Rush Lake Erosion Project

Mary Blickenderfer, University of Minnesota Extension Service, 888-241-0885

For decades, lakeshore owners and boaters on Rush Lake (part of the Whitefish Chain north of Brainerd) have viewed the steep, sandy, eroding banks of County and DNR Islands. Past efforts to stabilize these banks have been partially successful, but the erosion continued.

This summer, people on Rush Lake were greeted with a curious sight. The islands’ steep slopes resembled a patchwork quilt of colors and logs nestled along the shorelines. The islands had become research sites, testing the effectiveness of several erosion control methods. Combining the successes of past erosion control efforts with new technology and techniques, several state and local agencies, organizations, and businesses coordinated and established this research project.

Slope Stabilization

The goal for stabilizing the upland slope area is to establish deep-rooted, drought-tolerant, native plants. To facilitate installation (every footstep generates a small landslide of sand) and create a favorable growing environment for the plants, bio-terraces were installed by anchoring several brush bundles along the slope. Native grass seed, flower seedlings, and bare root shrub and tree seedlings were planted. Four types of protective layers were also applied to the soil surface to minimize slope erosion and to hold moisture for the plants during establishment: one layer of coconut fiber blanket, two layers of coconut fiber blanket, Futera – a blanket of wood fiber material, and hydro-mulch – a fiber slurry mixed with the native seed and sprayed on the slope. The table below summarizes the cost and first-year plant establishment success for each of the four trials of protective layers.

During this initial year, Rush Lake Association members watered the site during periods of drought, aiding establishment of the plants. Sixty percent of the bare-root seedlings established well. While the success of the native flower planting was evident, it is too early to comment on the success of the native grass seeding as very little growth is visible above ground the first year. Much of the plant cover on each plot at the end of this season consisted of annual weeds, native perennials that were not planted, and a few survivors of past planting efforts. A complete report of the project and subsequent updates can be found at www.extension.umn.edu/shoreland beginning January 2006.

Major Contributors

Rush Lake Association, Whitefish Area Property Owners Association, Crow Wing Soil and Water Conservation District, and University of Minnesota Extension Service, with significant financial support and contributions from the Minnesota Department of Natural Resources Shoreland Habitat Program, Pequot Sand and Gravel, Professional Lake Management, and Lakeside Lawn and Landscape Company.

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