Stormwater Regulatory History

Since 1972, the Clean Water Act and its amendments have prohibited the discharge of any pollutant to a water of the United States unless it has been authorized by a national pollutant discharge elimination system (NPDES) permit. The NPDES program is designed to track point sources-single identifiable sources that discharge pollutants into the environment-and require the implementation of controls necessary to minimize the discharge of pollutants.

The NPDES program initially targeted easily detected sources of water pollution such as municipal sewage and industrial process wastewater and was successful in improving water quality. However, the NPDES program was not addressing other significant sources of water quality impairment-nonpoint sources such as runoff from agricultural and forestry operations, and stormwater runoff.

The Clean Water Act was amended in 1987. As part of the amendments, Congress addressed the environmental impact of stormwater by adding section 402(p), which established a comprehensive, two-phase approach to stormwater control. Phase I and phase II stormwater regulations took a new approach and began to treat stormwater discharges from municipalities as point sources of pollution. As a result, local governments covered by the phase I and II regulations must-like all point source dischargers-obtain federally enforceable NPDES permits under the Clean Water Act.

An NPDES permitting authority issues NPDES stormwater permits. In South Dakota, the Department of Environment and Natural Resources is authorized to run the NPDES program. Once an NPDES permit is obtained, the conditions of the permit must be satisfied and periodic reports must be submitted to the NPDES permitting authority on the status and effectiveness of the local government program.

Phase I was promulgated on November 16, 1990. The phase I regulations require large sources of stormwater discharge to apply for NPDES permits. Large sources include medium and large municipal storm sewer systems usually serving 100,000 people or more as well as several categories of industrial activity including construction activity disturbing five or more acres of land. The NPDES permits require cities to develop a stormwater management program, track and oversee industrial facilities that are also regulated under the NPDES stormwater program, conduct monitoring, and submit periodic reports.

Phase II was promulgated on December 8, 1999. Phase II expanded the scope of the NPDES program to include smaller local governments-municipal separate storm sewer systems (MS4s) serving populations of less than 100,000. The stormwater phase II final rule requires local governments that fall within the scope of the rule-primarily local governments with small MS4s in urban areas (1000 people or more per square mile)-to obtain NPDES permit coverage. These local governments must design a stormwater management program to include the development and implementation of six specified measures that reduce stormwater pollution. Evaluation and reporting measures are also required. In addition, the rule sets requirements for construction activity that disturbs between one and five acres and extends a previously set deadline for municipalities that operate industrial activities regulated under phase I.

Stormwater Phase II Program
300 Sixth Street
Rapid City, SD 57701
(605) 394-5377 ext 227
Fax: (605) 394-6636