Posted on November 8, 2023
McGregor Lake Habitat Rehabilitation and Enhancement Project showcases many different features, including thin layer placement shoreline stabilization, island enhancement, island building as well as habitat dredging.
Thin layer placement
Something is being done at the McGregor Lake project, near Prairie du Chien, Wisconsin, and Marquette, Iowa, that’s never been done before on the Upper Mississippi River.
Thin layer placement is a technique that has historically only been used on coastal waterways. The placement at McGregor Lake marks a first for the St. Paul District and the Upper Mississippi River Restoration Program, or UMRR, for using this on an inland waterway. Thin layer placement places sand material in thin, uniform layers over eroding islands.
“It’s a newer concept that we’re trying to incorporate in UMRR to target a much larger area on a less intrusive scale to help raise some of these island areas into a more suitable habitat for tree species to grow in a less impactful way than what island building has been in the past,” said John Henderson, project manager.
Thin layer placement raises the forest levels to a point where it’s more suitable and get the islands out of the inundation period where the trees would see harm, he explained.
“This is another tool in the toolbox,” said Henderson. “We can use this is areas that are more sensitive to erosion and work around some of the limitations we have on these projects.”
“We’re in an unprecedented stage of habitat restoration on the Upper Mississippi River,” said Henderson.
Beneficial use of river sand is a win-win
One of the highlights of the McGregor restoration project is that the sand base material is coming directly out of the channel, said Henderson. The sand is removed rom the main channel of the Upper Mississippi River. Normally, the material would have to be hauled upland to a placement site.
“Here at McGregor, we’ve beneficially used almost 500,000 cubic yards of clean river sand, which is about half of our district’s annual dredging capacity,” said Henderson. “This is a testament to how we can beneficially put together two of the Corps’ missions – maintaining the 9-foot navigation channel and habitat restoration.”
Henderson added that the project will use 200,000 cubic yards of backwater dredging material, which will help enhance backwater fisheries and improve ice fishing and other recreational opportunities.
The Upper Mississippi River Restoration program
UMRR is a federally funded and multi-agency partnership with both state and federal partners between a multitude of Upper Mississippi River agencies spanning from St. Paul, Minnesota, to the delta at the southern tip of Illinois.
The program targets the Upper Mississippi River wildlife refuge and other areas across the Upper Mississippi River to rebuild, restore, study and overall implement better practices and rehabilitate some of the islands that have seen change based on climate change, flooding and invasive species.
“UMRR is a proven program. We’ve been doing this for over 35 years in multiple states, with different projects, and thousands of acres of habitat have been restored,” said Henderson. “We have dozens of projects in the queue. We’ve learned how to work together, build relationships and continue helping the Mississippi River, whether it be studying it or enhancing it.”
The relationships are some of the most important aspects of the program according to Henderson.
“Most of us, contractors and agencies, we don’t just work on the river, we enjoy the river and enjoy the outdoors. We get to have a hand in building and improving these things that we enjoy daily. We all enjoy working together in the field. We work together and solve problems, but we enjoy the same things on the outside world,” said Henderson.