Final TMDLs Approved by EPA: Prettyboy Reservoir

Prettyboy Reservoir (basin code 02130806) and Loch Raven Reservoir (basin code 02130805) lie in the Gunpowder Falls watershed.  Gunpowder Falls drains into Chesapeake Bay north of the City of Baltimore. The portion of the watershed draining to the reservoirs lies primarily in Baltimore and Carroll Counties, but also includes small portions of Harford County and York County, PA.  Both reservoirs are part of the water supply system for Baltimore City and surrounding jurisdictions.  Water supply intakes in Loch Raven Reservoir feed Baltimore City’s Montebello Water Treatment Plant.  Prettyboy Reservoir, which is upstream of Loch Raven Reservoir, is used as a secondary reservoir to maintain capacity in Loch Raven Reservoir.

Prettyboy Reservoir and Loch Raven Reservoir (referred to also as the Gunpowder Reservoirs), Use III-P waterbodies (COMAR, were identified on the 303(d) List submitted to EPA by the Maryland Department of the Environment (MDE) as impaired by nutrients (1996), sediments (1996 – Loch Raven), metals (1996), bacteria (2002 – Prettyboy), mercury in fish tissue (2002), and impacts to biological communities (2002 & 2004).  The document available below establishes TMDLs for the nutrient and sediment impairments.  TMDLs were completed in 2002 for both reservoirs for the mercury listings.  Water Quality Analyses were completed for both reservoirs for the metals listings in 2003.  Other impairments within these watersheds will be addressed separately at a future date.

Total Maximum Daily Loads of Phosphorus and Sediments for Loch Raven Reservoir and Total Maximum Daily Loads of Phosphorus for Prettyboy Reservoir, Baltimore, Carroll and Harford Counties, Maryland

Approved on March 27, 2007

EPA's Decision Letter EPA's Decision Letter
Main Report  gunpowder_tmdl_P_sed_final.pdf (1093KB)
Appendix A gunpowder_appendixA_P_sed_final.pdf (1496KB)
Appendix B gunpowder_appendixB_P_sed_final.pdf (232KB)
Appendix C gunpowder_appendixC_P_sed_final.pdf (153KB)
Appendix D gunpowder_appendixD_P_sed_final.pdf (27KB)
Point Source Tech Memo gunpowder_pstechmemo_P_sed_final.pdf (11KB)
Non-Point Source Tech Memo gunpowder_npstechmemo_P_sed_final.pdf (10KB)
Comment Response Document gunpowder_CRD_P_sed_final.pdf (44KB)

Contact Information

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