Final TMDLs Approved by EPA: Anacostia River

The Anacostia River watershed comprises a 173 square mile drainage area that includes highly urbanized areas in DC, old and newly developing suburban neighborhoods in the surrounding metropolitan area, croplands and pastures at the U.S. Department of Agriculture’s Beltsville Agricultural Research Center (BARC), and forested parklands throughout the watershed. The Anacostia and many of its tributaries cross interstate boundaries, with 145 square miles of the watershed (84%) lying in MD, and 28 square miles (16%) in DC.

The main channel of the Anacostia is 8.4 miles (13.5 kilometers) in length, extending from the confluence of its two largest tributaries, the Northwest Branch (NWB) and the Northeast Branch (NEB), in Bladensburg, MD, to the location where the Anacostia discharges into the Potomac River in DC. The main channel of the Anacostia is an estuary with a variation in water level of approximately three feet over a tidal cycle. Tidal influence extends into the lower reaches of the river’s tributaries to approximately the locations of the U.S. Geological Survey (USGS) gage stations 01649500 on the NEB and 01651800 on Watts Branch, and to the bridge at U.S. Route 1 (Rhode Island Avenue) on the NWB. Approximately 70% of the watershed is drained by the two largest tributaries, the NWB and the NEB. The other two major tributaries of the Anacostia, Lower Beaverdam Creek (LBC) and Watts Branch, drain highly urbanized areas in Prince George’s County and DC.

In Maryland, the Anacostia and its tributaries have been variously designated as Use I-P, II, III and IV waters [Code of Maryland Regulations (COMAR)]. The Maryland Department of the Environment (MDE) has identified the Anacostia (MD Basin #02140205) in the State’s 303(d) List as impaired by the following (listing years in parentheses): nutrients (1996), sediments (1996), fecal bacteria – non-tidal waters (2002), impacts to biological communities (2002), toxics – polychlorinated biphenyls (PCBs) (2002), toxics – heptachlor epoxide (2002) and fecal bacteria – tidal waters (2004). The document available below addresses the sediments impairment. Fecal bacteria TMDLs for MD tidal and non-tidal areas of the Anacostia were established in 2006.  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.

DC’s Section 303(d) List divides the Anacostia within the District’s borders into two segments. The lower Anacostia is identified as that portion of the river extending from the mouth of the river to the John Philip Sousa Bridge and Pennsylvania Avenue and the upper Anacostia as that portion from the bridge to the MD border. DC has classified the Anacostia for current and designated uses including category C: Protection and propagation of fish, shellfish and wildlife.” The upper and lower segments of the Anacostia were listed on DC’s 1998 Section 303(d) List as impaired by biochemical oxygen demand (BOD), bacteria, organics, metals, total suspended solids (TSS), and oil and grease. DC has already developed TMDLs addressing these impairments in the Anacostia. A TSS TMDL was established for the tidal Anacostia River in DC in 2002. The watershed-wide TMDLs developed in the report available below replace the 2002 DC TSS TMDLs.

On July 25, 2012 EPA approved a revised Sediment/TSS TMDL for the Anacostia River. The approved 2007 TMDL was vacated by a DC District Court judge as not adequately addressing applicable water quality standards to protect the designated uses of recreation and aesthetic enjoyment.  In response, MD and DC developed an addendum to the TMDL (Appendix E below) describing an analysis that demonstrates the TMDL is protective of all the designated uses of the Anacostia.  No other revisions were made to the 2007 TMDL main report, appendices and technical memoranda.   

Total Maximum Daily Loads of Sediment/Total Suspended Solids for the Anacostia River Basin, Montgomery and Prince George’s Counties, Maryland and The District of Columbia

(Approved on July 25, 2012)

EPA's Decision Letter EPA's Decision Letter
Main Report TMDL_anacostia_sediment.pdf (1817KB)
Appendix A TMDL_anacostia_appendixA_sediment.pdf (82KB)
Appendix B TMDL_anacostia_appendixB_sediment.pdf (116KB)
Appendix C TMDL_anacostia_appendixC_sediment.pdf (406KB)
Appendix D TMDL_anacostia_appendixD_sediment.pdf (70KB)
Appendix E TMDL_anacostia_appendixE_sediment.pdf (316KB)
NPS Tech Memo

TMDL_anacostia_NPS_Tech_Memo_sediment.pdf (40KB)

PS Tech Memo TMDL_anacostia_PS_Tech_Memo_sediment.pdf (67KB)

Comment Response Documents

2007_CRD_anacostia_sediment.pdf (218KB)

2012_CRD_appendix_E_anacostia_sediment.pdf (230KB)

Modeling Report

TMDL_anacostia_sediment_modeling_report.pdf (3253KB)


Contact Information

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