate earthquakes without structural damage but with some nonstructural damage, and (3) resist major earthquakes without collapse but with some structural as well as nonstructural damage. Conformance to the current building code recommendations does not constitute any kind of guarantee that significant structural damage would not occur in the event of a maximum magnitude earthquake; however, it is reasonable to expect that a well -designed and well -constructed structure will not collapse or cause loss of life in a major earthquake (SEAOC, 1996). 3.1.3 Liquefaction Soil liquefaction results from loss of strength during cyclic loading, such as imposed by earthquakes. The soil considered the most susceptible to liquefaction is clean, loose, saturated, uniformly graded fine sand below the groundwater table. Due to the soil classifications of the on -site soil/bedrock and the fines content, the risk of liquefaction at the site is low. 3.1.4 Seismically -Induced Landslide Deformation Existing landslides on the Kent and Vandam properties could be subject to seismically induced deformation, and will require corrective grading to improve slope stability as discussed below in Section 3.3. 3.2 2019 CBC SEISMIC DESIGN PARAMETERS The following table provides seismic design criteria utilizing ASCE 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures that will be incorporated into the 2019 California Building Code (CBC) criteria. TABLE 3.2-1: 2019 CBC Seismic Design Parameters, Latitude: 37.8056 Longitude:-121.9537 Site Class C Mapped MCER Spectral Response Acceleration at Short Periods, Ss (g) 2.21 Mapped MCER Spectral Response Acceleration at 1-second Period, S1 (g) 0.72 Site Coefficient, Fa 1.2 Site Coefficient, Fv 1.4 MCER Spectral Response Acceleration at Short Periods, SMs (g) 2.65 MCER Spectral Response Acceleration at 1-second Period, SM1 (g) 1.01 Design Spectral Response Acceleration at Short Periods, Sos (g) 1.77 Design Spectral Response Acceleration at 1-second Period, Sol (g) 0.68 3.3 LANDSLIDE HAZARDS 3.3.1 Landslides and Earthflows As depicted on Figures 6 and 7, most of the Kent property and a large portion of the Vandam property are underlain by existing landslides ranging in depth from several feet to up to about 40 feet. These landslides occur within highly expansive surficial clay soil and the upper portions of the weathered bedrock. The landslides can generally be categorized and earthflows and GEO rotational slumps, which are generally viscous and slow -moving, typically triggered by seasonal rainfall events. The landslide deposits along the northern portion of the Kent property were stabilized as part of the grading of the Subdivision 9014 project by construction of a 30- to 40-foot-deep, 80- to 100-foot-wide buttress key. However, the upslope portion of these landslides, as well as landslides on the Vandam property, will require additional corrective grading measures to stabilize the proposed cut and fill slopes depicted on the grading plans. The proposed stabilization measures are depicted on the Cross Sections, Figure 7, and on the corrective grading plan, Figure 8. 3.3.2 Off -site Landslides and Debris Flows Landslide deposits extend off the west and east sides of the Kent property and on to neighboring parcels. There are additional landslides in the existing swale area south of the Kent property. Based on these conditions, it will be necessary to provide some form of debris catchment along the west and south project boundaries. The most significant off -site debris flow risk occurs on the Kent property where the existing topographic swale extends up slope and to the south for several hundred feet, directly behind the proposed Lot 4. In our opinion, the project plans should be modified to provide a debris catchment basin with a minimum capacity of approximately 1,000 cubic yards. Along the western boundary of the Vandam property, some form of debris catchment will also be required, such as a debris catchment wall. Both debris catchment basins and catchment should be provided with a means of equipment access to allow periodic removal of debris. Regular maintenance of the debris catchment should be anticipated and some form of funding should be provided for yearly inspection and debris removal as needed. Because existing landslide deposits on the Vandam property extend across property lines, proposed corrective grading excavations are likely to result in off -site mobilization of landslide deposits on the adjacent property to the west. Corrective grading measures along the east property line are configured to minimize construction mobilization risks. The risk of off -site landslide mobilization can be accommodated by: • Obtaining permission to grade on adjacent properties, and extending corrective grading to completely remove and replace existing landslide deposits in conjunction with on -site corrective grading. This option is recommended for the western side of the Vandam property. • If access to the adjacent property west of the Vandam parcel cannot be obtained, construct a temporary shoring wall designed to support open excavations and to increase long-term slope stability. The shoring wall can also be designed with a minimum of 5 feet of exposed freeboard to also act as a debris catchment. • Perform corrective grading in narrow sections to reduce off -site landslide risks. This option could be applicable along the western side of the Vandam property. • Configure corrective grading to minimize the risk of off -site landslide mobilization by limiting the width of open exaction and by limiting maximum temporary slope inclination to 11/2:1. This option could be applied along the eastern property boundary at the Kent property. Along the western property boundary, HJA recommended a tangent pier wall with exposed freeboard. We provide recommendations for the shoring/catchment wall in Section 6.1. Based on landslide mapping provided on Figure 6, we recommend that the shoring/catchment wall extend for a minimum length of 300 feet. GEO 3.4 SLOPE STABILITY ANALYSIS 3.4.1 Geometry and Assumed Soil Parameters We analyzed three cross sections showing the geologic conditions and proposed grading at the site. Prior to performing slope stability analyses, we evaluated the strength of native soil and proposed engineered fill based on index testing, Consolidated Undrained (CU) Triaxial Compression Tests and Unconsolidated Undrained (UU) Triaxial Compression Tests. In our evaluation, we used previous testing for this project site and from the adjacent Tassajara Lane as well as additional test performed for this study. Based on our data review, we developed the idealized soil profiles shown on our slope stability results. TABLE 3.4.1-1: Slope Stability Analysis Material Properties Engineered Fill - Undrained 125 2000 0 Engineered Fill - Drained 130 200 23 Landslide 125 0 12 Tygt 125 1000 25 3.4.2 Method of Analysis We performed a simplified deformation analysis using the computer program SLIDE, which is a limit equilibrium program that allows the user various search routines to locate the minimum factor of safety and critical slip surface. We used circular searching methods and the Spencer's method for our analyses (Spencer, 1973). We used the design peak ground acceleration (PGA) of 0.71g for liquefaction analysis based on ASCE 7-16 seismic parameters. We used a moment magnitude (MW) of 7.1, based the maximum possible earthquake on the Calaveras fault. We performed a "pseudo -static" screening analysis as recommended in the California Geological Survey's (CGS) SP117A "Guidelines for Evaluating and Mitigating Seismic Hazards in California." For this screening analysis, we selected a seismic coefficient of 0.26g for an assumed displacement threshold of about 15 centimeters or approximately 6 inches. 3.4.3 Results of Slope Stability Analyses TABLE 3.4.3-1: Summary of Slope Stability Analyses LOCATION STATIC PSEUDO -STATIC (0.15g) Cross Section 2-2' 1.2 1.2 Cross Section 44 2.4 1.3 Cross Section 5-5' 2.1 1.1 Our analyses indicate a factor of safety greater than 1.5 for the static analysis, except for Cross Section 2-2', and 1.0 for the Pseudo -Static analysis. Based on SP117, the lateral displacement for a design seismic event is anticipated to be less than 6 inches. According to SP117A, this amount of lateral displacement is generally considered small enough that residential structures can be designed with foundations stiff enough to allow for the movement without serious damage. Appendix D presents select printouts of our analyses. GEO Cross Section 2-2' cuts through an existing landslide partially located on an adjacent property that is discussed in Section 3.3.2. If remedial grading cannot be performed on the adjacent property and the upper portion of the landslide were to remain in place, then the static factor of safety is less than 1.5 as shown in our slope stability analysis. In addition, this area would likely be subject to failure during construction, as the remedial grading for the lower portion of the landslide is performed. We recommend that a shoring/catchment wall be constructed to stabilize the upper portion of the landslide. We present recommendations for this retaining wall in Section 6.1. 3.5 SOIL CORROSION POTENTIAL Soil corrosion testing performed on the adjacent Subdivision 9014 indicated a moderate sulfate exposure for concrete. For planning purposes, it should be an assumed that soil sulfate levels at subject project will be similar. The final soil conditions on graded pads will not be known until the completion of site grading. We recommend that additional sulfate testing be performed at the completion of finished grading. 3.6 EXPANSIVE SOIL Expansive soil shrinks and swells because of moisture changes. This can cause heaving and cracking of slabs -on -grade, pavements, and structures founded on shallow foundations. Site soil and bedrock soil encountered in current and previous explorations consisted of highly expansive clay with Pls generally ranging from 31 to 55, indicating high to critically expansive soil conditions. It will therefore be necessary to design improvements to mitigate expansive soil conditions. 4.0 EARTHWORK RECOMMENDATIONS Based on the findings of our subsurface exploration, geologic mapping, laboratory testing, and field experience, we provide the following geotechnical recommendations for use during grading and construction. We should be notified at least 48 hours prior to grading to coordinate our schedule with the grading contractor. All grading operations should meet the requirements of our Geotechnical Contract Standards presented in Appendix G and must be observed and tested by our field representatives. Ponding of stormwater, other than within engineered detention basins, should not be permitted at the site, particularly during work stoppage for rainy weather. Before the grading is halted by rain, positive slopes should be provided to carry surface runoff to storm drainage structures in accordance with the approved Storm Water Pollution Prevention Plan (SWPPP). 4.1 GENERAL SITE CLEARING Areas to be developed should be cleared of surface and subsurface deleterious materials, including existing building foundations, slabs, buried utility and irrigation lines, septic systems, pavements, debris, and designated trees, shrubs, and associated roots. Following clearing, the site should be stripped to remove surface organic materials. Strip organics from the ground surface to a depth of at least 2 to 3 inches below the surface. Tree roots should be removed to a depth of at least 5 feet below finished grade in cut lots and 3 feet below original GEO grade in fill lots. Our field representative shall determine actual depths of stripping and tree root removal during grading. Within the development areas, excavations resulting from demolition and stripping, which extend below final grades, should be cleaned to firm undisturbed soil as determined by our field representative. No loose or uncontrolled backfilling of depressions resulting from demolition and stripping is permitted. The surface should then be scarified, moisture conditioned, and backfilled with compacted engineered fill. The requirements for backfill materials and placement operations are the same as for engineered fill. 4.2 REMOVALS 4.2.1 General Subexcavation The soil/bedrock should be excavated to a minimum depth of 5 feet below existing grade in areas to receive fill and 5 feet below finish grade in areas of cut, and replaced with uniformly mixed fill compacted in accordance with Section 4.5. 4.2.2 Existing Fill Our supplemental exploration and the previous studies encountered existing undocumented fill material up to 12 feet thick on the project site. The existing fill generally overlays landslide deposits and will be removed and replaced during corrective grading for landslide stabilization. Existing engineered fill on the northern portion of the Kent property will be suitable for supporting improvements, but localized keying and benching will be required to support proposed fill slopes as shown on Figures 7 and 8. 4.2.3 Landslide Removals Landslide removals are depicted on the Cross Sections, Figure 7, and the corrective grading plan, Figure 8. The removal depicted on the Figures are intended to provide general guidelines for corrective grading to increase site stability to acceptable static and seismic factors of safety. Landslide removals should be observed in the field by ENGEO so that we can make appropriate recommendation for adjusting the depth and extents of removals based on revealed conditions. 