San Francisco Stormwater Design Guidelines
Pesticides (herbicides, fungicides, rodenticides, and insecticides) are often detected in stormwater at toxic levels, even when they have been applied in accordance with label instructions. As pesticide use has increased, so have concerns about their adverse effects on the environment and human health. Accumulation of these compounds in simple aquatic organisms, such as plankton, provides an avenue for biomagnification through the food web, potentially resulting in elevated levels of toxins in organisms that feed on them, such as fish and birds. Organics can be found in stormwater in low concentrations. They include synthetic compounds associated with adhesives, cleaners, sealants, and solvents that are widely used and are often stored and disposed of improperly. Bacteria can enter stormwater via sources such as animal excrement, decay of organic materials, and combined sewer discharges. High levels of bacteria in stormwater runoff can lead to beach closures and fishing advisories. Dissolved metals including lead, zinc, cadmium, copper, chromium, and nickel are mobilized by stormwater when it runs off of surfaces such as galvanized metal, paint, automobiles, and preserved wood, whose surfaces corrode, flake, dissolve, decay, or leach. Metals are toxic to aquatic organisms, can bioaccumulate in fish and other animals, and have the potential to contaminate drinking water supplies. PCBs and Mercury are legacy contaminants that are found in low concentrations in soils associated with historically industrialized areas. San Francisco Bay is listed by the USEPA as an “impaired water body” for these contaminants. Control of PCBs and mercury will be implemented through design measures that limit the mobilization of these pollutants in contaminated soils.
Synergy with other Regulations and Initiatives
The Guidelines are designed to work with San Francisco’s existing and emerging regulatory programs and policies. For example, development along the San Francisco waterfront is subject to policies adopted by the Port of San Francisco and the San Francisco Bay Conservation and Development Commission (BCDC); the Guidelines are consistent with these policies. Federal, state, and local regulations most relevant to the Guidelines are shown in Table 2 at the end of this section.
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Regulatory Context