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83-560: The Ogallala Aquifer ( oh-gə- LAH -lə ) is a shallow water table aquifer surrounded by sand, silt, clay, and gravel located beneath the Great Plains in the United States. As one of the world's largest aquifers, it underlies an area of approximately 174,000 sq mi (450,000 km) in portions of eight states ( South Dakota , Nebraska , Wyoming , Colorado , Kansas , Oklahoma , New Mexico , and Texas ). It

166-431: A strengthening of the water cycle (also called hydrologic cycle). This effect has been observed since at least 1980. One example is when heavy rain events become even stronger. The effects of climate change on the water cycle have important negative effects on the availability of freshwater resources, as well as other water reservoirs such as oceans , ice sheets , the atmosphere and soil moisture . The water cycle

249-490: A $ 300,000 annual demonstration project to conserve water that farmers pump from the Ogallala Aquifer. Participating farmers grow corn with just over half of the water that they would normally require to irrigate the fields, or they plant several weeks later than customary. Pivot sprinklers are used in the project, rather than the more expensive drip irrigation. According to district manager Steve Walthour, conservation

332-581: A given vicinity. The groundwater may be from precipitation or from groundwater flowing into the aquifer. In areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through the unsaturated zone. At increasing depths, water fills in more of the pore spaces in the soils, until a zone of saturation is reached. Below the water table, in the phreatic zone (zone of saturation), layers of permeable rock that yield groundwater are called aquifers . In less permeable soils, such as tight bedrock formations and historic lakebed deposits,

415-441: A permanent change in the water table in such regions. Most crops need a water table at a minimum depth. For some important food and fiber crops a classification was made because at shallower depths the crop suffers a yield decline. A water table close to the surface affects excavation, drainage, foundations, wells and leach fields (in areas without municipal water and sanitation), and more. When excavation occurs near enough to

498-857: A rally at the National Mall drew an estimated 40,000 in protest of Keystone XL. In January 2014, the U.S. State Department released its Keystone pipeline Final Supplemental Environmental Impact Statement for the Keystone XL Project Executive Summary , which concluded that, according to models, a large crude oil spill from the pipeline that reached the Ogallala could spread as far as 1,214 feet (370 m), with dissolved components spreading as much as 1,050 ft (320 m) further. Early in his presidency, U.S President Donald Trump overturned U.S. President Barack Obama's decision by signing executive memos in support of

581-413: A reservoir within the hydrologic cycle is the average time a water molecule will spend in that reservoir ( see table ). It is a measure of the average age of the water in that reservoir. Groundwater can spend over 10,000 years beneath Earth's surface before leaving. Particularly old groundwater is called fossil water . Water stored in the soil remains there very briefly, because it is spread thinly across

664-452: A technique that retains moisture for a longer period of time. Soil sensors permit farmers to gather accurate information about the moisture level of their crops. The motivation to save water comes from the district's regulations on extracting water from the aquifer. The United States Geological Survey determined the water level in the aquifer has dropped more in Texas than in any other state in

747-499: Is a biogeochemical cycle that involves the continuous movement of water on, above and below the surface of the Earth . The mass of water on Earth remains fairly constant over time. However, the partitioning of the water into the major reservoirs of ice , fresh water , salt water and atmospheric water is variable and depends on climatic variables . The water moves from one reservoir to another, such as from river to ocean , or from

830-473: Is about 32% of the cumulative depletion during the entire 20th century. In the United States, the biggest users of water from aquifers include agricultural irrigation and oil and coal extraction. "Cumulative total groundwater depletion in the United States accelerated in the late 1940s and continued at an almost steady linear rate through the end of the century. In addition to widely recognized environmental consequences, groundwater depletion also adversely impacts

913-546: Is also estimated that the oceans supply about 90% of the evaporated water that goes into the water cycle. The Earth's ice caps, glaciers, and permanent snowpack stores another 24,064,000 km accounting for only 1.7% of the planet's total water volume. However, this quantity of water is 68.7% of all freshwater on the planet. Human activities can alter the water cycle at the local or regional level. This happens due to changes in land use and land cover . Such changes affect "precipitation, evaporation, flooding, groundwater, and

