Wingdam

A wing dam is a manmade barrier that, unlike a conventional dam, only extends partway into a river. These structures force water into a fast-moving center channel which reduces the rate of sediment accumulation, while slowing water flow near the riverbanks.The Mississippi River in North America has thousands of wing dams which were originally constructed to reduce the amount of dredging required when the main navigation channel was maintained to at least 4½ feet (1.37 m). Since that time, additional conventional dams have been built to increase the water level in the river, doubling the depth of the navigation channel to 9 feet (2.75 m). The wing dams still serve their purpose, but to a lesser extent than before.
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A rock and sand dike extending from the right or left bank of the river outward toward the channel. Often lies just below the surface of the water at pool stage. Wingdams are used to direct the flow of water into the main channel to assist in its maintenance. (TNDOT1)