South Fork Kinnickinnic River - Brook Trout Reserve
South Fork Kinnickinnic River Project
The Kiap TU Wish Chapter’s project, “Restoration/Habitat Improvement for the South Fork of the Kinnickinnic River” is located in Pierce County, Wisconsin just east of the City of River Falls. The South Fork of the Kinnickinnic River contains a wild, naturally reproducing, Brook Trout fishery. This fishery is fairly unique in the area, in that there are no competing Brown Trout present, due to a natural barrier at its junction with the Kinnickinnic River.
The South Fork of the Kinnickinnic River has been identified by the WDNR as a “Brook Trout Reserve” stream. Brook Trout Reserves represent “a selection of some of the places in Wisconsin where brook trout have the best chance of enduring the effects of climate change and other environmental perturbations. The designation of reserves enables the WDNR and its partners to focus their specific tools to ensure that brook trout remain viable in the state”.
Lying at the northernmost part of the driftless area, the South Fork is impacted by glacial outwash sand resulting in wide shallow channels with a mostly sand substrate. Traditional habitat improvement techniques such as stream narrowing, and overhead structures have failed to significantly alter the carrying capacity of the stream due to the sand burden in the watershed. Our purpose is to employ a new, locally developed, habitat structure to enhance the Brook Trout population. The primary goals and objectives are to increase Brook Trout numbers and size within the project area of the South Fork, and to engage our members and the community in this restoration. This project includes significant efforts to control SandBar Willow (Salix exigua) and other less desirable plant species. This complements the goals of the local Chapter of Pheasants Forever which is working with the WDNR to manage the upland habitat with native grasslands in the wildlife area.
Working with the Wisconsin Department of Natural Resources (WDNR), past Chapter Board member Loren Haas developed Elevated Riparian Optimization (ERO) structures. A number of these were implemented on the South Fork and they have been proven to create scoured deep runs which provide habitat and cover for mature fish. The project includes a significant land management component to control Willows and other undesired plant species within the riparian corridor.
What is an Elevated Riparian Optimization (ERO) Structure?
The ERO structure design is based on the Bernoulli principle, a key concept in fluid dynamics that relates pressure, speed, and height. In short, the narrower the river is, the faster the water will flow. ERO structures are a constricting channel structure which narrows the stream to increase velocity. Additionally, the structures allow the optimization of the force of the water under high flows to scour the downstream corridor. The scouring provides depth/cover and exposes gravel providing spawning and insect habitat.
Working with the Wisconsin Department of Natural Resources (WDNR), past Chapter Board member Loren Haas developed Elevated Riparian Optimization (ERO) structures. A number of these were implemented on the South Fork and they have been proven to create scoured deep runs which provide habitat and cover for mature fish.
Estimated Project Timeline
Rock for the ERO structures will be placed along the stream in the winter of 2024/2025 to ensure heavy equipment can take advantage of the frozen ground. The rock will be placed at Eighteen ERO sites spread along the South Fork. These sites were selected by Chapter member Loren Haas in consultation with Nate Anderson, Trout Habitat Specialist, of the WDNR. The ERO Structures were developed by Loren Haas, a current Kiap TU Wish Chapter member. Loren is a conservation minded member that is passionate about stream restoration efforts. He has worked alongside our WI DNR partners since the first use of ERO structures in the South Fork in 2020. Loren has continued to monitor this stream improvement technique over the past 4 years to ensure the structures provide the desired outcome and scour sediment as intended. His knowledge and understanding of the stability and benefit of these structures has led him to be a subject matter expert in addition to our local respective DNR staff.
Installation of ERO structures will begin in summer of 2025. A second fall spraying will be conducted in the fall of 2025. Monitoring and chemically treating the willow regrowth will continue through 2029 to prevent reinfestation. Installation of ERO structures will be completed by fall of 2026.
The chapter intends to hold several workdays at the project site to aid in the removal of Willow and other undesirable and invasive plant species. Workdays will include but not be limited to brushing, mowing, spraying herbicide, and burning. The majority of these workdays will be volunteer based and led by the Kiap TU Wish Workday Coordinator and chapter members. Workdays are typically held in the winter season with snow cover to allow for the removal and burning of brush. Additionally, the cold temperature allows volunteer crews access to otherwise lowland and marshy areas that are too wet to access via machinery or even on foot. The Kiap TU Wish has identified the South Fork as a priority location for future workday events in conjunction with our restorative goals with this project.
Thank you to our local partners, chapter volunteers, and conservation champions!
