Restoring historic flood patterns could make Missouri wildlife refuge better for birds | St. Louis Public Radio

Restoring historic flood patterns could make Missouri wildlife refuge better for birds

Aug 30, 2018

About 70 miles north of St. Louis, a serene, 3,750-acre area covered in prairie grasses, forests and wetlands serves as a crucial habitat for migratory birds.

The Clarence Cannon National Wildlife Refuge in Annada sits next to the Mississippi River, surrounded by farmland. Last year, the U.S. Army Corps of Engineers and the U.S. Fish and Wildlife Service began a $29-million project to improve wildlife habitats in the refuge.

The agencies aim to bring back historic flood cycles that support native plants. They provide food and habitat for birds and other wildlife.

Flood patterns have changed in the area around the refuge, largely due to agricultural levees built throughout the 20th century. Over many decades, wildlife habitats along the Upper Mississippi River have degraded. Clarence Cannon, for example, has areas where there are monocultures — or a low variety of plants. Invasive species, such as spikerush, have also set up shop there, said Jason Wilson, manager of the Clarence Cannon National Wildlife Refuge.

“Before the levee system, the river was wild,” Wilson said. “It would meander, it would deposit sediments, and these habitats would naturally occur up and down the river. Nowadays, they don't. So why we have to manage so intensely is to fill that void that’s gone.”

Jason Wilson manages the Clarence Cannon National Wildlife Refuge in Annada, Missouri.
Credit Randall Hyman

The project, a part of the Corps of Engineers' Upper Mississippi River Restoration Program, involves installing a new pump station, restoring native plants and building a setback levee. Officials will degrade a portion of the levee between the Mississippi River and Clarence Cannon to allow water to enter the refuge. The corps also plans to let some of the interior berms — or raised areas of land — degrade and build water-control structures to improve water flow.

“Especially after a major flood, the various vegetation, the trees and other plants we like to have tend to get drowned out, and they go away, and we get invasives that we don’t like to have out there,” said Jason Brown, program manager of restoration program.

The U.S. Army Corps of Engineers and the U.S. Fish and Wildlife Service in 2017 began a $29-million project to improve wildlife habitats in the Clarence Cannon National Wildlife Refuge.
Credit Mapbox, OpenStreetMap

Connecting the river with the floodplain would allow more natural flooding to occur. It will also let fish and other aquatic wildlife enter the refuge. Clarence Cannon will be the only national wildlife refuge along the Upper Mississippi to have a setback levee.

The refuge sees many bird species that use the Mississippi River Flyway, such as bald eagles, great blue herons, sandpipers and mallard ducks.

“The birds come down here in the fall,” Wilson said. “They need us to refuel, and they go down south in the spring, and they come back in the spring, and they refuel again to go back up and reproduce.”

Wetlands at Clarence Cannon National Wildlife Refuge are being restored by pumping in Mississippi River water from beyond the levee to regulate wetland levels year round.
Credit Randall Hyman

The project could finish in five years; it could take longer, depending on any major flooding that occurs, Wilson said. In the nine years he has served as a refuge manager, there has been a major flood nearly every other year.

In recent years, the refuge has focused on using “moist soil” management, or drawing down water on mudflats to promote native plants that provide food for waterfowl. The restoration technique helped increase the number of ducks that come to the refuge. Wilson expects that the project with the Corps will similarly raise numbers for other birds species.

“We're a link in the chain,” Wilson said. “If we don't do our job, then other [refuges] that are doing their job, it won’t matter. We all have to work together on this.”

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