barrage
A dam consisting of a series of movable gates used to regulate water flow in a channel.
A barrage is a type of dam which consists mainly of a framework with a series of gates which can be opened and closed to regulate the flow of water in a river or other channel. Like a weir, its purpose is not to create a reservoir behind it; therefore its impact on the landscape is less than that of a regular dam. Unlike a weir, water is allowed to flow through the gates in a barrage (rather than over the top).
The movable gates control passages through the barrier. The flow route distinguishes the barrage from a weir, where water passes over the top.
The stated purpose is regulation of channel flow rather than creation of a reservoir. The gates and their supporting framework provide that control.