A water well is an excavation or structure made on the ground by digging, driving, boring, or drilling to access ground water in underground aquifers. Well water is taken by the pump, or using a container, such as a bucket, which is mechanically lifted or by hand. Wells was first built at least eight thousand years ago and has historically varied in construction from a simple spoon in sediment from dried waterways to Indian stepwells, qanats of Iran, and Indian shaviofs and sakiehs. Placing the lining on the wellbore helps to create stability and coating of wood or work dates back at least until the Iron Age.
Wells have traditionally been drowned by hand excavations as they do in rural areas. These wells are cheap and low-tech because most use manual labor and the structure can be lined with bricks or stones during excavation. A more modern method is called caissoning using pre-casted reinforced concrete rings that are lowered into the hole. The pushed well may be made in a non-consolidated material with a wellbore structure, comprising a hardened drive point and a perforated pipe screen, after which the pump is installed to collect water. Deeper wells can be extracted by hand drilling or drilling methods, using little in drill holes. Drill wells are usually coated with factory-made pipes consisting of steel or plastic. Drilled wells can access water at much deeper depths than digging wells.
Two large classes of wells are shallow or non-terraced wells completed in the highest saturated aquifer at the site, and deep or limited wells, submerged through an impermeable layer into the underlying aquifer. A collecting well can be built adjacent to a freshwater lake or stream with water seeping through an intervening material. The location of a well can be chosen by a hydrogeologist, or groundwater surveyor. Water can be pumped or withdrawn. Dirt from the surface can easily reach shallow sources and supply contamination by pathogens or chemical contaminants should be avoided. Well water usually contains more minerals in solution than surface water and may require treatment before it can be taken. Soil claying can occur when the water level falls and the surrounding soil begins to dry out. Another environmental problem is the potential for methane to seep into the water.
Video Water well
History
The well-lined wooden wells are known from the Neolithic Linear Pottery culture, for example in KÃÆ'¼ckhoven (the remote center of Erkelenz), dated 5090 BC and Eythra, dated 5200 BC in Schletz (isolated center of Asparn an der Zaya) in Austria.
Some of the earliest evidence of water wells is located in China. Neolithic Chinese find and use extensive groundwater drilled in for drinking. The Chinese text The Book of Changes, originally a text of the Western Zhou Dynasty (1046 -771 BCE), contains an entry explaining how ancient Chinese maintained their wells and protected their water resources. Ancient Chinese archaeological evidence and documents reveal that prehistoric and ancient China had the talent and skill to dig deep wells for drinking water from 6000 to 7000 years ago. A well dug at the Hemedu excavation site is believed to have been built during the neolithic era. The well was lined with four rows of wooden blocks with a square frame attached to them at the top of the well. 60 additional tile wells southwest of Beijing are also believed to have been built around 600 BC for drinking and irrigation.
In Egypt, shadoofs and sakieh are used. But when compared to each other, Sakkieh is much more efficient, as it can carry water from a depth of 10 meters (versus 3 meters of shadoof). The Sakieh is an Egyptian version of Noria. Some of the oldest known wells in the world, located in Cyprus, dated 7000-8500 BC. Two wells from the Neolithic period, around 6500 BC, have been found in Israel. One is at the Athletes, on the north coast of Israel, and the other is the Jezreel Valley.
Maps Water well
Type
Dug well
Until recent centuries, all artificial wells were hand-digging wells with varying degrees of sophistication, and they remain a vital source of water in some rural areas where they are routinely excavated and used today. Their limitations have produced a number of literary, literal and figurative references, for them, including references to the incident Jesus met a woman in Jacob's well (John 4: 6) in the Bible and the nursery rhyme of "Ding Dong Bell" about the cat in a well.
