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Groundwater is the
water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , even though it provide ...

water
present beneath
Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% is Water distribution on Earth, covered wi ...

Earth
's surface in rock and soil pore spaces and in the
fracture Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...

fracture
s of
rock formations , Nevada Nevada (, ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah ...
. A unit of rock or an unconsolidated deposit is called an
aquifer An aquifer is an underground layer of -bearing , rock fractures or unconsolidated materials (, , or ). can be extracted using a water . The study of water flow in aquifers and the characterization of aquifers is called . Related terms include a ...

aquifer
when it can yield a usable quantity of water. The depth at which
soil Surface-water- gley developed in glacial till, Northern Ireland.">Northern_Ireland.html" ;"title="glacial till, Northern Ireland">glacial till, Northern Ireland. Soil is a mixture of organic matter, minerals, gases, liquids, and organisms tha ...

soil
pore spaces or fractures and voids in rock become completely saturated with water is called the
water table The water table is the upper surface of the Phreatic zone, zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is ...

water table
. Groundwater is recharged from the surface; it may discharge from the surface naturally at
springs Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a heli ...
and seeps, and can form
oases In geography, an oasis (, plural oases, ) is a fertile land in a desert or semi-desert environment.
or
wetland A wetland is a distinct ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles ...

wetland
s. Groundwater is also often withdrawn for
agricultural Agriculture is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary Image:Family watching television 1958.jpg, Exercise trends, Increases in sedentary behaviors such as watching tele ...

agricultural
,
municipal A municipality is usually a single administrative division Administrative division, administrative unitArticle 3(1). , country subdivision, administrative region, subnational entity, first-level subdivision, as well as many similar terms, ...

municipal
, and
industrial Industrial may also refer to: Industry * Industrial archaeology, the study of the history of the industry * Industrial engineering, engineering dealing with the optimization of complex industrial processes or systems * Industrial loan company, a f ...
use by constructing and operating extraction
wells Wells most commonly refers to: * Wells, Somerset, a cathedral city in Somerset, England * Well, an excavation or structure created in the ground * Wells (name) Wells may also refer to: Places ;Canada *Wells, British Columbia ;England * Wells ( ...

wells
. The study of the distribution and movement of groundwater is
hydrogeology Hydrogeology (''hydro-'' meaning water, and ''-geology'' meaning the study of the ) is the area of that deals with the distribution and movement of in the and of the Earth's (commonly in s). The terms groundwater hydrology, geohyd ...
, also called groundwater
hydrology Hydrology (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approxi ...
. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain
soil moisture Soil moisture is the water content 300px, Soil composition by Volume and Mass, by phase: air, water, void (pores filled with water or air), soil, and total. Water content or moisture content is the quantity of water Water is an Inorganic ...
,
permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean The ocean (also the sea The sea, connected as the world ocean or simply the ocean The oc ...

permafrost
(frozen soil), immobile water in very low permeability
bedrock Bedrock in geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rocks of which it is composed, and ...

bedrock
, and deep geothermal or oil formation water. Groundwater is hypothesized to provide
lubrication Lubrication is the process or technique of using a lubricant A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the f ...
that can possibly influence the movement of faults. It is likely that much of
Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% is Water distribution on Earth, covered wi ...

Earth
's subsurface contains some water, which may be mixed with other fluids in some instances. Groundwater is often cheaper, more convenient and less vulnerable to
pollution Pollution is the introduction of s into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). s, the components of po ...

pollution
than surface water. Therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of usable water storage in the United States, and California annually withdraws the largest amount of groundwater of all the states. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, including the
Great Lakes The Great Lakes also called the Great Lakes of North America or the Laurentian Great Lakes, is a series of large interconnected freshwater lake A lake is an area filled with water, localized in a basin, surrounded by land Land ...

