A penstock is a

sluice A sluice ( ) is a water channel containing a sluice gate, a type of lock to manage the water flow and water level. There are various types of sluice gates, including flap sluice gates and fan gates. Different depths are calculated when design s ...

gate A gate or gateway is a point of entry to or from a space enclosed by walls. The word is derived from Proto-Germanic language, Proto-Germanic ''*gatan'', meaning an opening or passageway. Synonyms include yett (which comes from the same root w ...

or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and

sewerage Sewerage (or sewage system) is the infrastructure that conveys sewage or surface runoff ( stormwater, meltwater, rainwater) using sewers. It encompasses components such as receiving drains, manholes, pumping stations, storm overflows, and scr ...

systems. The term is of Scots origin, and was inherited from the earlier technology of

mill pond A mill pond (or millpond) is a body of water used as a reservoir for a water-powered mill. Description Mill ponds were often created through the construction of a mill dam or weir (and mill stream) across a waterway. In many places, the co ...

s and

watermill A watermill or water mill is a mill that uses hydropower. It is a structure that uses a water wheel or water turbine to drive a mechanical process such as mill (grinding), milling (grinding), rolling, or hammering. Such processes are needed in ...

s, with penstocks diverting pond waters to drive the mills.

Hydroelectric systems and dams

Penstocks for

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

installations are normally equipped with a gate system and a surge tank. They can be a combination of many components such as anchor block, drain valve, air bleed valve, and support piers depending on the application. Flow is regulated to suit

turbine A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced can be used for generating electrical ...

operation and is cut off when turbines are not in service. Penstocks, particularly where used in polluted water systems, need to be maintained by hot water washing, manual cleaning,

antifouling Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...

coatings, allowing waters to go

anoxic Anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of dissolved ox ...

, and

desiccation Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. The ...

used to dry fouling out so that it may slough off or become easier to remove through manual processes. The term is also used in irrigation dams to refer to the channels leading to and from high-pressure

sluice gates A sluice ( ) is a water channel containing a sluice gate, a type of lock to manage the water flow and water level. There are various types of sluice gates, including flap sluice gates and fan gates. Different depths are calculated when design s ...

. Penstocks are also used in mine

tailings dam A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Tailings can be liquid, solid, or a slurry of fine particles, and are usually highly toxic and poten ...

construction. The penstock is usually situated fairly close to the center of the tailings dam and built up using penstock rings, short reinforced ring-like sections of pipe which nest one within the other when stacked and thereby control the water level, letting the slimes settle out of the water. This water is then piped under the tailings dam back to the plant via a penstock pipeline.

Watermills

Inlet valves on the downstream end of penstocks are often used at mill sites to control the flow of water through the mill wheel, or to pen water into a mill pool.

Similar structures

Similar structures which are not enclosed are ''head races'' or

leat A leat (; also lete or leet, or millstream) is the name, common in the south and west of England and in Wales, for an artificial watercourse or aqueduct dug into the ground, especially one supplying water to a watermill or its mill pond. Othe ...

s (non elevated), and

flume A flume is a human-made channel for water, in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch. Flumes are not to be confused with aqueducts, which are built to t ...

s (elevated).

Hydraulics

Penstocks are commonly used in water management systems such as surface water drainage and foul water sewers. Penstocks provide a means of isolation of flows and regulate the flow of water while delivering it to waste management facilities or power plants.

Landfills

Penstocks are incorporated into the surface water management systems (drainage) of many landfill sites.

Retention basin A retention basin, sometimes called a retention pond, wet detention basin, or storm water management pond (SWMP), is an artificial pond with vegetation around the perimeter and a permanent pool of water in its design. It is used to manage ...

s are constructed in order to store storm water, limiting the discharge from the site to its pre-development rate. Valved penstocks are installed at the outfall of the basin to isolate potentially contaminated surface waters from discharging into a main watercourse.

References

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External links

Penstock cross-sections for the Grand Coulee Dam
Aqueducts Hydroelectric power stations Water management in mining