Storm Water Pollution Prevention Plan (SWPPP) - the City of Lompoc!

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Section 2Project Information2.1 Project and Site DescriptionThis project constructs municipal water well (#11) on the north side of Hwy 246 near its intersection with theSanta Ynez River, to provide additional water supply to the City of Lompoc. A transmission water main will beconstructed, in conjunction with the well, to pipe water from the well site north to Riverside Dr., Pine St., 3 rd St.and North Ave. and then to connect to a water main on North Ave. The project is 2.3 acres and includesdrilling of the well, construction of a pump building, an electrical building, a CMU wall surrounding wellstructures, a driveway, drainage improvements, a transmission water main line, landscaping and mitigationplanting. The well portion of the project is defined as a traditional project while the transmission water main isdefined as a linear project. Requirements for both project types are covered under this SWPPP.2.2 Vicinity MapA vicinity map is provided in Figure 1.Figure 1. Vicinity Map of Project2.3 Unique Site FeaturesThe well site and portion of the transmission water main are within an environmentally sensitive area, adjacentto the Santa Ynez River and its riparian zone. Though characterized by upland plants in the area ofconstruction, the site drains directly to the Santa Ynez River overland through sheet flow. The transmissionwater main, access drive and other improvements are located within the 100-year flood plain. Any portion ofthe well site which is located within the 100-year flood plain will be flood-proofed and constructed at anelevation which meets the requirements of the City’s Flood Ordinance. The project has been designed tominimize the impact to the Santa Ynez River and its riparian zone. Mitigation measures have been applied toaddress potential biological impacts.The site of the proposed Well 11 is relatively flat, dropping off to the east toward the river bank. Run-onoccurs in the area of the access drive and a culvert is proposed to direct the run-on through the site in aMunicipal Water Well No. 11 and Transmission Water Main – SWPPP July 20, 2010Page 6
proposed drainage swale. Run-on also occurs along the length of the transmission water main location,through sheet flow heading towards the Santa Ynez River. At the north end of the proposed transmissionwater main alignment, run-on occurs from a storm drain which terminates in a large, relatively steep gully,through which the transmission water main will be placed.The site is relatively flat to very gently sloping and drains by sheet flow. There is no run-on to the well site.Soils at the well site consist of layered sands that were moist to wet with a medium dense to denseconsistency. A isolated layer of silt soil exists at 14 -19 ft below the ground surface and the silt was moist andvery stiff. Groundwater was encoutered at a depth of 38 ft below the ground surface.The project is subject to requirements of the California Department of Fish and Game. The contractor shall beresponsible for ensuring compliance with all CDFG requirements and with the specific mitigation measures ofthe project. The letter from the California Department of Fish and Game, the Notification of StreambedAlteration Agreement and its attachments are provided in Appendix J2.4 SWPPP ObjectivesThis SWPPP has been designed to address the following objectives:1. All pollutants and their sources, including sources of sediment associated with construction,construction site erosion and all other activities associated with construction activity are controlled;2. Where not otherwise required to be under a Regional Water Board permit, all non-storm waterdischarges are identified and either eliminated, controlled, or treated;3. Site BMPs are effective and result in the reduction or elimination of pollutants in storm waterdischarges and authorized non-storm water discharges from construction activity to the best availabletechnology economically achievable (BAT) / best conventional pollutant control technology (BCT)standard;4. Calculations and design details as well as Best Management Practices (BMPs) controls for site run-onare complete and correct, and5. Stabilization BMPs installed to reduce or eliminate pollutants after construction are completed.2.5 Stormwater Run-on and Runoff from Offsite AreasRun-on is considered insignificant to the linear project and is received on site as sheet flow. The well site isapproximately 2 feet above existing grade and will not have any run–on. Runoff will also be minimal. The wellsite is less than 0.5 acre and runoff is directed to an existing roadside ditch. The disturbed area for thetransmission water lines site is approximately 30 ft wide in unpaved areas and approximately 3’ wide in pavedareas. On unpaved areas, it is adjacent to stable vegetation and low gradients. On paved areas, water will beconveyed by the existing municipal storm drain system. There are no calculations.2.6 Risk AssessmentThe