Final TMDLs Approved by EPA: Gwynns Falls

The Gwynns Falls is a free flowing stream that originates in Baltimore County, Maryland and flows 25 miles in a southeasterly direction until it empties into the tidal Patapsco River. The watershed is located in the Patapsco River sub-basin of the Chesapeake Bay watershed within Baltimore County and Baltimore City, Maryland and covers approximately 65 square miles. 

MDE has identified the waters of the Gwynns Falls watershed on the 2008 Integrated Report as impaired by sediments (1996), nutrients – phosphorus (1996), bacteria (2002), and impacts to biological communities (2002). The designated uses of the Gwynns Falls mainstem and its tributaries is Use I (Water Contact Recreation, and Protection of Nontidal Warmwater Aquatic Life), except for the Gwynns Falls mainstem and its tributaries above Reisterstown Road and Red Run and its tributaries, which are designated as Use III (Nontidal Cold Water), and Dead Run and its tributaries, which are classified as Use IV (Recreational Trout Waters).

A TMDL for fecal bacteria was approved by the EPA in 2007, and a Water Quality Analysis for nutrients to address the phosphorus listing was submitted to the EPA in 2009. The listing for impacts to biological communities was refined in the 2010 Integrated Report’s list of impaired waterbodies as a result of a stressor identification analysis. 

Revised Final Document

On March 10, 2010, the U.S. Environmental Protection Agency (EPA) approved the “Total Maximum Daily Load of Sediment in the Gwynns Falls Watershed, Baltimore City and Baltimore County, Maryland,” developed by the Maryland Department of the Environment.

As a result of the Envirotech Consultants, Inc. permit application (14-DP-3788), an update is being made to the Gwynns Falls Sediment TMDL to include the proposed permit.  This facility was not included in this TMDL and so, the facility is being added to the TMDL allocations.  This addition would shift allocations among the facilities within the wastewater treatment plant wasteload allocation (WWTP-WLA).  The reallocation of the wasteload allocations does not affect the nonpoint source load allocations (LAs) or the overall TMDLs.  The revised point source technical memorandum and document were available for public comment from September 11, 2015 through October 13, 2015.  No comments were received.


Total Maximum Daily Load of Sediment in the Gwynns Falls Watershed, Baltimore City and Baltimore County, Maryland

(Approved on March 10, 2010)

Comment Response Document CRD_Gwynns Falls_sediment_revision.pdf (9KB)
Revised Main Report TMDL_Gwynns_Falls_sediment_revisedfinal.pdf (889 KB)
Revised Point Source Technical Memorandum PS_tech_memo_Gwynns_Falls_sed_revisedfinal.pdf (50 KB)
EPA's Decision Letter EPA's Decision Letter 
(Revised version of letter based on MDE's edits below has not yet been posted on EPAs website)
MDE's Edits to EPA's Decision Letter MDE's Decision Letter Edits (23KB)
Main Report TMDL_Gwynns Falls_sediment_final.pdf  (2,493KB)
Point Source Technical Memorandum PS tech memo Gwynns Fall sediment final.pdf (21KB)
Nonpoint Source Technical Memorandum NPS tech memo Gwynns Falls sediment final.pdf (16KB)
Comment Response Document CRD_Gwynns Falls_sediment_final.pdf (37KB)

Additional Supporting Information

Biological Stressor Identification Gwynns Falls Watershed Report (707KB)
Biological Stressor Identification Methodology (459KB)
Nontidal Sediment TMDL Methodology Report (361KB)
Addendum to the Nontidal Sediment TMDL Methodology Report (23KB)


Contact Information

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