4.3 SLOPE GRADING Graded slopes should be constructed at inclinations no steeper than 2:1 (horizontal:vertical) for height of up to 8 feet. Slopes higher than 8 feet should be inclined no steeper than 3:1. The contractor is responsible to construct temporary construction slopes in accordance with CALOSHA requirements. 4.3.1 Toe Keyways and Benching After stripping and clearing, mass grading should begin with construction of toe keyways. We recommend constructing a keyway at the toe of fill slopes and reconstructed cut and cut -fill transition slopes. The keyways should be a minimum of 25 feet wide and extend at least 5 feet below original grade or proposed grade into firm competent soil or rock, as determined by our field representative during grading. The bottom of the keyway should slope at least 2 percent downward toward the heel of the key. GEO Typical keyway and benching details are shown on Figure 9. We may recommend deeper keyways and/or benches based on actual soil/rock conditions observed during construction. The area beyond the toe of fill slope shall be sloped for sheet overflow or other drainage provisions. We should observe and approve the keyways and benches in the field prior to placement of engineered fill. 4.3.2 Subsurface Drainage Subsurface drainage systems should be installed in keyways and in swales or natural drainage ways that are to be filled, as shown on our Corrective grading plan (Figure 8). Additional subdrains should be added, where seepage, springs, or wet conditions are encountered during excavation as recommended by our field representative. Place subdrains at bottom of keyway where possible to gravity flow. The anticipated locations, approximate elevations and recommended outfall points for subdrains are depicted on the corrective grading plans, Figure 8. Subdrain systems should consist of a minimum 6-inch-diameter perforated pipe encased in an 18-inch minimum thickness of Caltrans Class 2 permeable material or clean crushed rock wrapped in geotextile filter fabric, as shown on the typical detail on Figure 10. We recommend that subdrains have a minimum fall of 1 percent. The subdrain pipe and filter fabric should meet the requirements contained in our Geotechnical Contract Standards presented in Appendix G. Discharge from the subdrains will generally be low but in some instances may be continuous. Subdrains should outlet into the storm drain system or other approved outlets, and their locations should be surveyed and documented by the project Civil Engineer for future maintenance. Subdrains should gravity flow to the approved outlet. Not all sources of seepage are evident during the time of grading because of the intermittent nature of some of these conditions and their dependence on long-term climatic conditions. Furthermore, new sources of seepage may be created by a combination of changed topography, manmade irrigation patterns, and potential utility leakage. Since uncontrolled seepage is one of the major causes of detrimental soil movements, it is of utmost importance that we be advised of any seepage conditions so that remedial action may be initiated, if necessary. 4.3.3 Cut Slopes Cut slopes on the proposed project will expose either existing landslide deposits of relatively weak and expansive Tassajara Formation bedrock. As shown on Figure 7, we recommend that the proposed cut slope be overexcvated and reconstructed as a drained fill buttress. 4.4 REMEDIAL GRADING EVALUATION/ACCEPTANCE We will observe and/or document remedial grading areas, including keyways, benches, and subexcavation areas, prior to receiving fill. The areas receiving fill and subdrains should be surveyed. 4.5 FILL PLACEMENT The contractor should perform subgrade compaction prior to fill placement to provide adequate bonding with the initial lift of fill. The contractor should first scarify the exposed soil to a depth of at least 12 inches then moisture condition and compact the subgrade in accordance with the requirements listed in the table below. The lift thickness should not exceed 12 inches or the depth of penetration of the compaction equipment used, whichever is less. Track rolling to compact faces of slopes is usually not sufficient; typically, slopes should be overfilled a minimum of 2 feet and cut back to design grades. The following compaction recommendations should be used for the placement and compaction of subgrade and fill: TABLE 4.5-1: Subgrade and Engineered Fill Compaction and Moisture Content Requirements Expansive On -site Material* 87 to 92 90 5 Non -Expansive Import Fill* 90 95 2 Pavement AB** 95 -- 0 *Expansive material defined as PI>12 **As specified in Section 7.0 The relative compaction and optimum moisture content of soil and aggregate base referred to in this report are based on the most recent ASTM D1557 test method. We recommend that the fill be compacted at higher than optimum moisture contents, as shown above, to minimize the effects of swell and/or hydrocompression. The term "moisture condition" refers to adjusting the moisture content of the soil by either drying if too wet or adding water if too dry. Compacted soil is not acceptable if it is unstable. It should exhibit only minimal flexing or pumping, as observed by our field representatives. 4.6 SELECTION OF MATERIALS On -site soil material is suitable as fill material provided it is processed to remove concentrations of organic material (soil which contains more than 2 percent organic content by weight), and debris. Imported fill materials should meet the above requirements and the Geotechnical Contract Standards in Appendix G. 4.7 UNDERGROUND UTILITY BACKFILL The contractor is responsible for conducting trenching and shoring in accordance with CALOSHA requirements. We recommend that utility trench backfilling be done under our observation. Pipe zone backfill (i.e., material beneath and immediately surrounding the pipe) may consist of a well -graded import less than 1/4 inch in maximum dimension. Trench zone backfill (i.e., material placed between the pipe zone backfill and the ground surface) may consist of native soil. Trench zone back fill should be compacted according to the recommendations in Section 4.5. We recommend the import material used for pipe zone backfill consist of fine- to medium -grained sand or a well -graded mixture of sand and gravel and that this material not be used within 2 feet of finish grades. In general, uniformly graded gravel should not be used for pipe or trench zone backfill due to the potential for migration of: (1) soil into the relatively large void spaces present in this type of material and (2) water along trenches backfilled with this type of material. Where utility trenches pass under a building perimeter, they must be provided with an impervious seal consisting of native materials or concrete. The impervious plug should extend at least 3 feet to each side of the crossing. This is to reduce surface -water percolation into the material under GEO foundations and pavements where such water would remain trapped in a perched condition, allowing clay to develop its full expansion potential. Care should be exercised where utility trenches are located beside foundation areas. Utility trenches constructed parallel to foundations should be located entirely above a plane extending down from the lower edge of the footing at an angle of 45 degrees. Utility companies and Landscape Architects should be made aware of this information. Compaction of trench backfill by jetting should not be allowed at this site. If there appears to be a conflict between The City or other agency requirements and the recommendations contained in this report, this should be brought to the Owner's attention for resolution prior to submitting bids. 4.8 EROSION CONTROL The tops of fill or cut slopes should be graded in such a way as to prevent water from flowing freely down the slopes. Due to the nature of the site soil and bedrock, graded slopes may experience severe erosion when grading is halted by heavy rain. Therefore, before work is stopped, a positive gradient away from the tops of slopes should be provided to carry the surface runoff away from the slopes to areas where erosion can be controlled. It is vital that no completed slope be left standing through a winter season without erosion control measures having been provided. Because the existing bedrock is relatively nutrient poor, it may be difficult for vegetation to become properly established, resulting in a potential for slope erosion. Revegetation of graded slopes can be aided by retaining the organic -rich strippings and spreading these materials in a thin layer (approximately 6 inches thick) on the graded slopes prior to the winter rains and following rough grading. All landscaped slopes should be maintained in a vegetated state after project completion. The use of drought -tolerant vegetation requiring infrequent drip irrigation during summer is recommended. No pressurized irrigation lines should be placed on or near the tops of graded slopes. 4.9 STORMWATER BIORETENTION AREAS If bioretention areas are implemented, we recommend that, when practical, they be planned a minimum of 5 feet away from structural site improvements, such as buildings, streets, retaining walls, and sidewalks/driveways. When this is not practical, bioretention areas located within 5 feet of structural site improvements can either: 1. Be constructed with structural side walls capable of withstanding the loads from the adjacent improvements, or 2. Incorporate filter material compacted to between 85 and 90 percent relative compaction and a waterproofing system designed to reduce the potential for moisture transmission into the subgrade soil beneath the adjacent improvement. In addition, one of the following options should be followed. 1. We recommend that bioretention design incorporate a waterproofing system lining the bioswale excavation and a subdrain, or other storm drain system, to collect and convey water to an approved outlet. The waterproofing system should cover the bioretention area GEO excavation in such a manner as to reduce the potential for moisture transmission beneath the adjacent improvements. 2. Alternatively, and with some risk of movement of adjacent improvements, if infiltration is desired, we recommend the perimeter of the bioretention areas be lined with an HDPE tree root barrier that extends at least 1 foot below the bottom of the bioretention areas/infiltration trenches. Site improvements located adjacent to bioretention areas that are underlain by base rock, sand, or other imported granular materials, should be designed with a deepened edge that extends to the bottom of the imported material underlying the improvement. Where adjacent site improvements include buildings greater than three stories, streets steeper than 3 percent, or design elements subject to lateral loads (such as from impact or traffic patterns), additional design considerations may be recommended. If the surface of the bioretention area is depressed, the slope gradient should follow the slope guidelines described in earlier section(s) of this document. In addition, although not recommended, if trees are to be planted within bioretention areas, HDPE Tree Boxes that extend below the bottom of the bioretention system should be installed to reduce potential impact to subdrain systems that may be part of the bioretention area design. For this condition, the waterproofing system should be connected to the HPDE Tree Box with a waterproof seal. Given the nature of bioretention systems and possible proximity to improvements, we recommend that we be retained to review design plans and provide testing and observation services during the installation of linings, compaction of the filter material, and connection of designed drains. It should be noted that the contractor is responsible for conducting all excavation and shoring in a manner that does not cause damage to adjacent improvements during construction and future maintenance of the bioretention areas. As with any excavation adjacent to improvements, the contractor should reduce the exposure time such that the improvements are not detrimentally impacted. 