Great Lakes
. Many municipal water supplies are derived solely from groundwater. Use of groundwater has related environmental issues. For example, polluted groundwater is less visible and more difficult to clean up than pollution in rivers and lakes. Groundwater pollution most often results from improper disposal of wastes on land. Major sources include industrial and household chemicals and garbage
landfills A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the waste w ...
, excessive
fertilizer A fertilizer (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American E ...

fertilizer
s and pesticides used in agriculture, industrial waste lagoons, tailings and process
wastewater Wastewater is generated after the use of fresh water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the ...

wastewater
from mines, industrial fracking, oil field brine pits, leaking underground oil storage tanks and pipelines,
sewage sludge Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of that is produced by a of people. It is typically transported through a . Sewage consists of wastewater discharged from residences and from commercial, instit ...
and
septic systems A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for Sewage treatment, basic treatment. Settling and Anaerobic digestion, anaerobic processes reduce solids and organi ...

septic systems
. Additionally, groundwater is susceptible to
saltwater intrusion Saltwater intrusion is the movement of saline water Saline water (more commonly known as salt water) is water that contains a high concentration of solvation, dissolved salts (mainly sodium chloride). The salt concentration is usually expressed i ...
in coastal areas and can cause
land subsidence File:SubsidedRoad.jpg, Mam Tor road destroyed by subsidence and shear stress, shear, near Castleton, Derbyshire, Castleton, Derbyshire Subsidence is the sudden sinking or gradual downward settling of the ground's surface with little or no horiz ...
when extracted unsustainably, leading to sinking cities (like
Bangkok Bangkok is the capital and most populous city of Thailand Thailand ( th, ประเทศไทย), historically known as Siam, () officially the Kingdom of Thailand, is a country in Southeast Asia Southeast Asia or Southeastern ...

Bangkok
)) and loss in elevation (such as the
multiple meters lost in the Central Valley of California) Multiple may refer to: Economics *Multiple finance, a method used to analyze stock prices *Multiples of the P/E, price-to-earnings ratio *Chain stores, are also referred to as 'Multiples' *The ratio of a film's total gross to that of its opening w ...
. These issues are made more complicated by
sea level rise Tide gauge measurements show that the current global sea level rise began at the start of the 20th century. Between 1900 and 2017, the globally averaged sea level Mean sea level (MSL) (often shortened to sea level) is an average In colloqui ...

sea level rise
and other changes caused by climate changes which will change precipitation and
water scarcity Water scarcity (water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. Humanity is facing a water crisis, due to unequal distribution (exacerbated by climate change Climate change inclu ...

water scarcity
globally.


Characteristics


Location (aquifers)

An
aquifer An aquifer is an underground layer of -bearing , rock fractures or unconsolidated materials (, , or ). can be extracted using a water . The study of water flow in aquifers and the characterization of aquifers is called . Related terms include a ...

aquifer
is a layer of porous substrate that contains and transmits groundwater. When water can flow directly between the surface and the saturated zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are usually more saturated since gravity causes water to flow downward. The upper level of this saturated layer of an unconfined aquifer is called the
water table The water table is the upper surface of the Phreatic zone, zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is ...

water table
or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the
phreatic zone The phreatic zone, or zone of saturation, is the part of an aquifer, below the water table, in which relatively all pores and fractures are saturated with water. Above the water table is the vadose zone. The phreatic zone size, color, and depth m ...
. Substrate with low porosity that permits limited transmission of groundwater is known as an aquitard. An aquiclude is a substrate with porosity that is so low it is virtually impermeable to groundwater. A confined aquifer is an aquifer that is overlain by a relatively impermeable layer of rock or substrate such as an aquiclude or aquitard. If a confined aquifer follows a downward grade from its recharge zone, groundwater can become pressurized as it flows. This can create
artesian well :''See Great Artesian Basin for the water source in Australia.'' scheme: 1. Aquifer 2. Impervious strata 3. Infiltration area 4. Artesian well 5. Saturation level 6. Subartesian well 7. Artesian spring Image:Artesian Well (PSF).png, 300px, Schem ...

artesian well
s that flow freely without the need of a pump and rise to a higher elevation than the static water table at the above, unconfined, aquifer.


