Cannon River Fish Passage
Learn about Fish Passage and Rock Arch Rapids
What is fish passage?
Dams alter the natural flow of rivers and transform rivers and streams into static reservoirs. This fundamentally changes the ecology of the river and results in several changes, such as sediment and nutrient accumulation, an increase in algae and algae blooms, warmer water temperatures, lower dissolved oxygen, and blocked fish passage. Preventing fish from passing the dam reduces the number of fish present upstream and prevents several fish species from reaching spawning grounds upstream, limiting the natural reproduction of those species. Furthermore, native mussel species that use fish as hosts to travel upstream can no longer be transported above the dam, which negatively impacts biodiversity and water quality.
What are rock arch rapids?
Rock arch rapids are a nature-inspired fish passage design used to replace or modify low-head dams. This design allows fish to swim freely, resembling the flowing stream riffles in which they thrive. Picture a series of descending boulders creating pools of water like a staircase just for fish! Rock Arch Rapids ensure that fish can pass under any flow conditions and enhance the natural movement of sediments. Besides the ecological benefits of boosting aquatic diversity and restoring sediment flow, Rock Arch Rapids also require little to no maintenance and enhance safety for recreational activities.
Resources to Learn More
Why is this relevant to folks in the Cannon River Watershed?
We’re excited to share that we’re partnering with the Minnesota DNR on a fish passage project in the Cannon River watershed. Thanks to the State of Minnesota’s Get Out MORE funding, the Gorman Lake Dam near Le Center and the Lower Sakatah Lake (Schmidtke) Dam near Morristown will be modified to Rock Arch Rapids.
The Lower Sakatah Lake and Gorman Lake Dams are aging and ready for conversion to Rock Arch Rapids. These low-head dams on the Cannon River neither generate power nor supply drinking water, creating safety concerns as they can trap swimmers and boaters, often referred to as "drowning machines." Reconstructing them will open 23 miles for fish passage, enhance recreational safety, and be more cost-effective in the long term.
We are in the very early stages of these projects, and construction will likely begin in Winter 2026. The construction is weather-dependent, but it is proposed to be completed by Summer 2027.
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Questions about this project?
Contact Anna Holman (she/her), our
Conservation Program Manager, Habitat
anna@cleanriverpartners.org
(507) 200-8219