The Army Corps consistently has stood behind the projects, their engineering and environmental record, rebuffing requests by the wildlife federation to abandon the questioned river-management approaches that use the river’s current to clear sentiment out of navigation channels, lessening the need for more costly dredging.

The groups argue that dozens of published scientific studies since 1986 link the construction of river training structures to increased flood heights. More than 15 studies from 2000 to 2010 suggest such Army Corps projects “significantly” elevated the mid-Mississippi’s water levels, by 10 to 15 feet in some cases, posing a threat to riverside communities, the plaintiffs claim.

The wildlife federation says the more than 40,000 feet of wing dikes and bendway weirs built in the three years prior to the catastrophic flood of 1993 contributed to record crests in 1993, 1995, 2008 and 2011. Many more such structures have been added since, including at least 23 chevrons between 2003 and 2010, with more such projects in the works.

The Army Corps already has built more than 1,375 wing dikes, bendway weirs, chevrons and similar structures in a 143-mile stretch of the middle Mississippi River.