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

Runoff Treatment Control Measure Fact SheetVegetated Filter StripDescriptionCaltransA Vegetated Filter Strip is a gently sloped soilsurface planted with dense, sod-forming vegetationand designed to receive and treat sheet flow runofffrom adjacent surfaces. As the runoff flows throughthe vegetation and over the soil surface at a shallowdepth, pollutants are removed by a variety ofphysical, chemical, and biological mechanisms,including sedimentation, filtration, adsorption,precipitation, and microbial degradation andconversion.Siting Considerations• Drainage area: 5 acres maximum per filter strip.• Longitudinal Slope: 1% - 4%• Terracing may be used for slopes > 4%• Minimum length in flow direction: 25 ft.• Minimum depth to groundwater table: 2 ft.• Maximum ponding depth: 1 ft.• Type A & B soils only.Vector Considerations• Potential for mosquitoes due to standing water will be greatlyreduced or eliminated if the strip is properly designed,constructed, and operated.Advantages• Relatively inexpensive when used to replace part of aconventional storm drainage system and integrated into sitelandscaping.• Attractive.• Easy to maintain.POLLUTANT REMOVALEFFECTIVENESSSedimentNutrientsTrashMetals*Bacteria*Oil and GreaseOrganics*MediumLowLowMediumLowMediumMedium*The following are target pollutants forSacramento area: copper; lead; mercury;pathogens; diazinon; and chlorpyrifosSource: CASQA California StormwaterBMP Handbook, January 2003Limitations• Possible conflicts with water conservation ordinances for landscape irrigation requirements.• Not appropriate for industrial sites or locations where spills may occur.• Removes high percentage of particulate pollutants, but not soluble pollutants.General Maintenance Recommendations (Low to Moderate)• Periodically remove debris and sediment from filter strip surface.• Repair/replace vegetation as necessary to maintain full cover and prevent erosion.• See table VFS-2 for additional vegetation maintenance recommendation.Stormwater Quality Design Manual for the Sacramento and South Placer RegionsMay 2007VFS-1