Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Zekiah Swamp

The Zekiah Swamp watershed is located in the central Maryland region of the Potomac River tidal estuary.  It is located in a small portion of southern Prince George’s County and Charles County.  The watershed drains south from southern Prince George’s County in Zekiah Swamp Run until it discharges into the Wicomico River at Allens Fresh.  The Zekiah Swamp is non-tidal except for the southern-most portion of the watershed near the discharge to the tidal Wicomico River.

Zekiah Swamp (basin code 02-14-01-08), located in Charles County and southern Prince George’s County, MD, was identified on the State’s list of water quality limited segments (WQLSs) as impaired by nutrients (1996 listing), suspended sediments (1996 listing), copper (Cu) (1996 listing), lead (Pb) (1996 listing), selenium (Se) (1996 listing), zinc (Zn) (1996 listing), and impacts to biological communities (2002/2004 listing).  All impairments were listed for the tidal waters except for impacts to biological communities and nutrients, which are listed as non-tidal impairments.  Code of Maryland Regulations (COMAR) defines tributaries to the Potomac River upstream of St. Catherine’s Island, which includes Zekiah Swamp, as freshwater.  The listing for Cu, Pb, Se, and Zn is based on a water quality assessment found in the 1996 305(b) report developed by the Maryland Department of Natural Resources (DNR). 

The report available below provides analyses of recent monitoring data, which shows that the aquatic life criteria and designated uses associated with Cu, Pb, Se, and Zn are being met in Zekiah Swamp, and that the 303(d) impairment listings for Cu, Pb, Se, and Zn are not supported by the analyses contained herein.  The analyses support the conclusion that TMDLs for Cu, Pb, Se, and Zn are not necessary to achieve water quality standards.  Barring the receipt of contradictory data, this report will be used to support a Cu, Pb, Se, and Zn listing change for the Zekiah Swamp from Category 5 (“waterbodies impaired by one or more pollutants requiring a TMDL”) to Category 2 (“Surface waters that are meeting some standards and have insufficient information to determine attainment of other standards”), when the Maryland Department of the Environment (MDE) proposes the revision of Maryland’s 303(d) list for public review in the future.  The listings for nutrients, suspended sediments, and impacts to biological communities will be addressed separately at a future date. 

Although the waters of the Zekiah Swamp watershed do not display signs of toxic impairments due to Cu, Pb, Se, and Zn, the State reserves the right to require additional pollution controls in Zekiah Swamp if evidence suggests that these metals are contributing to downstream water quality problems. 

WQA of Copper Lead, Selenium and Zinc for Zekiah Swamp, Prince George's and Charles Counties, MD
(EPA Concurrence: September 11, 2006)

EPA's Decision Letter

EPA's Decision Letter

Main Report 

WQA_Zekiah_Cu_Pb_Se_Zn.pdf (978KB)

Comment Response Document

CRD_Zekiah_Cu_Pb_Se_Zn.pdf (81KB)

Contact Information

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