Final TMDLs Approved by EPA: Baltimore Harbor

The watershed draining into the Baltimore Harbor estuary is the Patapsco River Watershed.  The Patapsco River Watershed is located in the western shore region of Maryland, and includes the mainstem Patapsco and the tributaries of Jones Falls, Gwynns Falls, Colgate Creek, Bear Creek, Curtis Creek, Stony Creek, and Rock Creek.  The Patapsco River Mesohaline (PATMH) segment, or Baltimore Harbor estuary, is located on the west side of the upper Chesapeake Bay about 160 miles from the Virginia Capes at the entrance to the Bay.  The Harbor estuary is the 15-mile tidal region of the lower Patapsco River.  It is the end of the Patapsco River where it joins the Chesapeake Bay.  The PATMH segment includes the Baltimore Harbor estuary and the tidal segments of the Colgate Creek, Bear Creek, Curtis Creek, Stony Creek, Rock Creek and Bodkin Creek tributaries.  Bodkin Creek is identified in the 303(d) list as a separate waterbody and will be addressed in the future.

Baltimore Harbor (basin number 02130903) was identified on the State’s 1996 list of water quality limited segments (WQLSs) submitted to the U.S. EPA by the Maryland Department of the Environment (MDE) as impaired by nutrients.  The Baltimore Harbor has also been identified on the 303(d) list as impaired by bacteria (fecal coliform) (1998), toxics (polychlorinated biphenyls, or PCBs) (1998), metals (chromium, zinc and lead) (1998), suspended sediments (1996), and impacts to biological communities (2004).  These other impairments will be addressed separately.  The TMDLs described in the document below were developed to address the water quality impairments associated with excess nutrient loadings. 

EPA Region 3 has approved the TMDLs described in the document with the exception of the Deep Channel.  EPA recommends that the Deep Channel portion of the PATMH segment remain on the State's 303(d) list as impaired by nutrients and evaluate the water quality needs of this portion of the Harbor, possibly through a Use Attainability Analysis. At this time, the Deep Channel area of the estuary will continue to be on Maryland's list of impaired waters as impaired by nutrients until further action is taken.

Revised Final Document

On December 17, 2007, the U.S. Environmental Protection Agency (EPA) approved the “Total Maximum Daily Loads of Nitrogen and Phosphorus for the Baltimore Harbor in Anne Arundel, Baltimore, Carroll and Howard Counties and Baltimore City, 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 Baltimore Harbor Nitrogen and Phosphorus 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  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 Loads of Nitrogen and Phosphorus for the Baltimore Harbor in Anne Arundel, Baltimore, Carroll and Howard Counties and Baltimore City, Maryland

Approved on December 17, 2007

Comment Response Document on the Revisions Harbor_CRD_Eutro_revision.pdf (9KB)
Revised Main Report Harbor_TMDL_eutro_revised_final.pdf (773KB)
Revised Point Source Tech Memo Harbor_pstechmemo_eutro_revisedfinal.pdf (54KB)
EPA's Decision Letter

EPA's Decision Letter

Main Report  Harbor_tmdl_eutro_final.pdf (2497KB)
Appendix A Harbor_appendixA_eutro_final.pdf (390KB)
Appendix B Harbor_appendixB_eutro_final.pdf (289KB)
Appendix C Harbor_appendixC_eutro_final.pdf (25KB)
Point Source Tech Memo Harbor_pstechmemo_eutro_final.pdf (23KB)
Non-Point Source Tech Memo Harbor_npstechmemo_eutro_final.pdf (21KB)
Comment Response Document Harbor_CRD_eutro_final.pdf (52KB)

Contact Information

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