Construction is complete on six streambank toe stabilization projects on the Rum and Mississippi Rivers in Anoka. These sites have had significant and accelerating erosion in recent years due to sustained high water and recreational watercraft. Most of the sites lie between two popular boat launches on the rivers.
Cumulatively, over 720 linear feet of eroding riverbank was stabilized. The primary stabilization technique is rock riprap installed on the lower portion of the slope, with a seeded and blanketed vegetative zone above the rock. The primary immediate goal of these projects was to halt the backwards march of the riverbanks by stabilizing the lower portion (or toe). An additional vegetation component is planned for these sites in the following year(s) to help stabilize the upper slope, which is only subject to wave action during the highest water periods. This vegetative zone will be comprised of native woody species, as well as grasses, sedges, and forbs, to enhance the habitat and aesthetic value of the shorelines, while also providing deep root structure to anchor the soil in place above the rock.
The projects were done via barge from the water, a first for ACD-managed projects. Many of these sites had been on our inventories, but were not cost-effectively constructible from land. With a contractor that can install projects from the water, concerns about equipment access between buildings and site restoration on individual properties are non-factors. Beyond stabilizing these six eroding shorelines, we are hopeful that this new construction technique opens up more potential streambank stabilization projects that would have otherwise not been possible or cost-effective from land. To see these and other streambank stabilization projects installed throughout Anoka County, please see the virtual project tour on ACD's website.