Lake Superior Low Cost Shoreline Erosion Control Demonstration Projects
St. Louis County, MN

Grantee: Minnesota Board of Water and Soil Resources and Lake Superior Association of Soil and Water Conservation Districts
Basin Program Funds: $13,500
Non-federal Funds: $13,557
Project Duration: 06/1997 - 07/1998
Status: complete

Problem Statement
Conventional soil erosion projects are very expensive for Lake Superior shoreline due to long fetches and the lake's severe wave climate. Most projects cannot be funded solely by the landowners, nor do state share-cost funds cover many large scale projects. If low cost alternatives can be demonstrated as acceptable options under certain conditions, state share-cost funds will go further and more shoreline can be protected.

Pinned rock wall method: before project.

Recently, a large scale erosion control project has been completed at Sucker Bay. From that site an estimated 3,000 tons of sediment eroded annually from the four adjacent shoreline areas. Remediation of these areas cost an average $250-$300 per linear foot. Forty more such projects have been identified by the Lake Superior Association of Soil and Water Conservation Districts, at least 15 of which have been classified as potential low cost shore protection project sites. Low cost sites are defined as those with eroding shorelines substantially above lake level or with partial protection already in place. Potential low cost solutions include greater and more efficient use of vegetation, use of pinned rock rather than poured concrete and use of rock filled gabions in lower wave impact areas.

Four sites were selected for low cost demonstration projects representing different specific problems: use of selected dump and fill rip-rap to protect a very steep erosion pocket; use of large rectangular pinned rock in place of a concreted wall; use of gabions to protect an eroding area of Lake Superior; installation of a modular wall system to protect a sandy beach back shore area; and pinning the outer row of rip-rap in a revetment in order to build over a bedrock outcrop. A matching project, a pinned toe stone revetment, was also constructed.

Pinned rock wall method: after project completion.

The six projects will save an estimated 545 tons/year of sediment from entering Lake Superior. This is expected to be an ongoing saving. As these techniques are adopted elsewhere along the lakeshore, further soil savings are expected to occur. If successful over the long term, fish habitat and ambient lake water quality are expected to improve through the reduction of direct sedimentation into Lake Superior.

At a July 1998 Sea Grant workshop, inquiries about the projects and requests for further information indicate a basin-wide interest leading to the conclusion that the cost and erosion benefits will accrue to other Great Lakes shorelines as well.

Contact: Gene R. Clark, (218) 723-4752


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