Final TMDL Approved by EPA: Back River Watershed

The Back River watershed is located in the western shore region of Maryland in Baltimore City and Baltimore County, northeast of the Baltimore Harbor, and drains into the Chesapeake Bay.  The basin is part of the Patapsco/Back River Tributary Strategy Basin. The watershed is located in the Coastal Plain and Piedmont regions, two of three distinct eco-regions identified in the Maryland Department of Natural Resources (MDDNR) Maryland Biological Stream Survey (MBSS) Index of Biological Integrity (IBI) metrics. According to the Chesapeake Bay Program’s Phase 5.3.2 watershed model, the total drainage area of the Maryland 8-digit watershed is approximately 34,800 acres, not including water/wetlands. Approximately 185 acres of the watershed area is covered by water. The total population in the Back River watershed is approximately 255,000.  There are no “high quality,” or Tier II, stream segments (BIBI and FIBI aquatic life assessment scores > 4 [scale 1-5]) located within the Back River watershed. Tier II segments would require the implementation of Maryland’s anti-degradation policy.
The Back River watershed is associated with two assessment units in Maryland’s Integrated Report: a non-tidal 8-digit watershed (02130901) and an estuary portion [Back River Oligohaline (BACOH)]. A sediment TMDL for the BACOH was established as part of the Chesapeake Bay TMDLs in 2010.   A data solicitation for TSS/sediment was conducted by MDE in September 2016, and all readily available data has been considered.

The TMDL, available below, will ensure that watershed sediment loads are at a level to support the designated uses for the Back River watershed, and more specifically, at a level to support aquatic life. 

Total Maximum Daily Load of Sediment in the Non-tidal Back River Watershed, Baltimore County and Baltimore City, MD

(Approved on March 5, 2018)

EPA's Decision Letter EPA's Decision Letter (7,398KB)
​Fact Sheet Back_River_Sed_TMDL_FactSheet.pdf (413KB)
Main Report

Back_River_Sed_TMDL_final.pdf (1,730KB)

Point Source Technical Memorandum Back_River_Sed_TMDL_PS_TechMemo.pdf (37KB)
Nonpoint Source Technical Memorandum Back_River_Sed_TMDL_NPS_TechMemo.pdf (27KB)
Comment Response Document Back_River_Sed_TMDL_CRD.pdf (34KB)

Additional Supporting Information

Biological Stressor Identification Back River Watershed Report (466KB)

Biological Stressor Identification Methodology (459KB)

Nontidal Sediment TMDL Methodology Report (361KB)

Addendum to the Nontidal Sediment TMDL Methodology Report (23KB)


Contact Information

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