Army Corps keeps creating islands in Mississippi River
La Crosse Tribune, Wis. (MCT)
LANSING, Iowa — The shorebirds already have discovered Capoli Slough’s Island F.
It and Island L form a rough horseshoe of land in the Mississippi River that curls to create some shallows, attracting a hoard of busy sandpipers, carefully picking their way through the mud.
This infant island, only a year old, already boasts a healthy stand of willow, and the surrounding waters are thick with arrowhead and tall, blooming yellow lotus.
“A lot more benefit for a lot more species,” said Jeff Janvrin, Mississippi River habitat specialist for the Wisconsin Department of Natural Resources.
The Capoli Slough project just south of Lansing, Iowa, is the latest in the U.S. Army Corps of Engineers’ efforts to re-create some of the patchwork of islands that once harbored birds, fish and other species in the Upper Mississippi River National Wildlife and Fish Refuge.
Past projects have included building islands in Polander Lake and the Weaver Bottoms area near Winona, Minn.; Spring Lake near Buffalo City, Wis.; and the extensive cluster done between Brownsville, Minn., and Stoddard, Wis.
Construction on the $8 million Capoli project began in March 2012. When completed in 2014, the 2,000-acre slough will boast 11 new islands and see several of its few remaining island remnants reinforced, project manager Tom Novak explained.
Like other parts of the river, this section across from Ferryville, Wis., once had a natural network of islands that fell victim to erosion after installation of the lock and dam system. When project planning began, Capoli’s islands had been whittled down to only 11 acres.
Stage 2 of the project began this year with Island G, being built by McHugh Excavating and J.F. Brennan Marine, both based in the La Crosse area.
Shaped like a backward numeral 7, Island G is long and narrow, with a base of sandy dredge materials topped with some soil for later plantings and seeding. Rock chunks and stone extensions that look like oars reaching into the water will help stabilize some of the shoreline, but much of it has been left sandy to make it easier for turtles and other wildlife to haul out.
The configuration “gives the critters that are going to use the island a different place to refuge,” Novak explained. He expects deer and a host of predators will venture out to some of the new terrain.
The Corps has learned from each island project, experimenting with heights, shapes and configurations to see what might prove more effective, said Scott Baker, resident engineer based in Winona. The hope is the new islands will last at least a half-century.
The overall results of the habitat restoration efforts, though, have been a definite success, Janvrin said. The stretch between Stoddard and Brownsville has become a prime annual gathering site for massive numbers of tundra swans, ducks, geese, pelicans and other migrating birds.
The vegetation that has thrived along the new islands, especially the fields of aquatic arrowhead plants, provide many of them with a bounty of tasty tubers for fueling that flight, Janvrin said.
Fishing near Stoddard, too, has gone from just a summer season to year-round as fish make use of the shelter offered by the vegetation, he said.
The Harpers Ferry, Iowa, area will be the next target for islands, the group said. Federal funding, for now, has remained stable, Baker said.