EPA Proposes ‘Next Generation’ Storm Water Controls in Clean Water Permit for Washington, D.C.

The U.S. Environmental Protection Agency announced that it has issued a proposed permit to the District of Columbia requiring the district to continue improving its Municipal Separate Storm Sewer System (MS4) program for controlling storm water runoff. EPA is accepting comments on the permit until June 4.

“The innovations in this new permit are vital to restoring and protecting the health of local waterways in the district, as well as the Chesapeake Bay,” said Shawn M. Garvin, EPA mid-Atlantic regional administrator. “We all need to do our part, and this permit can serve as a model to other municipalities for preventing runoff from washing harmful pollutants into streams and rivers in the Bay watershed.”

Medium and large MS4s such as the District of Columbia’s are required by federal law to have permits covering their discharges. The permit requires the district to take progressive steps that were not required by the old permit issued in 2004, including:
• Implementing a sustainable and enforceable approach to promoting low impact development and green infrastructure, including enhanced tree planting, green roofs and water reuse on site to slow down the rate of runoff from paved areas of the district;
• Complying with strict discharge limits and new performance standards requiring 90% onsite retention of storm flows at non-federal facilities for new development, redevelopment and retrofit projects, to avoid pollutant runoff and stream damage;
• Increasing monitoring of total maximum daily loading (TMDL) or “pollution diet,” for impaired waterways, including the Anacostia and Potomac rivers, Rock Creek and the Chesapeake Bay; and
• Controlling and reducing trash through enhanced street sweeping and implementing the Anacostia River TMDL for a “trash-free Potomac” by 2013.

The new permit conditions are necessary because large portions of impervious surfaces such as roads, rooftops and parking lots in the district channel storm water directly into local streams and rivers. Improperly managed storm water runoff from the district can damage streams, cause significant erosion and carry excessive nitrogen phosphorus, sediment, toxic metals, volatile organic compounds and other pollutants downstream and into the Chesapeake Bay.

Source: U.S. EPA