Sluice

Description

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.

Basic design

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:

• ${\displaystyle Y_U}$: upstream depth
• ${\displaystyle Y_G}$: opening of the sluice gate
• ${\displaystyle Y_m}$: the minimum depth of flow after the sluice gate
• ${\displaystyle Y_{J1}}$: the initial depth of the hydraulic jump
• ${\displaystyle Y_{J2}}$: the secondary depth of the hydraulic jump
• ${\displaystyle Y_D}$: downstream depth

Types

Fan gate

(Dutch: waaiersluis) This type of gate was invented by the Dutch hydraulic engineer Jan Blanken in 1808. He was Inspector-General for Waterstaat (Water resource management) of the Kingdom of Holland at the time. The fan door has the special property that it can open in the direction of high water solely using water pressure. This gate type was primarily used to purposely inundate certain regions, for instance in the case of the Hollandic Water Line. Nowadays this type of gate can still be found in a few places, for example in Gouda. A fan gate has a separate chamber that can be filled with water and is separated on the high-water-level side of the sluice by a large door. When a tube connecting the separate chamber with the high-water-level side of the sluice is opened, the water level, and with that the water pressure in this chamber, will rise to the same level as that on the high-water-level side. As there is no height difference across the larger gate, it exerts no force. However the smaller gate has a higher level on the upstream side, which exerts a force to close the gate. When the tube to the low water side is opened the water level in the chamber will fall. Due to the difference in the surface areas of the doors there will be a net force opening the gate.

Flap sluice gate

A fully automatic type, controlled by the pressure head across it; operation is similar to that of a check valve. It is a gate hinged at the top. When pressure is from one side, the gate is kept closed; a pressure from the other side opens the sluice when a threshold pressure is surpassed.

Logging sluices

In the mountains of the United States, sluices transported logs from steep hillsides to downslope sawmill ponds or yarding areas. Nineteenth-century logging was traditionally a winter activity for men who spent summers working on farms. Where there were freezing nights, water might be applied to logging sluices every night so a fresh coating of slippery ice would reduce friction of logs placed in the sluice the following morning.

Mill race

A mill race, leet, flume, penstock or lade is a sluice channeling water toward a water mill.

Needle sluice

A sluice formed by a number of thin needles held against a solid frame through water pressure as in a needle dam.

Radial sluice gate

A structure, where a small part of a cylindrical surface serves as the gate, supported by radial constructions going through the cylinder's radius. On occasion, a counterweight is provided.

Rising sector sluice gate

Also a part of a cylindrical surface, which rests at the bottom of the channel and rises by rotating around its centre.

Vertical rising sluice gate

A plate sliding in the vertical direction, which may be controlled by machinery.