Lake Superior Low Cost Shoreline Erosion Control Demonstration Projects
St. Louis County,
Minnesota Board of Water and Soil Resources and Lake Superior Association of Soil and Water Conservation Districts
Basin Program Funds:
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.
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.
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
Contact: Gene R. Clark, (218) 723-4752