What is the Storm Water Program?
Rainwater, also known as Storm Water, can either soak into the ground or runoff the land. As it runs off the land, it can pick up harmful pollutants that effect our drinking water and environment. In urban and suburban areas, much of the land surface is covered by buildings, pavement and compacted landscapes with impaired drainage. These surfaces do not allow rain and snowmelt to soak into the ground, which greatly increases the volume and velocity of storm water runoff.
The National Pollutant Discharge Elimination System (NPDES) Storm Water Program regulates storm water discharges from three potential sources: municipal separates storm sewer systems (MS4s), construction activities and industrial activities. Most storm water discharges are considered point sources and the operators of these sources may be required to receive an NPDES permit before they can discharge. This permitting mechanism is designed to prevent storm water runoff from washing harmful pollutants into local surface waters such as streams, rivers, lakes or coastal waters.
What is Phase II?
The U.S. EPA's storm water program addressed storm water runoff in two phases. Phase I addressed storm water runoff from large and medium MS4's. Large municipalities with a separate storm sewer system serving a population greater than 250,000 and medium municipalities with a service population between 100,000 and 250,000 had to obtain NPDES permits.
Phase II regulations address storm water runoff of MS4s serving populations less than 100,000, called small MS4s. More particularly, small MS4's located partially or fully within Urbanized Areas (UAs), as determined by the U.S. Bureau of the Census, and also on a case by case basis for those small MS4's located outside of UAs that Ohio EPA designates into the program. Automatically designated MS4s, those in UAs, were required to apply for permit coverage and develop and submit a SWMP by March 10, 2003.