Final TMDLs Approved by EPA: Back River

The Back River Oligohaline Chesapeake Bay Segment is a tidal estuary, or embayment, located on the western shore of the Chesapeake Bay, just north of the Patapsco River embayment. Herring Run is the major freshwater tributary that drains to the Back River embayment. The tidal range of the embayment is 0.37 meters (m). The watershed draining to the embayment covers approximately 141.7 square kilometers (km2) (35,014 acres) and spans portions of Baltimore City and Baltimore County.

Maryland water quality standards state that all surface waters of Maryland shall be protected for water contact recreation, fishing, and protection of aquatic life and wildlife. Additionally, the specific designated use of the Back River Oligohaline Tidal Chesapeake Bay Segment is Use II – Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting. The Maryland Department of the Environment (MDE) has identified the waters of the Back River Oligohaline Tidal Chesapeake Bay Segment (Integrated Report Assessment Unit ID: BACOH) on the State’s Integrated Report as impaired by PCBs in both sediment (1998) and fish tissue (2008), sediments (1996), chlordane (1996), zinc (1998), nutrients – nitrogen and phosphorus (1996), and impacts to biological communities (2002). The Back River Oligohaline Tidal Chesapeake Bay Segment is also referred to as the Back River embayment.

Chlordane and nutrients (nitrogen and phosphorus) TMDLs, and a zinc water quality analysis (WQA) were approved by the EPA in 1999, 2005, and 2004, respectively. Then, in 2010, the Chesapeake Bay nutrient and sediment TMDLs were developed by EPA, which addressed the sediment impairment listing for the embayment. The listing for impacts to biological communities will be addressed at a future date.  The document, available below, establishes a total PCB (tPCB) TMDL for the Back River embayment, for which a data solicitation was conducted, and all readily available data from the past five years have been considered.  

Total Maximum Daily Load of Polychlorinated Biphenyls in the Back River Oligohaline Tidal Chesapeake Bay Segment, Maryland

(Approved on October 1, 2012)

EPA's Decision Letter EPA's Decision Letter
(Does not include MDE's requested revisions)
MDE's Edits to EPA's Decision Letter MDE's Decision Letter Edits
Main Report

BackRiver_PCB_TMDL_100212_Final.pdf (3,461KB)

Comment Response Document


Contact Information

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