5.0 FOUNDATION RECOMMENDATIONS 5.1 PIER AND GRADE BEAM The proposed residential structures are proposed to be constructed on split-level pads. We recommend that these structures be support by a pier -and -grade -beam foundation. Isolated piers should be avoided and individual piers should be connected with grade beams. Support on drilled friction piers can be designed using the following criteria. Minimum Pier Diameter: 16 inches Minimum Pier Depth: 15 feet (for piers located within 10 feet from an adjacent downslope, the pier depth should be increased by 3 feet for a 3:1 slope and 5 feet for a 2:1 slope to account for the sloping foreground.) GEO Maximum Allowable Friction Value: 500 psf (pounds per square foot). This value may be increased by one-third to allow for short-term seismic or wind loads. The upper 36 inches of soil should be ignored in the pier -load computation. Lateral Load: Uniform pressure of 20 psf over the upper 10 feet Pier Spacing: Minimum three pier diameters on center. Where closer spacing is unavoidable, the pier depth should be increased. We should make specific recommendations for increased pier depths in each specific case during our foundation plan review. Lateral passive resistance: 250 pcf acting over two pier diameters, The upper 5 feet of the pier should be neglected for passive pressure resistance. A Structural Engineer should design the pier reinforcement. The pier reinforcement should be tied to the grade beams as recommended by the Structural Engineer. Expansive soil may exert upward pressure on the base of grade beams. Therefore, the subgrade soil should be well over optimum moisture at the time of concrete placement. Under no circumstance should concrete be cast upon dry, desiccated soil. We recommend a 2-inch void under grade beams to reduce the uplift pressure on grade beams. Expansive soil may exert upward pressure on over -poured concrete collars at the tops of the piers or piers constructed in an excavation that has an inverted bell -shape in the upper portions of the pier. To avoid these conditions, the top of all piers should be constructed with the use of Sonotube®, or equal, concrete forms with the same nominal diameter as the pier excavation. Pier -drilling operations and concrete placement should be coordinated so that pier holes are left open a minimum amount of time. We should observe the pier -hole drilling operations and make appropriate recommendations in the field to accommodate required depth and embedment criteria. We should review structural plans and calculation prior to construction to check for conformance with these recommendations and to verify that subdrains will be avoided. 5.2 CRAWL SPACE MOISTURE CONTROL For the portions of the structures constructed with raised floors and underlying crawl space areas, there is an inherent risk of excessive ground moisture and water vapor leading to wood damage, mold, mildew, etc. To reduce the potential for ground moisture in crawl spaces, we recommend that measures be implemented to control moisture below and around the structures. It is important that the crawl space designer provides necessary measures to properly and liberally ventilate crawl space areas to reduce adverse effects of high water vapor conditions. The crawl space ground surface should be covered with either: (1) a concrete slab with a thickness of at least 2 to 3 inches, often called a rat slab, placed directly over a polyethylene membrane, or (2) a durable vapor retarder/liner conforming to Class A of ASTM E 1745. Vapor retarders shall be installed in accordance with manufacturer's recommendations including sealing seams, pipe penetrations and attached to perimeter concrete stemwalls. As a minimum, we recommend that ventilation GEO openings be provided through foundation walls or exterior walls for the under -floor space, between the bottom of the floor joists and the earth under the building, in accordance with 2019 California Building Code. Additionally, locations of the ventilation openings shall be around all sides of foundation perimeters, and crawl -space airflow shall allow for adequate evacuation of excessive water vapor. 5.3 PAD AND FOUNDATION DRAINAGE Due to the split -pad configuration of the proposed lots, surface and shallow subsurface drainage will require close attention during the design and construction of pad improvements. Subsurface drains should be constructed beneath and around the building perimeter to limit subsurface seepage under foundations for buildings with a raised floor. The subsurface drain trench should be at least 12 inches wide and a minimum of 18 inches deep. All perimeter trenches and pipes should have a minimum slope of 1 percent and must be within 12 inches of the foundation. The closed roof downspout collector pipe and the perimeter subdrain can be constructed in a single trench if desired; however, the closed collector pipe must be placed above the perimeter subdrain pipe, and in no case may the subdrain pipe be connected to the closed drainpipe system. A schematic of a typical foundation drain system and details for drain construction are presented in Figure 10. Finished grades established following fine grading should provide positive surface gradients away from foundations to provide for rapid removal of surface water. Surface water flows on the finished graded lot should be directed to appropriate surface drainage collection facilities such as area drains or drainage swales. All surface drainage should be collected and conveyed to the stormwater drainage system in a manner that is approved by the project Civil Engineer. Ponding of stormwater must not be permitted on the building pads during prolonged periods of inclement weather. As a minimum requirement, finished grades should have slopes of at least 5 percent within 10 feet from the exterior walls, at right angles to them, to allow surface water to drain positively away from the structure. For paved areas, the slope gradient can be reduced to 2 percent. All roof stormwater should be collected and directed to downspouts. Stormwater from roof downspouts should be directed to a solid pipe that discharges to an approved outlet. 5.4 EXTERIOR SLAB -ON -GRADE Exterior flatwork includes items such as concrete sidewalks, steps, and outdoor courtyards exposed to foot traffic only. Provide a minimum section of 6 inches of concrete over 4 inches of aggregate base. Compact the aggregate base to at least 90 percent relative compaction (ASTM D1557) at a minimum 2 percentage points above optimum moisture content. Thicken flatwork edges to at least 10 inches to help control moisture variations in the subgrade and place reinforcement within the middle third of the slab to help control the width and offset of cracks. The Structural Engineer should design the exterior slab -on grade reinforcement, but as a minimum, we suggest any recommended slab reinforcement consist of steel bars in lieu of welded wire mesh. In our experience, welded wire mesh may not be sufficient to control slab cracking in an expansive soil environment. Minor cracking and distress should also be anticipated in slabs -on -grade as a result of concrete shrinkage and the highly expansive nature of the on -site soil. Frequent control joints should be provided to control cracking as recommended by the American Concrete Institute (Publication ACI 302.1 R-89). GEO The subgrade material under exterior slabs -on -grade should be uniform. Where exterior slab -on -grade construction is planned, care must be exercised in attaining a near -saturation condition of the subgrade soil before concrete placement, and the subgrade should not be allowed to dry prior to concrete placement. Exterior slabs -on -grade should be constructed structurally independent of the foundation system. An expansion joint material should be provided between structural elements and slabs to allow for each element to move independently and with a reduced potential for distress to the adjacent element. Slabs -on -grade should slope away from the building to prevent water from flowing toward the foundations. 6.0 RETAINING WALL RECOMMENDATIONS 6.1 SHORING/CATCHMENT WALL As discussed in Section 3.3.2, the uppermost portions of existing landsides along the western boundary of the Vandam property extend across the property line. If it is not possible to obtain permission to access the adjacent property and perform earthwork repairs, it will be necessary to construct a retaining to support the existing landslide that will remain in place on the adjacent property. If groundwater will be able to drain through the retaining wall, such as for a soldier pile and lagging wall, then a lateral equivalent fluid pressure of 125 pcf should be used for wall design. If water won't be able to freely drain through the wall, such as for a secant pile wall, then a lateral equivalent fluid pressure of 155 pcf should be used for design. Passive pressure of 250 pcf acting over two pier diameters can be used for design. The passive pressure should start below 3 feet for a 3:1 slope and 5 feet for a 2:1 slope. The shoring catchment wall should include a minimum of 5 feet of catchment height at the top of the wall and the piers should extend a minimum of 10 feet below the landslide base. 6.2 CONVENTIONAL RETAINING WALLS Retaining walls should be designed using the earth pressures in the table below. Retaining walls greater than 6 feet in height should be analyzed for seismic stability by adding the seismic increment to the active earth pressure. TABLE 6.2-1: Retaining Wall Design Earth Pressures Level 50 pcf 30 3:1 70 pcf 40 2:1 90 pcf 50 Retaining walls should be supported on drilled piers designed in recommendations in Section 5.1. Drainage should be provided behind recommended below to prevent any build-up of hydrostatic pressure infiltration and/or a rise in the groundwater level. GEO accordance with the the retaining walls as s from surface water 6.2.1 Retaining Wall Surcharge If a sidewalk or traffic is planned behind the wall, a minimum surcharge load of 50 psf or 100 psf, respectively (rectangular distribution), should be added to the top 10 feet of the wall. Design unrestrained walls to resist an additional uniform pressure equivalent to one-third of any surcharge loads applied at the surface. Design restrained walls to resist an additional uniform pressure equivalent to one-half of any surcharge loads applied at the surface. 6.3 MECHANICALLY STABILIZED EARTH (MSE) WALLS MSE walls may be considered for landscape area retaining walls that are 4 feet or less in exposed height and located at least 10 feet away from building foundations. Due to the highly expansive nature of the on -site soil, MSE walls backfilled with native material can be expected display some amount of lateral movement over time. We expect that this movement could be up to 2 inches. Alternatively, the anticipated lateral movement can be reduced if the MSE walls are backfilled with non -expansive import soil. The following general assumptions and design guidelines should be incorporated into MSE wall design. • Keystone (Standard 21'/2-inch) blocks, or pre -approved equivalent, with positive connection (fiberglass pins) should be used. • Site soil may be used as the foundation soil, retained soil, and reinforced fill soil. • For level foreground, the base of the lowest block should be embedded at least 1 foot below lowest adjacent grade. • For downsloping foreground, the walls should be embedded to achieve at least 8 feet of horizontal distance to the nearest free face from the base of the lowest block. For select, non -terraced front and side yard landscape walls with a total retained height less than 5 feet and without building, flatwork or other improvements within 5 feet behind the top of wall, a reduced embedment depth to achieve at least 5 horizontal feet from the front base edge of the lowest block to the nearest slope face may be feasible. Surcharge loads from vehicles should be included in the wall design if the surcharge loading is situated above a 1:1 line of projection extending up from the rear base edge of the bottom block. • For tiered wall systems, the lower retaining wall(s) should consider surcharge loads from walls and soil backfill located above. In addition, the upper wall should be embedded to at least 1 foot below the top of the lower wall and global stability analyses should be performed. We recommend that following soil criteria be used in the MSE wall design. TABLE 6.3-1: Soil Material Parameters Reinforced Fill 0 25 125 Retained Soil 0 25 125 Foundation Fill 0 25 125 GEO We recommend that the following minimum factors of safety be used in the MSE wall design. TABLE 6.3-2: Stability Factors of Safety Sliding 1.5 / 1.2 External Bearing Capacity 2.0 / 1.5 Overturning 2.0 / 1.5 Internal Pull-out Resistance 1.5 / 1.2 6.4 RETAINING WALL DRAINAGE AND BACKFILL All retaining walls should be provided with drainage facilities to prevent the build-up of hydrostatic pressures behind the walls. Wall drainage may be provided using a 4-inch-diameter perforated pipe embedded in Class 2 permeable material or free -draining gravel surrounded by synthetic filter fabric. The width of the drain blanket should be at least 12 inches. The drain blanket should extend to about one foot below the finished grades. The upper 1 foot of wall backfill should consist of on -site clayey soil. Collector perforated pipes should be directed to an outlet approved by the Civil Engineer. All backfill should be placed in accordance with recommendations for engineered fill provided in the referenced report. Light equipment should be used during backfill compaction to reduce possible overstressing of the walls. 7.0 PRELIMINARY PAVEMENT DESIGN Using estimated traffic indices for various pavement loading requirements and an assumed R-value of 5 for a clayey subgrade, we developed the following recommended pavement sections using Chapter 630 of the Caltrans Highway Design Manual (including the asphalt factor of safety), presented in the table below. The civil engineer should determine the appropriate traffic indices based on the estimated traffic loads and frequencies. TABLE 7.0-1: Preliminary Flexible Pavement Design 4.0 12 3 5.0 13 3'/2 6.0 14 4 7.0 16 4'/2 Notes: AB is aggregate base Class 2 Material with minimum R = 78 AC is asphalt concrete These sections are for estimating purposes only; actual sections should be based on R-Value tests performed on samples of actual subgrade materials recovered at the time of grading. Pavement construction and all materials should comply with the requirements of the Standard Specifications of the State of California Department of Transportation, Civil Engineer, and appropriate public agency. GEO The contractor should compact finish subgrade and aggregate base in accordance with Section 5.6. Aggregate Base should meet the requirements for 3/4-inch maximum Class 2 AB in accordance with Section 26-1.02a of the latest Caltrans Standard Specifications. 