Beavers, Streams and Steelhead

Researchers led by Karen Gran will examine how beaver dams influence the movement of sports fish, water temperatures and stream flow in the Knife River, a Minnesota tributary to Lake Superior. Experts estimate the Knife encompasses 70% of North Shore spawning habitat for steelhead, a migratory strain of Rainbow Trout. The Minnesota Department of Natural Resources (MNDNR) routinely removes beaver dams along the river to ensure steelhead can access this habitat.

During the two years of this project, MNDNR staff will work with the research team to clarify whether beaver activity influences water temperature and stream flow rate while also tracking whether the dams actually limit trout migration. The research team is particularly interested in examining the impact of dam removal on stream conditions in late summer.

They will monitor stream temperatures and flow, conduct fish surveys and develop a computer simulation to help resource managers make decisions about northern streams. Streams and rivers that lack significant groundwater inputs, such as the Knife and others along the north shore, are sensitive to alterations in the exchange of surface water and groundwater associated with beaver dams and changing weather patterns.

The researchers anticipate that natural resource managers will use the project information to refine management policies in cold-water trout streams.

Minnesota Sea Grant provided research support through our 2018-2020 biennial competitive Request for Proposal (RFP) process.