A gatehouse, gate house, outlet works or valve house for a

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

is a structure housing

sluice gate Sluice ( ) is a word for a channel controlled at its head by a movable gate which is called a sluice gate. A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway and can be considered ...

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ...

s, or

pump A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...

s (in which case it is more accurately called a

pumping station Pumping stations, also called pumphouses in situations such as well drilling, drilled wells and drinking water, are facilities containing pumps and equipment for pumping fluids from one place to another. They are used for a variety of infrastru ...

). Many gatehouses are strictly utilitarian, but especially in the nineteenth century, some were very elaborate.

Background

A set of outlet works is a device used to release and regulate water flow from a

. Such devices usually consist of one or more pipes or tunnels through the embankment of the dam, directing water usually under high pressure to the river downstream. These structures are usually used when river flow exceeds the capacity of the

power plant A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid. Many pow ...

or diversion capacity of the dam, but do not have flows high enough to warrant the use of the dam

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...

s. They may also be utilized when river flows must be bypassed due to maintenance work in the power station or diversion gates. Although similar in purpose to spillways, outlet works provide a more controlled release to meet downstream flow requirements. A typical set of outlet works begins in an intake structure, which is usually a

canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow un ...

intake tower An intake tower or outlet tower is a vertical tubular structure with one or more openings used for capturing water from reservoirs and conveying it further to a hydroelectric or water-treatment plant. Unlike spillways, intake towers are intended ...

. A regulating gate or

controls water flow into the pipes of the outlet works, which discharge downstream into a stilling basin or directly into the river. The inlets of the outlet works may consist of either gates or valves, or be composed of a more primitive system of

stoplogs Stoplogs are hydraulic engineering control elements that are used in floodgates to adjust the water level or discharge in a river, canal, or reservoir. Stoplogs are sometimes confused with ''flashboards'', as both elements are used in bulkhead ...

. Inlets may also contain a series of other devices for different purposes, including

trash rack A trash rack (US) or debris screen is a wooden or metal structure, frequently supported by masonry, that prevents water-borne debris (such as logs, boats, animals, masses of cut waterweed, etc.) from entering the intake of a water mill, pumping sta ...

s and

fish screen A fish screen is designed to prevent fish from swimming or being drawn into an aqueduct, cooling water intake, intake tower, dam or other diversion on a river, lake or waterway where water is taken for human use. They are intended to supply debr ...

References

Dams Hydraulic engineering {{architecture-stub

Background

See also

References