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996-481: Is an aquifer that occurs above the regional water table. This occurs when there is an impermeable layer of rock or sediment ( aquiclude ) or relatively impermeable layer ( aquitard ) above the main water table/aquifer but below the land surface. If a perched aquifer's flow intersects the surface, at a valley wall, for example, the water is discharged as a spring . On low-lying oceanic islands with porous soil, freshwater tends to collect in lenticular pools on top of

1079-444: Is essential considering declining levels of the aquifer. The local non-profit organization Ogallala Commons, named for the aquifer itself, which not only collaborates and supports the local communicates, also works to conserve the Ogallala Aquifer and the surrounding area. Eleven farmers in 2013 participated in the conservation program, with some planting in dry earth, rather than watered soil. They are leaving more space between plants,

1162-438: Is essential to life on Earth and plays a large role in the global climate system and ocean circulation . The warming of our planet is expected to be accompanied by changes in the water cycle for various reasons. For example, a warmer atmosphere can contain more water vapor which has effects on evaporation and rainfall . The underlying cause of the intensifying water cycle is the increased amount of greenhouse gases in

1245-410: Is less dense. Due to the significant difference in density, buoyancy drives humid air higher. As altitude increases, air pressure decreases and the temperature drops (see Gas laws ). The lower temperature causes water vapor to condense into tiny liquid water droplets which are heavier than the air, and which fall unless supported by an updraft. A huge concentration of these droplets over a large area in

1328-451: Is powered from the energy emitted by the sun. This energy heats water in the ocean and seas. Water evaporates as water vapor into the air . Some ice and snow sublimates directly into water vapor. Evapotranspiration is water transpired from plants and evaporated from the soil. The water molecule H 2 O has smaller molecular mass than the major components of the atmosphere, nitrogen ( N 2 ) and oxygen ( O 2 ) and hence

1411-443: Is referred to as the potentiometric surface , not the water table. The water table may vary due to seasonal changes such as precipitation and evapotranspiration . In undeveloped regions with permeable soils that receive sufficient amounts of precipitation, the water table typically slopes toward rivers that act to drain the groundwater away and release the pressure in the aquifer. Springs , rivers , lakes and oases occur when

1494-578: The Athabasca oil sands of Alberta to refineries near Houston, Texas . The proposed route of the pipeline crosses the eastern part of the Nebraska Sandhills ; opponents of the route cite the risk to the Ogallala Aquifer posed by the possibility of contamination from spilled dilute bitumen . Pipeline industry spokesmen have noted that thousands of miles of existing pipelines carrying crude oil and refined liquid hydrocarbons have crossed over

1577-531: The Conservation Reserve Program , along with increased restrictions on water use at the state level. Since the 1940s, pumping from the Ogallala has drawn the aquifer down by more than 300 feet (90 m) in some areas. Producers have taken steps to reduce their reliance on irrigated water. Streamlined operations allow them to produce significantly greater yield using roughly the same amount of water needed four decades ago. Still, losses to

1660-553: The Platte , run below the water level of the aquifer. Because of this, the rivers receive groundwater flow (baseflow), carrying it out of the region rather than recharging the aquifer. The $ 46.1-million Optima Lake dam in western Oklahoma was rendered useless when the dropping level of the aquifer drastically reduced flow of the Beaver River , the lake's intended source of water. The depletion between 2001 and 2008, inclusive,

1743-455: The evolution of land animals from fish ) and Xenophanes of Colophon (530 BCE). Warring States period Chinese scholars such as Chi Ni Tzu (320 BCE) and Lu Shih Ch'un Ch'iu (239 BCE) had similar thoughts. The idea that the water cycle is a closed cycle can be found in the works of Anaxagoras of Clazomenae (460 BCE) and Diogenes of Apollonia (460 BCE). Both Plato (390 BCE) and Aristotle (350 BCE) speculated about percolation as part of

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1826-404: The exobase , the lower limit of the exosphere , where the gases can then reach escape velocity , entering outer space without impacting other particles of gas. This type of gas loss from a planet into space is known as planetary wind . Planets with hot lower atmospheres could result in humid upper atmospheres that accelerate the loss of hydrogen. In ancient times, it was widely thought that

1909-416: The hyporheic zone . Over time, the water returns to the ocean, to continue the water cycle. The ocean plays a key role in the water cycle. The ocean holds "97% of the total water on the planet; 78% of global precipitation occurs over the ocean, and it is the source of 86% of global evaporation". Important physical processes within the water cycle include (in alphabetical order): The residence time of

