A plate of wood or metal slides in grooves in the sides of the water channel. When fully raised, the water is unobstructed, when fully lowered water is prevented from flowing or spills over the sluice to flow at a reduced rate.
Usually a mechanism drives the sluice gate up or down. This may be a simple, hand-operated, worm drive or rack and pinion drive, or it may be electrically or hydraulically powered.
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