Coping with the titanic force of America’s largest river is one of the U.S. Army Corps of Engineers’ perpetual responsibilities. Starting in 1866, Congress authorized the Corps to improve its navigability by dredging, removing snags and clearing trees from the river’s banks. “The river flows over sand and clay, not bedrock, and is always cutting a new channel,” explains Col. Brian D. Sawser, commander of the Corps’ Memphis District. “Since 1921 for navigation reasons and commerce we are trying to keep the channel in its spot.” The Corps is mandated to maintain the channel at 9 ft deep and 300 ft wide.

One of the longstanding items in the Corps’ toolkit are wing dams, dikes typically extending hundreds of feet out into the river, perpendicular to the shore. Most often built with piles and stone, they force the water towards the center of the river, speeding its flow, causing it to clear sediment and scour away sandbars. “The roughly 1,000 dikes built by the Corps over decades have vastly reduced the amount of dredging needed,” says Sawser. Early ENR articles described them as “contraction works.”