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J:\FORMS\Templates\Storm Water Requirements\Certification of Engineered Storm Water Treatment for New & Redevelopment Projects.doc (Rev. 03/08) Page 1 of 2 CITY OF CAMPBELL Statement of Engineered Stormwater Treatment for New and Redevelopment Projects The Purpose of this statement is to state that: The project’s engineered storm water treatment BMPs and other control measures have met the selection, sizing, and preliminary design criteria required by the City’s NPDES permit No. 01119. The Qualified Engineer, hired by the developer, will provide or has provided a review and assessment of the accuracy of cost estimates for the design, construction, and /or installation of the stormwater treatment BMPs and other control measures. Note • Numeric sizing criteria for pollutant removal treatment systems based on the amount of impervious surface present at a site, are addressed in Chapter 4 of the SCVURPPP C.3 Stormwater Handbook – May 2004. • Reference www.scvurppp.org, link to “Reports and Products” for 20033004. Review the “Guidance Manual” called C.3 Stormwater Handbook. Statement By A Qualified Engineer The engineer providing this statement must be qualified, or have a qualified individual under their supervision, according to the requirements in the City’s NPDES permit, No. 01119, Provision C.3.h. The City of Campbell requires developers of Group 1 and Group 2 projects to provide a signed Statement from a civil engineer or a licensed architect or landscape architect, registered in the State of California. Each person shall provide said statement establishing that such person, or a qualified individual under their supervision, has been trained on best management practice design for water quality not more than three years prior to the signature date, and that each qualified person understands the groundwater protection principles applicable to the project site. Training conducted by an organization with storm water treatment best management design expertise such as a university, the American Society of Civil Engineers, American Society of Landscape Architects, American Public Works Association, or the California Water Environment Association may be considered qualifying. Statement of adherence to design criteria Treatment best management practices (BMPs) for Group 1 and Group 2 projects shall incorporate the following hydraulic sizing design criteria to treat storm water runoff. NPDES permit 01119, Provision C.3.d. numeric sizing criteria for treatment systems ---PAGE BREAK--- J:\FORMS\Templates\Storm Water Requirements\Certification of Engineered Storm Water Treatment for New & Redevelopment Projects.doc (Rev. 03/08) Page 2 of 2 1. Volume Hydraulic Design Basis: Treatment BMPs whose primary mode of action depends on volume capacity, such as detention/retention units or infiltration structures, shall be designed to treat stormwater runoff equal to: A. The maximized stormwater quality capture volume for the area, based on historical rainfall records, determined using the formula and volume capture coefficients set forth in Urban Runoff Quality Management, WEF Manual of Practice No. 23/ ASCE Manual of Practice No. 87, (1998), pages 175178 approximately the 85 th percentile 24hour storm runoff event); or B. The volume of annual runoff required to achieve 80 percent or more capture, determined in accordance with the methodology set forth in Appendix D of the California Stormwater Best Management Practices Handbook, (2003), using local rainfall data. 2. Flow Hydraulic Design Basis: Treatment best management practices (BMPs) whose primary mode of action depends on flow capacity, such as swales, sand filters, or wetlands, shall be sized to treat: A. 10% of the 50year peak flow rate; or B. The flow of runoff produced by a rain event equal to at least two times the 85th percentile hourly rainfall intensity for the applicable area, based on historical records of hourly rainfall depths or C. The flow of runoff resulting from a rain event equal to at least 0.2 inches per hour intensity. The sizing, selection, and preliminary design of treatment BMPs and control measures for the site named below, meet the requirements of the City of Campbell’s NPDES permit, No. 01119, Provision C.3. Date: Project Location/Name Project APN Responsible Engineer License No. Expiration Date:. This form must be signed and stamped, by the responsible Engineer.