NPDES MS4 Stormwater Management Plan Update 2008

Clean Water Services is updating the Stormwater Management Plan as required by its National Pollutant Discharge Elimination System (NPDES) Permit. The updated Plan will be submitted to the Oregon Department of Environmental Quality by August 1, 2008.

What is the NPDES MS4 Permit and Stormwater Management Plan?

Not everyone understands NPDES MS4 permits, but everyone is concerned about clean water. This crash course will help bring you up to speed.

To protect water quality, the nation’s Clean Water Act regulates what can be discharged to waterways through National Pollutant Discharge Elimination System (NPDES) permits. Large municipalities have NPDES permits for their wastewater treatment facilities and also have an NPDES permit for stormwater runoff, called a Municipal Separate Storm Sewer System (MS4) permit.

In urban Washington County, Clean Water Services holds these permits. In fact, it has been entrusted with the nation’s first watershed-based NPDES permit which combines wastewater and stormwater requirements.

The Plan describes the best management practices (BMPs) that Clean Water Services, its member Cities and Washington County employ to reduce pollutants in the municipal storm sewer system.

Surface Water Management is much more than MS4 The MS4 permit only applies to the publicly-owned system constructed to convey stormwater runoff (ie. catch basins, storm sewers, drainage ditches, curbs and gutters, etc.). The permit targets pollutants of concern and establishes benchmarks for pollutants for which a Total Maximum Daily Load (TMDL) has been established. To protect and enhance water quality, Clean Water Services’ Surface Water Management Program provides a broader range of services than strictly required by the MS4 permit. The Healthy Streams Plan, award-winning public education programs, flow management, water supply and drainage improvements are among the many activities that have made the Tualatin River and its tributaries healthier than they have been in decades.