Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Deep Creek Lake

The Deep Creek Lake watershed is located within the Western Maryland Sub-basin in Garrett County, Maryland and is a sub-basin of the Youghiogheny watershed.  The watershed drains an area of 41,435 acres and is mostly forested with significant agricultural acreage and recreational home development generally along the lake’s shoreline.   

The Maryland Department of the Environment (MDE) has identified the waters of 1) the Deep Creek Lake Impoundment and 2) the Deep Creek Watershed (basin code 05020203) as two listings on the State’s 303(d) List as impaired by the following (water type and years listed in parentheses): total phosphorus (watershed – 1996, impoundment – 1998), low pH (Cherry Creek – 1996), impacts to biological communities (1st through 4th order streams – 2002), methylmercury (impoundment – 2002), and fecal coliform (watershed – 2006).  A TMDL to address the low pH in Cherry Creek, a sub-basin of the Deep Creek watershed, was approved by the EPA in 2003, and a TMDL to address the mercury impairment of Deep Creek Lake, an impoundment in the Deep Creek watershed, was approved by the EPA in 2004. 

The report available below provides an analysis of recent data and computer simulation modeling that supports the removal of the nutrients (phosphorus) listings for Deep Creek Lake and the Deep Creek Lake watershed when MDE proposes the revision of the State’s Integrated Report.  The remainder of this report lays out the general setting of the Deep Creek Lake watershed area, presents a discussion of the water quality characteristics in the basin in terms of the existing water quality standards relating to nutrients, and presents an analysis of the available nutrient data.  This analysis supports the conclusion that the waters of Deep Creek Lake and the Deep Creek Lake watershed overall do not display signs of eutrophication or nutrient over-enrichment.

Although the waters of the Deep Creek watershed do not display signs of eutrophication, the State reserves the right to require future controls in the Deep Creek watershed if evidence suggests nutrients from the basin are contributing to downstream water quality problems. 


WQA of Eutrophication for Deep Creek, Garrett County, Maryland

(EPA Concurrence: September 9, 2011)

EPA's Decision Letter EPA's Decision Letter

Main Report 

WQA_Deep_Creek_Nut_07292011_final.pdf (1433KB)
Appendix A DCL_AppendixA.pdf (313KB)

Comment Response Document

Deep_Creek_Nut_CRD_11052010_final.pdf (55KB)

Additional Supporting Information

Biological Stressor Identification Deep Creek Lake Watershed Report  (611 KB)
Biological Stressor Identification Methodology (459KB)

Contact Information

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