Coeur d'Alene Basin Water-Quality Monitoring

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We partner with the EPA to conduct long-term water-quality and streamflow monitoring in the Coeur d’Alene River Basin, which has been widely impacted by historic mining activities.

USGS hydrologic technicians collecting water-quality samples

U.S. Geological Survey hydrologic technicians Kevin Kirlin (left) and Ryan Smith collect water-quality samples from the Coeur d'Alene River near Cataldo (USGS 12413500) as part of an ongoing monitoring program that the USGS conducts on behalf of the U.S. Environmental Protection Agency.

(Credit: Deena Green, USGS Idaho Water Science Center. Public Domain)

We collect water-quality samples 2-4 times per year at 20 sites throughout the basin. Our scientists analyze these samples for metals, hardness, sediment, and nutrients. In addition, we maintain 12 streamgages in the basin. The data from sampling and monitoring are used to help the EPA target remedial actions, to evaluate the effectiveness of remedial actions, and to describe long-term water-quality and streamflow trends.

As part of its ongoing cleanup efforts, the U.S. Environmental Protection Agency is constructing a groundwater collection and treatment system to intercept and treat this contaminated water before it reaches the river. To establish conditions prior to construction, the USGS conducted a seepage study in September 2017 to quantify the rate and quality of groundwater discharging into the South Fork Coeur d’Alene River between Kellogg and Smelterville. We will conduct a second seepage study after construction and treatment plant system optimization are complete. This second study will evaluate changes in groundwater discharge to and water quality in the South Fork Coeur d’Alene River compared to the pre-construction conditions.