7.1 CUT-OFF CURBS Due to the high plasticity soil at the project site, pavement cracking and distress can be expected, especially in pavements adjacent to unirrigated slopes. We recommend that a cutoff curb be constructed to limit the moisture variation in the pavement subgrade and reduce cracking and distress. 8.0 LIMITATIONS AND UNIFORMITY OF CONDITIONS This report presents geotechnical recommendations for design of the improvements discussed in Section 1.3 for the Kent and Vandam Properties project. If changes occur in the nature or design of the project, we should be allowed to review this report and provide additional recommendations. It is the responsibility of the owner to transmit the information and recommendations of this report to the appropriate organizations or people involved in design of the project, including but not limited to developers, owners, buyers, architects, engineers, and designers. The conclusions and recommendations contained in this report are solely professional opinions and are valid for a period of no more than 2 years from the date of report issuance. Whenever the words "supervision", "inspection", "approve", "certify", or "control" are used, they shall mean observation of the work and/or testing of the compacted fill by our field representative to assess whether substantial compliance with plans, specifications and design concepts has been achieved, and does not include direction of the actual work of the contractor or the contractor's personnel. We strived to perform our professional services in accordance with generally accepted geotechnical engineering principles and practices currently employed in the area; no warranty is expressed or implied. There are risks of earth movement and property damages inherent in building on or with earth materials. We are unable to eliminate all risks; therefore, we are unable to guarantee or warrant the results of our services. This report is based upon field and other conditions known to us at the time of report preparation. We developed this report with limited subsurface exploration data. We assumed that the subsurface exploration data are representative of the actual subsurface conditions across the site. Considering possible underground variability of soil, rock, stockpiled material, and groundwater, additional changes may be required to complete the project. Such changes may result in additional costs. We recommend that the owner establish a contingency fund to cover such costs. If unexpected conditions are encountered, we must be notified immediately to review these conditions and provide additional and/or modified recommendations, as necessary. Our geotechnical exploration did not include work to determine the existence of possible hazardous materials. If any hazardous materials are encountered during construction, the proper regulatory officials must be notified immediately. This document must not be subject to unauthorized reuse that is, reusing without our written authorization. Such authorization is essential because it requires us to evaluate the document's applicability given new circumstances, not the least of which is passage of time. GEO Actual field or other conditions will necessitate clarifications, adjustments, modifications, or other changes to our recommendations and documents. Therefore, we must be engaged to prepare the necessary clarifications, adjustments, modifications, or other changes before construction activities commence or further activity proceeds. If our scope of services does not include on -site construction observation, or if other persons or entities are retained to provide such services, we cannot be held responsible for any or all claims arising from or resulting from the performance of such services by other persons or entities, and from any or all claims arising from or resulting from clarifications, adjustments, modifications, discrepancies, or other changes necessary to reflect changed field or other conditions. It should be noted that we relied on data compiled from multiple sources, including subsurface data collected by others. We are unable to make any representation as to the accuracy of those data. For exploration performed by us, we determined the lines designating the interface between layers on the exploration logs using visual observations. The transition between the materials may be abrupt or gradual. The exploration logs contain information concerning samples recovered, indications of the presence of various materials such as clay, sand, silt, rock, existing fill, etc., and observations of groundwater encountered. The field logs also contain our interpretation of the subsurface conditions between sample locations. Therefore, the logs contain both factual and interpretative information. Our recommendations are based on the contents of the final logs, which represent our interpretation of the field logs. GEO REFERENCES American Concrete Institute, 2005, Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary (ACI 318R-05). Bryant, W.A., and Hart, E.W., 2007, 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, 42 p. California Building Code (CBC), 2016. Crane, R. C., 1995, Preliminary Geologic Map of the Diablo Quadrangle, Contra Costa County, California, Draft available from H. & L. Hendry, Concord, California. Dibblee, Thomas W. Jr., 1980, Preliminary Geologic Map of the Diablo Quadrangle, Contra Costa County, California, United States Geological Survey. ENGEO, 1999, Preliminary Geotechnical Reconnaissance, Tassajara Lane, Subdivision 8389, Danville, California; November 24, 1999; Project No. 4674.5.001.01. ENGEO, 2000a, Preliminary Geotechnical Exploration, Tassajara Lane, Subdivision 8389, Danville, California; January 10, 2000; Project No. 4674.5.001.01. ENGEO, 2000b, Preliminary Geotechnical Exploration Proposed Tassajara Lane Improvements, Danville, California; March 21, 2000; Project No. 4674.5.002.01. ENGEO; Supplemental Geotechnical Exploration, Tassajara Lane, Subdivision 8389, Danville, California; February 20, 2002; Project No. 4674.1.003.02. ENGEO; Geotechnical Exploration, Gates and Kent Properties, Danville, California; July 12, 2005; Project No. 5393.1.100.01. ENGEO; Geotechnical Corrective Grading Plans, Gates Property, Danville, California; January 2007; Project No. 5393.1. 100.01. ENGEO; Final Report of Testing and Observation Services Provided during Rough Grading, Gates Property, Danville, California; July 5, 2007; Project No. 5393.1.100.02. Field, E.H., and 2014 Working Group on California Earthquake Probabilities, 2015, UCERF3: A new earthquake forecast for California's complex fault system: U.S. Geological Survey 2015-3009, 6 p., https://dx.doi.org/10.3133/fs20l53009. Google Earth; program accessed September 2019. Graymer, R.W., et al, 1994, Preliminary Geologic Map Emphasizing Bedrock Formations in Contra Costa County, USGS, Open File Report 94-822. Mikola, R.G, Candia, G., Sitar, N., 2014, Seismic Earth Pressures on Retaining Structures and Basement Walls, Tenth U.S. National Conference of Earthquake Engineering., Frontiers of Earthquake Engineering, July 2015, Anchorage Alaska. GEO REFERENCES (Continued) Nilsen, Tor H., 1975, Preliminary Photointerpretation Map of Landslide and other Surficial Deposits of the Diablo 7'/2 Quadrangle, Contra Costa County, California. Slide v8.024[Computer Software], 2018, RocScience. Spencer, E., 1967, A method of analysis of the stability of embankments assuming parallel inter - slice forces, Geotechnique, v. 17(1), pp. 11-26. Structural Engineers Association of California (SEAOC), 1996, Recommended Lateral Force Requirements and Tentative Commentary, ("Blue Book"), 6th Edition, Seismology Committee, Structural Engineers Association of California, Sacramento, California. Unruh, J. R., and T. L. Sawyer, 1997, Assessment of Blind Seismogenic Sources, Livermore Valley, Eastern San Francisco Bay Region: Final Technical Report, U.S. Geological Survey, National Earthquake Reduction Hazards Program. Wagner, J. R., 1978, Late Cenozoic History of the Coast Ranges East of San Francisco Bay, Ph.D. Dissertation, UCB. TECHNICAL REFERENCES Aerial Photographs: • BUU-279-110,111 flown 7-25-1939 • Cartwright Aerial Surveys, CC 9-200,201, flown 5-15-1965 • Pacific Aerial Surveys, AV-253-23-29,30, flown 5-23-1957 • Pacific Aerial Surveys, AV-1860-09-15,16, flown 5-15-1980 • Pacific Aerial Surveys, AV-2131-09-15,16, flown 4-27-1982 GEO GENERAL NOTES: OWNER/DEVELOPER: TASSAJARA HOLDINGS, LLC 603J LAURELSPUR LOOP SAN RAMON, CA 94582 PHONE. (925) 413-2625 ATTN. 07HMAR VAN DAM CIVIL ENGINEER. MILANI AND ASSOCIATES 2650 STANWELL DRIVE, SUf CONCORD, CA 94520 PHONE. (925) 674-9082 CONTACT KEN ALCOCK SOIL ENGINEER. ENGEO 2010 CROW CANYON PLACE, SAN RAMON, CA 94583 PHONE. (925) 866-9000 CELL: (925) 570-7521 ATTN. ANDY FIRMIN, GE, Q� PROPERTY ADDRESS. 2449 & 2451 TASSAJARA L DANVILLE, CA 94506 ASSESSOR PARCEL NUMBER. 207-061-008 & 207-061- EXIS7ING ZONING. R-40 PROPOSED ZONING. R-40 STRUCTURE SETBACKS. FRONT - 25' SIDE - 20' REAR - 30' EXISTING USE: SINGLE FAMILY & VACANT PROPOSED USE: SINGLE FAMILY BENCHMARK: CONTRA COSTA COUNTY BE CHISELED "r IN NORTH EN! TASSAJARA - ELEVA71ON = SITE BENCHMARK: SET REBAR AS SHOWN. EL EASEMENT 50' RIGHT OF WAY EASEMEI SHOWN IS PER 18 LSM 18 LEGAL DESCRIPTION: LOTS 2 & 3, 18 LSM 18 BASIS OF BEARINGS: THE BEARING N0R7H 1851, MONUMENTS AS SHOWN ON FILED IN BOOK 505 OF MAF WAS TAKEN AS 7HE BASIS CONTOUR INTERVAL: ONE (1) FOOT AREA: 8.49 ACRES (GROSS) 7.63 , LOT GROSS SVAC 1 40, 733/0.94 2 42,21110.97 3 43, 58411.00 4 45,311/1.04 5 84, 84211.95 6 62, 78911. 44 7 40, 00410. 92 U71LI71ES & SERVICES. CABLE - COMCAST FIRE - SAN RAMON VALLEY FIRE PRC GAS & ELECTRIC - PACIFIC GAS & ELECTRIC POLICE - TOWN OF DANVILLE SANITARY SEWAGE - CENTRAL CONTRA COSTA SAN STORM DRAINAGE - CONTRA COSTA COUNTY FL00 TELEPHONE - AT&T WATER - EAST BAY MUNICIPAL UTILITY PROJECT NOTES: ANYWHERE ON THIS SET OF PLANS WHERE THE PATIOS, AND C.3 TREATMENT FACILITIES ARE SH CONCEPTUAL AND FOR CONTEXT PURPOSES ONL PAD GRADE NOTE: PAD GRADES ARE SUBJECT TO CHANGE, AND WII GEOTECHNICAL REPORT AND FOUNDATION DESIGN EARTHWORK NOTE: TOTAL CUT VOLUME. Z800 CYt TOTAL FILL VOLUME. 96,500 CYt APPROXIMATE SLIDE REPAIR VOLUME. • 155,000 C C.3 TREATMENT NOTE: EACH LOT WILL PROVIDE TREATMENT FOR THE R NO. DATE APPD. REVISION & E GREG & BEVERLY KENT PO BOX 236 ALAMO, CA 94507 PHONE. (925) 828-7810 ATT GREG KENT E #105 STE 250 V ANE -009 JCHMARK NO. 285 1 OF CONCRETE HEADWALL ON CAMINO 456.312' NATION = 526.94' 'T 2" WEST BETWEEN TWO FOUND THAT CERTAIN SUBDIVISION MAP NO. 9014 S AT PAGE 29, CONTRA COUNTY RECORDS, DF ALL BEARINGS SHOWN UPON THIS MAP. ICRES (NET) NET SF/AC 37, 43210.86 39, 39810.90 39,18210.90 42,16310.97 76,19111.75 60, 59411.39 37, 34210.86 7ECTION DISTRICT TARP DISTRICT ) CONTROL AND WATER CONSERVATION DISTRICT )IS7RICT 3UILDING ENVELOPES, CONCRETE )WN ON THE INDIVIDUAL LOTS ARE .L BE BASED ON THE FINAL rf )OF RUN-OFF ON THAT LOT. DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA VESTING TENTATIVE MAP - Su3DIVISION KENT & VAN DAM PROPERTIES TOWN OF DANVILLE, CONTRA COSTA COUNTY, CALIFORNIA WILLIAMS 217-010-039 AMBROSIUS & THE 207-071-001 LOT 4 GITAS LIVING TRUST 217-010-040 1 1 LOT 3 do G mow' R4THE y LOT 6 217-44CET440-020 i LOT 2 I � I LOT 6 LOT 5 505 M 29 HUANG CHUNG-HO SUJAN THE 2 / 07-061 -058 LOT 1 GARSHI MUHAIUDDIN THE h GARSHI SEEMA THE I207-061-010 LOT 7 LOT 6 A7TOLU \ 505 M 29 207-061 -059 LOT 7 A SULL RAJINDER SINGH THE V SANE & SULL SUKHVINDER HATSUSHI 207-051-017 207-051-016 100 50 0 100 200 SCALE: 1 "=100' ABBREVIATIONS ABBREVIATION DESCRIPTION ABBREVIATION DESCRIPTION ACP ASBESTOS CEMENT PIPE MAX MAXIMUM AD AREA DRAIN MIN MINIMUM ADTT ANNUAL DAILY TRUCK TRAFFIC N/A NOT APPLICABLE AP ANGLE POINT OG ORIGINAL GROUND BC BEGIN CURVE O.H.U. OVERHEAD U7ILITY BCDC BAY CONSERVA71ON & DEVELOPMENT COMMISSION PA PAVEMENT BO BLOW OFF PAVE PRIVATE ACCESS AND U7ILITY EASEMENT BVC BEGIN VER71CAL CURVE PCC POINT OF COMPOUND CURVE BW BACK OF WALK PERF PERFORATED PIPE CB CATCH BASIN PIV POST INDICATOR VALEVE CL CENTERLINE POC POINT ON CURVE DCDV DOUBLE CHECK DETECTOR VALVE PRC POINT OF REVERSE CURVATURE DG DECOMPOSED GRANITE PVC POLYVINYL CHLORIDE DWY DRIVEWAY PVI POINT OF VERTICAL INTERSECTION EC END OF CURVE R RADIUS EG EXISTING GRADE RCP REINFORCED CONCRETE PIPE ELEV ELEVATION RET RETURN (CURB) EVC END OF VERTICAL CURVE RSR RISER EW END WALL RT RIGHT EX EXISTING RW RIGHT OF WAY FF FINISH FLOOR S SLOPE FG FINISH GRADE SD STORM DRAIN FH FIRE HYDRANT SO SIDE OPENING FI FIELD INLET SS SANITARY SEWER FL FLOW LINE SSCO SANITARY SEWER CLEAN OUT FLSO FLOW LINE SIDE OPENING SSMH SANITARY SEWER MANHOLE FP FIRE LADDER PAD SWK SIDEWALK FW FIRE WATER MAIN TC TOP OF CURB GB GRADE BREAK 7DC TOP OF DEPRESSED CURB GFF GARAGE FINISH FLOOR TFC TOP OF FLUSH CURB GL GARAGE LIP 7P TOP OF PAVEMENT GR GRATE TR TOP OF RAMP HDPE HIGH -DENSITY POLYETHYLENE IS TOP OF STEP HP HIGH POINT TW TOP OF WALL INV INVERT VCP VITRIFIED CLAY PIPE JPCP JOINTED PLAIN CONCRETE PAVEMENT U.U. UNDERGROUND UTILITY LA LATERAL W WATER MAIN OR WATER SERVICE LP LOW POINT WM WATER METER LT LEFT Q�ovEss/p� � 0 No.35121 z � EXP. 09/30/25 � CIVIL �� �qTF OF CA'\ DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE LEGEND EXISTING DESCRIPTION PROPOSED MAJOR CONTOUR 100 MINOR CONTOUR 100 PROPERTY LINE - CENTERLINE - - - EASEMENT LINE - - - CONCRETE CURB & GUTTER FENCE - CONCRETE SIDEWALK ° GAS LINE GAS ELECTRICAL LINE JT JT RECYCLED WATER SANITARY SEWER SS STORM DRAIN SD WATER LINE W SOLAR CANOPY NIA GRADE PERCENTIDIREC77ON OF FLOW 27. RIP RAP, SPLASH BLOCK STREET LIGHT °_� TREE O AREA DRAIN BLOW OFF .