Water intake facilities are arranged to receive water from surface sources and deep layers. They are located on the banks of reservoirs, rivers, lakes. For industrial purposes, structures on the shores of the seas are used, followed by supply to the pressure pipeline. If in the coastal areas there is no fresh water, then the system of desalination and purification of sea water is used in accordance with economic and technical justifications.
To extract water from underground currents, deep-type structures using a pumping system are arranged. When the water level fluctuates in the body of water, coastal structures are built on artificially created bases, piles, and a foundation to protect the station from ice drift and floating objects. According to the method of location, water intake structures are coastal, special and gravity (channel).
Varieties of stations
Gravity-type channel stations are built on the shore of a shallow reservoir with a small gentle slope and weak soil. Their design provides for a receiving well, a free-flow pipeline, and a head protected by a grate. The resulting water through a system of pumps is fed into the pressure pipe for further use. The heads are arranged completely submerged, flooded only during the spill, or superficial. The pump station works together with the water intake or is installed as an independent device.
On steep banks of water bodies, shore-type water intake structures are provided, which in the structure do not contain heads and pipelines. Water intake is provided through the holes, as its level allows you to do this under any conditions. A shore well is arranged half a meter above the highest rise in water level, a pumping station is necessarily set. If this indicator in the river fluctuates significantly, then the well has several separate sections in accordance with the number of suction lines. The upper windows are used to collect the surface layer during the flood, which makes it possible to take a clean liquid.
A special type of water intake station is used if a large amount of liquid is needed or if the climate requires constant control of ice crusts. In such intakes, an artificial bucket is arranged like a canal. Its dimensions are determined depending on the ascent rate of the deep ice blocks. Buckets with a grassroots reception set upstream mouths to receive near-bottom currents and fight deep ice. Buckets with an upper entrance are intended for installation at the mouth against the flow and are used to receive surface clarified liquid. These types of water intake facilities allow digging buckets into the coastal rock to a depth of up to 3.5 m or moving them into the river channel, separated by a dam.
With the help of filtration and purification facilities, a well-clarified liquid is obtained in a flood or ice drift. Before being fed into the pressure pipe, moisture is filtered through a thick layer of gravel and sand layers, naturally located on the bottom or banks, only then it is taken by shaft, tubular or horizontal devices.
If it is required to provide a temporary supply of water, build floating or mobile water intake facilities. For the location of mobile stations on the shore of a reservoir, railways are provided with a slope along which they move depending on the level of water rise. Floating structures are arranged on barges or pontoons fixed by anchor. The disadvantages of temporary water intakes are that all pipelines are made of flexible materials, and this leads to their premature damage and inconvenience of use during the ice period.
To extract moisture from gravel and sandy soils of the upper pressureless horizontal layer, mine wells are arranged. The material for them is concrete on a metal frame. Water enters the receivers through openings in the walls and floor. The bottom of the well is equipped with a reverse filter layer consisting of sand up to 0.6 m thick and several gravel layers with a total thickness of 0.15 m. The well protrudes 0.8 m above the ground surface. The walls are protected by a clay castle with a thickness of up to 0.5 m , which goes underground by 0.3-1.2 m. An adjacent concrete blind area with a slope of 1-1.5 m wide from the walls is required.
The operation of water intake facilities in the northern regions is complicated by the harsh winter climate, when open ponds freeze. Buildings are used only during ice melting. Northern areas are characterized by an almost complete absence of underground sources, rare waters contain a large amount of minerals and are unsuitable for drinking. Moisture in the winter is scarce, so it is taken from layers located under frozen ground. To increase the water level in reservoirs, artificial dams are arranged and the area of reservoirs is expanded, thus contributing to the regulated feeding of rivers and lakes from underground non-freezing sources.
Types of sources
Water intake for use in cities and villages is carried out from the surface and underground layers. Aquifers in the thickness of the soil are pressure and gravity. Horizontal layers at the surface or in the thickness of rivers and lakes are called ground. Groundwater is characterized by increased pollution and must be cleaned before entering the pressure water supply.
