The Washington State Department of Ecology just re-issued the general permits that regulate discharges from municipal separate storm sewer systems (MS4s) in Western Washington.  The re-issued permits will require local governments in Western Washington to make changes in their regulation and management of polluted stormwater runoff.

As explained by Ecology, the agency re-issued the permits in response to the recent resolution of administrative appeals of the permits, which were originally issued in 2012. The changes will affect how local governments will implement requirements related to watershed planning, Low Impact Development (LID) techniques such as green roofs and rain gardens, and other issues.

Ecology has also modified the Stormwater Management Manual for Western Washington (SWMMWW), which provides guidance on the measures necessary to manage stormwater impacts caused by new development and redevelopment. 

The 60-day comment period on the proposed modifications to the permits and the SWMMWW ends on October 6, 2014.