Final TMDLs Approved by EPA: Prettyboy Reservoir

The Prettyboy Reservoir watershed is located in both Maryland (MD) and Pennsylvania (PA) with a drainage area of 79.8 square miles (51,062 acres).  The majority of the watershed is in MD (in Baltimore and Carroll Counties) with a portion in York County, PA.

The watershed includes the towns of Manchester and Hampstead in the west, and Rayville and Middletown to the east.  The headwaters of the Gunpowder Falls begin in PA north of Lineboro, MD.  The tributaries to the reservoir include Gunpowder Falls, Dykes Creek, Poplar Run, Grave Run, Compass Run, Georges Run and Prettyboy Branch.

The Maryland Department of the Environment (MDE) has identified the tributaries of Prettyboy Reservoir in the State of Maryland’s 303(d) List as impaired by fecal bacteria (listed in 2002) and impacts to biological communities (listed in 2002 and 2004).  The reservoir itself is not listed as impaired by fecal bacteria.  The Prettyboy Reservoir and all its tributaries have been designated as Use III-P (Nontidal Cold Water and Public Water Supply).  See Code of Maryland Regulations (COMAR)  The document available below establishes a TMDL for fecal bacteria in the Prettyboy Reservoir watershed that will allow for attainment of the beneficial use designation of water contact recreation.  The listings for impacts to biological communities will be addressed in a separate TMDL document.  TMDLs for the impoundment were developed for mercury in 2002 and nutrients in 2006, and approved by EPA in 2004 and 2007, respectively. 

Total Maximum Daily Loads of Fecal Bacteria for the Prettyboy Reservoir Basin in Baltimore and Carroll Counties, Maryland

(Approved on October 8, 2009)

EPA's Decision Letter

EPA's Decision Letter 

MDE's Edits to EPA's Decision Letter

MDE's Decision Letter Edits  (24KB)

Main Report

report_prettyboyreservoir_final_bacteria.pdf (1448KB)

Comment Response Document

CRD_prettyboyreservoir_final_bacteria.pdf (7KB)


Contact Information

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