Coeur d’Alene Lake Management, moving forward

The health of Coeur d’Alene Lake and its trajectory have received a lot of attention over the last few years. Recently the conversation has centered around two tandem efforts: 1) the National Academy of Science’s (NAS) review of lake data and recommendations for future lake management and 2) Gov. Brad Little’s Leading Idaho Initiative for Coeur d’Alene Lake. Both efforts were spurred by recent data reports of lake water quality trends that showed key indicators (including phosphorus, a nutrient in the water column) moving in a direction that state and tribal scientists didn’t want to see. The NAS review and Leading Idaho Initiative for Coeur d’Alene Lake were the State of Idaho’s response to these trends.

The basin-wide community needs to keep phosphorus concentrations in the lake and its tributaries as low as possible to keep trace metals such as lead, cadmium, zinc, and arsenic in the approximately 80 million metric tons of contaminated legacy mining deposits at the bottom of the lake. Because phosphorus, as a nutrient, is a major stimulant to the amount of foodstuff or “biomass” in the water column, it ultimately determines how much oxygen is used up from the water. As the concentration of phosphorus increases, so does the oxygen demand. In the deep water of Coeur d’Alene Lake where oxygen is not replenished quickly, the environment can change in ways that increase the risk of the metals in lakebed sediments entering the overlying water. This is something we want to avoid. This process is one of the few places over which we have some influence in the watershed to help protect the lake’s water quality.

Enter the Leading Idaho Initiative to help reduce phosphorus loading from the Coeur d’Alene Basin. Gov. Little launched this initiative in 2020 as an immediate action to help protect the lake. The initiative provided funding for projects to lower phosphorus loading to water bodies throughout the basin, while the community awaited the completion of the NAS review of lake water quality data. The review was launched the same year and was intended to help inform the best path forward for the lake. Leading Idaho projects are ongoing and include stormwater treatment, streambank protection, road drainage improvements and wastewater treatment plant upgrades. In addition to these phosphorus-focused projects, Leading Idaho is now providing funding for other important recommendations from the NAS report released in the fall of 2022.

In its Consensus Report, "The Future of Water Quality in Coeur d’Alene Lake,” the NAS provided a long list of recommendations to improve our understanding of lake conditions and help move management activities forward. One recommendation highlighted the need to better coordinate the collection and analysis of environmental data throughout the basin. The NAS highlighted a need to make these data and analyses available to the public and decision-makers. As a result, the Idaho Department of Environmental Quality (IDEQ), through Leading Idaho funding, has initiated a “Science Coordination Team” to help guide future science-related efforts. The team consists of representatives from IDEQ, the Coeur d’Alene Tribe, the U.S. Environmental Protection Agency (EPA), the U.S. Geological Survey and the University of Idaho. This group has rolled up their collective sleeves and is getting down to business setting objectives, determining their mode of operation, and keeping the momentum moving in a cohesive and focused way.

The team will provide technical leadership and coordination of a multilateral effort to further scientific understanding of Coeur d’Alene Lake with the goal to incorporate and build on recommendations of the NAS 2022 review and analysis of Coeur d’Alene Lake water quality. The effort aims to generate scientific knowledge supporting resource management decisions that protect public health, beneficial uses, ecosystem health and cultural uses of Coeur d’Alene Lake.

Initially, the priorities will originate from the NAS report recommendations and may include additional priorities not identified or emphasized by the NAS. The team will provide an annual work plan and a brief achievements report that summarizes the accomplishments of the previous year. Updates to science priorities will be reviewed and amended periodically. Another goal will be to facilitate the development of a basin-wide, regularly updated integrated trend analysis – a large effort that is envisioned to coincide with the EPA's five-year reviews of basin cleanup activities.

For more information on the Leading Idaho Initiative for Coeur d’Alene Lake and projects funded through this initiative, visit https://www.deq.idaho.gov/leading-idaho-and-the-coeur-dalene-lake/.

The Our Gem Coeur d’Alene Lake Collaborative is a team of committed and passionate professionals working to preserve lake health and protect water quality by promoting community awareness of local water resources through education, outreach and stewardship. Our Gem includes local experts from the University of Idaho Community Water Resource Center, Coeur d’Alene Tribe, Idaho Department of Environmental Quality, the Basin Environmental Improvement Project Commission, Kootenai Environmental Alliance, Coeur d’Alene Regional Chamber of Commerce and Connect Kootenai.