Water cycle

Groundwater makes up about thirty percent of the world's
fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in ...

fresh water
supply, which is about 0.76% of the entire world's water, including oceans and permanent ice. About 99% of the world's liquid fresh water is ground water. Global groundwater storage is roughly equal to the total amount of freshwater stored in the snow and ice pack, including the north and south poles. This makes it an important resource that can act as a natural storage that can buffer against shortages of
surface water An example of surface water is Lake Kinney. Surface water is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which ...
, as in during times of
drought A drought is an event of prolonged shortages in the water supply, whether atmospheric (below-average precipitation In meteorology Meteorology is a branch of the atmospheric sciences Atmospheric science is the study of the Earth's atm ...

drought
. Groundwater is naturally replenished by surface water from
precipitation In meteorology Meteorology is a branch of the (which include and ), with a major focus on . The study of meteorology dates back , though significant progress in meteorology did not begin until the 18th century. The 19th century saw mod ...
,
stream A stream is a body of water (Lysefjord) in Norway Norway, officially the Kingdom of Norway,Names in the official and recognised languages: Bokmål Bokmål (, ; literally "book tongue") is an official written standard for the No ...

stream
s, and
river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

river
s when this recharge reaches the water table. Groundwater can be a long-term '
reservoir A reservoir (; from French ''réservoir'' ) is most commonly an enlarged natural or artificial lake A lake is an area filled with water, localized in a basin, surrounded by land Land is the solid surface of Earth that is not per ...

reservoir
' of the natural water cycle (with
residence time The residence time of a fluid parcelIn fluid dynamics In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including aerodynamics ...
s from days to millennia), as opposed to short-term water reservoirs like the atmosphere and fresh surface water (which have residence times from minutes to years). The figure shows how deep groundwater (which is quite distant from the surface recharge) can take a very long time to complete its natural cycle. The
Great Artesian Basin bathing thermes supplied by artesian bore water Image:ThargomindahHydro.jpg, upright=1.2, Hot water bore hole into the Great Artesian Basin in Thargomindah, Queensland, Thargomindah The Great Artesian Basin (GAB), located in Australia, is the ...

Great Artesian Basin
in central and eastern
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Australia
is one of the largest confined aquifer systems in the world, extending for almost 2 million km2. By analysing the trace elements in water sourced from deep underground, hydrogeologists have been able to determine that water extracted from these aquifers can be more than 1 million years old. By comparing the age of groundwater obtained from different parts of the Great Artesian Basin, hydrogeologists have found it increases in age across the basin. Where water recharges the aquifers along the
Eastern Divide
Eastern Divide
, ages are young. As groundwater flows westward across the continent, it increases in age, with the oldest groundwater occurring in the western parts. This means that in order to have travelled almost 1000 km from the source of recharge in 1 million years, the groundwater flowing through the Great Artesian Basin travels at an average rate of about 1 metre per year. Recent research has demonstrated that
evaporation Evaporation is a type of that occurs on the of a as it changes into the gas phase. The surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other bas ...

evaporation
of groundwater can play a significant role in the local water cycle, especially in arid regions. Scientists in
Saudi Arabia (''Shahada'') , national_anthem = "National Anthem of Saudi Arabia, " "National Anthem of Saudi Arabia" , image_map = Saudi Arabia (orthographic projection).svg , capital = Riyadh , coordinates ...

Saudi Arabia
have proposed plans to recapture and recycle this evaporative moisture for crop irrigation. In the opposite photo, a 50-centimeter-square reflective carpet, made of small adjacent plastic cones, was placed in a plant-free dry desert area for five months, without rain or irrigation. It managed to capture and condense enough ground vapor to bring to life naturally buried seeds underneath it, with a green area of about 10% of the carpet area. It is expected that, if seeds were put down before placing this carpet, a much wider area would become green.


