By Craig Moorhead
Special for the Argus
Corps of Engineers Project Manager Tom Novak looked out at the room full of Mississippi River enthusiasts in Brownsville. “We’re not trying to build all the islands or all the land mass back,” he explained. “We’re trying to get the channels defined and get the vegetation protected. There’s a method to our madness.”
Novak was joined by representatives from the US Fish and Wildlife Service, along with Wisconsin and Minnesota DNR personnel and other specialists at the public meeting held April 14 at the Brownsville Community Center.
“The objective of this meeting,” Novak said, “is to not only fill you in on what was done last year and what we plan for this year and following years, but to get your feedback and address your questions and concerns.”
The Pool 8 Islands Habitat Project is a huge undertaking. Began in 1988, the project has picked up steam in recent years with the construction of islands in the Brownsville/Stoddard area. Construction will continue for several more years, with the last phase scheduled for completion in September of 2012.
According to Corps documents, since lock and dam number eight was built in 1937, most of the natural islands in this area of pool 8 have disappeared due to erosion.
(Quoting from “Project Summary, Phase III, Stage 2”)
“Island loss allows more wind and wave action in the backwaters, keeping sediment suspended (turbidity). The suspended sediment in turn makes it difficult for sunlight to penetrate the water and reach aquatic plants. All this results in the loss of valuable aquatic plant beds that migrating waterfowl and fish use for food and cover.”
Wisconsin DNR Biologist Jeff JanVrin, responding to questions about fish habitat, said, “Getting that channel defined, throughout the raft channel (phase three), is going to help diversify the fishery.” JanVrin said that phase two of the project, now nearly complete, especially focused on fish habitat, including spawning and over-wintering sites.
Jeff Dezellar, also a Corps project manager, explained some specifics after the meeting. Seventeen islands are being built. Another seven “seed islands,” structures which will capture sediment and cause the formation of islands, will also be built. Dezellar estimates that it will take close to $10 million to finish the last two parts of the plan, called Stage 2b and Stage 3. The project, he said, is 100 percent federally funded.
It takes a lot of material to build an island. Novak said that last year the contractor was told to pump sand from Crater Island, a sand collection site for channel dredging. “We had three booster pumps,” Novak said. The pumps moved sand past Brownsville in a huge pipeline which stretched for miles down the river. “How many heard those booster pumps at night?” Novak asked, (almost all hands are raised). “How many called the mayor?” (laughter).
Pumping around the clock from June until September, 415,000 cubic yards of sand were moved last year. Novak said that the amount of sand moved would cover a football field to a height of 240 feet. Last year’s islands were then topped with about 22,000 cubic yards of soil, or “fines.”
The hole or pool left behind above Brownsville is 15 to 17 feet deep, and is open for public recreation, although eventually more channel dredging spoils will be deposited there.
Rock berms are used to keep the restored islands from washing away, but in some areas, erosion is being used as part of the building process.
“We’re trying a lot of things that have never been tried before,” said Corps Hydraulic Engineer Jon Hendrickson. “We’re basically learning from every one of these projects,” he explained.
For example, some islands are being built with “sand tips,” designed to erode away, leaving long, gently sloping shoreline habitat.
“It would be difficult and expensive to have a contractor try and do that,” Hendrickson said.
Jim Nissen, La Crosse District manager with the U.S. Fish and Wildlife Service, agreed. “Some of these are experimental features,” he said.
Nissen said that plantings are being done on the new islands to stabilize the soil, and provide habitat and bio-control. “We’re about three years into bio-control, and up in pool seven it’s paying dividends,” Nissen said. “You’re going to see purple loosestrife, but we’re hoping that with the bio-control plan to be able to get ahead of it. Purple loosestrife is a tough one.”
The area lies within the Upper Mississippi River National Wildlife and Fish Refuge. The refuge requires quality resting areas for waterfowl, and good habitat for aquatic species, including game fish, but that is only part of the reason for the project.
Biologists from Wisconsin DNR, Minnesota DNR, and the U.S. Fish and Wildlife Service all cited the same rationale for the project. By restoring the river to a more natural state, they said, with a more diverse range of habitats, many species of plants and animals will benefit.
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