Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Loch Raven Reservoir Impoundment

Loch Raven Reservoir is an impoundment located near Timonium in Baltimore County, Maryland.

The Loch Raven Reservoir (basin code 02130805) was identified on the 1996 303(d) list submitted to EPA by the Maryland Department of the Environment (MDE) as impaired by heavy metals, nutrients and suspended sediments, with fecal coliform, methylmercury, polychlorinated biphenyls (PCBs) and biological impairments added to the list in 2002.  The heavy metal, nutrient, suspended sediment and PCB impairments were listed for the impoundment and the biological, and fecal coliform impairments were listed for the non-tidal streams.  The initial listing for heavy metals was questionable because:  1) no specific pollutants were defined; 2) the original listing was based on total recoverable metals (current standard is for dissolved metals); 3) inappropriate sampling techniques were applied (lack of filtration); 4) supporting data needed to interpret criteria was not available (hardness); and 5) a default hardness of 100 mg/l was used to convert and relate the total recoverable metals to the dissolved criteria, which superceded the total recoverable metals criteria. A water quality analysis (WQA) of heavy metals for the Loch Raven Reservoir impoundment was performed using recent water column and sediment toxicity data.  Results show no impairment for heavy metals.  The non-tidal streams are not listed for heavy metals therefore they are not addressed in the WQA.  A TMDL for methylmercury in fish tissue was completed in 2002.  Nutrient and sediment TMDLs were completed in 2006.  The bacteria and biological impairments will be addressed separately at a future date. 

WQA of Heavy Metals for the Loch Raven Reservoir Impoundment, 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.