Stormwater Quality Design Manual (May 2007) - City of Sacramento ...

Runoff Reduction Control MeasuresDevelopers and designers who use trees as part of an integrated stormwater qualityplan can receive interceptor tree credits, as described in this chapter. In addition,shade trees may also be counted as interceptor trees if they are listed on the approvedinterceptor tree list in Appendix D.Selecting Runoff Reduction Control Measuresfor Your ProjectRefer to Table 3-2 to determine which runoff reduction control measures may beused in your project. Work with your civil/geotechnical engineer and planner tostudy the infiltration capacity of the soils and the future use of the site when makingthis determination. The local permitting agency may require permeability tests,depending on the type of control measure and site conditions. For perviouspavement, identify parking areas, walkways and patios that will not experience hightraffic loadings. Involve your landscape architect in the initial site layout to locateand slope paved areas toward vegetated areas whenever possible. Once you'veselected the measures most appropriate for the site, refer to the runoff reductioncredit worksheets (Appendix D) to prepare the site design.Runoff Reduction Fact SheetsFact sheets are included at the end of this chapter for the six runoff reduction controlmeasures listed in Table 3-2 and introduced above. Each fact sheet describes thepurpose of the control measure, applicability, design requirements, and anyoperation and maintenance issues that may affect design of the measure.Runoff Reduction Credit WorksheetsAppendix D includes worksheets for calculating runoff reduction credits forresidential and commercial developments and background information documentingthe process used to derive the credits. Use the worksheets to determine to whatextent you can reduce project runoff by incorporating one or more of the runoffreduction control measures described in this chapter. Use the worksheets todetermine the required treatment water quality volume or flow adjusted for runoffreduction use, and then use Chapter 6 and Appendix E to guide you through theprocess of selecting and sizing your treatment measures.Sacramento and South Placer Regions Stormwater Quality Design ManualMay 2007 5-3