Temperature

The high
specific heat capacity In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quan ...
of water and the insulating effect of soil and rock can mitigate the effects of climate and maintain groundwater at a relatively steady
temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical concept ...

temperature
. In some places where groundwater temperatures are maintained by this effect at about 10 °C (50 °F), groundwater can be used for controlling the temperature inside structures at the surface. For example, during hot weather relatively cool groundwater can be pumped through radiators in a home and then returned to the ground in another well. During cold seasons, because it is relatively warm, the water can be used in the same way as a source of heat for
heat pump A heat pump is a system used to heat or cool an enclosed space or domestic water by transferring thermal energy from a cooler space to a warmer space using the Heat pump and refrigeration cycle, refrigeration cycle, moving heat in the opposite ...

heat pump
s that is much more efficient than using air.


Quantities

The volume of groundwater in an aquifer can be estimated by measuring water levels in local wells and by examining geologic records from well-drilling to determine the extent, depth and thickness of water-bearing sediments and rocks. Before an investment is made in production wells, test wells may be drilled to measure the depths at which water is encountered and collect samples of soils, rock and water for laboratory analyses. Pumping tests can be performed in test wells to determine flow characteristics of the aquifer. The characteristics of aquifers vary with the geology and structure of the substrate and topography in which they occur. In general, the more productive aquifers occur in sedimentary geologic formations. By comparison, weathered and fractured crystalline rocks yield smaller quantities of groundwater in many environments. Unconsolidated to poorly cemented alluvial materials that have accumulated as
valley A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a ...

valley
-filling sediments in major river valleys and geologically subsiding structural basins are included among the most productive sources of groundwater. Fluid flows can be altered in different lithological settings by brittle deformation of rocks in fault zones; the mechanisms by which this occurs are the subject of fault zone hydrogeology.


Uses

Most land areas on
Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% is Water distribution on Earth, covered wi ...

Earth
have some form of aquifer underlying them, sometimes at significant depths. In some cases, these aquifers are rapidly being depleted by the human population. Of all
natural resource Natural resources are resource Resource refers to all the materials available in our environment which help us to satisfy our needs and wants. Resources can broadly be classified upon their availability — they are classified into renewabl ...
s, groundwater is the most extracted resource in the world. As of 2010, the top five countries by volume of groundwater extraction were India, China, the US, Pakistan, and Iran. A majority of extracted groundwater, 70%, is used for agricultural purposes. Groundwater is the most accessed source of freshwater around the world, including as
drinking water Drinking water, also known as potable water, is water that is safe to drinking, drink or use for food preparation. The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related ...

drinking water
,
irrigation Irrigation is the agricultural Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated Domesti ...