- FIRE HYDRANT AK GATE VALVE, PIV ►� MANHOLE OS OD SANITARY SEWER CLEANOUT • STORM DRAIN INLETIJUNC71ON BOX 0 B WATER/IRRIGATION METER ED Storm Water Monitoring & Reporting Land Development Engineering & Associates Environmental Engineering MILANI Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE C,q�/NO S DANVILLE q�q'Qq CONTRA COSTA COUNTY Q� CALIFORNIA pOQ' c PROJECT Z J��� \ SITE C. VICINITY MAP N. T.S rl SHEET INDEX SHEET # DESCRIPTION 1 COVER SHEET 2 GENERAL NOTES 3 EXISI TING SITE CONDITIONS 4 DEMOLITION PLAN 5 LOTTING EXHIBIT 6 LOTTING EXHIBIT - CONTEXT MAP 7 OVERALL SITE PLAN 8 LANDSLIDE PLAN 9 PRELIM GRADING AND DRAINAGE PLAN 10 PRELIM GRADING AND DRAINAGE PLAN 11 PRELIM UTILITY PLAN 12 PRELIM UTILITY PLAN 13 PRELIM C.3 EXHIBIT 14 PRELIM C.3 NOTES AND DETAILS 15 CUT -FILL MAP 16 PRELIM EROSION CONTROL PLAN 17 EROSION CONTROL PLAN NOTES AND DETAILS 18 SECTIONS AND DETAILS 19 PROFILES: ROAD, CUL-DE-SAC, DRIVEWAYS 20 HYDROLOGY MAP 21 HYDROLOGY MAP RIGID PAVEMENT SECTIONS INDEX (TI) ADTT (INCHES) C LASS (INCHES) B 4.0 1 5.5" 6" 5.0 5 6" 6" 6.0 25 6.5" 6" 7.0 100 7.5" 6" FLEXIBLE PAVEMENT SECTIONS SGRADE R-VALUE TRAFFIC INDEX (TI) AGGREGATE BASE (AB) ASPHALT CONCRETE 5 4.0 12" 3" 5 5.0 13" 3 5" 5 6.0 14" 4" 5 7.0 16" 4.5" TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 RIGID PAVEMENT NOTES: 1. AGGREGATE BASE CLASS 2 MATERIAL (AB) WITH R=78 (MIN). 2. AGGREGATE BASE SHALL MEET REQUIREMENTS FOR %-INCH MAXIMUM CLASS 2 AB IN ACCORDANCE WITH SEC71ON 26-1.02A OF THE LATEST CAL7RANS STANDARD SPECIFICATIONS FLEXIBLE PAVEMENT NOTES. 1. COMPACT AGGREGATE BASE TO AT LEAST 959 RELA77VE COMPAC77ON AT A MOISTURE CONTENT OF AT LEAST OP77MUM MOISTURE CONTENT. 2. STRUCTURAL ENGINEER SHALL DESIGN THE EXTERIOR SLAB -ON -GRADE REINFORCEMENT. REINFORCEMENT SHALL CONSIST OF STEEL BARS IN LIEU OF WELDED WIRE MESH. J. FREQUENT CONTROL JOINTS SHALL BE PROVIDED TO CONTROL CRACKING AS RECOMMENDED BY THE AMERICAN CONCRETE INSTITUTE (PUBLICATION ACI 302.1 R-89). REFERENCE. GE07ECHNICAL REPORT (PROJECT NO. 5393.000.000) PREPARED BY ENGEO INCORPORATED DATED FEBRUARY 10, 2022. REVIEW COP Y SUBJECT TO REVISION NOT FINAL THIS N077CE TO BE REMOVED UPON COMPLETION OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP COVER SHEET JOB NO. 270019 I SHEET NO. 1 OF 21 Cn 0 m CO) 1 a W W I Cz Z coo W a U J 0 It N 1 U) N 1 w 0 0 I 0 O r- N ,Z v a� c a� rn 0 O r- N m 0 ATTACHMENT F GENERAL 1. NOTES: THE ENGINEER ASSUMES NO RESPONSIBILITY BEYOND THE AD OF HIS/HER DESIGN CONTAINED HEREIN. 2. THE CONSTRUCTION CONTRACTOR AGREES, THAT IN ACCORD' GENERALLY ACCEPTED CONSTRUCTION PRACTICES, TO ASSU& AND COMPLETE RESPONSIBILITY FOR JOB SITE CONDITIONS D COURSE OF CONSTRUCTION OF THE PROJECT, INCLUDING SAI PERSONS AND PROPERTY; THAT THIS REQUIREMENT SHALL E APPLY CONTINUOUSLY AND NOT BE LIMITED TO NORMAL W01 AND THE CONSTRUCTION CONTRACTOR FURTHER AGREES TO INDEMNIFY AND HOLD THE DESIGN PROFESSIONAL HARMLESS ANY AND ALL LIABILITY, REAL OR ALLEGED, IN CONNECTION PERFORMANCE OF WORK ON THIS PROJECT, EXCEPTING LIABI ARISING FROM THE SOLE NEGLIGENCE OF THE DESIGN PROFE J. CONTRACTOR SHALL COMPLY WITH THE RULES AND REGULATi THE STATE CONSTRUCTION SAFETY ORDER. 4. THE CONTRACTOR'S ATTENTION IS DIRECTED TO THE REQUIRE OF THE DIVISION OF INDUSTRIAL SAFETY PERTAINING TO "CO SPACES". ANY MANHOLE, CULVERT, DROP INLET OR TRENCI COULD CONTAIN AIR), THAT IS NOT READILY VENTILATED, M� CONSIDERED A "CONFINED SPACE". 5. THE CONTRACTOR SHALL PROVIDE EMERGENCY TELEPHONE NI FOR PUBLIC WORKS, AMBULANCE, POLICE AND FIRE DEPARTII AT THE JOB SITE 6. CONTRACTOR SHALL PROVIDE ALL NECESSARY PUBLIC SAFET IN ACCORDANCE WITH CURRENT CALIFORNIA MUTCD 2012, INCLUDING, BUT NOT LIMITED TO, LIGHTS, SIGNS, BARRICADE: FLAGPERSONS IN ADDITION, TEMPORARY FENCING SHALL BE ALONG ALL PROPERTY LINES AS DIRECTED BY THE TOWN OF 7. EXCAVATIONS SHALL BE ADEQUATELY SHORED, BRACED AND SO THAT THE EARTH WILL NOT SLIDE OR SETTLE AND SO 71 EXISTING IMPROVEMENTS OF ANY KIND WILL BE FULLY PR071 FROM DAMAGE. ANY DAMAGE RESULTING FROM A LACK OF SHORING, BRACING OR SHEETING SHALL BE THE RESPONSIB11 THE CONTRACTOR AND HE SHALL EFFECT NECESSARY REPAI, RECONSTRUCTION AT HIS OWN EXPENSE. WHERE THE EXCAI A CONDUIT TRENCH, STRUCTURE ANDfOR BORING OR JACKIA FIVE FEET OR MORE IN DEPTH THE CONTRACTOR SHALL COA THE APPLICABLE CONSTRUCTION SAFETY ORDERS OF THE DI INDUSTRIAL SAFETY OF THE STATE OF CALIFORNIA. THE CO SHALL ALWAYS COMPLY WITH OSHA REQUIREMENTS. 8. THE CONTRACTOR SHALL PROVIDE FOR INGRESS AND EGRESS PRIVATE PROPERTY ADJACENT TO THE WORK AREA THROUGI PERIOD OF CONSTRUCTION. 9. ENCROACHMENT PERMITS REQUIRED FOR WORK WITHIN EXIS7II RIGHTS -OF -WAY SHALL BE OBTAINED BY THE CONTRACTOR. 10. ALL CONSTRUCTION STAKING SHALL INCLUDE BUT NOT LIMITS GRADING, CURBS, STREET IMPROVEMENTS AND STORM DRAIN, SHALL SHALL BE PERFORMED BY A LICENSED LAND SURVEYi THE NUMBER AND LOCATION OF CONSTRUCTION STAKES REQUIRED SHALL BE DETERMINED BEFORE THE CONSTRUC710 ALL STAKING REQUESTS SHOULD BE DIRECTED TO THE ENGIh MINIMUM OF 48 HOURS PRIOR TO ACTUAL NEED. ANY ADDI STAKING OR RESTAKING WILL BE DONE ONLY AS DIRECTED A AUTHORIZED BY THE OWNER OR THE OWNER'S AUTHORIZED , TOWN ENGINEER HAS THE AUTHORITY TO REQUIRE THE OWNS OWNER'S AUTHORIZED AGENT TO PLACE ADDITIONAL STAKES AS HE DEEMS NECESSARY FOR THE PROPER CONSTRUCTION AVOID CONFLICTS ANY CONTRACTOR REQUESTING STAKES RESPONSIBLE FOR THE PROTECTION OF SAID STAKES CON] SHALL CONSIDER THE USE OF STAKE FOR MORE THAN ONE 11. ALL EXISTING ELEVATIONS SHOWN ARE AS MEASURED IN THE UNLESS OTHERWISE NOTED. 12. OBSTRUCTIONS INDICATED ARE FOR INFORMATION ONLY. IT I. CONTRACTOR'S RESPONSIBILITY TO VERIFY THE LOCATION AN WITH THE APPROPRIATE AGENCIES. THE CONTRACTOR SHALT U.S.A. (UNDERGROUND SERVICE ALERT) FOR THE UTILITY LO( 48 HOURS PRIOR TO ANY CONSTRUCTION OR EXCAVATION (t 2444). THE U.S.A. AUTHORIZATION NUMBER SHALL BE KEPi JOB SITE 13. THE CONTRACTOR SHALL NOT DISTURB OR DESTROY ANY PEI SURVEY POINTS WITHOUT THE APPROVAL OF THE CITY ENGIA PERMANENT MONUMENTS OR POINTS DISTURBED OR DESTROI BE REPLACED BY A LICENSED SURVEYOR AT THE CONTRACT EXPENSE. 14. IT SHALL BE THE CONTRACTOR'S RESPONSIBILITY TO NOTIFY ENGINEER OF ANY DIFFERENCES IN LOCATIONS OR EXISTING SHOWN, OR ANY CONFLICTS WITH THE DESIGN, BEFORE CON] WORK IN THAT AREA. 15. IT IS THE RESPONSIBILITY OF THE CONTRACTOR TO OBTAIN F NECESSARY TO PERFORM THE WORK IN THESE PLANS FROM APPROPRIATE AGENCIES. 16. PRIOR TO COMMENCEMENT OF ANY WORK ON ADJACENT PRO THE OWNER SHALL OBTAIN WRITTEN PERMISSION FROM AFFB PROPERTY OWNERS 17. ANY DEVIATION FROM APPROVED PLAN REQUIRES APPROVAL THE TOWN OF DANVILLE ENGINEERING DEPARTMENT. 18. THE CONTRACTOR SHALL BE HELD RESPONSIBLE FOR ANY FIE CHANGES MADE WITHOUT WRITTEN AUTHORIZATION FROM THE TOWN OF DANVILLE. 19. IF ARCHAEOLOGICAL MATERIALS ARE UNCOVERED DURING GR) TRENCHING OR OTHER EXCAVATION, EARTHWORK WITHIN 100 THESE MATERIALS SHALL BE STOPPED, THE TOWN DEVELOP& SERVICES DEPARTMENT NOTIFIED AND A PROFESSIONAL ARCI WHO IS CERTIFIED BY THE SOCIETY OF CALIFORNIA ARCHAEG ANDfOR THE SOCIETY OF PROFESSIONAL ARCHAEOLOGY (SO) NO. DATE APPD. REVISION =QUACY NCE WI TH E SOLE ]RING THE ETY OF ALL E MADE TO 'KING HOURS; DEFEND, FROM WITH THE _I TY 3S10NAL. ONS OF IdEN IS VFINED (WHICH Y BE IMBERS IENTS DEVICES AND PROVIDED DANVILLE. SHEETED AT ALL CTED ADEQUATE ITY OF ?S OR ATION FOR G PIT IS FORM TO 1SION OF V TRACTOR FOR 'OUT THE IG PUBLIC ) TO i AND )R. I BEGINS. EER A 70NAL ND IGENT. THE R OR THE OR RESTAKE OR TO HALL BE 4ACTOR 9PERATION. FIELD, > THE DEPTH CONTACT A7TONS 00-642- AT THE 'MANENT EER. ANY ED SHALL )RS THE 1 TILT TIES INUING ERMI IS THE 'ERTIES, :TED OF LD DING, FEET OF ENT IAEOLOGIST LOGY (SCA) 'A) HAS HAD DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA AN OPPORTUNITY TO EVALUATE THE SIGNIFICANCE OF THE FIND AND SUGGEST APPROPRIATE MITIGATION MEASURES IF THEY ARE DEEMED NECESSARY. IF PREHISTORIC ARCHAEOLOGICAL DEPOSITS ARE DISCOVERED DURING DEVELOPMENT OF THE SITE, LOCAL NATIVE AMERICAN ORGANIZATIONS SHALL BE CONSULTED AND INVOLVED IN MAKING RESOURCE MANAGEMENT DECISIONS. 20. THE CONTRACTOR SHALL VERIFY THE FLOWLINE ELEVATION OF THE EXISTING SEWER/STORM DRAIN AT THE POINT OF CONNECTION AND NOTIFY THE ENGINEER IMMEDIATELY IF MORE THAN 0.10 FOOT OF DIFFERENCE EXISTS FROM THIS PLAN. 21. ALL CONSTRUCTION AND GRADING OPERATIONS, INCLUDING DELIVERY OF MATERIALS AND WARMING UP OF MACHINERY, SHALL BE LIMITED TO WEEKDAYS DURING THE HOURS FROM 7.30 A.M. TO 5.30 P.M., PER PROVISIONS OF THE TOWN OF DANVILLE MUNICIPAL CODE, UNLESS OTHERWISE APPROVED IN WRITING BY THE TOWN ENGINEER. IF DETERMINED NECESSARY BY THE TOWN ENGINEER, THE PROJECT DEVELOPER SHALL PROVIDE SECURITY FENCING AROUND THE ENTIRE SITE DURING CONSTRUCTION OF THE PROJECT. PRIOR TO ANY CONSTRUCTION WORK ON SITE, INCLUDING GRADING, SHALL INSTALL A MINIMUM 3' X 3' SIGN AT THE PROJECT ENTRY WHICH SPECIFIES THE ALLOWABLE CONSTRUCTION WORK DAYS AND HOURS, AND LISTS THE NAME AND CONTACT PERSON FOR THE OVERALL PROJECT MANAGER AND ALL CONTRACTORS AND SUB -CONTRACTORS WORKING ON THE JOB. 22. ALL CUT AND FILL SLOPES AT THE BOUNDARY LINES SHALL BE CONSTRUCTED IN SUCH A MANNER THAT ADJACENT FENCES WILL NOT BE DAMAGED UNLESS SUCH FENCE IS SPECIFIED TO BE REPLACED IN THIS PLAN OR THERE IS AGREEMENT BETWEEN THE DEVELOPER AND THE ADJACENT PROPERTY OWNER. NO BUILDING CONSTRUCTION WILL BE PERMITTED KiTHIN a5 FEET OF THE FENCE UNLESS OTHERWISE INDICATED ON THE PLANS 23. THE CONTRACTOR SHALL COORDINATE THE SEWER, WATER AND STORM DRAIN CONSTRUCTION IN A MANNER TO PREVENT ANY CONFLICTS WHERE UTILITY LINES CROSS EACH OTHER. THE CONTRACTOR SHALL BE RESPONSIBLE FOR OBTAINING PLANS FOR ALL OTHER UTILITIES FOR THIS PROJECT AND SHALL FAMILIARIZE HIMSELF THEREWITH, AND SHALL NOTIFY THE ENGINEER IMMEDIATELY OF ANY CONFLICT WITH THIS PLAN PRIOR TO THE START OF CONSTRUCTION. 24. MANHOLE, VALVE, METER BOX, AND CLEAN OUT RIM ELEVATIONS, SHOWN OR NOT SHOWN HEREON, ARE APPROXIMATE ONLY. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ADJUSTING THE RIMS AND COVERS TO THE FINISHED PAVEMENT GRADE. 25. FIRE HYDRANTS SHALL BE APPROVED BY THE SAN RAMON VALLEY FIRE PROTECTION DISTRICT. 26. THE CONTRACTOR IS RESPONSIBLE FOR MATCHING EXISTING STREETS, SURROUNDING LANDSCAPE AND OTHER IMPROVEMENTS WITH A SMOOTH TRANSITION IN PAVING, CURBS, GUTTERS, SIDEWALKS, GRADING, ETC., AND AVOIDING ANY ABRUPT OR APPARENT CHANGES IN GRADES OR CROSS SLOPES, LOW SPOTS OR HAZARDOUS CONDITIONS 27. THE ENGINEER ASSUMES NO RESPONSIBILITY FOR FINAL GRADE OF CONCRETE UNLESS FORMS ARE CHECKED BY THE ENGINEER PRIOR TO POURING. 28. IT SHALL BE THE RESPONSIBILITY OF THE CONTRACTOR TO COORDINATE ALL NECESSARY UTILITY RELOCATIONS WITH THE APPROPRIATE UTILITY COMPANIES. 29. PAVING CONFORMS SHALL BE MADE AT A SMOOTHLY TRIMMED BUTT JOINT. DO NOT OVERLAP EXISTING PAVEMENT. 30. ALL STORM DRAIN INLETS AND MANHOLES OVER 4 FEET IN DEPTH SHALL BE PROVIDED WITH STEPS. THE STEPS SHALL BE INTEGRALLY CAST ONTO THE WALLS OF THE MANHOLE OR INLET WHETHER PRECAST OR FIELD CAST. THE STEPS SHALL BE INSTALLED IN ACCORDANCE WITH CONTRA COSTA COUNTY STANDARD PLAN "C05". 31. ALL SEWER AND STORM DRAIN CONSTRUCTION SHALL PROCEED FROM THE DOWNSTREAM CONNECTION TO THE UPSTREAM TERMINUS. 32. ALL WATER MAINS AND APPURTENANCES SHALL BE CONSTRUCTED IN ACCORDANCE WITH THE EAST BAY MUNICIPAL UTILITY DISTRICT PLANS AND SPECIFICATIONS. ALL WATER MAINS TO BE OF THE MATERIAL SPECIFIED ON THE EAST BAY MUNICIPAL UTILITY DISTRICT CONSTRUCTION PLANS FOR THIS PROJECT. 33. ALL EXISTING UTILITIES AND IMPROVEMENTS THAT BECOME DAMAGED DURING CONSTRUCTION SHALL BE COMPLETELY RESTORED TO THE SATISFACTION OF THE CITY ENGINEER, AT THE CONTRACTOR'S SOLE EXPENSE. 34. EXISTING PRIVATE AND PUBLIC UTILITIES SHOWN HEREON REFLECT AVAILABLE RECORD DATA. THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING AND PROTECTING ALL UTILITIES WHICH ARE TO REMAIN IN USE, WHETHER OR NOT SHOWN HEREON. THE CONTRACTOR SHALL NOTIFY ALL PUBLIC UTILITY COMPANIES AND OWNERS OF PRIVATE UTILITIES WI THIN THE CONSTRUCTION AREA 48 HOUR PRIOR TO THE START OF ANY CONSTRUCTION. 35. ALL CONSTRUCTION AND TRANSPORT EQUIPMENT SHALL BE MUFFLED IN ACCORDANCE WITH STATE AND FEDERAL REQUIREMENTS. STATIONARY NOISE GENERATING EQUIPMENT SHALL BE LOCATED AS FAR AWAY FROM EXISTING RESIDENCES AS FEASIBLE. 36. ALL NEW UTILITY DISTRIBUTION SERVICES SHALL BE UNDERGROUND. 37. DIMENSIONS LOCATING CURB AND GUTTER ARE TO FACE OF CURB. 38. PRIOR TO PLACING OF CURB, SIDEWALK, ASPHALT CONCRETE, SUBBASE OR BASE MATERIAL, ALL UNDERGROUND UTILITIES WITHIN THE RIGHT- OF-WAY SHALL BE INSTALLED, BACKFILLED, COMPLETED, AND THE TOWN ENGINEER'S INSPECTOR SHALL BE N011FIED BY EACH OF THE UTILITY COMPANIES HAVING FACILITIES WITHIN THE WORK AREA, THAT THE UTILITY INSTALLATION HAS SATISFACTORILY PASSED ACCEPTANCE TESTS Q�ovEss/O� � No.35121 z � EXP. 09/30/25 � CIVIL �� �qTF r7F CA\�F�� DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE 39. SHOULD IT APPEAR THAT THE WORK TO BE DONE, OR ANY MATTER RELATIVE THERETO, IS NOT SUFFICIENTLY DETAILED OR EXPLAINED ON THESE PLANS, THE CONTRACTOR SHALL CONTACT KEN ALCOCK AT (925) 674-9082 FOR FURTHER EXPLANATIONS AS MAY BE NECESSARY. 40. NICHOLAS ENGINEERING CONSULTANTS IS RESPONSIBLE FOR INSPECTING THE RETAINING WALLS OUTSIDE OF THE PUBLIC ROAD RIGHT-OF-WAY. A LETTER STATING THAT ALL WALLS WERE CONSTRUCTED IN ACCORDANCE WITH THE STRUCTURAL AND SOILS ENGINEER'S RECOMMENDATIONS, IF APPLICABLE, MUST BE SUBMITTED TO TOWN OF DANVILLE PUBLIC WORKS DEPARTMENT PRIOR TO ACCEPTANCE. 