1992-544: The water consumption efficiency of the center-pivot irrigator improved over the years, farmers chose to plant more intensively, irrigate more land, and grow thirstier crops rather than reduce water consumption--an example of the Jevons Paradox in practice. One approach to reducing the amount of groundwater used is to employ treated recycled water for irrigation; another approach is to change to crops that require less water, such as sunflowers . Several rivers, such as

2075-481: The 22nd verse that the Sun heats up water and sends it down as rain. By roughly 500 BCE, Greek scholars were speculating that much of the water in rivers can be attributed to rain. The origin of rain was also known by then. These scholars maintained the belief, however, that water rising up through the earth contributed a great deal to rivers. Examples of this thinking included Anaximander (570 BCE) (who also speculated about

2158-457: The Earth, and is readily lost by evaporation, transpiration, stream flow, or groundwater recharge. After evaporating, the residence time in the atmosphere is about 9 days before condensing and falling to the Earth as precipitation. The major ice sheets – Antarctica and Greenland – store ice for very long periods. Ice from Antarctica has been reliably dated to 800,000 years before present, though

2241-569: The Federal Energy Regulatory Commission in preparing environmental impact statements for other proposed TransCanada projects. Although it is "common for companies applying to build government projects to be involved in assigning and paying for the impact analysis", several opponents of the project suggested there could be a conflict of interest. In response to that concern, the Department of State's Office of

2324-633: The Inspector General conducted an investigation of the potential conflict of interest. The February 2012 report of that investigation states no conflict of interest existed either in the selection of the contractor or in the preparation of the environmental impact statement. U.S. President Barack Obama "initially rejected the Keystone XL pipeline in January 2012, saying he wanted more time for an environmental review." On February 17, 2013,

2407-642: The Keystone XL pipeline in January 2017. On January 20, 2021, President Joe Biden signed an executive order to revoke the permit that was granted to TC Energy Corporation for the Keystone XL Pipeline (Phase 4). On June 9, 2021, TC Energy abandoned plans for the Keystone XL Pipeline. Since 2010, the North Plains Groundwater Conservation District, which encompasses eight counties north of Amarillo , including Moore and Dallam Counties, has offered

2490-479: The Ogallala Aquifer are some of the most productive regions in the United States for ranching livestock , and growing corn , wheat , and soybeans . The success of large-scale farming in areas that do not have adequate precipitation and do not always have perennial surface water for diversion has depended heavily on pumping groundwater for irrigation. Early settlers of the semiarid High Plains were plagued by crop failures due to cycles of drought , culminating in

2573-641: The Ogallala Aquifer for years, in southeast Wyoming, eastern Colorado and New Mexico, western Nebraska, Kansas, Oklahoma, and Texas. The Pioneer crude oil pipeline crosses east-west across Nebraska, and the Pony Express pipeline , which crosses the Ogallala Aquifer in Colorado, Nebraska, and Kansas, was being converted as of 2013 from natural gas to crude oil, under a permit from the Federal Energy Regulatory Commission . As

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2656-606: The Ogallala Formation ranges from a few feet to more than 1,000 feet. Its deepest part is 1200 ft. (300 m) and is generally greater in the Northern Plains. The depth of the water below the surface of the land ranges from almost 400 feet (120 m) in parts of the north to between 100 and 200 feet (30 and 61 m) throughout much of the south. Present-day recharge of the aquifer with fresh water occurs at an exceedingly slow rate, suggesting that much of

2739-490: The Texas Panhandle, the water table has been drained (dewatered). "Vast stretches of Texas farmland lying over the aquifer no longer support irrigation. In west-central Kansas, up to a fifth of the irrigated farmland along a 100-mile swath (160 km) of the aquifer has already gone dry." The center-pivot irrigation system is considered to be a highly efficient system which helps conserve water. However, by 2013, as

2822-415: The adaptation of automotive engines to power groundwater wells. Today about 27% of the irrigated land in the entire United States lies over the aquifer, which yields about 30% of the ground water used for irrigation in the United States. The aquifer is at risk of over-extraction and pollution. Since 1950, agricultural irrigation has reduced the saturated volume of the aquifer by an estimated 9%. Once depleted,

