In response to the 1987 Amendments to the Clean Water Act (CWA), the United States Environmental Protection Agency (EPA) developed the National Pollutants Discharge Elimination System (NDPES) storm water program. The initial phase targeted the medium and large municipal storm water systems and in December of 1999, Phase II was established requiring small municipal separate storm sewer systems (MS4) to create stormwater management programs.
Compliance with Phase II is required for all municipal separate storm sewer systems located within and Urbanized Area. Several miles of Cass County's stormwater system fall within this urbanized area, requiring the County to comply with the federal stormwater regulations.
The stormwater management program was designed to address the increased rate and volume of runoff from the impervious surfaces often found in urbanized areas and the corresponding concentration of pollutants as result of the land use changes. These changes impact an areas hydrology and water quality in a variety of ways:
Operators of the regulated municipal separate storm sewer systems (MS4s) are required to design programs to reduce the discharge of pollutants to the "maximum extent practicable" to protect water quality and satisfy the appropriate water quality requirements of the Clean Water Act.
Implementation of the program requires the development of Best Management Practices (BMPs) and the achievement of measurable goals to satisfy each of the six Minimum Control Measures.
Phase II Minimum Control Measures
Under the stormwater program, MS4s are required to develop and implement a Stormwater Pollution Prevention Program (SWPPP). The SWPPP must cover six minimum control measures:
The MS4 must identify best management practices (BMP) and measurable goals associated with each minimum control measure. An annual report on the implementation of the SWPPP must be submitted each year.
RiverKeepers Resources - "Promoting a renewed vision for the Red River of the North"