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

Steps to Managing Stormwater RequirementsGather other information about the site that is essential to choosing stormwaterquality control measures, but does not necessarily need to be submitted to the localpermitting agency during the initial planning phase:• Topography• Soil types• Natural hydrologic features and existing site drainage• Depth to groundwater• Existing vegetation• Receiving water quality conditions (e.g., State 303(d) List impaired water bodies)See Chapter 2 for more information about evaluating site conditions to best integratestormwater control measures into site design.Table 3-1. Project Categories and Associated Potential PollutantsProject CategoryPotential PollutantSedimentNutrientsTrashMetals (a)Bacteria (a)Oil andGreaseOrganics/Pesticides(a)Residential • • • • • • •General Commercial (b) (b) • • (b) • (b)Auto Repair • • •Retail Gas Outlet • • •Restaurant • • •Industrial (b) (b) • • • (b)Hillside•Parking Lot • • • •Road • • • •(a)Target Pollutants for Sacramento area: Metals (Copper, Lead, and Mercury), Coliform/Pathogens, and Organophosphatepesticides (Diazinon, Chlorpyrifos).(b) This table provides a generalization of what pollutants to expect for different land uses, but actual pollutants will vary tosome extent depending on the individual development. For example, sediment, nutrients and pesticides will be additionalpollutants of concern for a commercial home improvement store with a garden center, and bacteria will be an additionalpollutant of concern for a kennel operation.Also see CASQA’s New Development Handbook (May 2003; Table 1-1) for information about impacts of these various pollutants onwater quality and beneficial uses.Step 2: Determine RequirementsUse Table 3-2 (Selection Matrix) to determine stormwater quality requirements foryour project. Requirements depend on the size and/or planned new impervious areaof your project.All projects require source control measures applicable to the planned site activities,as described in Chapter 4. Some of the local permitting agencies may require runoffreduction measures (Chapter 5). Many projects will also require treatment controlmeasures (Chapter 6). For those requiring treatment control measures, applyingStormwater Quality Design Manual for the Sacramento and South Placer RegionsMay 2007 3-3