Pressure water completely fills horizontal layers, is located below neighboring reservoirs or serves to recharge them. Artesian springs have valuable clean water; for their extraction, they arrange such types of water intake structures that do not contain treatment facilities in the design. In the well for receiving water from the horizontal pressure head, there is a conditional line for raising the liquid, which coincides with the surface level of the nearest reservoir. If such a line passes above the surface of the soil, then moisture is poured out of the well, which is called the artesian.
Pressure and non-pressure water seeping to the surface of the soil form descending and ascending keys, supplying high quality water that is used for drinking purposes without the use of expensive treatment systems. Qualitative indicators of the source, such as thickness, occurrence depth, and mineral saturation, are used to select the type of structure of the intake station. At the same time, technical and economic considerations and the need for a certain type of liquid are taken into account (for industrial, drinking, and household needs).
Location Terms
The construction of water intake facilities is based on forecasts of the properties of the fluid from the selected source, the need for re-equipment of the coastal zone, the reorganization of the river bed or other reservoir and hydraulic conditions. When the water level changes more than 6 m and the steep slope of the shore, sufficient for normal water flow, combined coastal structures are built.
If you plan an average capacity, due to the low height of the water rise, water intakes are combined with pumping complexes. Separate type water receivers are built with the required low productivity and a large depth of the reservoir. If the fluctuation of the water surface is less than 6 m, the depth is shallow, then the channel type of water intake with a pumping station is used in the design of the shore receiver.
Hydraulic calculation
To determine the optimal parameters of the pipeline, hydraulic calculation is used. The throughput of pipes and other elements for the entire estimated validity period is taken into account. Water consumption is defined as the need for it during maximum analysis by connected consumers. Based on these data, the diameters of the pipes necessary for cost-effective passage of a given mass with the lowest losses are calculated.
An axonometric diagram is made indicating the direction from the input to the connected water-folding unit, choosing the location with the least number of turns. The lengths of the sections from one nodal point to another are calculated, taking into account the number of liquid analysis points. The diameter of the pipes varies in another section, within one section of the pipe provide the same size. The construction of water intake facilities is carried out after full hydraulic calculation.
Treatment plant
Water quality is determined on the basis of such indicators:
- physical properties, such as turbidity, smack, color, smell, temperature;
- chemical qualities characterizing the ability to oxidize, stiffness, active reaction, mineral content;
- bacteriological properties that show the degree of infection with bacteria that enter the water from nearby sewage, precipitation, animal excrement.
Drinking water is under close scrutiny. The requirements for the quality of liquid for household use are standardized and are contained in GOST R51232 - 1998. The document takes into account the requirements for chemical, physical and bacterial indicators. If the purity of the water obtained does not correspond to the given regulatory data, then water intake treatment facilities are being built. The most common cleaning methods are disinfection and clarification. For clarification, filtration and sedimentation are used in several stages, as a result of which impurities settle to the bottom. Bactericidal radiation, normalized chlorination, and ozonation are used to get rid of pathogenic microorganisms.
Obtaining water from underground sources
The choice of a water intake station for receiving fluid from underground layers is affected by the depth of the location and thickness of the layer. Facilities are divided into four types:
- water intake wells;
- mine wells;
- horizontal water intakes;
- hood devices.
Groundwater intake structures in the form of boreholes or tubular wells are used to extract fluid from the formation at a depth of more than 10 m. The construction consists in drilling the borehole and strengthening the walls with casing pipes. Gradually, with a set of depth, the diameter of the pipes decreases. A filter is installed in the lower part of the hole, and an observation chamber is built on the surface, above the well. If the pressure of the aquifer is strong enough, water rises to the surface under pressure, otherwise the moisture is pumped upward.
Structures of the type of mine wells are used to receive water from a depth of more than 30 m. The walls of the well - concrete, brick or wooden, often use ready-made unified elements that are installed one on top of the other in series. In the lower part of the walls and the bottom of the well provide openings for the natural flow of fluid. At the bottom make a filter layer of sand and gravel. With increased demand for water, several mine wells are organized, interconnected by siphons with a water collector, from where moisture is pumped into the water supply.
Horizontal underground water intake facilities are used to collect moisture at a shallow depth. They are performed at a depth of 8 m from standard reinforced concrete or ceramic elements with holes or slots in the side surfaces. The simplest horizontal types are made of thinned brick or rubble masonry, for preventive maintenance, inspection chambers are designed every 100 m.
Capsule chambers are used to take water from the keys. They are the simplest mine wells arranged above the place where water appears on the surface. To obtain liquid from the downstream key sources, make cowling chambers for collecting moisture through vertical walls as a horizontal intake.
Collection of water from surface sources
With this method of water intake, measures are taken to ensure uninterrupted production of moisture throughout the year. To do this, the structure is located closer to the consumer on a stable, least polluted place on the coast, built above industrial plants and sewage sites. Water intake facilities from surface sources are arranged taking into account the possible turn of the riverbed over time. Elements of the system are positioned so that after the formation of ice in winter, at least 0.3 m remains to the top of the structure, and the bottom of the water intake does not reach the bottom of the river by 1 m.
Water intake facilities are often built according to the combined principle of two or more types, this is determined by the characteristics of the reservoir and the required volume of consumption. Before starting operation, the system passes a technical test. The surface water intake facilities are run by running and washed with water at a speed of 1 m / s. Domestic water pipes are chlorinated for disinfection.
The device of external water supply networks
The external system includes main highways and secondary branch lines. As a pipe material, environmentally friendly components are used, selected according to GOST. Between the intake station and the pressurized water supply, the liquid flows through the treatment facilities, settles in the tanks and is sent to the consumer using control devices. The diameter of the pipes of the main line is taken according to the hydraulic calculation, and the branch diameters are used taking into account the fire flow rate.
Water lifting devices
Pumping complexes are placed in the water movement circuit to convert the engine energy into the hydraulic energy of the transmitted fluid. With the help of these devices, moisture is raised to the desired height, fed over long distances and forced to flow in a closed water supply system, which implies the operation of water intake facilities. The choice of pumps for the comprehensive maintenance of water intake facilities is carried out depending on the type of engine, power, pressure, efficiency and other indicators. The most common in use are centrifugal pumps, which have enough advantages over other types.
Tanks and water towers
To achieve pressure in the water supply network and to raise the liquid to high floors, water towers are used that work according to the physical principle of communicating vessels. The tank tank in the tower is calculated on the volume of water, which regulates the supply of liquid to consumers for a certain time if the intake structures from underground sources fail.
In the tank of the water tower is stored the supply of water necessary for emergency fire fighting within 10 minutes after the fire. The water tower in the construction contains a tank supporting the base, made to the height of the tallest building in the village. In the northern regions, a warming casing is arranged, while in the southern regions only a cover is made above the tank.
Tanks for storing water are placed in various places in the water supply system; they serve to store stocks of liquid. The volume of tanks depends on their purpose and the need to saturate the pressure system of consumers with water. The material for the structures is burnt brick, various types of natural stone and reinforced concrete. The shape distinguish between round and rectangular tanks. Overlapping is performed in a monolithic or prefabricated way.
Repair of underground and underwater pipelines
Installation of water intake facilities with an extended pipeline after a period of operation requires periodic repair and maintenance. Sometimes the throughput of the water supply is reduced due to deposits in the pipes of blockages and deposits. Its cleaning is carried out periodically, in mild cases, washing with a reverse or direct current of water is enough. In more complex cases, use scrapers or ruffs.
Removing damaged piping to the surface is troublesome and expensive. Therefore, a special device has been designed for cleaning, moving inside the pipe. The device moves, and rotating hard brushes remove deposits on the walls. To clean the pipeline from which the liquid is removed, weights are made that do not allow structures from the pipes to float to the surface.
To remove complex breaks or holes in the pipes, they are raised to the surface, and after replacing the damaged area, they are repeatedly lowered to the bottom. Not too complex damage is repaired by underwater welding.
In conclusion, it should be noted that the construction of water intake facilities requires special knowledge to determine the type of structures, choose a place and arrange structural units. But since modern consumers do not see their existence without life-giving moisture, over time, new design solutions and ideas for extracting water from the bowels of the planet appear.