2905-581: The aquifer between 2001 and 2011 equated to a third of its cumulative depletion during the entire 20th century. The Ogallala is recharged primarily by rainwater, but only about one inch of precipitation actually reaches the aquifer annually. Rainfall in most of the Texas High Plains is minimal, evaporation is high, and infiltration rates are slow. During the 1990s, the aquifer held some three billion acre-feet of groundwater used for crop irrigation as well as drinking water in urban areas. The demand for

2988-409: The aquifer is overlain, in the vadose zone , with a shallow layer of caliche that is practically impermeable ; this limits the amount of water able to recharge the aquifer from the land surface. However, the soil of the playa lakes is different and not lined with caliche, making these some of the few areas where the aquifer can recharge. The destruction of playas by farmers and development decreases

3071-489: The aquifer will take over 6,000 years to replenish naturally through rainfall. The aquifer system supplies drinking water to 82% of the 2.3 million people (1990 census) who live within the boundaries of the High Plains study area. The deposition of aquifer material dates back two to six million years, from the late Miocene to early Pliocene ages when the southern Rocky Mountains were still tectonically active. From

3154-477: The aquifer, but levels are generally still dropping in areas including southwestern Kansas and the Texas Panhandle . In other areas, such as parts of eastern and central Nebraska and of the region south of Lubbock, Texas , water levels have risen since 1980. The center-pivot irrigator was described as the "villain" in a 2013 New York Times article, "Wells Dry, Fertile Plains Turn to Dust" recounting

3237-476: The area, such as the Kansas River and its tributaries. The major differences are time and depth. The depth of the Ogallala varies with the shape of then-prevailing surface, being deepest where it fills ancient valleys and channels. The Ogallala Formation consists mostly of coarse sedimentary rocks in its deeper sections, which transition upward into finer-grained material. The water-saturated thickness of

3320-451: The atmosphere becomes visible as cloud , while condensation near ground level is referred to as fog . Atmospheric circulation moves water vapor around the globe; cloud particles collide, grow, and fall out of the upper atmospheric layers as precipitation . Some precipitation falls as snow, hail, or sleet, and can accumulate in ice caps and glaciers , which can store frozen water for thousands of years. Most water falls as rain back into

3403-449: The atmosphere replenishes the land with freshwater. The flow of liquid water and ice transports minerals across the globe. It also reshapes the geological features of the Earth, through processes including erosion and sedimentation . The water cycle is also essential for the maintenance of most life and ecosystems on the planet. Human actions are greatly affecting the water cycle. Activities such as deforestation , urbanization , and

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3486-484: The atmosphere, which lead to a warmer atmosphere through the greenhouse effect . Fundamental laws of physics explain how the saturation vapor pressure in the atmosphere increases by 7% when temperature rises by 1 °C. This relationship is known as the Clausius-Clapeyron equation . While the water cycle is itself a biogeochemical cycle , flow of water over and beneath the Earth is a key component of

3569-506: The availability of freshwater for a variety of uses". Examples for such land use changes are converting fields to urban areas or clearing forests . Such changes can affect the ability of soils to soak up surface water. Deforestation has local as well as regional effects. For example it reduces soil moisture, evaporation and rainfall at the local level. Furthermore, deforestation causes regional temperature changes that can affect rainfall patterns. Aquifer drawdown or overdrafting and

3652-522: The available recharge area. The prevalence of the caliche is partly due to the ready evaporation of soil moisture and the semiarid climate; the aridity increases the amount of evaporation, which in turn increases the amount of caliche in the soil. Both mechanisms reduce the amount of recharge water that reaches the water table. Recharge in the aquifer ranges from 0.024 inches (0.61 mm) per year in parts of Texas and New Mexico to 6 inches (150 mm) per year in south-central Kansas. The regions overlying

3735-405: The average residence time is shorter. In hydrology, residence times can be estimated in two ways. The more common method relies on the principle of conservation of mass ( water balance ) and assumes the amount of water in a given reservoir is roughly constant. With this method, residence times are estimated by dividing the volume of the reservoir by the rate by which water either enters or exits

3818-468: The basin. Farmers on their own land may draw water from the aquifer without charge. Pumping costs are low because the fuel used, natural gas , is inexpensive. The North Plains district first established limits on pumping in 2005 and tightened the regulations four years later. Certain wells are now required to have meters. Yet another challenge facing the district is that higher prices for crops have prompted some to plant additional fields and further increase

