Final TMDLs Approved by EPA: Anacostia River

There are three major drainage areas comprising the Anacostia River watershed: the Northwest Branch, the Northeast Branch, and the tidal drainage. The Northwest and Northeast Branches are free-flowing (non-tidal) streams, and their confluence forms the tidal Anacostia River in the vicinity of Bladensburg, Maryland.

The Anacostia River proper begins at Bladensburg, Maryland, where the Northwest and Northeast Branches meet. The many smaller tributaries of the branches form a broad, fan-shaped drainage basin of 17 square miles. Just below Bladensburg, the Anacostia River drops to near sea level and changes from a free-flowing river into a tidal freshwater embayment of the Potomac estuary.

The tidal drainage area consists of the tidal river and its floodplain, as well as small Coastal Plain streams that flow directly to the tidal river.  Most of these streams are enclosed in storm sewer systems. The tidal reach of the Anacostia River is 8.4 miles (13.5 kilometers) in length from the confluence of the Northwest and Northeast branches downstream to the Potomac River. The river joins the Potomac approximately 108 miles (174 kilometers) upstream of the Chesapeake Bay.

The Maryland Department of the Environment (MDE) has identified the Anacostia River, a Use I-P, II, III and IV waterbody [Code of Maryland Regulations (COMAR) O], on the State’s 303(d) list as impaired by nutrients (1996), sediments (1996), fecal bacteria – non-tidal waters (2002), impacts to biological communities (2002), toxics – poly-chlorinated biphenyls (PCBs) (2002), toxics - heptachlor epoxide (2002), and fecal bacteria – tidal waters (2004).  The document available below establishes TMDLs of fecal bacteria in the tidal and non-tidal portions of the Anacostia River watershed within the State of Maryland that will allow for the attainment of the designated use of primary water contact recreation.  A watershed-wide TMDL for sediment/TSS, addressing the listings for those impairments to the Anacostia in their respective jurisdictions, was established jointly by DC and MD in 2007.  A multi-jurisdictional TMDL for PCBs in the tidal portions of the Potomac and Anacostia Rivers were established jointly by DC, MD and VA in 2007.  A watershed-wide TMDL for nutrients/biochemical oxygen demand (BOD), addressing the listings for those impairments to the Anacostia in their respective jurisdictions, were established jointly by DC and MD in 2008. The listings for other impairments in tidal and non-tidal waters will be addressed separately at a future date. 

The U.S. Environmental Protection Agency (EPA) initially approved the TMDL on September 19, 2006.  However, during the review and approval process a number of edits occurred and a few were completed incorrectly.  As a result, the Department resubmitted the corrected document for approval.

Note: Following the approval of the TMDL, two clerical errors were discovered in Tables and  related to the wasteload allocations (WLAs) for the Montgomery and Prince George’s Counties’ municipal storm sewer systems (MS4).  The document available for download below contains the corrected version of these tables.  When corrected, the revisions did not affect the overall TMDL; rather, they merely altered the WLAs between the two applicable county MS4 jurisdictions within Maryland.  The change in reduction requirements per MS4 jurisdiction was less than 5%.

Total Maximum Daily Loads of Fecal Bacteria for the Anacostia River Basin in Montgomery and Prince George’s Counties, Maryland

(Approved on March 14, 2007)

EPA's Decision Letter EPA's Decision Letter
Main Report TMDL_anacostia_fc.pdf (3202KB)

Comment Response Document

CRD_anacostia_fc.pdf (148KB)

Contact Information

Please direct questions or comments concerning this project to Maryland's TMDL Program at (410) 537-3818.