Final TMDLs Approved by EPA: Maryland Coastal Bays

The Coastal Bays are a shallow coastal lagoon system that spans three states; however, the majority of the system is located in Maryland. The Maryland Coastal Bays are comprised of several individual MD 8-Digit waterbodies: Assawoman Bay, Isle of Wight Bay (including the St. Martin’s River), Sinepuxent Bay, Newport Bay and Chincoteague Bay. The Coastal Bays are located on the eastern side of the Delmarva (Delaware-Maryland-Virginia) Peninsula and include portions of Worcester County (Maryland), Sussex County (Delaware), and Accomack County (Virginia) (see Figure 1). Areas of interest in the watershed are Ocean City (Maryland), Assateague Island National Seashore, Ocean Pines (Maryland), Berlin (Maryland), Chincoteague National Wildlife Refuge (Virginia), Wallops Island National Wildlife Refuge (Virginia), Selbyville (Delaware), Fenwick Island (Delaware), South Bethany (Delaware), Bethany Beach (Delaware), and Ocean View (Delaware). The system connects to the Atlantic Ocean through two inlets: Ocean City Inlet and Chincoteague Inlet.

The designated use for the tidal MD 8-Digit Assawoman Bay, Isle of Wight Bay, Newport Bay, Sinepuxent Bay, and Chincoteague Bay (Maryland Coastal Bays) is Use II: Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting. The Maryland Coastal Bays are not attaining its Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting designated use because of impacts from the nutrients nitrogen and phosphorus. The Maryland Department of the Environment has identified the waters of the Maryland Coastal Bays on the Integrated Report of Surface Water Quality in Maryland as impaired by the nutrients, nitrogen and phosphorus. Nitrogen and phosphorus TMDLs for areas within Maryland’s Northern Coastal Bays were approved by the USEPA in 2002. Nitrogen and Biological Oxygen Demand (BOD) TMDLs for the MD 8-Digit Newport Bay were approved by the USEPA in 2003. The TMDLs available below, were developed to address the water quality impairments associated with excess nutrient loadings, and supersede the previous TMDLs. 

Total Maximum Daily Loads of Nitrogen and Phosphorus for Assawoman Bay, Isle of Wight Bay, Sinepuxent Bay, Newport Bay and Chincoteague Bay in the Coastal Bays Watersheds in Worcester County, Maryland

(Approved on August 7, 2014)

EPA's Decision Letter EPA's Decision Letter (5144KB)

Portable Document Format

Main Report

TMDL_MCBs_Nutrients_Main_Report_final.pdf (1442KB)

Appendix A:
Assawoman Bay

TMDL_MCBs_Nutrients_Appendix_A_final.pdf (252KB)

Appendix B: Isle of Wight Bay

TMDL_MCBs_Nutrients_Appendix_B_final.pdf (1449KB)

Appendix C:
Sinepuxent Bay

TMDL_MCBs_Nutrients_Appendix_C_final.pdf (193KB)

Appendix D:
Newport Bay

TMDL_MCBs_Nutrients_Appendix_D_final.pdf (733KB)

Appendix E: Chincoteague Bay

TMDL_MCBs_Nutrients_Appendix_E_final.pdf (1331KB)

Appendix F: Technical Approach Used to Generate Maximum Daily Loads

TMDL_MCBs_Nutrients_Appendix_F_final.pdf (97KB)

Technical Memorandum Significant Nutrient Point Sources in the Maryland Coastal Bays Watershed

TMDL_MCBs_Nutrients_PS_Tech_Memo_final.pdf (70KB)

Technical Memorandum Significant Nutrient Nonpoint Sources in the Maryland Coastal Bays Watershed

TMDL_MCBs_Nutrients_NPS_Tech_Memo_final.pdf (99KB)

Comment Response Document

TMDL_MCBs_Nutrients_CRD_final.pdf (401KB)

Additional Supporting Information

Maryland Coastal Bays Watershed Modeling Report

MCBs_Nutrients_Watershed_Modeling_Report.pdf (2597KB)

Maryland Coastal Bays Water Quality Modeling Report

MCBs_Nutrients_Water_Quality_Modeling_Report.pdf (12212KB)


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