Hand excavation wells are excavations with a diameter large enough to hold one or more people with shovels dug down below the water surface. Excavations are made horizontally to avoid landslides or erosions that harm the diggers. They can be coated with stones or bricks; Extending this layer up above the soil surface to form a wall around the well serves to reduce both contamination and injury by falling into the well. A more modern method called caissoning uses either reinforced concrete or pre-molded concrete well that is lowered into the hole. A well digging team digs under the cutter ring and the well column is slowly sinking into the aquifer, while protecting the team from the collapse of the borehole.
Dug wells are cheap and low tech (as compared to drilling) because they use most of the manual labor to access groundwater in rural locations in developing countries. They may be built with high levels of community participation, or by local entrepreneurs who specialize in hand-digging wells. They have been dug up to 60 meters (200 feet). They have low operational and maintenance costs, in part because water can be extracted with hand-release, without pumps. Water often comes from aquifers or groundwater, and can be easily deepened, which may be required if groundwater levels go down, with telescoping more layers into the aquifer. The results of existing hand excavate wells can be improved by deepening or introducing vertical tunnels or perforated pipes.
The disadvantages to dug wells very much. It can be impractical to dig wells in areas where hard rock is present, and they can spend time digging and lining even in lucrative areas. Because they exploit a shallow aquifer, wells may be vulnerable to produce fluctuations and possible contamination of surface water, including waste. Hand-held dug wells generally require the use of trained construction teams, and capital investment for equipment such as concrete ring molds, heavy lifting equipment, fine shaft formwork, sprayed de-water pumps and fuel can be great for people in developing countries. Construction of hand dug wells can be dangerous because of the collapse of wells, falling objects and shortness of breath, including from the exhaust fumes of dewatering pumps.
Woodingdean well, dug up between 1858 and 1862, claimed to be the deepest dug well in the world with 392 meters (1,285 feet). The Great Well in Greensburg, Kansas is billed as the largest dug well in the world, at a depth of 109 feet (33 m) and 32 feet (9.8 m). However, the well of Joseph in the Citadel of Cairo at a depth of 280 feet (85 m) and Pozzo di S. Patrizio (St. Patrick's Well) was built in 1527 in Orvieto, Italy, at 61 meters (200Ã, ft) depth 13 meters (43Ã, ft) wide both are larger by volume.
The well pusher
The pushed well may be very easy to make in non-consolidated material with wellbore structures, which consists of a hardened drive point and screen (hollow pipe). The point is just hammered to the ground, usually with a tripod and driver , with the pipe section added as needed. The driver is a weighted pipe that slides over a pipe that is pushed and repeatedly falls on it. When ground water is found, wells are washed in sediment and pumps are installed.
Drilled wells
Drill wells are usually made using a head-up turn, turntable, or tool-wrenching drill machine, all of which use drilling rods rotated to make cutting actions in the formation, hence the term drilling .
Drilled wells can be extracted by simple drilling methods (augering, sludging, jetting, driving, hand perkusions) or drilling machines (swivel, percussion, down hammer hole). Deeprock rotary drilling methods are the most common. Rotary can be used in 90% of the formation type.
Drilled wells can get water from a much deeper level of dug wells dug - often down to several hundred meters.
Drill wells with electric pumps are used worldwide, usually in rural or sparsely populated areas, although many urban areas are supplied in part by city wells. Most shallow well drilling machines are installed in large trucks, trailers, or tracked car carriages. Water wells typically range from 3 to 18 meters (10-60 feet) deep, but in some areas may be deeper than 900 meters (3,000 feet).
Rotary drilling machines use segmented steel drilling strings, typically consisting of 6 meters (20 ft) parts of galvanized steel pipes threaded together, with little or other drilling devices at the lower end. Some rotary drilling machines are designed to install (by riding or drill) steel casing into the well along with actual drill hole drilling. Air and/or water is used as a circulating fluid to remove cuttings and cold bits during drilling. Another form of rotary drilling, called mud rotary, utilizes specially designed sludge, or drilling fluid, which is constantly altered during the drill so that it can consistently create sufficient hydraulic pressure to hold open sidewall walls , regardless of the existence of the casing in the well. Typically, drill holes drilled into solid rock are not closed until the drilling process is complete, regardless of the machine used.