41. ALL PAVED SURFACES WILL BE SUBJECT TO AIR PERMEABILITY TESTS. BASED ON THESE TESTS, ADDITIONAL PAVEMENT TREATMENT MAY BE NECESSARY. 42. EXISTING CURB, GUTTER, PAVEMENT AND SIDEWALK WITHIN THE PROJECT LIMITS THAT ARE DAMAGED OR DISPLACED, EVEN THOUGH THEY WERE NOT TO BE REMOVED, SHALL BE REPAIRED OR REPLACED EVEN IF DAMAGE OR DISPLACEMENT OCCURRED PRIOR TO ANY WORK PERFORMED BY THE CONTRACTOR. 43. THE THICKNESS OF SUBBASE, BASE AND AC PAVEMENT. TO BE DETERMINED BY THE SOILS ENGINEER BASED ON TRAFFIC INDEX AND SOIL TEST FOR `R' VALUE AND SHALL BE APPROVED BY THE CITY ENGINEER PRIOR TO COMMENCEMENT OF CONSTRUCTION. 44. ALL TRAFFIC STRIPING AND MARKINGS WITHIN PUBLIC RIGHT OF WAY SHALL BE TRAFFIC PAINT AND THERMOPLASTIC. SEE IMPROVEMENT PLANS. 45. STORM DRAIN PIPE SHALL BE SDR-35 PVC. ACP SHALL NOT BE USED IN CONSTRUCTION OF STORM DRAIN FACILITIES. 46. THE CONTRACTOR SHALL COMPLY WITH ALL RULES, REGULATIONS AND PROCEDURES OF THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) FOR MUNICIPAL CONSTRUCTION AND INDUSTRIAL ACTIVITIES AS PROMULGATED BY THE CALIFORNIA STATE WATER RESOURCE CENTRAL BOARD OR ANY OF ITS REGIONAL WATER QUALITY CONTROL BOARDS. 47. APPROVAL OF THESE PLANS DOES NOT RELEASE THE DEVELOPER OF THE RESPONSIBILITY FOR CORRECTION OF MISTAKES, ERRORS OR OMISSIONS CONTAINED THEREIN. IF DURING THE COURSE OF CONSTRUCTION OF THE IMPROVEMENTS, PUBLIC INTEREST REQUIRES A MODIFICATION OF OR A DEPARTURE FROM THE SPECIFICATIONS AND DETAILS OF TOWN OF DANVILLE THESE PLANS, THE CITY ENGINEER SHALL HAVE THE AUTHORITY TO REQUIRE SUCH MODIFICATION OR DEPARTURE AND TO SPECIFY THE MANNER IN WHICH THE SAME IS TO BE MADE. 48. CONTRACTOR SHALL PROVIDE SECURITY FENCING AROUND THE SITE, TO THE SATISFACTION OF THE CITY ENGINEER ANDfOR CHIEF BUILDING OFFICIAL. 49. WHERE SOILS OR GEOLOGIC CONDITIONS ENCOUNTERED IN GRADING OPERATIONS ARE DIFFERENT FROM THAT ANTICIPATED IN THE SOILS REPORT, A REVISED SOILS REPORT SHALL BE SUBMITTED FOR REVIEW AND APPROVAL BY THE TOWN ENGINEER. IT SHALL BE ACCOMPANIED BY AN ENGINEERING AND GEOLOGICAL OPINION AS TO THE SAFETY OF THE SITE FROM SETTLEMENT AND SEISMIC ACTIVITY. 50. ALL DEVELOPMENT SHALL TAKE PLACE IN COMPLIANCE WITH THE TOWN EROSION CONTROL ORDINANCE (ORD 91-25). RESTRICTIONS INCLUDE LIMITING CONSTRUCTION PRIMARILY TO THE DRY MONTHS OF THE YEAR (MAY THROUGH OCTOBER) AND, IF CONSTRUCTION DOES OCCUR DURING THE RAINY SEASON, THE DEVELOPER SHALL SUBMIT AN EROSION CONTROL PLAN TO THE CITY ENGINEER FOR REVIEW AND APPROVAL. THIS PLAN SHALL INCORPORATE EROSION CONTROL DEVICES SUCH AS, THE USE OF SEDIMENT TRAPS, SILT FENCING, PAD BERMING AND OTHER TECHNIQUES TO MINIMIZE EROSION. 51. A WATERING PROGRAM, WHICH INCORPORATES THE USE OF A DUST SUPPRESSANT AND WHICH COMPLIES WITH REGULATION 2 OF THE BAY AREA AIR QUALITY MANAGEMENT DISTRICT, SHALL BE ESTABLISHED AND IMPLEMENTED FOR ALL ON -SITE AND OFF -SITE CONSTRUCTION ACTIVITIES EQUIPMENT AND HUMAN RESOURCES FOR WATERING ALL EXPOSED OR DISTURBED SOIL SURFACES SHALL BE SUPPLIED ON WEEKENDS AND HOLIDAYS AS WELL AS WORKDAYS DUST -PRODUCING ACTIVITIES SHALL BE DISCONTINUED DURING HIGH WIND PERIODS 1. INSTALL REFLECTIVE " BLUE MARKER " IN THE MIDDLE OF THE ROAD, 6" (150mm) OFF CENTER ON THE HYDRANT SIDE. (UFC, 1988, SEC. 10.301D). 2. FIRE APPARATUS ROADWAYS MUST BE INSTALLED AND FIRE HYDRANTS IN SERVICE PRIOR TO THE COMMENCEMENT OF FRAMING. J. PRIOR TO COMMENCEMENT OF FRAMING, CONTACT SAN RAMON VALLEY FIRE PROTECTION DISTRICT TO SCHEDULE AN INSPECTION OF ROADWAYS AND FIRE HYDRANTS (UFC, 1988, SEC. 10.301 E). 4. A WEED ABATEMENT PROGRAM WITHIN 100 FT (30.480m) FROM COMBUSTIBLE CONSTRUCTION MUST BE PROVIDED. 5. THE PROJECT ENTRY WILL BE POSTED WITH A NO PARKING ON ANY STREET SIGN. THE SIGN WILL BE POSTED PER SAN RAMON VALLEY FIRE PROTECTION DISTRICT SPECIFICATIONS. Storm Water Monitoring & Reporting Land Development Engineering =00& Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE 6�T�1�:�I1>�7�_��I�1►�7i1:1►1�3�1�1►� MATERIALS AND CONSTRUCTION OF SANITARY SEWERS SHALL CONFORM TO THE CENTRAL CONTRA COSTA SANITARY DISTRICT'S STANDARD SPECIFICATIONS (LATEST EDITION). THERE SHALL BE A BACKWATER OVERFLOW DEVICE (SEE SECTION 18-023) INSTALLED ON THE SIDE SEWER AT EACH BUILDING CONNECTION. Cd�P,IJ[�3�1���X►7��� COMPACTION TESTING OF PIPE BEDDING AND BACKFILL, CONDUCTED UNDER THE DIRECTION OF A CIVIL OR GE07ECHNICAL ENGINEER LICENSED BY THE STATE OF CALIFORNIA, IS REQUIRED ON THIS PROJECT. AS A CONDITION OF THE DISTRICT'S ACCEPTANCE OF COMPLETE PROJECT WORK, A CERTIFICATION REPORT INDICATING THAT COMPACTION RESULTS MEET OR EXCEED THE REQUIREMENTS OF THE CCCSD STANDARD SPECIFICATIONS SHALL BE SUBMITTED BY THE ENGINEER IN RESPONSIBLE CHARGE OF THE COMPACTION TESTING. COMPACTION TESTING SHALL BE COMPLETED PRIOR TO ACCEPTANCE, TELEVISING THE SEWER, AND INSTALLATION OF FINAL PAVING. NOTIFICATION OF PROPERTY OWNERS. THE CONTRACTOR OR PROJECT OWNER SHALL PROVIDE WRITTEN NOTIFICATION TO ADJACENT PROPERTY OWNERS) OR RESIDENTS, WHOSE PROPERTY IS TO BE ENTERED OR CONSTRUCTED UPON, THAT PROPOSED SEWER IMPROVEMENTS ARE GOING TO BE INSTALLED. THIS NOTIFICATION SHALL BE MADE BEFORE SEWER PLANS ARE SUBMITTED FOR FINAL REVIEW OF CONSTRUCTION PLANS AND SHALL INCLUDE INFORMATION ON MAJOR ACTIVITIES THAT WILL BE PERFORMED ON EACH SPECIFIC PROPERTY. A COPY OF THIS NOTIFICATION SHALL BE SUBMITTED TO CCCSD AS PART OF THE FINAL CONSTRUCTION PLAN REVIEW. CONNECTION OF STRUCTURES. THIS PROJECT IS FOR THE CONSTRUCTION OF THE MAIN SEWER LINE AND LATERAL SEWERS ONLY. STRUCTURES SHALL NOT BE CONNECTED TO THE SANITARY SEWER UNTIL: 1. THE SEWER MAIN EXTENSION IS COMPLETED BY A PROPERLY LICENSED CONTRACTOR REGISTERED WITH CCCSD AND THE WORK IS ACCEPTED BY CCCSD. 2. THE BUILDING ROUGH PLUMBING IS COMPLETE AND APPROVED BY THE PROPER AUTHORITY. 3. APPLICABLE CONNECTION FEES ARE PAID TO CCCSD. 4. A PROPERLY LICENSED SEWER CONTRACTOR REGISTERED WITH CCCSD OBTAINS A CONNECTION PERMIT FROM CCCSD. EASEMENT STAKING. SURVEY STAKING OF ALL PUBLIC AND PRIVATE EASEMENTS IS REQUIRED FOR THIS PROJECT. THESE SURVEY STAKES SHALL BE SET AT THE SAME TIME AS THE SEWER CUT STAKES IN ORDER TO VERIFY THAT THE PROPOSED SANITARY SEWER WILL BE CONSTRUCTED PROPERLY WITHIN THE EASEMENT. MINIMUM ACCEPTABLE SURVEY STAKING SHALL BE DONE AT FIFTY (50) FOOT INTERVALS, AT ALL ANGLE POINTS, AND AT THE BEGINNING AND END OF CURVES. ALL EASEMENT STAKING AND SEWER CUT STAKES SHALL BE AVAILABLE FOR PRECONSTRUCRON INSPECTION BY CCCSD PRIOR TO ACCEPTANCE OF THE FINAL CONSTRUCTION PLANS PAVEMENT RESTORATION: 1. PAVEMENT CUT FOR TRENCHING OR DAMAGED DURING THE WORK MUST BE RESTORED WITH A CROSS SECTION EQUAL TO THAT OF THE EXISTING ROAD, OR A MINIMUM OF 2 112 INCHES OF ASPHALT OVER 6 INCHES OF AGGREGATE BASE (WHICHEVER IS GREATER). 2. THE LIMITS OF PAVEMENT RESTORATION MUST EXTEND TO COMPETENT EXISTING PAVEMENT, AND BE A MINIMUM "T-CUT" WIDTH EQUAL TO THE TRENCH WIDTH PLUS 6" ON EACH SIDE OF THE TRENCH. J. WHERE THE EDGE OF THE "T-CUT" IS WITHIN 24 INCHES OF THE EDGE OF THE EXISTING PAVING, RESTORATION IN THAT AREA MUST EXTEND TO THE EDGE OF THE ROAD. 4. LOCAL AGENCY, WHICH HAS JURISDICTION OVER THIS ROADWAY, MAY HAVE MORE STRINGENT REQUIREMENTS FOR PAVEMENT RESTORATION. PRE -CAST MANHOLES. IF THE CONTRACTOR PROPOSES TO USE PRE -CAST BASES FOR ANY MANHOLES, COMPLETE SHOP DRAWINGS FROM THE MANUFACTURER SHALL BE SUBMITTED AND RECEIVE FAVORABLE REVIEW BY CCCSD PRIOR TO ORDERING THE BASES SANITARY SEWER MANHOLES. ALL SANITARY SEWER MANHOLE LID/COVER SHALL BE INSCRIBED "SANITARY SEWER". ROAD MAINTENANCE RESPONSIBILITY.• AN "ACCESS ROAD MAINTENANCE AGREEMENT" WHICH REQUIRES PROPERTY OWNERS TO MAINTAIN THE ALL-WEATHER ACCESS ROADS SHALL BE EXECUTED AND RECORDED PRIOR TO ISSUANCE OF PERMIT. EXISTING MONUMENTS. CONTRACTOR IS RESPONSIBLE FOR PRESERVATION ANDfOR PERPETUATION OF ALL EXISTING MONUMENTS (THAT CONTROL SUBDIVISIONS, TRACTS, STREETS OR HIGHWAYS, OR PROVIDE SURVEY CONTROL), WHICH WILL BE DISTURBED OR REMOVED DUE TO CONTRACTOR'S WORK. THE CONTRACTOR SHALL PROVIDE A MINIMUM OF 10 WORKING DAYS NOTICE TO PROJECT ENGINEER/SURVEYOR, PRIOR TO THE DISTURBANCE OR REMOVAL OF EXISTING MONUMENTS PROJECT ENGINEER/SURVEYOR SHALL COORDINATE WITH THE CONTRACTOR TO RESET MONUMENTS OR PROVIDE PERMANENT WITNESS MONUMENTS AND FILE THE REQUIRED DOCUMENTATION WITH THE COUNTY SURVEYOR, PER BUSINESS AND PROFESSIONS CODE 8771. SEWER ABANDONMENTfREM0VAL: ALL SEWER ABANDONMENT RELATED TO THIS PROJECT SHALL BE PERFORMED IN ACCORDANCE WITH SECTION 23 OF THE LATEST CCCSD STANDARD SPECIFICATIONS. TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP GENERAL NOTES JOB NO. 270019 I SHEET NO. Z OF 21 0 U D C a� 0 J It N I i U) w 0 z I N a rn 0 O r- N / a v a� c a� rn 0 O N m 0 x LAJ CHJJ\JG & GRACE THE 2 1 7-440-020 WILLIAMS 217-010-039 `s80 GJTAS I_JVJNG TRUST 2 "1 7-0 1 0-040 540 —560 —570 x\ "OAi �610 x ' 590 / � 580 OgC / �-------------- EARTHEN l SWALE l l l — 5170 / / j I / / I / I / I 50 WHIPPET REVOCABLE TRUST BEVERLY 2 061 —008 I 1,2"TREE l 60"OAK / / \ EXISTING BARN /- - - SHED EAK=535.1 f / /l h SHED 20 \ HB G \ \ G \ Wo Sc GG \ HUANG CHUNG—HO COD \ `sue & SUJAI\J THE \\ 207-061—D53 ROOF PEAK=536.1'f INV.EX. THRU LOT 6 505 NJ 29 400 SDDI 508.31RIM\ 24 OUT 503.11 / AYTOLU 207-06 1 —059 ROOF PEAK=534.0'f IN EX. " OUT 509. LOT 7 505 NJ 29 EX. SSMH 512.11 INV.EX. 10" THRU .26 If NO.I DATE IAPPD.I REVISION 1 N JJ L-117.89' "' R-750.00' / A-09 00'22" / EX. SDCB 515.05TC INV.EX. 24" OUT 509.05 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA �'q7F 3 o CONCRETE 10" THRU 519.76 &. SDCB 531.88TC EX. SDCB 539.01 TC INV.EX. 24" THRU 526.68 INV.EX. 24" THRU 533.71 SULL RAJINDRR SJJNG-H THE & SULL SUKHVINDER 207-06 1 —01 7 DESIGNED UNDER THE DIRECTION OF: 'epFESS/O49 0 w No.35121 z Aw MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 ANIBROSIUS & THE 207-071 —00 "1 L=286.10' CD R=750.00' ` _\ A=2151'24" x x lJ9 �• 8' 0) c� 0 B RA HOLDINGS LLC 2 7-061-009� J U, 0 • 48"OAK i 0 48"OAK VP� ,moo �o ,6ARSHJ NJUHAJUDDJN THE & QARSHI SEEN1A THE 207-06 1 —01 D INV.EX. 10" THRU 545.57 HAT S U S H J X. SDCB 55 . CON CURB & GUTTER INV.EX. 18 IN 552.86 2 D 7- D 6 '1 - D '1 6 INV.EX. 24" THRU 551.52 Storm Water Monitoring & Reporting APPROVED Land Development Engineering & Associates Environmental Engineering STEVEN JONES Municipal Engineering CITY ENGINEER M I LAN I Surveying &Mapping R.C.E. 2655 Stanwell Drive, Suite 105 Construction Staking EXPIRES DATE Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 40 20 0 40 80 SCALE: 1 "=40' ABBREWA TIONS EL ELECTRICAL UTILITY EX EXISTING FH FIRE HYDRANT HB HOSE BIB INV INVERT SDCB STORM DRAIN CATCH BASIN SSMH SANITARY SEWER MANHOLE TC TOP OF CURB TIP TYPICAL USA UNDERGROUND SERVICE ALERT WM WATER METER WV WATER VALVE SITE BENCHMARK SET REBAR AS SHOWN ELEVA 770N=526.94' BEACHMARK CONTRA COSTA COUNTY BENCHMARK NO 285 CHISELED "T" IN NORTH END OF CONCRETE HEADWALL ON CAMINO TASSAJARA ELEVATION=456.312 EASEMENTS 50' RIGHT OF WAY EASEMENT SHOWN IS PER 18 LSM 18 BASKS OF BEARINGS THE BEARING NORTH 1851'32" WEST BETWEEN TWO FOUND MONUMENTS AS SHOW ON THAT CERTAIN SUBDIVISION MAP NO. 9014 FILED /N BOOK 505 OF MAPS AT PAGE 29, CONTRA COUNTY RECORDS, WAS TAKEN AS THE BASIS OF ALL BEARINGS SHOWN UPON THIS MAP. REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLETION OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP EXISTING SITE CONDITIONS JOB NO. 270019 I SHEET NO. 3 OF 21 Z y i 0 m y t IL a W F LU Cz Z y W i a U D C1 aD 0 J d Co 0 0 N I I x w I CP v rn 0 O N v v c a� 0 O r N m 0 40 20 0 40 80 SCALE: 1 "=40' DEMOLITION PLAN NOTES X O1 REMOVE (3) SHEDS O2 REMOVE BARN O3 REMOVE HOSE BIB ® REMOVE FENCE O5 REMOVE ELECTRIC U71LITY © REMOVE ASPHALTIC CONCRETE O7 REMOVE CONCRETE ® REMOVE WATER LINE DEMOLITION LEGEND EXISTING TREE TO BE REMOVED EXISTING ASPHALT TO BE REMOVED L EXISTING BUILDING TO BE REMOVED EXISTING CONCRETE TO BE REMOVED CHAIN LINK FENCE TO BE REMOVED UNLESS INDICATED EXIS71NG PROPERTY BOUNDARY REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA 0 a W i W cm Z W W i a U 7 J C N L 0 J n 0 N cij 0 It N I I O bi cl LAI CHINK GRACE f 217-440— LOT 5 JOJ NJ 29 H UAIN0 CH UI\I C— & SUJAj\J TR1 207-061 —05 LOT 6 505 IM 29 LOT 7 505 NJ 29 / NO. DATE APPD. REVISION WILLJAMS 2 1 7-0 "1 0-039 1 \ 1 / v `94�' a \ S 0 LOT 4 ry Air/JBR OS1 US & rR E 207-0 7 "1 —00 1 oAi ti OITAS LIVING- TRUST � �o � � o 44 2 "1 7-0 "1 0-04O / times• \\\ � /' � C-1V 02� \ �o N747122" W 117.67' A ,gyp, ,3p SF F'q,Q' � LOT 3 i 020 �- LOT 5%K ' & / \N7,3?2:j5.W.06 i I �C14�� I -------------- ' i / o so' ' 25' I� I N87 2326"W 244._32' %SIP Ck FRONTgk LOT 2 SETBACK N18'51'32"W / F- \ 34.29' N 25 \ N762 ' " I z Q FRONT UPSl S RFgR 235 W 27255' LOT 6 — — N04'00'04"E 4.80' �o HO \ W 0 N \ l 25' N \\ LOT 1 I S1 '`ZNT $ \ E ACKI 11 N N \ O \ \ I I o N \ In ca AY-rOLU \ N LU U) I N 207-061 —059 \ o I b \ \ "' — 4�0157'40" o d=002926" \ L=26.53' �u R=775.00' L=6.64' 75.00' L=121.82' R=7 ,_ n / ,691 N SAp,R J T AS DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA QOVESS/p� 0:� No.35121 z � EXP. 09/30/25 � /VI\. �� �qle OF CA�� 4=0157'35" R=750.00' 60=D L=2I65, Z I SETBACK i l E'lggC/r 0 4W 14.00, --- / O M^ v / N79 01'16"W 167.02' tSEFRONj�TBAC T ILOT 7 / K I R=7d7—_51g53L4J r6 0, pp /-_3 ='?j 'S4" 00. SL=J a 615iZ'J-61V Al SULL RAJINDER S1jNCH THE & SULL SUKHVJJ\JDER 207-061 —0 1 7 DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE HATSUSHI 207-00 "1 —0 1 0 Storm Water Monitoring & Reporting Land Development Engineering & Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE QARSHI NJUHAJUDDIN THE & QARSHJ SEEN1A THE 207-06 1 —0 "1 0 TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 AREA: 8.49 ACRES (GROSS) Z63 ACRES (NET) LOT # GROSS SVAC NET SVAC 1 40, 73310.94 37, 43210.86 2 42,21110.97 39,39810.90 3 43, 58411. 