3901-523: The cycling of other biogeochemicals. Runoff is responsible for almost all of the transport of eroded sediment and phosphorus from land to waterbodies . The salinity of the oceans is derived from erosion and transport of dissolved salts from the land. Cultural eutrophication of lakes is primarily due to phosphorus, applied in excess to agricultural fields in fertilizers , and then transported overland and down rivers. Both runoff and groundwater flow play significant roles in transporting nitrogen from

3984-399: The denser seawater intruding from the sides of the islands. Such an island's freshwater lens, and thus the water table, rises and falls with the tides. In some regions, for example, Great Britain or California , winter precipitation is often higher than summer precipitation and so the groundwater storage is not fully recharged in summer. Consequently, the water table is lower during

4067-482: The direction of groundwater flow typically has both a horizontal and a vertical component. The slope of the water table is known as the “hydraulic gradient”, which depends on the rate at which water is added to and removed from the aquifer and the permeability of the material. The water table does not always mimic the topography due to variations in the underlying geological structure (e.g., folded, faulted, fractured bedrock). A perched water table (or perched aquifer)

4150-444: The disastrous Dust Bowl of the 1930s. Only after World War II , when center-pivot irrigation became available, was the land mass of the High Plains aquifer system transformed into one of the most agriculturally productive regions in the world. Ground water levels decline when the rate of extraction by irrigation exceeds the rate of recharge. At places, the water table was measured to drop more than 5 ft (1.5 m) per year at

4233-532: The earlier Aristotle, the Eastern Han Chinese scientist Wang Chong (27–100 AD) accurately described the water cycle of Earth in his Lunheng but was dismissed by his contemporaries. Up to the time of the Renaissance, it was wrongly assumed that precipitation alone was insufficient to feed rivers, for a complete water cycle, and that underground water pushing upwards from the oceans were

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4316-435: The exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence the climate system . The evaporative phase of the cycle purifies water because it causes salts and other solids picked up during the cycle to be left behind. The condensation phase in

4399-522: The extraction of groundwater are altering natural landscapes ( land use changes ) all have an effect on the water cycle. On top of this, climate change is leading to an intensification of the water cycle . Research has shown that global warming is causing shifts in precipitation patterns, increased frequency of extreme weather events, and changes in the timing and intensity of rainfall. These water cycle changes affect ecosystems , water availability , agriculture, and human societies. The water cycle

4482-417: The future groundwater sustainability for portions of the aquifer. An aquifer is a groundwater storage reservoir in the water cycle . While groundwater is a renewable source, reserves replenish relatively slowly. The USGS has performed several studies of the aquifer, to determine what is coming in ( groundwater recharge from the surface), what is leaving (water pumped out and baseflow to streams), and what

4565-602: The global and regional level. These findings are a continuation of scientific consensus expressed in the IPCC Fifth Assessment Report from 2007 and other special reports by the Intergovernmental Panel on Climate Change which had already stated that the water cycle will continue to intensify throughout the 21st century. The effects of climate change on the water cycle are profound and have been described as an intensification or

4648-435: The highest quality for drinking and irrigation in the northern region while the southern region had the poorest. Human and natural processes over the past 60 to 70 years, including irrigation density, climate, and nitrogen applications, have caused higher concentrations of contaminants including nitrates. Nitrate levels generally meet USGS water quality standards, but continue to gradually increase over time. This trend can impact

4731-541: The land mass floated on a body of water, and that most of the water in rivers has its origin under the earth. Examples of this belief can be found in the works of Homer ( c.  800 BCE ). In Works and Days (ca. 700 BC), the Greek poet Hesiod outlines the idea of the water cycle: "[Vapour] is drawn from the ever-flowing rivers and is raised high above the earth by windstorm, and sometimes it turns to rain towards evening, and sometimes to wind when Thracian Boreas huddles

4814-406: The land surface and can seep back into surface-water bodies (and the ocean) as groundwater discharge or be taken up by plants and transferred back to the atmosphere as water vapor by transpiration . Some groundwater finds openings in the land surface and emerges as freshwater springs. In river valleys and floodplains , there is often continuous water exchange between surface water and ground water in

4897-587: The land to waterbodies. The dead zone at the outlet of the Mississippi River is a consequence of nitrates from fertilizer being carried off agricultural fields and funnelled down the river system to the Gulf of Mexico . Runoff also plays a part in the carbon cycle , again through the transport of eroded rock and soil. The hydrodynamic wind within the upper portion of a planet's atmosphere allows light chemical elements such as Hydrogen to move up to