The oldest form of a drill machine is a cable tool, still in use today. Designed specifically for raising and lowering a bit into the drill hole, drill
Drilled wells are usually coated with factory-made pipes, usually steel (in rotary air or cable drilling) or plastic/PVC (in mud wells, also present in wells drilled into solid rock). The casing is built by welding, either chemically or thermally, segment of the casing together. If the casing is installed during drilling, most drill will push the casing to the ground when the bore hole moves, while some newer engines will actually allow the casing to be rotated and drilled into the formation in the same way by advancing the bits. below. PVC or plastic is usually welded and then lowered into drilled wells, stacked vertically with the edges nested and glued or glued together. The chassis usually has a length of 6 meters (20 feet) or more, and a diameter of 6 to 12 inches (15 to 30 cm), depending on the intended use of local groundwater and well conditions.
Contamination of the well surfaces in the United States is usually controlled by the use of surface seal . Large holes are drilled to a predetermined depth or to a restricted formation (clay or bedrock, for example), and then smaller holes for wells are completed from that point forward. The well is usually closed from the surface to a smaller hole with a casing of diameter equal to that hole. The annular space between large boreholes and smaller casing is filled with bentonite clay, concrete, or other sealant materials. It creates an impermeable seal from the surface to the next split layer that makes contaminants from traveling along the outer side wall of the casing or borehole and into the aquifer. In addition, wells are usually sealed with well-engineered seals or seals that funnel air through the screen into the well, but keep insects, small animals, and unauthorized persons accessing the wells.
At the bottom of wells, by formation, filtering devices, filter packages, hollow sheaths, or open pit holes are allowed to allow the flow of water into the well. Built-in screens are usually used in non-consolidated formations (sand, gravel, etc.), allowing water and formation percentages to pass through the screen. Allowing some of the passing material to make a large area filter from the rest of the formation, because the amount of material available to enter the well slowly decreases and is removed from the well. Stone wells are usually coated with PVC/casing and screen or hollow coverings at the bottom, these are mostly present only to prevent the stone from entering the pump assembly. Some wells use the filter pack method, where the sized screen or casing is placed inside the well and the filter media is packed around the screen, between the screen and the borehole or casing. This allows the water to be filtered from undesirable material before entering the well zone and pumping.
Classification
There are two large classes of wellbore types, based on the well type of aquifer:
- Shallow or unlimited well is completed in the highest saturated aquifer at the site (upper aquifer).
- Deep or confined wells sink through waterproof strata into aquifer wedged between two aquifers or aquicludes. Most of the deep aquifers are classified as artesian because the hydraulic head in the well is finite higher than the peak level of the aquifer. If the hydraulic head in the well is finite higher than the ground level, then it is a "flowing" artesian well (named Artois in France).
A special type of water well can be built adjacent to a freshwater lake or river. Generally called collectors well but sometimes referred to by either Ranney's trade name or Ranney collector, this type involves sinking the caisson vertically below the top of the aquifer and then forward the lateral collector out of the caisson and beneath the surface of the water body. Pumping from within the caisson induces water infiltration from surface water bodies into the aquifer, where it is collected by lateral collectors well and delivered to a caisson where it can be pumped to the soil surface.
Two broad classes of additional well types can be distinguished by the use of wells:
- production or pumping well , large diameter (more than 15 cm) cased (metal, plastic, or concrete) well water, built to collect water from aquifer with a pump (if the well is not artesian).
- well monitoring or piezometers , often a smaller diameter well that is used to monitor the hydraulic head or to sample groundwater for chemical content. Piezometers monitor wells that are completed over a very short section of the aquifer. Well monitoring can also be completed at various levels, allowing separate samples or measurements to be made at different vertical altitudes in the same map location.
