Environmental Protection

Stormwater

Regulations

The Clean Water Act
Congress enacted the Clean Water Act (CWA) in 1972 in response to nationwide concern over water pollution and to protect sources of drinking water. The Act established national programs for the prevention, reduction, and elimination of pollution in national navigable waters and ground waters. It also set standards and introduced required permits for the discharge and treatment of wastewater from industries and municipalities. The CWA has brought about significant progress in cleaning up industrial wastewater and municipal sewage – specifically, single origins of pollution known as point sources.

With the reduction of point source pollution, it became evident that pollution from different sources over a wide, non-specific area, also known as non-point sources, was a major cause of water pollution. This is the type of pollution associated with Stormwater runoff. According to the Environmental Protection Agency, urban runoff is a major source of pollution for lakes and rivers. The 1987 Amendments to the CWA created provisions to address this issue.

The National Pollutant Discharge Elimination System (NPDES)
In an effort to reduce non-point source urban runoff pollution, the NPDES Stormwater Program was developed under the Federal Water Quality Act of 1987. Phase I of NPDES was introduced in 1990, targeting facilities determined most likely to impact water quality. This program made it necessary for these facilities to obtain permit coverage under NPDES for stormwater discharges. Phase I covers discharges from 10 industrial categories, construction activity disturbing 5 or more acres, and municipal separate storm sewer systems (MS4s), serving a population of at least 100,000. The Phase II rule was introduced in 1999. This program increased the number of facilities affected by the Stormwater Program. Under Phase II, MS4s serving a population of less than 100,000 and small construction sites, disturbing between 1 and 5 acres, are required to obtain permit coverage for stormwater discharges.

In addition to the Phase I and II permitting requirement, NPDES also specifies monitoring and reporting requirements. Under the municipal Stormwater program, each permittee is required to develop and implement a Stormwater Management Program (SWMP), a set of plans and procedures intended to reduce pollutants to the “maximum extent practicable.” With the SWMP, a permittee is required to:

  • Identify system outfalls and pollutant loadings
  • Detect and eliminate non-stormwater discharges
  • Reduce runoff pollutants
  • Control stormwater discharges from development and redevelopment areas
And implement these measures:
  • Public education, outreach, and participation
  • Illicit discharge detection and elimination
  • Construction site runoff control
  • Post-construction runoff control
  • Pollution prevention/good housekeeping measures