The Washington Ship Channel and the Tidal Basin are man-made water bodies located in the southwest section of the District along the Potomac River. The Tidal Basin was built in the late 19th century by the Army Corps of Engineers to flush the Washington Ship Channel with the freshwater from the Potomac River. The Tidal Basin and Washington Ship channel were listed in 1998 for elevated levels of organics and metals in fish tissue and sediment from the Anacostia River. The total maximum daily loads (TMDLs) were approved for the Tidal Basin and Washington Ship Channel toxic parameters identified in the table below on December 15, 2004.
The TMDLs were challenged in Friends of the Earth v. EPA 446 F.3d 140 (D.C. Cir. 2006) because the loads were not expressed in daily loads. Following the case, a settlement agreement was reached between the US Environmental Protection Agency (EPA) and Anacostia Riverkeeper, Friends of the Earth, and Potomac Riverkeeper (Case No.: 1:09-cv-00098-JDB of January 15, 2009). To meet the settlement requirements, EPA will revise the applicable TMDLs to express daily loads. The District Department of the Environment (DDOE) is working with EPA to collect/analyze data and revise the TMDLs for toxic parameters. The table below lists the TMDL water bodies and pollutant pair with the current impairment status in the District’s 2014 Integrated Report. In the table below, those water body/pollutant pairs categorized in 4a will be revised. However, recent data was insufficient to support an impairment determination for most of the parameters.
Toxic parameters and Impairment Status (2014 Integrated Report)
Tidal Basin
| Arsenic | Copper | Lead | Mercury | Zinc | 4,4' DDD | 4,4' DDE | 4,4' DDT | Chlordane | Dieldrin | Hepatchlorn Epoxide | PAHs | PCBs |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3 | 3 | 3 | 3 |
Washington Ship Channel
| Arsenic | Copper | Lead | Mercury | Zinc | 4,4' DDD | 4,4' DDE | 4,4' DDT | Chlordane | Dieldrin | Hepatchlorn Epoxide | PAHs | PCBs |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3 | 3 | 3 | 3 |
Notes:
Categories reflect the District’s category definitions in the Integrated Report
Category 3 - There is insufficient available data and/or information to make a use support determination. In this case, they were previously in category 4a, now in category 3.
Category 4a - A State developed TMDL has been approved by EPA or a TMDL has been established by EPA for any segment-pollutant combination.
Black boxes represent parameters not included in TMDL.
For more information, please see the District’s 2014 Integrated Report.
The 2004 final approved TMDL documents for organics and metals in the Tidal Basin and Washington Ship Channel are included below. The revised documents will be posted when available.