A well built to pump groundwater can be used passively as monitoring wells and small diameter wells can be pumped, but this difference with common usage.
Positioning
Prior to the excavation, information on geology, water depth, seasonal fluctuations, affix areas and rate must be found. This work is usually done by hydrogeologists, or groundwater surveyors using various tools including electro-seismic surveys, information available from nearby wells, geological maps, and occasionally geophysical imaging.
Contamination
Shallow pumping wells can often supply drinking water at a very low cost. However, dirt from the surface easily reaches a shallow source, leading to greater risk of contamination to this well than the deeper wells. Contaminated wells can lead to the spread of various waterborne diseases. Well-dug and driven wells are relatively easy to contaminate; for example, most dug wells are unreliable in most parts of the United States.
Pathogen
Most of the bacteria, viruses, parasites, and fungi that contaminate well water come from fecal matter from humans and other animals, for example from on-site sanitation systems (such as latrines and septic tanks). Common bacterial contaminants include E. coli, Salmonella, Shigella, and Campylobacter jejuni. Common viral contaminants include norovirus , sapovirus , rotavirus , enteroviruses, and hepatitis A and E. Parasites include Giardia lamblia , Cryptosporidium , Cyclospora cayetanensis , and microsporidia.
Chemical contamination
Chemical contamination is a common problem with ground water. Nitrates from sewage, sewage or fertilizer are special problems for infants and young children. Pollutant chemicals include pesticides and volatile organic compounds from petrol, dry-cleaning, methyl tert-butyl ether fuel additives (MTBE), and perchlorate from rocket fuel, airbag inflators, and other artificial and natural sources.
Some minerals are also contaminants, including heaps that are washed from brass fittings or old tin pipes, chromium VI from electroplating and other sources, arsenic, radon, and naturally occurring uranium - all of which can cause cancer - and naturally occurring fluoride desirable in low amounts to prevent tooth decay, but can cause dental fluorosis in higher concentrations.
Some chemicals generally exist in water wells at a non-toxic level, but can cause other problems. Calcium and magnesium cause what is known as hard water, which can precipitate and clog pipes or burn water heaters. Iron and manganese can appear as black spots that stain clothes and pipe, and can increase the growth of iron and manganese bacteria that can form slimy black colonies that clog the pipe.
Prevention
Well water quality can be significantly increased by coating wells, sealing wellheads, installing self-priming hand pumps, constructing aprons, ensuring the area is kept clean and free of puddles and animals, removing contamination sources (pit latrines, garbage cans, on-site disposal) and implementing hygiene education. The well should be cleaned with 1% chlorine solution after construction and periodically every 6 months.
The well hole must be closed to prevent the debris of loose, animal, animal dung, and the wind-blown foreign object falling into the pit and decaying. The cover should be in place at all times, including when taking water from the well. Roofs that hung over open holes help to some degree, but ideally cover must be tight and fully closed, with only filtered air vents.
Minimum distances and land percolation requirements between landfills and wells should be observed. Rules regarding the design and installation of private and municipal septic systems consider all these factors so that the nearest source of drinking water is protected.
Public education in the community also plays an important role in protecting drinking water.
Mitigation
Cleaning of contaminated groundwater tends to be very expensive. Effective groundwater recovery is generally very difficult. Groundwater contamination from surface and subsurface sources can usually be dramatically reduced by properly centering the casing during construction and filling the annulus of the casing with suitable sealing material. The grouting material should be placed from just above the production zone back to the surface, because, in the absence of a properly constructed chassis seal, contaminated fluid can travel to the well through the casing annulus. An important convergence tool (usually 1 per chassis length or at a maximum interval of 9 m) to ensure that the annular spaces fed with grouting have the same thickness. After the development of new tests well, it is considered best practice to invest in a complete battery of chemical and biological tests on the well water in question. Point-of-use treatments are available for individual property and plant treatments are often built for municipal water supplies suffering from contamination. Most of these treatment methods involve filtering of contaminants of concern, and additional protection can be collected by installing the casing screen only at depths where no contamination is present.
