Municipal Separate Storm Sewer Systems: Is Compliance with State Water Quality Standards Only a Pipe Dream?
Harrop, Stacy D., Environmental Law
In 1987, Congress added section 402(p) to the Clean Water Act, which addresses point source storm water(1) pollution, including discharges from municipal separate storm sewer systems (MS4s). The MS4 program, regulations for which were promulgated by EPA in 1990 and 1999, is just beginning to show some progress in improving storm water quality. However, EPA's program has not required MS4s to meet measurable standards or goals, or ensured compliance with water quality standards. In 1999, the Ninth Circuit held, in Defenders of Wildlife v. Browner, that the Clean Water Act does not require MS4 permits to ensure compliance with state water quality standards. That holding, if followed in other circuits, could stunt the progress of the MS4 program. This Chapter suggests that the weaknesses in the MS4 program--particularly the lack of storm water quality monitoring and characterization and lack of required measurable standards or goals--must be addressed for the program to be ultimately effective. Finally, this Chapter concludes that EPA should require MS4s to comply with water quality standards, a goal that can be more effectively achieved by requiring minimum performance standards and by incorporating total maximum daily loads (TMDLs) for water quality-limited waters into MS4 permits.
Storm water runoff is a leading cause of water quality impairment in many water bodies of the United States.(2) In 1998, the Environmental Protection Agency (EPA) reported that, of the waterways assessed by the states, urban runoff, or municipal separate storm sewer system (MS4) discharges, are a significant pollutant source affecting impaired waterways.(3) There are many examples across the nation of the severity of the problem. In the Pacific Northwest, endangered salmon are adversely affected by sediment, nutrients, and toxic chemicals found in urban storm water.(4) In 1998, over 7000 days of beach closures nationwide occurred due to poor water quality, for which the main culprits were elevated bacteria levels and specific pollutants that reached waters from sewage spills and urban storm water,(5) In 1997, excessive nutrient pollution in storm water runoff caused a toxic algae bloom in Maryland that left at least thirty people ill and caused fish kills and contamination resulting in $43 million in fishery losses.(6) In spite of these occurrences, the 1999 Ninth Circuit ruling in Defenders of Wildlife v. Browner(7) that MS4 permits need not require more stringent limitations necessary to comply with state water quality standards(8)--if followed in other circuits--may allow MS4 discharges to continue to threaten the health of the nation's waterways.
Storm water is a threat to water quality because as rainfall or snowmelt moves over the land it picks up numerous natural and human-made pollutants that are discharged directly into waterways.(9) Urbanization multiplies the adverse effects of storm water. Development creates large impervious areas--such as rooftops, roads, parking lots, and sidewalks--which change the hydrologic cycle by preventing storm water from infiltrating the soft.(10) Reduced infiltration impedes the natural filtering and removal of pollutants and the recharge of groundwater, which results in storm water flows that are higher in speed, volume, and temperature.(11) A great variety and number of pollutants reach waterways through urban storm water and as population density increases, so does the concentration of pollutants.(12)
These adverse water quality and quantity effects combine to increase pollutant loads, degrade or destroy aquatic and riparian habitat, and reduce the number and diversity of fish and macroinvertebrate species.(13) Storm water discharge threatens human health by increasing pollutant loads, such as bacteria, in water supplies and recreational areas, and degrades aesthetic conditions by discharging floatable trash, oil, and grease that cause surface scum and odor. …