Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Middle River

Middle River is a wide, shallow tidal estuary that extends southeastward approximately four miles from Eastern Boulevard in Baltimore County before entering the Chesapeake Bay.  Adjacent watersheds include the Gunpowder River to the northeast and the Back River to the southwest.  The Middle River watershed is located in urban and suburban portions of southeastern Baltimore County, Maryland.

The Middle River (basin code 02130807) was identified on the State’s 1996 303(d) list as impaired by nutrients and suspended sediment, with copper (Cu) and nickel (Ni) impairments added to the list in 1998, and cadmium (Cd) and lead (Pb) added to the list in 2002.  All impairments were listed for the tidal waters.  The listings for Cu and Ni were based on an analysis using salt water criteria.  Code of Maryland Regulations (COMAR) defines the Middle River as a fresh waterbody.  When applying freshwater criteria, Middle River was found not to be impaired by Cu or Ni, therefore, these listings were deleted when the 303(d) list was revised in 2002.  The listings for Cd and Pb were based on an analysis of 1992-1993 water column data using fresh water criteria at a standard hardness of 100 mg/l.  A water quality analysis (WQA) of Cd and Pb for the tidal waters of Middle River was performed using recent water column and sediment toxicity data.  Results show no impairment for Cd or Pb.  The non-tidal streams are not listed for Cd or Pb, therefore, they are not addressed in the WQA.  The nutrient and suspended sediment impairments will be addressed separately at a future date. 

WQA of Cadmium and Lead for the Middle River in Baltimore County, MD

(Concurrence November 10, 2003)

EPA's Decision Letter EPA's Decision Letter

Main Report 


Comment Response Document


Contact Information

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