Sluice

A sluice (/slus/ SLOOS) is a water channel containing a sluice gate, a type of lock to manage the water flow and water level.^{[citation needed]} There are various types of sluice gates, including flap sluice gates and fan gates.

Sluices are used for channeling water toward a water mill, including for transporting logs from steep hillsides. Different terms are used regionally for sluices; the terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry.^{[citation needed]}

The term "sluice" originates from the Middle English word scluse, which derived from the Old French escluse (modern French: écluse). This, in turn, came from the Late Latin exclusa, a shortening of aqua exclusa, meaning "excluded water" or "a shut-off water channel". The Latin exclusa is the feminine past participle of excludere ("to shut out, exclude"), from ex- ("out") and claudere ("to close").

A sluice is a water channel containing a sluice gate, a movable gate allowing water to flow under it. Sluices are a type of lock to manage the water flow and water level. When a sluice is lowered, water may spill over the top, in which case the gate operates as a weir. Usually, a mechanism drives the sluice up or down. This may be a simple, hand-operated, chain pulled/lowered, worm drive or rack-and-pinion drive, or it may be electrically or hydraulically powered. A flap sluice, however, operates automatically, without external intervention or inputs.

Sluice gates are one of the most common hydraulic structures used to control or measure the flow in open channels. Vertical rising sluice gates are the most common in open channels and can operate under two flow regimes: free flow and submerged flow. The most important depths in the designing of sluice gates are: