Marengo River bank restoration site at Vaillancourt project before work. - Photo courtesy of Ben Dufford ABDI-LCD

Marengo River bank restoration site at Vaillancourt project after work is completed. - Photo courtesy of Ben Dufford ABDI-LCD

Marengo River bank restoration site at Vaillancourt project submerged vane installation. - Photo courtesy of Ben Dufford ABDI-LCD

Marengo River bank restoration site at Vaillancourt project submerged vanes completed. - Photo courtesy of Ben Dufford ABDI-LCD

A 50-foot high and 200-foot long eroding bank on the Marengo River in Bayfield County Wisconsin had been causing sediment problems to this highly important brook trout water for many years. 

A literal wall of exposed and collapsing earth was present at the site.  Historic land use practices in the area had previously cleared the existing banks of stable vegetation which protected the site from large scale erosion. 

The private land owners, Julie and Jeff Vaillencourt, were concerned about the negative impacts to the fishery and the steady encroachment of the river bend into the adjoining field. 

To fix the problem they worked cooperatively with the Ashland Bayfield Douglas and Iron Land Conservation Department, the Natural Resource Conservation Service and the U.S. Fish and Wildlife Service’s Ashland Fishery Resources Office (FRO). 

Working through the Partners for Fish and Wildlife Program the Ashland FRO provided financial and technical assistance as well on the ground assistance with practice installation.

Recognizing that rivers are a dynamic resource and since no high priority infrastructure was in place that would require extreme hardening of the banks, the partners worked together to find a solution to the problem that would most benefit the environment and state and federal trust resources, while providing the long term stability the landowner desired. 

Multiple conventional restoration practices were put in place as well as cutting edge technology using submerged vanes.  Before the project, the near vertical bank allowed the river to slam into its side with great force. 

To solve this problem a local contractor, K & D Excavating of Ashland, Wisconsin, was hired to excavate the river bank to produce a more gradual slope.  This action will dissipate the energy of the water on a larger and more stable surface.  To complete this part of the construction process, the exposed soil was seeded and is protected with erosion blankets.

With the help of the University of Wisconsin Engineering Department submerged vane technology was used to help stabilize the toe of the slope.  Submerged vanes are rectangular plastic sheets placed in an eroding streambed. 

They cause the water flow to be redirected which results in deposition of sediment at the toe of the eroding bank.  Vanes stabilize the stream without affecting the sediment load and velocity of other parts of the stream, which sometimes happens with bank “hardening” practices.  In this case the vanes were an effective way to help solve the problem of the power of the water undermining the outside banks of the bend in the river.

Construction finished in the fall of 2006 and the site is presently being monitored to make sure no problems occur.  Riparian forest tree species will be planted at the site in the spring to further protect the river banks and reduce sediment, as well as provide additional habitat for migratory birds and other wildlife. 

The reduction in sediment from this site which once plagued brook trout spawning habitat, will have a positive impact for many miles downstream.  With the completion of the Vaillencourt project another piece of the puzzle is in place for overall large scale fish and wildlife habitat restoration and protection in the Great Lakes basin.