00 39,18210. 90 4 45,31111.04 42,16310.97 5 84,84211.95 76,19111.75 6 62, 78911. 44 60, 59411.39 7 40, 00410.92 37, 34210.86 40 20 0 40 80 SCALE: 1 "=40' REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO77CE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP LOTTING EXHIBIT JOB NO. 270019 1 SHEET NO 5 OF 21 y i 0 m y W I Cz Z y W i U Z3 J T a> 0 N I 0 J I U J� NO. DATE APPD. REVISION IC DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA Q�ovEss/O� � No.35121 z � EXP. 09/30/25 � CIVIL �� le OF CA'\ DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE Storm Water Monitoring & Reporting Land Development Engineering =00& Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 60 30 0 60 120 SCALE: 1 "=60' REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP LOTTING EXHIBIT - CONTEXT MAP JOB NO. 270019 I SHEET NO. 6 OF 21 U 3 J C N O J It N I M I x w z O U H O J He I \J CHINK �jRArr T 2 1 7 — 4 4 O - OT 5 505 1\/1 29 H Jr\N r CH U]\Jr— & SUJr\1\l TR 207-06 "1 —05 LOT 6 SOS 1\/1 29 LOT 7 505 1\/I 29 NO. DATE APPD. REVISION �c RE 020 HO 3 VVILLIANIS 2 "1 7-0 J 0-039 GITr\S IVIJ\Jr TRUST 2 J 7—O'1 0-040 1b r\YTOI J 207-06 "1 —059 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC [CHECKED: KRA i 5,o_LOT 4 PAD=570f 2172 SF 0.47 AC LOT 3 PAD= 555f 20,133 SF AC 550 LOT 2 PAD=542f 21,316 SF 0.49 AC \LOT 1 � PAD=535t 1$ 19,986 SF 0.46 AC 'eof Ess/O� al:� No.35121 z ;:a � EXP. 09/30/25 � /VI\. �� �qle OF CA�� 00 '41 U o0 �JI I RT\Jlj\]D R S11NrH TRr u SULL SUKHVIINDr R 207-06 "1 —0 1 7 DESIGNED UNDER THE DIRECTION OF MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 Z 10 I LOT 5 PAD= 552f 17,176 SF 0.39 AC LOT-6 PAD=545t 16, 743 SF 0.38 AC- OT 7 'AU=D4D2 11, 905 SF 0.27 AC DATE Q00 /*/]BROSIUS u TF Qr\RSHJ 1\/1JHr\JUDDJN TRr u Q,\RSHI Sr r NJr\ TEE i r\ A�qLAf Hr\TSUJ�-7� 207-06'1 —0 "1 6 Storm Water Monitoring & Reporting Land Development Engineering =00& Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 40 20 0 40 80 SCALE: 1 "=40' REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP OVERALL SITE PLAN JOB NO. 270019 SHEET NO. 7 OF 21 Ca W i a U J C 0 J Co 0 0 It N I I w F- U) I r 3 v 0 O r- N / c a� rn 0 O r- N m 0 80 40 0 80 160 SCALE: 1 "=80' DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA LEGEND ENGINEERED FILL BOUNDARY UNDOCUMENTED FILL BOUNDARY LANDSLIDE BOUNDARY N" LANDSLIDE DIRECTION rll LANDSLIDE DIRECTION (DORMANT) NOTES: 1. THE PROJECT PROPOSES TO IMPLEMENT ALTERNATIVE 1 (SOLDIER PILE WALL) TO THE WEST OF THE SUBJECT PROPERTY AS RECOMMENDED BY THE GEOTECHNICAL ENGINEER IN THE GEOTECHNICAL REPORT. 2. IMPLEMENT CORRECTIVE GRADING MEASURES PER THE GEOTECHNICAL REPORT BY ENGEO INC. DATED FEBRUARY 10, 2022. 3. THE REFERENCED GEOTECHNICAL CROSS SECTIONS ARE NOT PROVIDED IN THIS TENTATIVE MAP DRAWING. SEE THE REFERENCED GEOTECHNICAL REPORT FOR CROSS SECTION DETAILS. REFERENCE: GEOTECHNICAL REPORT BY ENGEO INCORPORATED, FEBRUARY 10, 2022 REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO77CE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP 0 a W i a W Z W W i N M W cl J U) .t N a LOT 4 PAD=570± 510 LOT 3 _ PAD=555± 553.61 TIN 553.11BW DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA BRIS BASIN � � 5 WALL DAYLIGHTS TO 0.5' HEIGHT Zz \ / 589.50 0.5' TALL RETAINING CURB/WALL / 589.00BW / 589.50TW 589.00BW N 587.75 / 582.75BW 5 3TW \ 589.50TW I 589.0 589.00BW I 587.46TW 582.46BW I I \ 589.50TW 589.00BW / \ / 5' TALL RETAINING WALL WALL DAYLIGHTS TO 0.5' HEIGHT S 20 10 0 20 40 SCALE: 1 "=20' I I I I I WALLS DAYLIGHT TO 0.5 HEIGHT it • vv 3 571 70BW 3' TALL RETAINING WALLS (6' MAX) LOT 5 PAD=t52± ( 569.40TW \ 566.40BW 565.90TW 562.90BW 562.40TW 561.90BW WALLS DAYLIGHT TO 0.5' HEIGHT 562.50TW 562.00BW .60TW .10BW LOT 6 maw wimrs belouL 811 bdore you REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NOIJCE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CUENT APPROVAL OF MAP v U Z3 J _T N O J d It 65 4 O N M 0 Q 0 O) 01 0 0 r- N a a� v c a� / rn 0 0 N m O 11 y SS0•� V \ o I \ 553.61TW J \ 553.11B y � 547.09TW 1 546.59BW 0 \ PRG 540.72TW 540.22BW 1 540.48TW 539.98BW --W 556.68TW 551..68BW- � 551.68BW-E 5JZ 48BW--E 5JZ 40TW 536.90BW �\ 533.78BW y\ 524. 72B IV \O525.22TW y� y\ REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NOTICE TO BE REMOVED UPON COMPLETION OF MAP AND UPON Oyu what �1�IaVYL AGENCY/CLIENT APPROVAL OF MAP before you dig. NO. DATE APPD. REVISION LOT 2 558.98TW 555.98BW-S PAD=542± 555.98BW-N DOSED 3' TALL RETAINING WALL (6' MAX) RETAINING WALL NOTES. 1. RETAINING WALLS DAYLIGHT TO 0.5' HEIGHT. 2. RETAINING WALLS SHALL NOT EXCEED 6' IN HEIGHT EXCEPT FOR STRUCTURAL OR GE07ECHNICAL REASONS PER SECTION 32-22 OF THE TOWN OF DANWLLE'S ZONING ORDINANCE. J. MAX SLOPE BETWEEN RETAINING WALLS SHALL BE J.1. -PROPOSED 5' TALL RETAINING WALLS (6' MAX) 553.17TW 551.67BW 548.5OTW 548.00BW DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA 541.43TW 'eovESS U� y m No.35121 z � EXP. 01/10/ �qTF F OCA�\2�� 540 PROPOSED 5' TALL RETAINING WALLS (6' MAX) LOT 1 PAD=535± DOSED 3' TALL RETAINING WALL (6' MAX) DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE 5JZ 98TW 534.98BW 535.50TW 5�J5.00BW 4 533.15TIN :02.65BW 530.24TW P�G�� �o 529.74BW 5 522.00TW 521.50BW 557.807W LOT 6 PAD=545± Storm Water Monitoring & Reporting Land Development Engineering & Associates Environmental Engineering M I LAN I Municipal Engineering Surveying &Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com LOT 7 PAD=545± 7 APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE 543. 542. 5t'r0 558.50TW 555.50BW 555. 552. `5so 543.50TW 543.00BW WALLS DAYLIGHT TO 0.5' HEIGHT h�O DAYLIGHT TO 0.5' HEIGHT 4 00 3 TALL RETAINING WALLS (6 MAX) M N z 5 4 8. 710 T W\\\\\\\ 544.70E 558. 555. 558.50TW 555.50BW TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 20 10 0 20 40 SCALE: 1 "=20' GRADING AND DRAINAGE PLAN JOB NO. 270019 SHEET NO. 10 OF 21 y W i a U 3 �1 (D 0 J d 60 0 0 N I i 0 a 0 CY) 0 rn 0 O r- N v a� c a� rn 0 O r- N m 0 / IY If NO.I DATE IAPPD.I REVISION 1 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JIVG/SMS/LLC CHECKED: KRA LOT 4 LOT 3 LOT 2 'eovEss/p� U� y m No.35121 z ;:a DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 I I \IS,/ IS, S CB DCB \ �� / —577.0 RIM \�� \ / 574.0 INV OUT I �o SSCO 4 SSMH I "SS SDCB \� �\ 5815RIM 6� 572.48 INV THRU / \\ 1 I y SDJB I/r � I �o SSW DATE Mm huh SSCO LOT 5 Storm Water Monitoring & Reporting Land Development Engineering & Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com LOT 6 APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 20 10 0 20 40 SCALE: 1 "=20' SDCB l/ REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NOIJCE TO BE REMOVED UPON COMPLETION OF MAP AND UPON AGENCY/CUENT APPROVAL OF MAP UTILITY PLAN JOB NO. 270019 I SHEET NO. 11 OF 21 C) U 7 J >, N 0 J 00 66 O 0 N I I F- I 0 O N Q c a� rn 0 O r- N m 0 yl � y I 2�° y ... SDCB 1 I II 1�5 ""r-So REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NOTICE TO BE REMOVED UPON COMPLETION OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP If NO.I DATE IAPPD.I REVISION : 00 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA I111011111K 'eovEss/p� 0:� No.35121 z DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 S SSCO LOT 1 AD 516.85 INV OUT (MIN ELE Sn o% DATE SDJB� SDJ8 SSCO DMH SSMH \ 0 00 1 I� I� 1 SDJB S SSCO CONNECT TO EXISTING SDCB 527.0 INV OUT CONNECT TO EXIS71NG SD 516.22f EX INV SSCO Storm Water Monitoring & Reporting Land Development Engineering & Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com LOT 6 SSMFI APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE \\ LOT 7 \� TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 SDCB 560.00± INV �w 'o ND �� s CONNECT TO EXIS71NG SDCB 553.72 EX INV OUT 20 10 0 20 40 SCALE: 1 "=20' UTILITY PLAN JOB NO. 270019 I SHEET NO. 1 Z OF 21 D 1 N 3 v rn 0 O r- N / a a c a� rn 0 O r- N m 0 iNO. DATE APPID. REVISION DMA-9-L ST 32,340 SF ..� -6-R, P —'� IMP-4 10,469 SF (#ST -L SF a. LOT 3 1 IMP' •• • 10,905 SF DMA-5-L ST 28,608 SF LOT 2 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA LOT 1 )MA-2-R, P IMP-2 9,618 SF IMP-1 BI0 1,002 SF gwovESS 0 No.35121 z � EXP. 09/30/25 � CIVIL �� �qTF OF CA��F�� IMP-3 BIO 495 SF IMP-2 I BIO ' 400 SF WA-g-R, P / IMP-5- 9,830 SF LOT 4 IMP-4 Bio 448 SF IMP-7 BIO 325 SF IMP-8 810 363 SF DMA-1-P IMP-1 4,903 SF, IMP-5 BIO 481 SF IMP-6 810 359 SF -10-R, IMP-6 LO 5 7,656 SF IMA-12-R,1 IMP-7 7,143 SF LOT 6 IMP-8 8,088 SF LOT 7 DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE DMA-t1-L ST 68,653 SF DMA-13-L ST 53,127 SF DMA-15-L ST 28,890 SF Storm Water Monitoring & Reporting Land Development Engineering map& Associates Environmental Engineering M I LAN I Municipal Engineering Surveying &Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com 40 20 0 40 80 SCALE: 1 "=40' APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE 0 0 0 C. 3 LEGEND IMPERVIOUS SURFACE C3 TREATMENT AREA SELF -TREATING DMA C.3 DMA & IMP BOUNDARY PROPERTY BOUNDARY DMA # �_ � DMA DESIGNATION -TYPE MA -A -A IMP—X IMP DESTINATION XXX SF DMA AREA IN SQUARE FEET IMP # IMP-X IMP TYPE X C3 ELEMENT # XXX SF C.3 ABBREVIATIONS BIO BIO-RETENTION AREA DMA DRAINAGE MANAGEMENT AREA FTP FLOW THROUGH PLANTER IMP INTEGRATED MANAGEMENT PRACTICE L LANDSCAPING P PAVED SURFACE(S) R ROOF SF SQUARE FEET ST SELF TREATING IMP IN AREA SQUARE FEET NOTES: THE BUILDING ENVELOPES, CONCRETE PATIOS, AND C.3 TREATMENT FACILITIES SHOWN ON EACH LOT ARE CONCEPTUAL AND FOR CONTEXT PURPOSES ONLY. TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP PRELIMINARY C.3 EXHIBIT JOB NO. 270019 I SHEET NO. 1 3 OF 21 y 0 m y 1 a W i I LU C3 Z W W i U 7 J _T N 0 J a O 0 0 N I i U I CP a 0 O N a 0 a� c a� rn 0 O N m 0 Project Name: Kent & Van Dam Project Type: Treatment Only Location: Danville, CA APN: 207-061-008 & 207-061-OC Drainage Area: 359473 sf Mean Annual Precipitation: 19 I. Self -Treating Areas DMA Name Area (sq ft) DMA3 21720 DMA5 28608 DMA7 28113 DMA9 32340 DMA11 68663 DMA13 53127 DMA15 28890 IV. Areas Draining to IMP. - IMP Name: IMP1 (Soil Tyl IMP Type: Flow -Through Planter Soil Type: D Post- C DMA DMA DMA a Proect Runoff Name Area Surface (sq ft) Type Factor Ri F� DMA1 24.903 Concrete or Asphalt 1.00 2 Total 2 IMP Name: IMP2 (Soil TyI IMP Type: Flow -Through Planter Soil Type: D DMA Post- Dr MA Ai DMA Area Project Runoff Name (sq ft) Surface Factor Rui TypeFar DMA2 9,51 a Conventional Roof1, 00 9 Total 9 IMP Name: IMPS (Soil TyI IMP Type: Flow -Through Planter Soil Type: D Post- Dr DMA DMA Project DMA Ai Name Area Surface Runoff : (sq ft) Type Factor Rui Far DMA4 10,905.Conventional Roof 1.00 10 Total 10 IMP Name: IMP4 (Soil TyI IMP Type: Flow -Through Planter Soil Type: ❑ DP Post - DMA A' DMA Project Runoff Area(sq Name ft) Surface Factor Rui Far DMA6'10,459 Conventional Roof • 1 00 10 Total 10 IMP Name: IMP5 (Soil TyI IMP Type: Flow -Through Planter Soil Type: D Post- Df DMA DMA Project DMA Ai Name Area Surface Runoff (sq ft) Type Factor Rui Far DMA8 9,830 Conventional Roof` 1.00 9 Total 9 IMP Name: IMP6 (Soil TyI IMP Type: Flow -Through Planter Soil Type: D Post- D M A DMA DMA Area Project Runif Name (sq ft) ST pee Factor'Ru Fa DMA10 7.656 Conventional Roof` 1,00 Total IMP Name: IMP7 (Soil TyI IMP Type: Flow -Through Planter Soil Type: D Post- D DMA DMA Project DMA A Area Runoff Name �Typee (sq ft) Factor Ru Fa DMA12 7,143 Conventional Roof' 1.DD' Total IMP Name: IMP8 (Soil TyI IMP Type: Flow -Through Planter Soil Type: D Post- D DMA DMA A DMA Area Project Runoff Name (sq ft) SType a Factor Ru Fa DMA14 8,088;Conventional Roof 1,00. f Total # Software Tool Warnings No warnings to report. NO. DATE APPD. REVISION 'roperties 3 ►e: D) MA rea x noff IMP Sizing ctor i,903 IMP Rain Proposed, Sizing Adjust- Minimum Area or 903 'Factor ment Area or Volume Volume Factor Area 0.040 1.000 996 1,002 ►e: D) IA m toff for IMP Sizing 518 Rain IMP Adjust- Minimum Prop Sizing ment Area or Volume Areaa r oor 318; Factor" Factor Volume Brea 0 040 1 000 385 400 ►e: D? IA Da toff' torIMP Sizing e 905Rain, IMP Proposed Adjust- Minimum Sizing ment Area or Volume Area or 905: Factor Factor Volume lrea 0,040 1000 436 495 le: D) IA m toff for IMP Sizing 469 Rain IMP Adjust Minimum Proposed Sizing ment Area or Volume Area or A69" Factor Factor Volume krea. 0 040 1 000' 419 448 le: Dy IA as toff' for IMP Sizing B30 IMP Rain Proposed Adjust- Minimum Sizing Area or Factor ment Area or Volume B30" Factor Volume lrea 0 040 1 000 393 481 ►e: D) AA •ea K noff :tor IMP Sizing .656 Rain IMP Adjust- Minimum Proposed Sizing meet Area or Volume Area or ,656 Factor Factor Volume Area. 0.040 1 000 305 359 ►e: D) OA -ea K iofF IMP Sizing Ao r 143 IMP Rain Proposed Adjust- Minimum Sizing ment Area or Volume' Area or 143 Factor FVolume Factor Area 0,040 1.000 286 325 ►e: D) 4A -ea K toff ;tor IMP Sizing 088 Rain IMP Adjust- Minimum Proposed Sizing ment Area or Volume Area or 088 Factor Factor. Volume Area,. 0 040 1 000 324 363 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA QwpFESS l EUGfN�, U� y m W No.35121 — EXP. 09/30/25 CIVIL �� �qle CF CA�� DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE 3.