irrigation
, and
manufacturing Manufacturing is the creation or production Production may be: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (g ...
. Groundwater accounts for about half of the world's drinking water, 40% of its irrigation water, and a third of water for industrial purposes. Fresh-water aquifers, especially those with limited recharge by snow or rain, also known as
meteoric waterMeteoric water is the water derived from Precipitation (meteorology), precipitation (snow and rain). This includes water from lakes, rivers, and icemelts, which all originate from precipitation indirectly. While the bulk of rainwater or meltwater fro ...
, can be over-exploited and depending on the local
hydrogeology Hydrogeology (''hydro-'' meaning water, and ''-geology'' meaning the study of the ) is the area of that deals with the distribution and movement of in the and of the Earth's (commonly in s). The terms groundwater hydrology, geohyd ...
, may draw in non-potable water or saltwater intrusion from hydraulically connected aquifers or surface water bodies. This can be a serious problem, especially in coastal areas and other areas where aquifer pumping is excessive. In some areas, the ground water can become contaminated by arsenic and other mineral poisons. Aquifers are critically important in human habitation and agriculture. Deep aquifers in arid areas have long been water sources for irrigation (see Ogallala below). Many villages and even large cities draw their water supply from wells in aquifers. Municipal, irrigation, and industrial water supplies are provided through large wells. Multiple wells for one water supply source are termed "wellfields", which may withdraw water from confined or unconfined aquifers. Using ground water from deep, confined aquifers provides more protection from surface water contamination. Some wells, termed "collector wells", are specifically designed to induce infiltration of surface (usually river) water. Aquifers that provide sustainable fresh groundwater to urban areas and for agricultural irrigation are typically close to the ground surface (within a couple of hundred metres) and have some recharge by fresh water. This recharge is typically from rivers or meteoric water (precipitation) that percolates into the aquifer through overlying unsaturated materials. Occasionally, sedimentary or "fossil" aquifers are used to provide irrigation and drinking water to urban areas. In Libya, for example, Muammar Gaddafi's
Great Manmade River Great may refer to: Descriptions or measurements * Great, a relative measurement in physical space, see Size * Greatness, being divine, majestic, superior, majestic, or transcendent People with the name * "The Great", a historical suffix to people ...
project has pumped large amounts of groundwater from aquifers beneath the Sahara to populous areas near the coast. Though this has saved Libya money over the alternative, desalination, the aquifers are likely to run dry in 60 to 100 years. Aquifer depletion has been cited as one of the causes of the food price rises of 2011.


Issues


Overview

Certain problems have beset the use of groundwater around the world. Just as river waters have been over-used and in many parts of the world, so too have aquifers. The big difference is that aquifers are out of sight. The other major problem is that water management agencies, when calculating the "
sustainable yield The sustainable yield of natural capital on "natural capital" and "balancing the budget of our resources" File:Fires along the Rio Xingu, Brazil - NASA Earth Observatory.jpg, Fires along the Rio Xingu, Brazil - NASA Earth Observatory. Loss of na ...
" of aquifer and river water, have often counted the same water twice, once in the aquifer, and once in its connected river. This problem, although understood for centuries, has persisted, partly through inertia within government agencies. In Australia, for example, prior to the statutory reforms initiated by the
Council of Australian Governments The Council of Australian Governments (COAG) was the primary intergovernmental forum in Australia from 1992 to 2020. Comprising the Government of Australia, federal government, the governments of the States and territories of Australia, six st ...
water reform framework in the 1990s, many Australian states managed groundwater and surface water through separate government agencies, an approach beset by rivalry and poor communication. In general, the time lags inherent in the dynamic response of groundwater to development have been ignored by water management agencies, decades after scientific understanding of the issue was consolidated. In brief, the effects of groundwater overdraft (although undeniably real) may take decades or centuries to manifest themselves. In a classic study in 1982, John D. Bredehoeft and colleagues modeled a situation where groundwater extraction in an intermontane basin withdrew the entire annual recharge, leaving ‘nothing’ for the natural groundwater-dependent vegetation community. Even when the borefield was situated close to the vegetation, 30% of the original vegetation demand could still be met by the lag inherent in the system after 100 years. By year 500, this had reduced to 0%, signalling complete death of the groundwater-dependent vegetation. The science has been available to make these calculations for decades; however, in general water management agencies have ignored effects that will appear outside the rough timeframe of political elections (3 to 5 years). Marios Sophocleous argued strongly that management agencies must define and use appropriate timeframes in groundwater planning. This will mean calculating groundwater withdrawal permits based on predicted effects decades, sometimes centuries in the future. As water moves through the landscape, it collects soluble salts, mainly
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salt (chemistry), salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With Molar mass, molar ...
. Where such water enters the atmosphere through
evapotranspiration Evapotranspiration (ET) is the sum of water evaporation and transpiration from a surface area to the Atmosphere of Earth, atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and ...

evapotranspiration
, these salts are left behind. In
irrigation Irrigation is the agricultural Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated Domesti ...

