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

Chapter 6• What are pollutants of concern for the future land use of the development?See Table 3-1 in Chapter 3, which correlates project types with likely pollutants ofconcern. When you have identified the pollutants, you can use the pollutantremoval effectiveness information on the fact sheets at the end of this chapter tofind control measures that would be most appropriate for treating thosepollutants.• What amount of stormwater runoff will need to be treated?The amount of stormwater runoff that needs to be treated for a site is defined bythe local permitting agencies as the water quality volume (WQV) or water qualityflow (WQF), described later in this chapter. Treating this amount is presumed toremove pollutants in urban runoff from the Sacramento and South Placer regionsto the maximum extent practicable. Using runoff reduction control measures(Chapter 5) will decrease the amount of runoff needing to be treated, which inturn will likely reduce costs and space requirements for the treatment controlmeasures.If you are using runoff reduction measures for your project, or if you would like todetermine if applying runoff reduction measures can help reduce your treatmentneeds, refer to Appendix D. Appendix D will lead you through the process ofcalculating runoff reduction credits and then determining the water qualityvolume or flow remaining to be treated.If you will not be using runoff reduction measures, refer to Appendix E tocalculate the expected water quality volume or flow for your site, based ondrainage area, rainfall and imperviousness.• How much space is available on the project site for a stormwater qualitytreatment facility?Refer to the fact sheets at the end of this chapter to determine the spacerequirements for the various types of stormwater quality control measures.Consider that vegetated facilities can typically be integrated into the landscapingalready required by the permitting agency for the site. Also, althoughunderground facilities do not take up as much space, they can be more costly toconstruct and maintain.• What are the site conditions and associated limitations on use ofstormwater quality treatment control measures for this property?As described in the fact sheets at the end of this chapter, the selection and designof stormwater quality control measures is largely dependent on soils,topography/slope and other natural site features.• What level of maintenance will the property owner agree to conduct as long ashe/she owns the property?Stormwater Quality Design Manual for the Sacramento and South Placer Regions6-2 May 2007