General Permit establishes three levels of risk possible for a construction site. Risk is calculated in twoparts: 1) Project Sediment Risk, and 2) Receiving Water Risk. The site's sediment risk and receiving water riskwas evaluated for the period of soil exposure (i.e. grading and site stabilization) using the methodology inAppendix 1 of the General Permit. This project is a combined traditional and linear project. The higher risklevel of Risk Level 2 (Type 2 LUP) was chosen to represent the entire site.Municipal Water Well No. 11Sediment Risk: MediumThe RUSLE equation was used through the Rainfall Erositivity Factor Calculator and the GIS Map Method todetermine soil risk. The online rainfall erosivity factor calculator (R) is based on soil erosivity and constructionscheduling. It was determined that the R factor is 24.62. Using the GIS Map Method and soil characteristicsdescribed in the Soils Engineering Report (2009), the project site lies in the KLS risk category of 1.0.Therefore, the project will contribute less than 75 tons/acre of sediment and has a medium sediment risk.Municipal Water Well No. 11 and Transmission Water Main – SWPPP July 20, 2010Page 7
Page 1 and 2: Storm Water Pollution Prevention Pl
Page 3 and 4: Section 1 Introduction1.1 Obtaining
Page 5: 1.7 Required Non-Compliance Reporti
Page 9 and 10: • Paint (for pavement markings)2.
Page 11 and 12: SE-10 Storm Drain Inlet ProtectionT
Page 13 and 14: Section 4 Construction Site Monitor
Page 15 and 16: Section 34.1 Visual Monitoring/ Ins
Page 17 and 18: Sampling personnel will collect sto
Page 19 and 20: • Discard sample bottles or sampl
Page 21 and 22: • A summary of all analytical res
Page 23 and 24: Section 6 Notice of TerminationWith
Page 25 and 26: Owner’s (or Authorized Representa
Page 27 and 28: Appendix BContractor Information
Page 29 and 30: Appendix CSite Map/Erosion and Sedi
Page 31 and 32: SILT FENCEINLET PROTECTIONAScale: N
Page 33 and 34: Risk Assessment DeterminationConstr
Page 35 and 36: 12Sediment Risk Factor WorksheetA)
Page 37 and 38: Combined Risk Level MatrixReceiving
Page 39 and 40: ATTACHMENT A.1EATTACHMENT A.1LUP Pr
Page 41 and 42: Risk Level 2 Requirements from Atta
Page 43: Any sediment basins shall be design
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Construction Site Monitoring PlanDa
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Maintenance, Inspection, and Repair
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Maintenance, Inspection and Repair
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Quality Assurance and Quality Contr
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Date:Date Rain Predicted to Occur:0
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Rain Event Action Plan (REAP)Date o
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Appendix HPollutant Testing Guidanc
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Appendix HIPollutant Testing Guidan
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Appendix JOther Plans and Permits
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TABLE OF CONTENTSI. FINDINGS ......
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Order3. This General Permit regulat
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OrderB. Activities Covered Under th
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Order35. Discharges occurring in ba
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OrderG. Determining and Reducing Ri
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Order55. This General Permit establ
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Ordercause physical impacts on rece
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OrderIT IS HEREBY ORDERED that all
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OrderJuly 1, 2010. If an existing d
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Order3. The discharger shall contin
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OrderIII. DISCHARGE PROHIBITIONSA.
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OrderIV. SPECIAL PROVISIONSA. Duty
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Order2. Access and copy at reasonab
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Order2. There were no feasible alte
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Order2. The Porter-Cologne Water Qu
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Ordershall be within the ranges spe
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OrderVI. RECEIVING WATER LIMITATION
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OrderEffective two years after the
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OrderXIII. POST-CONSTRUCTION STANDA
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OrderXIV. SWPPP REQUIREMENTSA. The
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OrderXVI. ANNUAL REPORTING REQUIREM
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Storm Water Pollution Prevention Plan (SWPPP) - the City of Lompoc!

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