River Restoration Projects


Pool 9 and Pool 10 habitat restoration

By Ted Pennekamp


The following are some brief updates regarding various habitat restoration projects in the Prairie du Chien area in Pool 9 and Pool 10.


Pool 9

Capoli Slough Project

“Construction of the Capoli Slough Project will be completed this summer and the project turned over to the U.S. Fish and Wildlife Service, McGregor District,” said Elliott L. Stefanik, Fishery Biologist/Regional Technical Specialist, St. Paul District, U.S. Army Corps of Engineers.

Part of the U.S. Army Corps of Engineers’ Upper Mississippi River Restoration - Environmental Management Program, the site is a side channel/island complex located on the Wisconsin side of the Mississippi River navigation channel in Pool 9, about five miles downstream of Lansing, Iowa. Many of the natural islands bordering the navigation channel and extending into the backwater have eroded, and many are disappearing. Erosion from wave action and main channel flows is reducing the size of the wetland complex, resulting in the loss of aquatic vegetation and the shallow protected habitats important for the survival of many species of fish and wildlife.

The proposed project would restore and stabilize islands to protect the area from large wind fetches. Breached areas would be stabilized using rock sills, and partial-closing structures would be constructed to reduce the effect of main channel flows. Material to restore the island complex would be dredged from the immediate vicinity to provide additional deepwater fish habitat benefits. The project would provide both fish and wildlife benefits by creating a “shadow” effect behind and downstream of the islands. About 700 acres of backwater habitat would be directly affected.

The Stage 2 plans and specifications were completed in June 2012 and a construction contract award was made in February 2013. This final stage includes the construction of five islands and completes all the work in Capoli Slough. This stage will be completed in July 2014.

The Stage 1 construction contract was awarded in September 2011. Construction of seven islands was initiated in March 2012 and was substantially complete in November 2012. This stage was completed in the fall of 2013.

The project is being constructed as part of a cooperative effort of the Corps of Engineers, the Wisconsin and Iowa Departments of Natural Resources, the U.S. Fish and Wildlife Service, and local interests.

Project design and construction costs are 100 percent federal, and the cost will be $ 9.4 million.


Harpers Slough Project 

“The Harper’s Slough Project design is undergoing review,” Stefanik said. “Citizens can anticipate a public review this spring, and the first construction contract awarded in August. Contractors likely won’t start actual construction until 2015.”

The Harpers Slough area is a 4,150-acre backwater area located primarily on the Iowa side of the Mississippi River in Pool 9, about three miles upstream of Lock and Dam 9. The site is in the Upper Mississippi River National Wildlife and Fish Refuge. The area is used heavily by tundra swans, Canada geese, puddle and diving ducks, black terns, nesting eagles, bitterns and cormorants and is also significant as a fish nursery area. Many of the islands in the area have been eroded or lost because of wave action and ice movement. The loss of islands allows more turbulence in the backwater area, resulting in less productive habitat for fish and wildlife.

The proposed project would protect five existing islands and construct an additional seven islands using material from the backwater and main channel. The project would slow the loss of existing islands, reduce the flow of sediment-laden water into the backwaters, reduce turbidity and increase the diversity of land and shoreline habitat.

The project is in the planning stage. Construction of the project would be in stages because of the estimated cost of the total project in relation to the anticipated program funding levels.

Project design and construction costs would be 100 percent federal. The project is projected to cost $22 million.


Conway Project

“We hope to start the detailed planning study this spring,” said Stefanik. “The study team, including the resource agencies, met recently to discuss the project and decided to modify the study area to include Zoll Lake. The project will focus on  overwintering fish habitat. Construction is a few years away.”

Conway Lake is a 130-acre isolated backwater lake in Mississippi River Pool 9, located about three miles upstream of Lansing, Iowa. Phillipi Lake is a 330-acre backwater lake located southeast of Conway Lake, and Shore Slough is a 100-acre slough lying just downstream of Conway Lake.

Conway Lake is relatively shallow with abundant aquatic vegetation. Dissolved oxygen depletion is a problem in the lake in summer and in winter. During the winter, excessive water enters Phillipi Lake through openings that are eroding larger, creating unsuitable habitat conditions for overwintering backwater fish. Shore Slough has less than optimal fish habitat conditions as a result of sedimentation and the high flows from Phillipi Lake. Introduction of flow from a small creek is being considered to improve dissolved oxygen levels in Conway Lake.

Flow restriction from Middle Slough would improve winter habitat conditions in both Phillipi Lake and Shore Slough. Dredging is being considered for all three water bodies to enhance habitat.

Planning efforts will resume in fiscal year 2014. A draft feasibility study will be completed in fiscal year 2014.

Planning and general design for the project initially began in 2001 but limited funding has delayed project planning.

Project design and construction costs would be all federal. The project is expected to cost $2.5 million. 


Pool 10

McGregor Lake Project

“This will be a similar path to Conway. There will be an initial public meeting in a couple weeks,” said Stefanik. “We hope to start the detailed planning study this spring. The project will focus on overwintering fish habitat. Construction is a few years away.”

A public meeting about the project has been scheduled for Feb. 20 from 5 to 8 p.m. in the Prairie du Chien City Hall.

McGregor Lake is a 200-acre backwater lake in pool 10 of the Mississippi River near Prairie du Chien. It is bordered on the west by islands separating it from the main channel and on the east by a peninsula separating it from the east channel. The lake is relatively shallow, with an average depth of 2½ feet. In 1989, about 75 percent of the lake had aquatic vegetation. Since then, aquatic vegetation and depth have decreased because of increased sedimentation and turbidity resulting from erosion of the barrier islands.

The proposed project would include dredging the lake, restoring or strengthening the barrier islands and constructing small islands within the lake to reduce wave action. It would provide diversity and productive habitat for fish and protect the lake from main channel flows. It would allow fish movement into and out of the lake during the winter. Increased aquatic vegetation would provide cover and food for young fish.

Planning of the project is scheduled to start in fiscal year 2014. A draft feasibility study will be completed in 2014.

Project design and construction costs will be completely federal and is expected to cost $6.5 million.

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