Final TMDLs Approved by EPA: Breton Bay

The Breton Bay watershed encompasses over 55 square miles of land on Maryland’s coastal plain between the Potomac and Patuxent Rivers.  Breton Bay is 6.5 miles long and drains 35,418 acres. Breton Bay ultimately drains to the Chesapeake Bay, and is a part of the Lower Potomac Tributary Strategy Basin.

Breton Bay (basin number 02140104) was first identified in 1996 as impaired by nutrients due to signs of eutrophication (expressed as high chlorophyll a levels), suspended sediments, and evidence of impacts to biological communities.  Breton Bay is impaired by nutrients (nitrogen, phosphorus) and BOD, causing occasional algal blooms and low dissolved oxygen.  The document available below establishes Total Maximum Daily Loads (TMDLs) for nitrogen, phosphorus and biochemical oxygen demand (BOD) in Breton Bay.  A bacteria TMDL was completed in 2005.  The suspended sediments and biological impairments will be addressed at a later date. 

Total Maximum Daily Loads of Nitrogen, Phosphorus and Biochemical Oxygen Demand for Breton Bay in St. Mary’s County, Maryland

(Approved on December 19, 2005)

EPA's Decision Letter EPA's Decision Letter
Main Report Report_bretonbay_nutrients_final.pdf (702KB)
Appendix A AppendixA_bretonbay_nutrients_final.pdf (390KB)
Point Source Tech Memo PStechmemo_bretonbay_nutrients_final.pdf (90KB)
Nonpoint Source Tech Memo NPSTechmemo_bretonbay_nutrients_final.pdf (92KB)

Comment Response Document

CRD_bretonbay_nutrients_final.pdf (158KB)


Contact Information

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