A dam.
Weir
A dam is a structure built across a river to control the flow of water. It helps regulate water levels, generate hydroelectric power, and provide water for irrigation and drinking. Dams can also prevent floods and create reservoirs for recreational activities.
a dam
A dam is a structure built across the water to hold water back.
A structure built in the Nile river to measure water levels.
A weir is a man-made structure that is built across a river or stream to regulate water flow, prevent flooding, or divert water for irrigation or other purposes. It is not naturally occurring.
A dam or a water wheel to produce electricity from the water flow. Hooweestik.
A dam is built across a river to restrict the flow of water.
A weir is a low dam built across a river - either to raise the level upstream, or to regulate the water flow.
An overwater structure.
A dam is a barrier built across a waterway to stop or control the flow of water. Man-made reservoirs are formed behind the dams. A dyke is a long wall of earth built along a waterway or along a sea coast to prevent the river water overflowing their channels. *A levee is the same thing as a dyke the difference being that the former word comes from French and the latter from Dutch.
Tigris river and the Euphrates river