NPDES - MS4
Walton County operates and maintains a municipal separate storm sewer system (MS4), which is a publicly-owned system comprised of ditches, curbs, catch basins, storm drains, and underground pipes that collect or transport stormwater and discharge it to the state’s surface waters.
The NPDES Stormwater Program is a national program, mandated by Congress under the Clean Water Act, to address non-agricultural sources of stormwater discharges which adversely affect the quality of our waters. The program, administered by the U.S. Environmental Protection Agency and delegated to the Florida Department of Environmental Protection, regulates the discharge of stormwater by municipalities, industries and certain construction activities. In 1990, the U.S. Environmental Protection Agency (EPA) published regulations requiring large and medium-sized municipalities to obtain NPDES operating permits for their Municipal Separate Storm Sewer Systems (MS4). These “Phase I” rules also required stormwater permits for a specified list of in dustries, and for construction sites five acres or larger in size. Prior to 1990, EPA regulations only required permits for traditional point sources of pollutant discharge, such as wastewater treatment plants and industrial process wastes.
In 1999, EPA extended the permit requirements to smaller municipalities (including Walton County). The “Phase II” requirements are considerably less cumbersome than those for the Phase I counties and cities. The Phase Two rules also lowered the threshold for construction sites from five acres to one acre or larger. In October 2000, EPA delegated the NPDES program to the Florida Department of Environmental Protection (FDEP).
Phase II Permits
The NPDES Phase II permit is unlike typical EPA permits in that, rather than dictating to counties and cities their permit requirements, the local governments were presented with six Minimum Control Measures, and allowed to select their own Best Management Practices (BMPs) and Measurable Goals for attaining those minimum measures that constitute our Stormwater Management Program.
Many of the permit program measures involve education – educating residents about how they can help prevent stormwater pollution, educating builders and businesses about ways they can prevent pollution, and educating county staff on pollution prevention. Other measures involve specific actions on the part of the County, such as storm sewer system operation and maintenance, recycling, construction and illicit discharge inspections, storm drain marking program, mapping the County’s stormwater outfalls, and application of BMPs at County facilities.
The Six Minimum Control Measures Are:
1.Public Education and Outreach: Perform educational outreach regarding the harmful impacts of polluted stormwater runoff.
2.Public Participation/Involvement: Comply with State and local public notice requirements and encourage other avenues for citizen involvement.
3.Illicit Discharge Detection and Elimination: Implement a plan to detect and eliminate any non-stormwater discharges to the MS4 and create a system map showing outfall locations.
4.Construction Site Runoff Control: Implement and enforce an erosion and sediment control program for construction activities.
5.Post-Construction Runoff Control: Implement and enforce a program to address discharges of post-construction stormwater runoff from new development and redevelopment areas. (NOTE: This minimum control measure is met by the State’s stormwater permitting program under the Water Management Districts, as a “qualifying alternative program,” thus there is no additional requirement for Walton County for this measure.)
6.Pollution Prevention/Good Housekeeping: Implement a program to reduce pollutant runoff from municipal operations and property and perform staff pollution prevention training.