EAST ST. LOUIS, Ill. (AP) — Environmental groups sued the U.S. Army Corps of Engineers on Thursday over the agency’s use of man-made structures meant to keep the Mississippi River navigable, claiming the techniques provoke flooding as seen during historic inundations four times in the last two decades.

The federal lawsuit asks the Army Corps to resist building more “river training structures” such as wing dikes, arch-shaped dikes known as chevrons, and rock dikes called bendway weirs until it comprehensively evaluates their environmental impacts along the vital commerce corridor.