irrigation
districts, poor drainage of soils and surface aquifers can result in water tables' coming to the surface in low-lying areas. Major
land degradation Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be deleterious or u ...
problems of
soil salinity 249x249px, Saline incrustation in a PVC irrigation pipe from Brazil Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can ...
and waterlogging result, combined with increasing levels of salt in surface waters. As a consequence, major damage has occurred to local economies and environments. Four important effects are worthy of brief mention. First, flood mitigation schemes, intended to protect infrastructure built on floodplains, have had the unintended consequence of reducing
aquifer recharge An aquifer is an underground layer of water-bearing permeability (Earth sciences), permeable rock, rock fractures or unconsolidated materials (gravel, sand, or silt). Groundwater can be extracted using a water well. The study of water flow in aqu ...
associated with natural flooding. Second, prolonged depletion of groundwater in extensive aquifers can result in land
subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope move ...
, with associated infrastructure damage – as well as, third, saline intrusion. Fourth, draining acid sulphate soils, often found in low-lying coastal plains, can result in acidification and pollution of formerly freshwater and
estuarine An estuary is a partially enclosed coastal body of brackish water Brackish water, also sometimes termed brack water, is water occurring in a natural environment having more salinity File:IAPSO Standard Seawater.jpg, upInternational Associatio ...

estuarine
streams. Another cause for concern is that groundwater drawdown from over-allocated aquifers has the potential to cause severe damage to both terrestrial and aquatic ecosystems – in some cases very conspicuously but in others quite imperceptibly because of the extended period over which the damage occurs.


Overdraft

Groundwater is a highly useful and often abundant resource. However, over-use, over-abstraction or overdraft, can cause major problems to human users and to the environment. The most evident problem (as far as human groundwater use is concerned) is a lowering of the water table beyond the reach of existing wells. As a consequence, wells must be drilled deeper to reach the groundwater; in some places (e.g.,
California California is a U.S. state, state in the Western United States. With over 39.3million residents across a total area of approximately , it is the List of states and territories of the United States by population, most populous and the List of ...

California
,
Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, ...

Texas
, and
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

India
) the water table has dropped hundreds of feet because of extensive well pumping. The GRACE satellites have collected data that demonstrates 21 of Earth's 37 major aquifers are undergoing depletion. In the
Punjab Punjab (; ; ; ; also as Panjāb or Panj-Āb) is a geopolitical, cultural, and in , specifically in the northern part of the , comprising areas of eastern and . The boundaries of the region are ill-defined and focus on historical accounts. ...
region of
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

India
, for example, groundwater levels have dropped 10 meters since 1979, and the rate of depletion is accelerating. A lowered water table may, in turn, cause other problems such as groundwater-related subsidence and
saltwater intrusion Saltwater intrusion is the movement of saline water Saline water (more commonly known as salt water) is water that contains a high concentration of solvation, dissolved salts (mainly sodium chloride). The salt concentration is usually expressed i ...
. Groundwater is also ecologically important. The importance of groundwater to ecosystems is often overlooked, even by freshwater biologists and ecologists. Groundwaters sustain rivers,
wetland A wetland is a distinct ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles ...

wetland
s, and
lake A lake is an area filled with water, localized in a basin, surrounded by land Land is the solid surface of Earth that is not permanently submerged in water. Most but not all land is situated at elevations above sea level (variable ove ...

lake
s, as well as subterranean ecosystems within
karst Karst is a topography Topography is the study of the forms and features of land surfaces. The topography of an area could refer to the surface forms and features themselves, or a description (especially their depiction in maps). Topography ...
or alluvial aquifers. Not all ecosystems need groundwater, of course. Some terrestrial ecosystems – for example, those of the open
desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of ...