Well water for personal use is often filtered with reverse osmosis water treatment; this process can remove very small particles. A simple and effective way to kill microorganisms is to bring water to a boil for one to three minutes, depending on the location. Well-contaminated households by microorganisms can initially be treated with chlorination of shocks using bleach, resulting in concentrations hundreds of times greater than those found in community water systems; However, this will not fix the structural problems that cause contamination and generally require some expertise and testing for effective applications.
After the screening process, it is common to apply the Ultraviolet (UV) system to kill the pathogens in the water. UV rays affect pathogenic DNA by UV-C photons that penetrate cell walls. UV disinfection has gained popularity in recent decades as it is a chemical-free method of water treatment.
Environmental issues
The risk of placing a water well is a ground salination that occurs when groundwater levels begin to fall and the salt begins to accumulate as the soil begins to dry out. Another very common environmental problem in drilling water wells is the potential for methane to seep.
Grounding
The potential for soil salination is a big risk when choosing the placement of water wells. Soil salination is caused when groundwater levels decrease over time and salt begins to accumulate. In turn, the increase in the amount of salt begins to dry the soil. This is a very harmful problem as increased salinity in the soil can lead to soil degradation and can be very harmful to vegetation.
Metana
Methane, an asphyxiant, is a chemical compound that is a major component of natural gas. When methane is introduced into restricted space, it displaces oxygen, reduces oxygen concentration to a low enough level to pose a threat to humans and other aerobic organisms but is still high enough for the risk of spontaneous or external explosions. It is this potential for explosions that pose a hazard in terms of drilling and placement of water wells.
Low levels of methane in drinking water are not considered toxic. When methane permeates the water supply, it is commonly referred to as "methane migration". This can be caused by an old natural gas well near the abandoned well water system and is no longer monitored.
Lately, however, the wells/pumps described are no longer highly efficient and can be replaced with handpump or stroke pumps. Another alternative is the use of self-explored wells, electric pumps in wells (for higher depths). Proper technological organizations as Practical Actions now supply information on how to build/regulate (DIY) pumps of handpumps and pedals in practice.
Society and culture
Springs and wells have cultural significance since prehistoric times, leading to the city's foundations like Wells and Bath in Somerset. Interest in health benefits led to the growth of many spa cities with wells in their names, for example Llandrindod Wells and Royal Tunbridge Wells.
Eratosthenes first calculated the radius of Earth around 230 BC by comparing the shadows in the well during the summer solstice.
Many events in the Bible take place around the well, such as the discovery of a wife to Isaac in Genesis and the conversation of Jesus with the Samaritan woman in the Gospels.
See also
- Abraham's well
- Drilling of the baptist well
- Brick-lined well
- The castle is fine
- Drainage by well
- History of water supply and sanitation
- Water supply and sanitation itself
- Spring supply
- One step well
References
Bibliography
- Driscoll, F. (1986). Ground Water and Wells . St. Paul: Johnson Filtration Systems. ISBN 978-0-9616456-0-1.
- Raymond Rowles (1995). Drilling for Water (2nd ed.). Avebury, Cranfield University. ISBNÃ, 1-85628-984-2.
External links
- The Sustainable Soil Water Development theme of the Rural Water Supply Network (RWSN)
- Water Portal - Akvopedia
- Sanitation Toolbox and Sustainable Water Management
- US. Health Centers for Disease Control and Prevention (CDC) - Well Water Sites that include the basics of wells, guidelines for proper placement and well location to avoid contamination, well testing, well-related diseases, emergency care well and other topics.
- US Geological Survey - Groundwater: Wells
- US Geological Survey - Picture Water Science Flows Artesia Well
- American Ground Water Trust
- International Lifewater Technical Library
- Technical Construction Resources Well for NGOs
Source of the article : Wikipedia
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