GunpowderBird final PCB TMDL

Final TMDLs Approved by EPA: Gunpowder River/Bird River

The Gunpowder River is a 6.8-mile-long (10.9 km) tidal inlet on the western side of Chesapeake Bay in Baltimore and Harford Counties, Maryland. It is formed by the convergence of two freshwater rivers, Gunpowder Falls (often referred to locally as "Big Gunpowder Falls") and Little Gunpowder Falls. The Bird River is located in Baltimore County, Maryland in the upstream tidal portion of the Gunpowder River watershed and flows east into the Gunpowder River.

Maryland water quality standards specify that all surface waters of the State shall be protected for water contact recreation, fishing, and protection of aquatic life and wildlife. The designated use of the waters of the Gunpowder River (8-digit Basin Code: 02130801) is Use II – Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting. The Maryland Department of the Environment (MDE) has identified the waters of the Gunpowder River (Integrated Report Assessment Unit ID: MD-GUNOH-02130801) on the State's 2012 Integrated Report as impaired by nutrients (1996), suspended sediment (1996) and PCBs in fish tissue (2006). Although Seneca Creek is part of the Lower Gunpowder River 8-digit basin, 02130801, it is not directly connected to the Gunpowder River and is not part of the Gunpowder Oligohaline Segment, GUNOH, which was used to define the boundary of this TMDL. Therefore, Seneca Creek is not included in this TMDL. The Chesapeake Bay nutrient and sediment TMDLs, which were approved by the EPA in December, 2010, has addressed the sediment and nutrients listings for the Gunpowder River.

The document, available below, establishes a total PCB (tPCB) TMDL for the tidal waters of the Gunpowder River and the Bird River, for which a data solicitation was conducted and all readily available data have been considered.


Total Maximum Daily Load of Polychlorinated Biphenyls in the Gunpowder River and Bird River Subsegments of the Gunpowder River Oligohaline Segment, Baltimore County and Harford County, Maryland

(Approved on October 3, 2016)

EPA's Decision Letter

EPA's Decision Letter (1,124KB)

Main Report

Gunpowder_Bird_PCB_TMDL_fa.pdf (1,943KB)

Comment Response Document

Gunpowder_Bird_PCB_TMDL_CRD_fa.pdf (48KB)


Contact Information

Please direct questions or comments concerning this project to Maryland's TMDL Program at (410) 537-3572.

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