Status: Ongoing

Location:

Southern end of Coeur d’Alene Lake.

Background:

Coeur d’Alene Lake integrates the physical, chemical and biological processes in the lake’s watershed and has been the recipient of the majority of mining related pollution from the Silver Valley. This has resulted in over 75 million tons of contaminated sediments being deposited on the lake bed of this waterbody. Although pollution sources are being reduced, significant amounts of heavy metals and nutrients continue to enter the Lake every year. As cleanup efforts progress, it is imperative that we continue to monitor the lake and its tributaries to assess how upstream activities are impacting the legacy metals at the bottom of “Our Gem,” Coeur d’Alene Lake.

The nutrients, metals, primary productivity and metabolism of Coeur d’Alene Lake have been monitored continuously since 2003 and it is critical to continue to; 1) ensure there are no gaps in the water quality monitoring data, 2) enhance our ability to refine the model to be a tool to predict EPA’s remedial effects and especially time critical “pre and post” Central Treatment Plant upgrades, and 3) keep track of all of the information this monitoring will give the Trustees to better inform and guide restoration as EPA continues to implement the remedy.

Restoration Completed:

As of 2023, four years of consecutive water quality data has been collected and analyzed to assist the Tribe in Lake management goals and objectives moving forward. Additional funding was awarded in January 2024 for 3 more years of modeling and monitoring.

Benefits:

Overall, this project measures, models and will improve understanding of the response of Coeur d’Alene Lake from anthropogenic stressors and also inform restoration and remediation projects is essential to manage the 75 million tons of metals-contaminated sediments in Coeur d’Alene Lake. This water quality monitoring and modeling of Coeur d’Alene Lake is described by section 4.3 of the Coeur d’Alene Basin Restoration Plan (2018).

Contact:

Coeur d’Alene Tribe
850 “A” Street
PO Box 401
Plummer, ID 83851
p: 208-686-1803
Dale.chess@cdatribe-nsn.gov

Sponsor:

Coeur d’Alene Tribe

Partners:

AVISTA