DVIDS – News – New island construction technology, the first of its kind on the upper Mississippi River

The Lake McGregor Habitat Rehabilitation and Enhancement Project offers several different features, including shoreline stabilization, island reinforcement and island construction as well as habitat dredging.

Apply a thin layer

Something is being done at the Lake McGregor project, near Prairie du Chien, Wisconsin, and Marquette, Iowa, that has never been done before on the upper Mississippi River.

Thin layer placement is a technique that has historically only been used in coastal waterways. The placement at Lake McGregor represents the first of its kind for the St. Paul area and the Upper Mississippi River Restoration, or UMRR, program for use on an inland waterway. Thin Layer Places sand material in thin, uniform layers over eroded islands.

“It’s a newer concept that we’re trying to incorporate into the UMRR to target a much larger area on a less intrusive scale to help elevate some of these island areas into more suitable habitat for tree species to grow in a less impactful way than they did before.” “The island construction is in the past,” said John Henderson, project manager.

He explained that applying a thin layer raises the level of the forest to the point where it is more suitable and brings the islands out of a period of inundation where trees are susceptible to damage.

“This is another tool in the toolbox,” Henderson said. “We can use these areas that are more sensitive to erosion and overcome some of the limitations that we have in these projects.”

“We are at an unprecedented stage of habitat restoration in the upper Mississippi River,” Henderson said.

The beneficial use of river sand is a win-win

One of the highlights of the MacGregor restoration project is that the sand base material comes straight out of the canal, Henderson said. Sand is removed from the main channel of the Upper Mississippi River. Normally, the materials must be transported to the placement site.

“Here at McGregor, we have beneficially used nearly 500,000 cubic yards of clean river sand, which represents about half of our area’s annual dredging capacity,” Henderson said. “This is a testament to how two of the Corps’ missions are usefully brought together — maintaining the 9-foot navigation channel and restoring habitat.”

Henderson added that the project will use 200,000 cubic yards of backwater dredging material, which will help enhance the backwater fishery and improve ice fishing and other recreational opportunities.

Upper Mississippi River Restoration Program

UMRR is a federally funded, multi-agency partnership with both state and federal partners among several Upper Mississippi River agencies extending 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, implement better practices overall, and rehabilitate some of the islands that have experienced 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,” Henderson said. “We have dozens of projects in the pipeline. We’ve learned how to work together, build relationships, and continue to help the Mississippi River, whether it’s by studying it or enhancing it.

Relationships are one of the most important aspects of the program, according to Henderson.

“Most of us, contractors and agencies, don’t just work on the river, we enjoy the river and we enjoy the outdoors. We get to have a hand in building and improving these things that we enjoy every day. We all enjoy working together in this field,” Henderson said. We solve problems, but we enjoy the same things in the outside world.”

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