, California, seen from above Penstocks for
hydroelectric 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 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 coatings, allowing waters to go
anoxic, and
desiccation 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. Penstocks are also used in mine
tailings dam 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==