Question 1853Navigation General

The correct answer is A) wingdam. A wingdam is a rock and sand structure that extends from the bank of a river or waterway towards the channel. Wingdams are constructed to help control the flow of water and prevent erosion of the riverbank. They are a common feature in many navigable waterways in the United States, including those under the jurisdiction of the US Coast Guard. The other answer choices are incorrect because: B) Landwall refers to a retaining wall built along the shoreline, not a structure extending into the water. C) Cutoff refers to a new channel formed when a river cuts across a meander, not a structure built on the bank. D) Towhead refers to a small, low-lying island in a river, not a structure built on the bank.