General Permit VAR 040126. Municipal Separate Storm Sewer System (MS4). July 1, 2020 through June 20, 2021

The MS4 Program Plan has guided USGS in effectively implementing the requirements of the permit at National Center. MS4 program effectiveness was evaluated by Operation Branch of the National Center (NCOB) in coordination with the Environmental Management Branch (EMB). Opportunities for improvement were evaluated and the program’s implementation was determined to be effective, thus no changes were made. A review of each MCM is included below: MCM 1 – Three high priorities were selected based on the most pressing stormwater-related issues at the National Center:

• Chesapeake Bay TMDL
• Impairment of Sugarland Run, a tributary of Potomac River
• Illicit Discharge

These issues have been selected because any mismanagement of stormwater program is likely to contribute to the impairment of the Chesapeake Bay. Illicit discharge of non-stormwater is the most likely cause of mismanagement of the program.