Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: St. Mary's Lake

St. Mary’s Lake is an impoundment located near Leonardtown in St. Mary’s County, Maryland. The impoundment, which is owned by the Maryland Department of Natural Resources (DNR), lies on Western Branch, a tributary of the St. Mary’s River. An earthen dam was installed in 1975 for the purposes of flood control, recreation, and fish and wildlife.

St. Mary’s Lake in the St. Mary’s River watershed (02140103) was identified on Maryland’s 1998 list of Water Quality Limited Segments (WQLSs) as being impaired by nutrients, with an additional impairment of mercury appearing on its 2002 list. The 1998 listing was prompted by an assessment of data associated with St. Mary’s Lake (Maryland Department of Natural Resources [DNR], 1998). The report available below provides more recent information that supports the removal of the nutrient impairment listing for St. Mary’s Lake when the 303(d) list is revised. The mercury impairment is being addressed in a document entitled "Total Maximum Daily Load of Mercury for St. Mary’s Lake, St. Mary’s County, Maryland". 

Water Quality Analysis of Eutrophication for St. Mary's Lake,
St. Mary's County, MD

(Concurrence February 27, 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.