 Background:
A TMDL for a water body is a document that identifies the amount of a pollutant that the water body can receive and still meet Water Quality Standards (WQS). It also allocates responsibility for reductions in the pollutant load that are necessary to achieve WQS. A TMDL is required by the Clean Water Act for any stream reaches included by States or Tribes on their lists of impaired waters required under Section 303(d) of the Clean Water Act. Impaired waters are those that do not attain State or Tribal Water Quality Standards.
The Snake River from its confluence with the Salmon River at RM 188 to its confluence with the Columbia River has been included on the 303(d) list of impaired waters for Temperature and TDG by either Idaho, Oregon or Washington as appropriate. Oregon and Washington included all of the Columbia River on their 303(d) lists for TDG and most of the Columbia River on their lists for Temperature. The Columbia River also exceeds the WQS of the Colville Confederated Tribes for Temperature and TDG. The Spokane Tribe of Indians has WQS for the Columbia River that have been adopted by the Tribe but not yet approved by EPA. These standards are also exceeded in the Columbia River.
A workgroup has been formed to develop the Temperature and TDG TMDLs. This workgroup consists of staff from the Idaho Department of Environmental Quality, the Oregon Department of Environmental Quality, the Washington Department of Ecology and the EPA. A number of Columbia Basin Tribes also participate on the committee. EPA will issue the TMDLs for the parts of the rivers that are in Tribal Reservations.
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Columbia and Snake River Mainstem TMDL Homepage
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ADDITIONAL RESOURCES |
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EPA Working with Others:
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