An intake tower or outlet tower is a vertical tubular structure with one or more openings used for capturing water from

reservoir A reservoir (; ) is an enlarged lake behind a dam, usually built to water storage, store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of wa ...

s and conveying it further to a

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 ...

or water-treatment plant. Unlike spillways, intake towers are intended for the reservoir's regular operation, conveying clean, debris-free water for further use.

Construction

An intake tower is typically made from

reinforced concrete Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ...

, with foundations laid in the river or lake bed. It has at least one water-collecting opening at the top, and may have additional openings along its height, depending on the purpose: towers for hydroelectric plants typically have only one inlet, while those in water-processing plants have multiple draw-off inlets. Near the bottom of the tower, depending on the dam construction and plant location, a horizontal or slanted outlet conduit takes the water from the tower into the plant. The most convenient location for an intake tower is in the proximity of the processing plant. In artificial lakes, those are typically placed near the dam. Lake bed near the dam also provides sufficient water depth to ensure substantial supply to the towers throughout the year, thus the exposed towers can be regularly seen along the dams. When built near the shore, an intake tower is equipped with a service bridge, used to gain access for maintenance.

Draw-off tower

Draw-off towers are intake towers specialized for drinking water reservoirs. They have multiple openings at various depths, typically equipped with valves, allowing drawing water only from the level where it is of highest quality. There are many possible designs of intakes and gates on dams These include 1. Floating rafts with pumps. 2. Intakes off concrete dam walls. 3. Self standing towers, especially on embankment dams. 4. Tunnels and bores through embankment or mountain. 5. Intake towers in deep dams which are often circular to minimize stresses. 6. Square towers where pressures are low. 7. Dry towers if there must be valves and pumps accessible. 8. Wet towers where there is no equipment to access. 9. No tower, just inlets on the dam wall or embankment leading to a collecting pipeline. The use of multiple valves in the intake tower with pipework, is space consuming and expensive. A minimum that is needed to minimize costs is a stoplog or plug in case access is needed. Flow control can be achieved with a valve on the downstream side of the dam wall. When that is closed the pressures on both sides of the stoplog or plug will equalize to enable the stopper to open.

Construction

Draw-off tower

References

See also