Final TMDLs Accepted as Information to Delist: Conococheague Creek

Conococheague Creek, a tributary of the Potomac River, is a free flowing stream that originates in Pennsylvania and empties into the Potomac River in Maryland. It is approximately 80 miles in length with 58 miles in Pennsylvania and 22 miles in Maryland. The watershed of Conococheague Creek has an area of approximately 566 sq. miles out of which only 65 sq. miles (12% of the area) are in Maryland.

The Maryland portion of Conococheague Creek (02140504) was identified on the State’s 1996 303(d) submitted to EPA by the Maryland Department of the Environment. It was listed as being potentially impacted by nutrients (nitrogen and phosphorus) and suspended sediments. The recent water quality data shows that the chlorophyll-a levels are not high enough to warrant nutrient control. Although the recent data does not show the stream being impaired by low dissolved oxygen, it is suspected that violations of the dissolved oxygen standard could occur with the future increase in biochemical oxygen demand (BOD) and total Kjeldahl nitrogen (TKN) loadings. The document available below demonstrates that the BOD loading in conjunction with TKN primarily affects the dissolved oxygen, and describes the development of a TMDL for BOD in Conococheague Creek.  The suspended sediment impairment will be addressed separately.


TMDL for Biochemical Oxygen Demand (BOD)
for Conococheague Creek in Washington County, MD
  (Approved on February 2, 2001)
EPA's Decision Letter EPA's Decision Letter

Main Report

conoco_final.pdf (1071 KB)

Appendix A

conoco_appx_final.pdf (235 KB)

Technical Memorandum

conoco_techmemo_final.pdf (76 KB)

Comment Response Document (CRD)

conoco_CRD_final.pdf (78 KB)


Contact Information

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