4980-502: The lead agency in the transboundary pipeline project, the U.S. State Department commissioned an environmental-impact assessment as required by the National Environmental Policy Act of 1969 . The Environmental Impact Statement concluded that the project posed little threat of "adverse environmental impacts", the report was drafted by Cardno Entrix , a company that assisted both the Department of State and

5063-479: The long-term sustainability of groundwater supplies to help meet the nation’s water needs." According to Matthew Sanderson, a professor of sociology at Kansas State University , these trends are exacerbated by an agricultural subsidy system and a United States tax code that encourage overinvestment in water-using technology due to a treadmill of production . Robertson suggests federal policy reforms to increase incentives to conserve groundwater, such as amendments to

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5146-443: The main contributors to river water. Bartholomew of England held this view (1240 CE), as did Leonardo da Vinci (1500 CE) and Athanasius Kircher (1644 CE). The first published thinker to assert that rainfall alone was sufficient for the maintenance of rivers was Bernard Palissy (1580 CE), who is often credited as the discoverer of the modern theory of the water cycle. Palissy's theories were not tested scientifically until 1674, in

5229-502: The net changes in storage are (rise, fall or no change). The USGS estimated that total water storage was about 2,925,000,000 acre-feet (3,608 km) in 2005. Withdrawals from the Ogallala Aquifer for irrigation amounted to 26 km (21,000,000 acre⋅ft) in 2000. Since major groundwater pumping began in the late 1940s, overdraft from the High Plains Aquifer has amounted to 332,000,000 acre-feet (410 km), 85% of

5312-511: The ocean or onto land, where the water flows over the ground as surface runoff . A portion of this runoff enters rivers, with streamflow moving water towards the oceans. Runoff and water emerging from the ground ( groundwater ) may be stored as freshwater in lakes. Not all runoff flows into rivers; much of it soaks into the ground as infiltration . Some water infiltrates deep into the ground and replenishes aquifers , which can store freshwater for long periods of time. Some infiltration stays close to

5395-420: The ocean to the atmosphere. The processes that drive these movements are evaporation , transpiration , condensation , precipitation , sublimation , infiltration , surface runoff , and subsurface flow. In doing so, the water goes through different forms: liquid, solid ( ice ) and vapor . The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation. The water cycle involves

5478-424: The processes that drive the movement of water throughout the hydrosphere . However, much more water is "in storage" (or in "pools") for long periods of time than is actually moving through the cycle. The storehouses for the vast majority of all water on Earth are the oceans. It is estimated that of the 1,386,000,000 km of the world's water supply, about 1,338,000,000 km is stored in oceans, or about 97%. It

5561-475: The pumping of fossil water increase the total amount of water in the hydrosphere. This is because the water that was originally in the ground has now become available for evaporation as it is now in contact with the atmosphere. Since the middle of the 20th century, human-caused climate change has resulted in observable changes in the global water cycle. The IPCC Sixth Assessment Report in 2021 predicted that these changes will continue to grow significantly at

5644-472: The relentless decline of parts of the Ogallala Aquifer. Sixty years of intensive farming using huge center-pivot irrigators has emptied parts of the High Plains Aquifer. Hundreds to thousands of years of rainfall would be needed to replace the groundwater in the depleted aquifer. In Kansas in 1950, irrigated cropland covered 250,000 acres (100,000 ha); with the use of center-pivot irrigation, nearly three million acres of land were irrigated. In some places in

5727-462: The reservoir. Conceptually, this is equivalent to timing how long it would take the reservoir to become filled from empty if no water were to leave (or how long it would take the reservoir to empty from full if no water were to enter). An alternative method to estimate residence times, which is gaining in popularity for dating groundwater, is the use of isotopic techniques. This is done in the subfield of isotope hydrology . The water cycle describes

5810-526: The rivers run into the sea, yet the sea is not full; unto the place from whence the rivers come, thither they return again" ( Ecclesiastes 1:6-7 ). Furthermore, it was also observed that when the clouds were full, they emptied rain on the earth ( Ecclesiastes 11:3 ). In the Adityahridayam (a devotional hymn to the Sun God) of Ramayana , a Hindu epic dated to the 4th century BCE, it is mentioned in

