Municipal separate storm sewer systems: Is compliance with state water quality standards only a pipe dream?

• Author: Harrop, Stacy D.

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.

1. INTRODUCTION

   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.(14) The effects of polluted urban storm water are preventing many waterways from achieving acceptable levels of water quality--not the least of which is the federal Clean Water Act's (CWA)(15) "fishable/swimmable" goal.(16)

   The CWA seeks "to restore and maintain the chemical, physical, and biological integrity of the Nation's waters" by controlling and abating discharges of pollutants into the waters of the United States.(17) The National Pollution Discharge Elimination System (NPDES), under section 402 of the CWA, requires entities seeking to discharge pollutants into a waterway to obtain an NPDES permit, subject to conditions set by the permitting authority.(18) The CWA also requires each state to establish water quality standards for its waterways.(19) Generally, NPDES permits must contain additional conditions designed to meet those standards if the applicable NPDES technology standard is not reducing the discharge of pollutants to acceptable levels.(20) Therefore, the CWA requires an MS4, as a discharging entity, to obtain and comply with an NPDES permit.

   MS4s capture and discharge storm water from outfalls into the waters of the United States.(21) These outfalls are considered point sources under the CWA.(22) Due to the significant adverse effects of storm water on water quality, MS4 discharges are a significant target for pollution control.(23) However, MS4 discharges are not as amenable to traditional pollution control measures as typically targeted water pollution sources, such as industrial discharges.(24) Storm water flows are intermittent and unpredictable because they fluctuate depending upon frequency and duration of precipitation.(25) Further, MS4s generally contain numerous outfalls (so designed to minimize flooding), the location of which may not be completely known to the municipality.(26) These problems can make sampling and measuring the water quality impact of storm water difficult and in some cases, impractical.(27) Moreover, local governments' limited financial resources can make traditional end-of-pipe treatment infeasible for many municipalities.(28) Despite these difficulties, MS4s require regulation to preserve and improve the quality of the nation's waters.

   In part to specifically address the regulation of storm water discharges, Congress passed the Water Quality Act of 1987.(29) The Act extensively amended the CWA, including the addition of section 402(p), which addresses storm water discharges.(30) The amendment directs EPA to proceed in two phases under the NPDES program.(31) The Phase I regulations, promulgated in 1990, require permits for storm water discharges from industrial sources, construction disturbing over five acres, and large and medium MS4s.(32) In 1999, the Phase II regulations were promulgated, adding small construction sites and small MS4s into the fold of regulated storm water discharges.(33)

   EPA attempted to create a flexible program to address MS4 pollution because of the inherent difficulty in controlling storm water and the sensitive nature of regulating municipalities.(34) The regulations outline a program that is substantially different from the other point source water pollution control programs under the CWA.(35) The MS4 storm water program uses a "performance-based" regulatory approach instead of the traditional "technology-based" approach used in end-of-pipe treatment.(36) Whereas a strictly "technology-based" approach focuses on attaining set effluent limits through the use of an end-of-pipe technology control, the "performance-based" approach focuses on the implementation of an overall plan that employs various methods of pollution control.(37) Municipalities are required to develop storm water management programs (SWMPs) that include best management practices (BMPs)(38) for reducing storm water pollution; these plans become permit conditions.(39) This approach allows for municipal flexibility in tailoring programs for particular circumstances.(40)

   In 1999, environmental groups brought the first lawsuit challenging the content of an MS4 permit. In Defenders of Wildlife v. Browner, Defenders of Wildlife sought review of an EPA decision to issue MS4 NPDES permits for five municipalities in Arizona.(41) Defenders of Wildlife argued that EPA violated section 402(p) of the CWA because the permits did not contain conditions requiring strict compliance with state water quality standards through the use of numeric effluent limits.(42) The Ninth Circuit disagreed, determining that section 402(p)(3) does not require strict compliance for MS4 permits.(43) However, the court determined that EPA, in its discretion, may require compliance with state water quality standards and can determine the level of, and method for, compliance.(44)

   There is limited information on whether EPA's approach to MS4 regulation is actually resulting in storm water discharges that comply with state water quality standards.(45) The studies that have been conducted focus on particular BMPs' ability to remove pollutants or control storm water volume and velocity.(46) These studies indicate that the implementation of appropriate BMPs do result in improvements in storm water quality on a site-specific basis, but information about watershed-scale improvement is lacking.(47) Further, EPA's flexible regulatory approach provides little guidance or standardization for monitoring BMP effectiveness, nor has EPA required MS4s to meet measurable goals.(48)

   This Chapter examines the MS4 storm water program, focusing on the potential for attainment of state water quality standards. Part II briefly describes the history of storm water regulation under the CWA, which resulted in Congress amending the CWA to include section 402(p). Part III summarizes EPA's Phase I and II regulations and the structure of the MS4 storm water program. Part IV examines Natural Resources Defense Council v. Environmental Protection Agency(49) and Defenders of Wildlife v. Browner, two Ninth Circuit opinions that have...