Idaho DEQ proposes TMDLs to improve water quality in Upper Salmon River subbasin

The Idaho Department of Environmental Quality (DEQ) recently submitted a plan to improve water quality in east-central Idaho’s Upper Salmon River subbasin, which it hopes will reduce levels of sediment and E. coli bacteria and lower temperatures.

In “Upper Salmon River Subbasin Assessment and TMDL: 2016 Addendum and Five-Year Review,” the DEQ seeks to define total maximum daily loads (TMDLs) for the subbasin, which would inform the department’s permitting and pollution prevention efforts. Reduction of sediment, E. coli and water temperatures in the affected water bodies will promote their use as water habitats, salmonid spawning areas and domestic water supplies, as well as for as primary and secondary contact recreation.

Excess sediment harms waterways by changing flow patterns and adversely impacting the aquatic life they support, the latter of which also becomes an issue when waterway temperatures become elevated. E. coli primarily threatens those using the water bodies, causing illness when ingested and preventing recreational use. In the Upper Salmon River Subbasin, the DEQ has found elevated temperatures and sediment levels in several streams and has detected E. coli in levels above water quality standards in Herd Creek.

The DEQ is accepting public comments on the regulation until March 14, which can be submitted on the department’s website, by email and by mail.