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In January of 2020, the water level of the lake rose to a record height as a result of the outlet pipe on the western shore clogging. This, and wave action hitting the south shore resulted in significant bank erosion, which some have also attributed to pesky muskrats, though none have been seen recently. Ground movements were monitored weekly in the spring of 2020 and showed no perceptible new displacements.
In January of 2020, the water level of the lake rose to a record height as a result of the outlet pipe on the western shore clogging. This, and wave action hitting the south shore resulted in significant bank erosion, which some have also attributed to pesky muskrats, though none have been seen recently. Ground movements were monitored weekly in the spring of 2020 and showed no perceptible new displacements.
Several solutions were studied including placement of sheet piling, riprap fill, concrete block retaining walls, Coir logs and geomodular block structures.
Several solutions were studied including placement of sheet piling, riprap fill, concrete block retaining walls, Coir logs and geomodular block structures.
This last option was found to be the most appropriate for our constraints and ecological concerns. This method is called "Mechanically Stabilized Earth" and has been patented (see www.FlexMSE.com). Geomodular bags of gravel and sand/compost are stacked to form a retaining struture (see figure below). The existing 1:4 lawn slope will be extended to the top of the 22" wall to replicate the original appearance. The bags can be vegetated for a natural appearance of the shoreline.
This last option was found to be the most appropriate for our constraints and ecological concerns. This method is called "Mechanically Stabilized Earth" and has been patented (see www.FlexMSE.com). Geomodular bags of gravel and sand/compost are stacked to form a retaining struture (see figure below). The existing 1:4 lawn slope will be extended to the top of the 22" wall to replicate the original appearance. The bags can be vegetated for a natural appearance of the shoreline.
Over the spring and summer of 2020, a 58-foot length of the south shore was retrofitted with this method. Costs for this project were paid from cost savings resulting from our new self-management approach, considerable volunteer efforts, and donations. No special assessments were charged to members for this needed retrofit.
Over the spring and summer of 2020, a 58-foot length of the south shore was retrofitted with this method. Costs for this project were paid from cost savings resulting from our new self-management approach, considerable volunteer efforts, and donations. No special assessments were charged to members for this needed retrofit.
Work commenced on May 22 when volunteers excavated the clay bluffs left by the erosion (see photo below). Bag and gravel placement concluded on July 3 and sod placement over the gravel and top soil was completed on September 4. Photos and details of the construction can be seen by copying the following link and pasting into your browser.
Work commenced on May 22 when volunteers excavated the clay bluffs left by the erosion (see photo below). Bag and gravel placement concluded on July 3 and sod placement over the gravel and top soil was completed on September 4. Photos and details of the construction can be seen by copying the following link and pasting into your browser.
https://www.dropbox.com/s/478ccjux2u9oz8c/Champaign%20erosion%20retrofit%20project.pdf?dl=0
The completed project is shown below.
The completed project is shown below.
In May of 2023, concrete pavers were placed over the top course of bags to protect against UV rays and provide strength. River stone gravel was placed along the pavers as an attractive alternative to the sod that had dried out during the hot summer months. See Landscape Plans for a photo.
In May of 2023, concrete pavers were placed over the top course of bags to protect against UV rays and provide strength. River stone gravel was placed along the pavers as an attractive alternative to the sod that had dried out during the hot summer months. See Landscape Plans for a photo.
MSE design drawing.pdfexcavation photo.pdfThe Wetzels excavating the unstable clay bluffs left by the erosion. Gary Miller helping in the background.
The Wetzels excavating the unstable clay bluffs left by the erosion. Gary Miller helping in the background.
Completed project (October 2020).
Completed project (October 2020).
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