Water Intake Works

Water Intake Works

 

a hydraulic-engineering installation for obtaining water from a source of supply (river, lake, reservoir, and so on) for purposes of hydroelectric power engineering, water supply, or irrigation. Water intake works are intended to ensure the delivery of water into a conduit (a canal, pipeline, tunnel, and so on) in specified amounts, of the proper quality, and according to a water-consumption chart.

Intake works for hydroelectric power plants (often called water receptacles) are built mostly on rivers and are part of hydraulic power systems. They are classified in two basic types, low-pressure and bottom. Low-pressure water intake works are built on mountain rivers and draw water from ponds backed up by relatively low dams (6-10 m). In case of large fluctuations of the water level in the reservoir, bottom intake works are used. Depending on the natural conditions of the area and the overall configuration of the hydraulic power system, the intakes can be of the dam, shore, or tower type. A tower intake is a free-standing tower that is situated in the headrace; it usually has several intake openings at different heights and is connected to the shore or the crest of the dam.

Intake works for water-supply systems (water receptacles) are classified according to the type of source (river, reservoir, lake, marine, and so on). The most widespread river water intake works are of the shore, channel, floating, and scoop types. They may also be combined with first-stage pumping stations or installed separately from them. A shore water intake, which is used on relatively steep river banks, consists of a large-diameter concrete or reinforced-concrete pit, with the forward wall projecting into the river. Water enters it through apertures protected by gratings and then passes through screens that effect a preliminary mechanical cleaning of the water. Channel water intake works are usu-ally used where the river banks are low; they have intakes that extend into the channel of the river. Such intakes vary widely in design. Water is delivered from the intake by gravity-flow pipes to a shore sump, which is often combined with a first-stage pumping station. Floating water intake works are pontoons or barges on which pumps for drawing water directly from the river are installed. The water is delivered to shore by a pipeline with flexible joints that is laid on a connecting trestle. In scoop intake systems the water is first brought from the river to a pond (artificial basin), at the end of which the intake system itself is situated. The pond serves to precipitate sediments and combat floating and bottom ice.

Irrigation water intake works may or may not involve a dam. Intake works without dams consist of an artificial channel (canal) that branches off from the river at a certain angle and diverts part of the stream flow. In order to prevent the deposition of bottom sediment in the irrigation canal, the intake is situated on a concave river bank so that surface currents, which carry less sediment, are diverted into the intake works, whereas the bottom currents are deflected by pumps into the riverbed. Where the riverbed is unstable and the current flows at appreciable speeds, a diversion intake (spur) is erected in the upstream part of a damless intake system to furnish the amount of water needed. The diversion barrage is usually made of local materials (rock or brush). In cases of heavy discharge, surface and bottom intake works with dams are used as part of hydraulic-engineering complexes and are equipped with scrubbing equipment, gratings, sluices, and settling pond to hold back suspended alluvium. From the standpoint of design, dam-type intake works for purposes of irrigation are analogous to those used in hydroelectric power engineering.

REFERENCES

Spetsial’nye vodozabornye sooruzheniia. Moscow, 1963.
Abramov, N. N. Vodosnabzhenie. Moscow, 1967.
Grishin, M. M. Gidrotekhnicheskie sooruzheniia. Moscow, 1968.
N. N. ABRAMOV and V. A. ORLOV
Ground water intake works are a hydraulic-engineering installation for catching groundwater and conveying it to pipelines, irrigation, and other water-use systems. The choice of a site for installing groundwater intake works is determined by the geological and hydrological features of the area (including the volume and depth of the water-bearing horizon) and by the distance from places of demand. The exploitation of water intake works is based on catchment devices. Depending on the conditions of operation and the purpose for which they are intended, these devices are classified as vertical or horizontal or as catchments that trap natural springs. Vertical intakes are built where the water-bearing horizons are relatively deep and whether or not the water is under pressure. In terms of design, vertical intake systems are classified as drill holes and or dug wells. Drill holes are the more common and technically more advanced type of intake; their productivity is quite high, and they meet sanitary requirements more completely. Dug wells can be sunk in water-bearing layers with a free surface (surface wells) and in water-bearing horizons under pressure (artesian wells) to depths of 100 m. If the intake works intersect a water-bearing seam at full capacity, they are called complete, but if they are sunk only partially into a water-bearing seam and do not reach the watertight bed, they are called partial. Dug wells are built mainly to meet the requirements of small-scale water consumers. Radial intakes are used for more complete catchment of groundwater. They are a combination of dug wells and drill holes that are sunk horizontally in various directions into the water-bearing seam. Horizontal intake works are classified as trenches, galleries (properly speaking, galleries and adits), and karez (underground irrigation canals). The type of horizontal intake system chosen depends on the depth of the groundwater and the type of water supply needed. In cases where the water-bearing horizons are at considerable depths, catchment galleries and adits are used to provide a constant supply to relatively large-scale consumers. Trench systems are used for relatively small-scale users where the water is not far below the surface. The karez type is an intake works of primitive construction that is used to supply water for agriculture and to irrigate small areas of land in semiarid regions where trapped water would otherwise be lost.

REFERENCES

Abramov, S. K., M. P. Semenov, and A. M. Chalishchev. Vodozabory podzemnykh vod, 2nd ed. Moscow, 1956.
Plotnikov, N. I. Poiski i razvedka presnykh podzemnykh vod dliaod dliatselei krupnogo vodosnabzheniia, parts 1-2. Moscow, 1965-68.65-68.

A. M. OVCHINNIKOV

References in periodicals archive ?
While the reservoir was closed to private boats in July, DCR divers inspected the water intake works for the presence of zebra mussels, but no mussels were found, Mr.