�,yAX NOTE: 1. SOIL MIX SHALL MEET REQUIREMENTS OF THE CONTA COSTA COUNTY I CLEAN WATER PROGRAM STORMWATER C.3 GUIDEBOOK, SIXTH EDITION, —_ APPENDIX B ' Storm Water Monitoring & Reporting Land Development Engineering &=PRAssociates Environmental Engineering M I LAN I Municipal Engineering Surveying &Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED BIO-RETENSION WIDTH VARIES FOVERFLOW DRAIN I I I i + + + + + + + + + + + + + III I + SEE NOTE + + + + + + + + + CLASS II PERM. TOP MIX + + + 4 + + + + + + + + +l+gO-Trom -MIX ++++++ IN -6" � ?II.D. PPE IN CLOSE PR —STRUCTURES PERF. PIP —LINED WI TH t —III III III III III III III III C3 BIO—RETENTION BASIN BIO-RETENSION WIDTH VARIES + + + + + + + + + + + + + ++++ LOAM'MIX+ ^ ++ + + + + + + + + + + + + + + + + + + + 0 CLASS II PERM. ��___,67 PERF. I PIPE 8" SOILD. PIPE —III - —I I C3 BIO-RETENTION BASIN TOP OF CURB CURB OPENING - 4" COBBLE STONES -MATCH OPENING WIDTH X 1' LENGTH STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE 0.5' C.3 BIO-RETENTION MATERIAL a as a c e d a 3:1 MAX IIlttllltt EAS LOCATED I TY TO PROPOSED - BE FULL Y LL I — �VIOUS LINER — III III II 2" MIN DROP FROM FL AC/AB SECTION T 14 REBAR 18" O.C. EACH WAY. AC/AB SECTION a 14 REBAR 18" O.C. EACHWAY SIDE VIEW DEEPENED CURB AT C3 BIO—RETENTION BASINS NOT TO SCALE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 T"^ OF CURB AT E OF PARKING W LINE FRONT VIEW REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS N07ICE TO BE REMOVED UPON COMPLEWV OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP PRELIMINARY C-3 NOTES AND DETAILS JOB NO. 270019 I SHEET NO. 1 4 OF 21 W 0) v U 7 J N 0 J a N 6 O 4 O N I r7 I F- W 0 (n U J Q U U I rs a 0 O N / a v c a� rn 0 O r- N m 0 If NO.I DATE IAPPD.I REVISION 1 i DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA 'eovEss/O� U� y m No.35121 z ;:a � EXP. 09/30/25 � /VI\. �� �qle OF CA�� = qTA 1 +00.0 ; UU.UU DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE i Storm Water Monitoring & Reporting Land Development Engineering =00& Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 EARTHWORK SUMMARY RAW CUT = 54,500 CY RAW FILL = 53,500 CY —1, 000 CY CUT TO FILL LEGEND CUT FILL 40 20 0 40 80 SCALE: 1 "=40' REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP CUT -FILL MAP JOB NO. 270019 I SHEET NO. 1 5 OF 21 a U 7 J C N L U J It N I I J _J L� D U I U, 0 O N a v a� c a� rn 0 O r- N m 0 f NO.I DATE IAPPD.I REVISION 1 DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA LOT 2 wwwwwww- 'eovEss/O� U� y m No.35121 z ;:a i LOT 4 i LOT 3 UK EROSION CONTROL LEGEND ■MMMM■ ♦♦♦♦252 �wr wn \ ♦♦� FIBER ROLLS INLET PROTECTION STABILIZED CONS7RUC71ON ENTRANCE N07ES. 1. SEE SHEET 16 FOR EROSION CONIROL DETAILS I 1\ 1w i LOT 5 i • Z LOT 6 j • � s • D , • • j ♦ • 40 20 0 40 80 s ■ ♦ SCALE: 1 "=40' III LOT 7 • • ME In an Me 0 •••••••.: REVIEW COPY SUBJECT TO RECISION NOT FINAL THIS NO7ICE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE Storm Water Monitoring & Reporting Land Development Engineering & Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 EROSION CONTROL PLAN JOB NO. 270019 I SHEET NO. 1 6 OF 21 a 0 7 J 0 J N O O O N I i U W I 0 O N a v a� c a� rn 0 O r- N m 0 Storm Drain Inlet Protection SE-10 It Fence per SE-01 NOTE. WRAP GRATE IN FILTER FABRIC x Drain inlet X VA ---- _— � f X Sheet flow Less than 1 acre 5" Min overlap at ends of silt fence. Geotextile Blanket Silt Fence per SE-01 o s PLAN 0 DI PROTECTION TYPE 1 NOT TO SCALE 1. For use in areas where grading has been completed and final soil stabilization and seeding are pending. 2. Not applicable in paved areas. 3. Not applicable with concentrated flows. �uly zu-IL California Stormwater BMP Handbook Construction www.casga.org 50' MINIMUM 8" MIN. DIVERSION RIDGE 8"MIN. TO DIVERT RUNOFF ° PROJECT SLOPE - SITE _-------- - - - - - - FILTER CLOTH (MIRAFT 70OXG OR EQUIVALENT) 50' MINIMUM PROFILE 7of10 PUBLIC RIGHT -OF- WA Y PROVIDE APPROPRIATE TRANSITION BETWEEN STABILIZED CONSTRUCTION ENTRANCE AND PUBLIC RIGHT OF WAY r----------------------------- - 2% SLOPE PUBLIC PROJECT AWAY FROM RIGHT SITE ROADWAY OF WAY --- --------------------- --I ``�� I 10' FILTER CLOTH MINIMUM 12" THICK (TYP) (MIRAFT 70OXG 3"-6" ANGULAR OR EQUIVALENT) STONE AGGREGA TE PLAN 15' MIN. 1. ENTRANCE SHALL SPAN THE FULL WIDTH OF ALL POINTS OF INGRESS OR EGRESS. 2. WHEELS SHALL BE CLEANED TO REMOVE SEDIMENT PRIOR TO LEAVING THE SITE. SEDIMENT SHALL DRAIN INTO AN APPROVED SEDIMENT TRAP OR SEDIMENT BASIN ALL SEDIMENT SHALL BE PREVENTED FROM ENTERING ANY STORM DRAIN, DITCH OR WA TERCOURSE. 3. THE ENTRANCE SHALL BE MAINTAINED IN A CONDITION WHICH PREVENTS TRACKING OR FLOWING OF SEDIMENT ONTO THE PUBLIC RIGHT OF WAY. THIS MAY REQUIRE TOP DRESSING WITH ADDITIONAL STONE AS CONDITIONS DEMAND. ALL SEDIMENT SPILLED, DROPPED OR TRACKED ONTO PUBLIC RIGHT OF WAY MUST BE REMOVED IMMEDIATELY. STABILIZED CONSTRUCTION ENTRANCE DETAIL NOT TO SCALE DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA Storm Drain Inlet Protection Stabilize area and grade uniformly around perimeter x Geotextile Blanket x 1:1 slope 1� 3 Min FUr , Drain inlet Note: s Remove sediment 4' before reaching one-third full. SE-10 Storm Drain Inlet Protection -Silt fence Per SE-01 12" Min 24" Max Section A —A NOTE. WRAP GRATE IN FILTER FABRIC Concentrated �� Rock filter(use if flow flow is concentrated) � X r----- --- - X Edge of I r--------------� I 00 sediment trap ; I I I V_AX i i + + i I x Drain inlet �0 I I I I J I f l I Sheet flow7 Geotextile x i i i i X Blanket Silt fence Per SE-01 I I OX L-------------------J X IX X X X—I 0 Plan co CD DI PROTECTION TYPE 2 NOT TO SCALE Notes 1. For use in cleared and grubbed and in graded areas. 2. Shape basin so that longest inflow area faces longest length of trap. 3. For concentrated flows, shape basin in 2:1 ratio with length oriented towards direction of flow. June 2012 California Stormwater BMP Handbook 8 of 10 Construction www.cosga.org 10' MIN. STAKE (TIP.) A VARIES I I e Ton I I I V/ �2n» A 1/8» DIA.yI I 4" STEEL WIRE STAPLE DETAIL NOT TO SCALE STRAW BALE ( TIP. ) 10 MIL PLASTIC LINING PLAN VIEW NOT TO SCALE SE-10 s 2—bags high TYPICAL PROTECTION FOR INLET ON SUMP NOTE. WRAP GRATE IN FILTER FABRIC Spillway, 1—bag high J \—Sandbags 2—bags high TYPICAL PROTECTION FOR INLET ON GRADE NOTES: 1. Intended for short—term use. 2. Use to inhibit non —storm water flow. 3. Allow for proper maintenance and cleanup. 4. Bags must be removed after adjacent operation is completed 5. Not applicable in areas with high silts and clays without filter fabric. 6. Protection can be effective even if it is not immediately adjacent to the inlet provided that the inlet is protected from potential sources of pollution. DI PROTECTION TYPE 3 NOT TO SCALE Storm Drain Inlet Protection eeEeeeEeEeEEeeEEeEeeee:eEeEeE................. EeeeEEe�� • .� .• • .• .• .•`�' �� .• ..� i.• .• •�i�i�i�i��i�i�=�►i:��i�i�i ,.. Runoff with sediment 0 Overflow 12 24" June 2012 California Stormwater BMP Handbook 9 of 10 June 2012 Construction www.casga.org Fiber Rolls SE-5- _V D _V'/�If}/ Note: y y ,�,�,//,/,/,/ Install fiber roll �/ ilj along a level contour. �,�,�,�a�i,�,�,�,'�' y / lIJ y y Fiber rolls I y XX '/// �i�/i� _V, yll Vertical spacing measured along the ',' II -V _Vface of the slope varies between Install a fiber roll near 10' and 20' i slope where it transitions I - _V into a steeper slope STAPLES 10 MIL BINDING WIRE (2 PER BALE) PLASTIC LINING TYPICAL FIBER ROLL INSTALLATION N.T.S. NATIVE MATERIAL WOOD OR METAL (OPTIONAL) STAKES (2 PER BALE) SECTION A —A NOT TO SCALE CONCRETE WASHOUT AREA NOTE.- 1. ACTUAL LAYOUT DETERMINED IN FIELD. 2. THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30FT OF THE TEMPORARY CONCRETE WASHOUT FACILITY. CONCRETE WASHOUT AREA DETAIL NOT TO SCALE h • ( • i�i A�� VAAAiV�AA vA ,i .D���i✓I• � ♦ � i �I✓I• � ♦ vv..o; vvv. � /ova vv�. Construction www.casga.org J G V 11 I I G I 1 l I IIII UYY III Lr VI V ll I wire mesh Filtered water DI PROTECTION - TYPE 4 NOT TO SCALE California Stormwater BMP Handbook Construction www.casga.org SE-10 Curb inlet REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO WE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CMENT APPROVAL OF MAP 10 of 10 v U D J c a� 0 J o_ N a7 0 0 N I uu 0 0 W I a rn 0 0 N a v > v c a� / rn 0 0 r- N m 0 o c- z cr- cc ca m � 0 0 o SERIES OF RETAINING WALLS 5 o s 3'-6' (MAX), WALLS R/W R/W o DAYLIGHT TO 0.5' AT ENDS o Q R/W m R/W Q OF RETAINING WALLS DEBRIS WALL FRONT YARD ( W FRONT YARD z o SETBACK CL m «� SETBACK 25 25 C, o o PROPOSED PAD PROPOSED GRADE 25' 18' 18' 25' o o z GRADE 537.2 AC PAV. o � � 5 0 CONC. C&G = 2 p' 28 10, 2 p' = VARIES Lol- PAD EXISTING GROUND DEBRIS BASIN PAD 1 I 4.5' SIDEWALK PAD EXISTING 12'f 12't 537.8 `` `;' 3 538.5 2:1 MAX 541.0 OUTLET STRUCTURE WITH RIM SET 2:1 MAX f— PROPOSED GRADE GROUND � � 1 PROPOSED 4 TO PROVIDE 2' MIN FREEBOARD TYPE "A� CURB W* SD° 'SS ° SS. c 2 GRADE I GROUND (TOWN OF DANVILLE TYPE "8" CURB EXISTING GROUND SO W SD° STANDARD PLAN 105 TOWN OF DANVILLE STANDARD PLAN 105 EXISTING V DITCH �V DITCH DRAINAGE PIPE TO CONNECT TO ) ( ) CURB &GUTIER EXISTING PROPOSED STORM DRAIN SYSTEM CURB &GUTTER CROSS SECTION A -A N.T.S. 6" AC/AB SECTION PER PLAN 4r-1 ,:: rrill � I I '�I III III II 6" SPILL CURB w/ GUTTER NOT TO SCALE CROSS SECTION B-B 6" CURB & GUTTER, MODIFIED CITY STD DWG C1-1 (SEE NOTE 1, THIS DETAIL) STREET DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA N.T.S. m r I I III I I I =lmmmm 74 NOTE 1. BOTTOM OF CURB TURN DOWN SHALL BE AT THE SAME ELEVATION AS BOTTOM OF STREET BASE. STANDARD 6" CURB & GUTTER NOT TO SCALE FRONT VIEW CROSS SECTION C-C N.T.S. #4 BARS @ 24" O.C. SHOP -III EDGE 15» FL 15.E EDGE r_ 3", , 3" FL=EDGE - 0.10' 77,01 P 6" PERE PIPE+-� BASE ROCK—T—� I TW=FL + 0.50' EX. GROUNp CONC. DITCH AT RETAINING WALL NOT TO SCALE CROSS SECTION D-D N.T.S. REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NO77CE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP a U 7 J c, a� 0 J a N 0 0 N I I w 0 0 w I 01 0 0 N a v a� v c a� / rn 0 0 N m 0 600 595 585 580 575 570 565 560 555 550 710 705 700 695 690 685 680 675 670 665 660 655 Lr 650 645 6 640 4 635 630 n 620 615 v 610 a 605 Li 600 a 590 C 580 c 575 570 565 560 555 550 545 540 535 530 525 520 515 510 N N� c) cd 00 cD + Lr) O Lil U > > m m HIGH PT STA: 1 +39.12 HIGH PT ELEV: 569.17 PVI STA:1 +39.12 PVI ELEV:569.92 K:16.67 LVC:100.00 AD:6.00 STA:1 +39.12 ELEV-5-rO .30 N N,d- d7 o6 00 co + Lr) -3.00% r Y Lr �cc Of m w o> Of (D LL N N r7 r7 � � O O r7 r7 N N N N N N 00 00 � � Ln Ln co co r• r• Ln Ln N N cl� cl� O O N N r r 00 00 cD cD LD co 00 00 O O N N r7 r7 r7 r7 T) T) CD CD rf r� Co CD r- r- � co co � r r r• r• r• r• r• r 00 00 00 00 00 00 00 00 r• r• co co L.r) L.r) U-) U-) Lo Lr) U') Lo LC) LC) Lf) Lo U) U) Lo U-) U-) U-) Lr) Lr) U-) U-) Lo Lo 0+00 0+25 0+50 0+75 1 +00 1 +25 1 +50 1 +75 2+00 2+25 2+50 2+75 TWOFILE - CUL-DE-SAC w 600 595 585 580 575 570 565 560 555 550 LVC:50.00 AD:16.00 710 705 700 695 690 685 680 675 670 665 660 655 650 640 635 625 620 615 605 600 595 585 580 575 570 565 560 555 550 545 540 535 530 525 520 515 510 CD M Lr? O cD U-) LC) M rn O cc (D (D U-) r• a0 N O � N U-) � M M O N cD LC) U-) O 00 O O r7 00 L.C) M r• 7 O CD (D r j O N : c.D r• n 00 O 00 O r` r ) N cD Lf) co O U-) Lf) n N U) M 00 O L.C) r- M L() O 00 zl: LC) r- n LC) L.[') 00 - r7 n n r7 cD r7 rn cD M Lo n Co rn n n cD O M n co 6) n N cD O n n r• n r'') r• n rr) r• n r7 r• N n n 00 N n n 00 n r7 n 00 r7 n n M � r7 n O r• n� N N � Lf) r• O LC) O LC) u r7 00 Lo U') r• LC) cD C) co co Lo co to r- 00 to cD N r` r- r7 Lr) r- r` n r` L() Lo Lr) Lo u) L() L() Lr) Lr) L() L() Lo Lr) Lo L() Lr) Lr) Lr) Lr) Lr) Lr) Lr) Lr) Lr) LC) L() L() n Lr) n n n n n n n n Lf) n n n n n n n Lf) Lf) n n LC) n 1 +00 1 +25 1 +50 1 +75 2+00 2+25 2+50 2+75 3+00 3+25 3+50 3+75 4+00 4+25 4+50 4+75 5+00 5+25 5+50 5+75 6+00 6+25 6+50 6+75 7+00 7+25 PROFILE - PROPOSED PRIVA-M ROAD REVIEW COP Y SCALE 1' 40' HORIZ "-8' SUBJECT TO RECISION 1 VERTICAL NOT FINAL THIS NO77CE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA v U 7 J c a� 0 J N It 6i 0 4 0 N I I L.� o n I rn 0 0 N a v a� v c a� / rn 0 0 r N m 0 I I I I I I I I I I I I 8/ �O F T FT� C�. C�. NO. DATE APPD. REVISION DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA Q�ovEss/p� � No.35121 z � EXP. 09/30/25 � CIVIL �� �qle OF CA�� DESIGNED UNDER THE DIRECTION OF: MICHAEL E. MILANI R.C.E. No. 35121 REGISTRATION EXPIRES 9/30/25 DATE Storm Water Monitoring & Reporting Land Development Engineering =00& Associates Environmental Engineering M I LAN I Municipal Engineering Surveying & Mapping 2655 Stanwell Drive, Suite 105 Construction Staking Concord, CA 94520 Phone: (925) 674-9082 www.milaniassociates.com APPROVED STEVEN JONES CITY ENGINEER R.C.E. EXPIRES DATE TOWN OF DANVILLE SUBDIVISION KENT AND VAN DAM PROPERTIES VESTING TENTATIVE MAP APN's: 207-061-008 & 207-061-009 200 REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NOTJCE TO BE REMOVED UPON COMPLETION OF MAP AND UPON AGENCY/CLIENT APPROVAL OF MAP LEGEND DA 12 — DRAINAGE AREA 623, 075 SF — AREA (SF) 14.3 ACRES — AREA (ACRES) C= 0.3 — C FACTOR Tc = 60' — Time of concentration DRAINAGE DIREC11ON DRAINAGE AREA BOUNDARY DRAINAGE PATH OF TRAVEL HYDROLOGY MAP 1 OF 2 JOB NO. 270019 SHEET NO. 20 OF 21 Ca W i v U 7 J C a� 0 J It N I I REVIEW COP Y SUBJECT TO RECISION NOT FINAL THIS NOIJCE TO BE REMOVED UPON COMPLE77ON OF MAP AND UPON AGENCY/CUENT APPROVAL OF MAP 80 40 0 80 160 SCALE: 1 "=80' LEGS D DA A 2 —DRANAGEAREA623, 0SF — AREA (SF) 14.3 ACRES — AREA (ACRES) C=0.3 — C FACTOR Tc = 60' — Time of concentration DRAINAGE DIREC11ON DRAINAGE AREA BOUNDARY DRAINAGE PATH OF TRAVEL DATE: OCTOBER 2023 SCALE: AS SHOWN DESIGNED: SMS/LLC DRAWN: JMG/SMS/LLC CHECKED: KRA 0 m y t W W i a LO 0 0 N 0 U) 0 n a rn 0 0 r- N Q a N a c a� / rn 0 0 N m 0