The Klamath River is listed as “impaired” under section 303 (d) of the federal Clean Water Act and TMDLs are created to address the identified sources leading to the impairment of various uses of the river, including salmon habitat, recreational use, agricultural use and municipal use, among a number of others.

The various parameters considered in the Klamath TMDLs include temperature, dissolved oxygen, organic matter, total phosphorous, total nitrogen and microcystin. The sources affecting those parameters, according to the pollutant source analysis provided by the North Coast Regional Water Quality Control Board (WQCB), are conversion of wetlands, grazing activities, irrigated agriculture, timber harvest and roads, each affecting to varying degrees based on region and type of practice.

For California, the WQCB has also identified the stateline as a major loading source, with municipal water systems in Oregon acting as contributors of pollutants to the river.

The WQCB, which formulated the TMDLs under a Memorandum of Understanding with the Oregon Department of Environmental Quality, has also provided “target” values for pollutant sources in order to correct the river’s impaired status.

For example, at the Iron Gate dam, the average daily maximum target temperature increase for tail waters leaving the dam is .18 degrees Fahrenheit above the temperature of water entering the facility.

Matt St. John, a lead on the Klamath TMDLs, stated that the TMDL basin plan amendment and administrative record will now go to the Office of Administrative Law and to the United States Environmental Protection Agency for final review.

Siskiyou County and PacifiCorp, which owns Iron Gate and other dams on the river, have taken issue throughout the process with the levels used by the WQCB in its formulation of the Klamath TMDLs. The county also alleged  in comments submitted to the State Water Board that the WQCB allowed undue outside influence on the process.