Final TMDLs Approved by EPA: Upper Monocacy River

The Upper Monocacy River watershed is located in Carroll and Frederick Counties in MD. The drainage area of the Upper Monocacy River considered in this analysis is approximately 462 square miles (295,638 acres), and lies west of the Westminster metropolitan area. The Upper Monocacy River and its tributaries flow through several small towns, including Thurmont, Taneytown, and Emmitsburg. The basin receives drainage from the Double Pipe Creek basin, as well as from areas in PA. The headwaters of the Upper Monocacy originate in Pennsylvania (PA), just north of Gettysburg, flowing south toward the town of Emmitsburg, MD, and eventually emptying into the Middle Potomac River near the town of Dickerson. The town of Gettysburg in Adams County, PA, is centrally located between two large streams (Rock Creek and Marsh Creek) that drain to the Upper Monocacy River basin.

The Upper Monocacy River basin includes the following tributaries: Fishing Creek, Hunting Creek, Marsh Creek, Owens Creek, Toms Creek, Piney Creek, Rock Creek, Tuscarora Creek and Double Pipe Creek. Marsh Creek and Rock Creek are located almost entirely in PA. Toms Creek and Piney Creek flow through both PA and MD, and the other tributaries are located entirely in MD. There are two major drainage areas comprising the Double Pipe Creek watershed: Big Pipe Creek and Little Pipe Creek. These branches and tributaries are free-flowing (non-tidal) streams, and flow into the Monocacy River.

The Maryland Department of the Environment (MDE) has identified the Upper Monocacy River in the State of Maryland's 303(d) List as impaired by the following (years listed in parentheses): nutrients (1996), sediments (1996), impacts to biological communities (2002) and fecal bacteria (2002). The Upper Monocacy River mainstem in Maryland (MD), the MD portions of tributaries Toms Creek and Piney Creek, and the tributary Double Pipe Creek (entirely in MD) have been designated as Use IV-P waters (Water Contact Recreation, Protection of Aquatic Life, Recreational Trout Waters and Public Water Supply). The tributaries Tuscarora Creek, Fishing Creek, Hunting Creek, and Owens Creek, all located within MD, are designated as Use III-P (Water Contact Recreation, Protection of Aquatic Life, Non-tidal Cold Water and Public Water Supply). See Code of Maryland Regulations (COMAR) P. The document available below establishes a TMDL for fecal bacteria in the Upper Monocacy River watershed in Maryland that will allow for attainment of the beneficial use designation of primary contact recreation. The listings for nutrients, sediments, and impacts to biological communities will be addressed separately at a future date. A data solicitation for fecal bacteria was conducted by MDE in 2003, and all readily available data from the past five years were considered. 

Total Maximum Daily Loads of Fecal Bacteria for the Upper Monocacy River in Frederick and Carroll Counties, Maryland

(Approved on December 3, 2009)

EPA's Decision Letter

EPA's Decision Letter

Main Report

Upper_Monocacy_Bacteria_TMDL_Final.pdf (4,708KB)

Comment Response Document

Upper Monocacy_CRD_Final.pdf (17KB)


Contact Information

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