The construction and operation of Libby Dam, a U.S. Army Corps of Engineers (USACE) project located in northwestern Montana, has altered the natural hydrograph, thermal regime, sediment transport, and nutrient loadings on the Kootenai River. Dam operation impacts riverine ecosystem function and many fish species, including the federally endangered Kootenai River White Sturgeon and federally threatened Bull Trout, as well as resident Burbot and other focal species important to a broad group of stakeholders in the region. Additionally, the ecological impact of increased trends in selenium and nitrate loading to Koocanusa Reservoir is of growing concern.
The U.S. Army Corps of Engineers (USACE) has identified a need to develop a numerical model of Libby Dam and Koocanusa Reservoir to help evaluate the water quality impacts of future operational changes on reservoir thermal properties, constituent transport, productivity, and trophic state. These water quality impacts ultimately influence temperature and nutrient loadings in the Kootenai River downstream of the dam. In response, the U.S. Geological Survey (USGS) is developing a CE-QUAL-W2 model to provide flow and temperature simulations, and potentially water-quality simulations, for Koocanusa Reservoir (Canada and US) and the Kootenai River downstream of Libby Dam.
To better understand the temperature and water-quality dynamics in Koocanusa Reservoir and evaluate structural and operational measures to optimize flow, water temperature, and nutrients in the Kootenai River for the benefit of Endangered Species Act-listed and other focal species, the USGS, in cooperation with the USACE is developing a CE-QUAL-W2 model of Koocanusa Reservoir and about 114 miles of the Kootenai River downstream of Libby Dam. CE-QUAL-W2 is a two-dimensional hydrodynamic model capable of modeling flow, temperature, and a large suite of water-quality parameters, which is optimized for the simulation of long, narrow water bodies that stratify. Phase I of the study (Fiscal Years 2023 – 2024) includes flow and temperature simulations for temperature management scenarios at Libby Dam. In future years, the USGS and USACE will explore expanding the Kootenai model capabilities to include water-quality parameters such as nutrients, dissolved oxygen, dissolved solids, organic matter, inorganic suspended sediment as well as selenium transport.
Assessing the impacts of mining on the Transboundary Koocanusa Reservoir
Bathymetric Mapping of the Kootenai River
Kootenai River Water-Quality Monitoring Related to Transboundary Coal Mining
Evaluating Spatial and Temporal Fine-Scale Movement of Kootenai River White Sturgeon
Kootenai River Sediment Studies
- Overview
The construction and operation of Libby Dam, a U.S. Army Corps of Engineers (USACE) project located in northwestern Montana, has altered the natural hydrograph, thermal regime, sediment transport, and nutrient loadings on the Kootenai River. Dam operation impacts riverine ecosystem function and many fish species, including the federally endangered Kootenai River White Sturgeon and federally threatened Bull Trout, as well as resident Burbot and other focal species important to a broad group of stakeholders in the region. Additionally, the ecological impact of increased trends in selenium and nitrate loading to Koocanusa Reservoir is of growing concern.
Sources/Usage: Public Domain. Visit Media to see details.USGS personnel preparing to survey Lake Koocanusa bathymetry. The U.S. Army Corps of Engineers (USACE) has identified a need to develop a numerical model of Libby Dam and Koocanusa Reservoir to help evaluate the water quality impacts of future operational changes on reservoir thermal properties, constituent transport, productivity, and trophic state. These water quality impacts ultimately influence temperature and nutrient loadings in the Kootenai River downstream of the dam. In response, the U.S. Geological Survey (USGS) is developing a CE-QUAL-W2 model to provide flow and temperature simulations, and potentially water-quality simulations, for Koocanusa Reservoir (Canada and US) and the Kootenai River downstream of Libby Dam.
To better understand the temperature and water-quality dynamics in Koocanusa Reservoir and evaluate structural and operational measures to optimize flow, water temperature, and nutrients in the Kootenai River for the benefit of Endangered Species Act-listed and other focal species, the USGS, in cooperation with the USACE is developing a CE-QUAL-W2 model of Koocanusa Reservoir and about 114 miles of the Kootenai River downstream of Libby Dam. CE-QUAL-W2 is a two-dimensional hydrodynamic model capable of modeling flow, temperature, and a large suite of water-quality parameters, which is optimized for the simulation of long, narrow water bodies that stratify. Phase I of the study (Fiscal Years 2023 – 2024) includes flow and temperature simulations for temperature management scenarios at Libby Dam. In future years, the USGS and USACE will explore expanding the Kootenai model capabilities to include water-quality parameters such as nutrients, dissolved oxygen, dissolved solids, organic matter, inorganic suspended sediment as well as selenium transport.
Sources/Usage: Public Domain.Map showing Kootenai River basin and location of Libby Dam. - Science
Assessing the impacts of mining on the Transboundary Koocanusa Reservoir
Lead Researcher: Travis Schmidt Project Manager: Melissa Schaar Water-Quality Field Lead: Chad ReeseBathymetric Mapping of the Kootenai River
The Kootenai River white sturgeon (Acipenser transmontanus) and other native fish species are culturally important to the Kootenai Tribe of Idaho, but their habitat and recruitment have been affected by anthropogenic changes to the river. The Tribe has undertaken a large-scale restoration project and needs objective information on which to base restoration decisions.Kootenai River Water-Quality Monitoring Related to Transboundary Coal Mining
The Kootenai River (Kootenay in Canada) rises from the Canadian Rockies and flows south in an arc through Montana and Idaho before swinging back into British Columbia and the Columbia River. The uplifted sedimentary rocks forming the southern Canadian Rockies have rich coal deposits that have been mined for many decades. The coal beds and associated rock layers are enriched with other minerals as...Evaluating Spatial and Temporal Fine-Scale Movement of Kootenai River White Sturgeon
The U.S. Fish and Wildlife Service has published a plan for recovering the endangered Kootenai River white sturgeon. This study supports the objectives of that plan by quantifying white sturgeon habitat preference within a recently restored reach of the Kootenai River. Fine-scale acoustic telemetry positioning data will be integrated with quasi-three-dimensional hydraulic model simulations for the...Kootenai River Sediment Studies
The Kootenai River white sturgeon (Acipenser transmontanus) and other native fish species are culturally important to the Kootenai Tribe of Idaho, but their habitat and recruitment have been affected by anthropogenic changes to the river. White sturgeon and burbot have not successfully spawned in the Kootenai River since the completion of Libby Dam upstream in Montana. In recent years, most white... - Partners