5893-433: The summer. This disparity between the level of the winter and summer water table is known as the "zone of intermittent saturation", wherein the water table will fluctuate in response to climatic conditions. Fossil water is groundwater that has remained in an aquifer for several millennia and occurs mainly in deserts . It is non-renewable by present-day rainfall due to its depth below the surface, and any extraction causes

5976-409: The thick clouds." In the ancient Near East , Hebrew scholars observed that even though the rivers ran into the sea, the sea never became full. Some scholars conclude that the water cycle was described completely during this time in this passage: "The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to its circuits. All

6059-469: The time of maximum extraction. In extreme cases, the deepening of wells was required to reach the steadily falling water table. In the 21st century, recognition of the significance of the aquifer has led to increased coverage from regional and international journalists. Water conservation practices ( terracing and crop rotation ), more efficient irrigation methods (center pivot and drip ), and reduced area under irrigation have helped to slow depletion of

6142-473: The uplands to the west, rivers and streams cut channels in a generally west to east or southeast direction. Erosion of the Rockies provided alluvial and aeolian sediment that filled the ancient channels and eventually covered the entire area of the present-day aquifer, forming the water-bearing Ogallala Formation. In that respect, the process is similar to those currently prevailing in other modern rivers of

6225-413: The use of water from the aquifer. 36°59′26″N 101°26′52″W  /  36.99056°N 101.44778°W  / 36.99056; -101.44778 Water table The water table is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0). It may be visualized as the "surface" of the subsurface materials that are saturated with groundwater in

6308-526: The volume of Lake Erie. Many farmers in the Texas High Plains , which rely particularly on groundwater, are now turning away from irrigated agriculture as pumping costs have risen and as they have become aware of the hazards of overpumping. The rate at which groundwater is recharged is limited by several factors. Much of the plains region is semiarid , with steady winds that hasten evaporation of surface water and precipitation. In many locations,

6391-442: The water cycle. Aristotle correctly hypothesized that the sun played a role in the Earth's hydraulic cycle in his book Meteorology , writing "By it [the sun's] agency the finest and sweetest water is everyday carried up and is dissolved into vapor and rises to the upper regions, where it is condensed again by the cold and so returns to the earth.", and believed that clouds were composed of cooled and condensed water vapor. Much like

6474-413: The water in its pore spaces is paleowater , dating back to the most recent ice age and probably earlier. Groundwater within the Ogallala generally flows from west to east at an average rate of a foot per day. Hydraulic conductivity , or the ability for a fluid (water) to move through porous material, ranges from 25 to 300 feet (7.6 to 91.4 m) per day. Water quality within the Ogallala varies with

6557-505: The water outstrips its replenishment. The water level is particularly on the decline in Texas and New Mexico. Continued long-term use of the aquifer is "troublesome and in need of major reevaluation," according to the historian Paul H. Carlson , professor-emeritus from Texas Tech University in Lubbock . In 2008, TransCanada Corporation proposed the construction of the 1,661-mile (2,673 km) Keystone XL pipeline to carry oil from

6640-413: The water table may be more difficult to define. “Water table” and “ water level ” are not synonymous. If a deeper aquifer has a lower permeable unit that confines the upward flow, then the water level in this aquifer may rise to a level that is greater or less than the elevation of the actual water table. The elevation of the water in this deeper well is dependent upon the pressure in the deeper aquifer and

6723-420: The water table reaches the surface. Groundwater entering rivers and lakes accounts for the base-flow water levels in water bodies. Within an aquifer, the water table is rarely horizontal, but reflects the surface relief due to the capillary effect ( capillary fringe ) in soils , sediments and other porous media . In the aquifer, groundwater flows from points of higher pressure to points of lower pressure, and

6806-544: The water table to reach its capillary action, groundwater must be removed during construction. This is conspicuous in Berlin , which is built on sandy, marshy ground, and the water table is generally 2 meters below the surface. Pink and blue pipes can often be seen carrying groundwater from construction sites into the Spree river (or canals). Water cycle The water cycle (or hydrologic cycle or hydrological cycle )

6889-616: Was named in 1898 by geologist N. H. Darton from its type locality near the town of Ogallala, Nebraska . The aquifer is part of the High Plains Aquifer System, and resides in the Ogallala Formation , which is the principal geologic unit underlying 80% of the High Plains . Large-scale extraction for agricultural purposes started after World War II due partially to center pivot irrigation and to

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