In December 1999, EPA finalized the "Phase II" regulations, which require controls on stormwater discharges from the broader sector of municipalities, industries, and construction sties. Specifically for construction, the Phase II rule requires construction sites disturbing equal to or greater than one acre to control pollutants in stormwater runoff. Construction activity disturbing less than one acre requires a permit if it is part of the larger common plan of development or sale disturbing a total of one acre or greater, or is individually designated for permit coverage by the National Pollutant Discharge Elimination System permitting authority.
Stormwater - Water resulting from rain, melting or melted snow, hail or sleet.
Stormwater Runoff - The stormwater derived within a tributary basin, flowing over the surface of the ground or collected in channels or conduits.
Stormwater Management - The recognition of adverse drainage resulting from altered runoff and the solution resulting from the cooperative efforts of public agencies the private sector to mitigate, abate, or reverse those adverse results.