desert
s and similar arid environments – exist on irregular rainfall and the moisture it delivers to the soil, supplemented by moisture in the air. While there are other terrestrial ecosystems in more hospitable environments where groundwater plays no central role, groundwater is in fact fundamental to many of the world's major ecosystems. Water flows between groundwaters and surface waters. Most rivers, lakes, and wetlands are fed by, and (at other places or times) feed groundwater, to varying degrees. Groundwater feeds soil moisture through percolation, and many terrestrial vegetation communities depend directly on either groundwater or the percolated soil moisture above the aquifer for at least part of each year.
Hyporheic zone The hyporheic zone is the region of sediment and porous space beneath and alongside a stream bed A stream is a body of water ( Lysefjord) in Norway Norway ( nb, ; nn, ; se, Norga; smj, Vuodna; sma, Nöörje), officially the ...
s (the mixing zone of streamwater and groundwater) and
riparian zone A riparian zone or riparian area is the interface between land and a river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground an ...
s are examples of
ecotone An ecotone is a transition area between two biological communities, where two communities meet and integrate. It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and gras ...
s largely or totally dependent on groundwater.


Subsidence

Subsidence occurs when too much water is pumped out from underground, deflating the space below the above-surface, and thus causing the ground to collapse. The result can look like craters on plots of land. This occurs because, in its natural equilibrium state, the
hydraulic pressure Hydraulics (from Greek: Υδραυλική) is a technology and applied science Applied science is the use of the scientific method The scientific method is an Empirical evidence, empirical method of acquiring knowledge that has ch ...

hydraulic pressure
of groundwater in the pore spaces of the aquifer and the aquitard supports some of the weight of the overlying sediments. When groundwater is removed from aquifers by excessive pumping, pore pressures in the aquifer drop and compression of the aquifer may occur. This compression may be partially recoverable if pressures rebound, but much of it is not. When the aquifer gets compressed, it may cause land subsidence, a drop in the ground surface. The city of
New Orleans, Louisiana New Orleans (,New Orleans
In the first half of the 20th century, the San Joaquin Valley experienced significant subsidence, in some places up to 8.5 metres (28 feet) due to groundwater removal. Cities on river deltas, including Venice in Italy, and
Bangkok Bangkok is the capital and most populous city of Thailand Thailand ( th, ประเทศไทย), historically known as Siam, () officially the Kingdom of Thailand, is a country in Southeast Asia Southeast Asia or Southeastern ...

Bangkok
in Thailand, have experienced surface subsidence; Mexico City, built on a former lake bed, has experienced rates of subsidence of up to 40 cm (1'3") per year. For coastal cities, subsidence can increase the risk of other environmental issues, such as
sea level rise Tide gauge measurements show that the current global sea level rise began at the start of the 20th century. Between 1900 and 2017, the globally averaged sea level Mean sea level (MSL) (often shortened to sea level) is an average In colloqui ...

sea level rise
. For example, Bangkok is expected to have 5.138 million people exposed to
coastal flooding Coastal flooding normally occurs when dry and low-lying land is submerged by seawater. The range of a coastal flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography Topography is ...
by 2070 because of these combining factors.


Seawater intrusion

Seawater intrusion is the flow or presence of seawater into coastal aquifers; it is a case of
saltwater intrusion Saltwater intrusion is the movement of saline water Saline water (more commonly known as salt water) is water that contains a high concentration of solvation, dissolved salts (mainly sodium chloride). The salt concentration is usually expressed i ...
. It is a natural phenomenon but can be caused or worsened by anthropogenic factors, such as climate change caused
sea level rise Tide gauge measurements show that the current global sea level rise began at the start of the 20th century. Between 1900 and 2017, the globally averaged sea level Mean sea level (MSL) (often shortened to sea level) is an average In colloqui ...

sea level rise
. In the case of homogeneous aquifers, seawater intrusion forms a saline wedge below a transition zone to fresh groundwater, flowing seaward on the top. These changes can have other effects on the land above the groundwater: as an example a 2020 study published in ''
Nature Nature, in the broadest sense, is the natural, physical, material world or universe The universe ( la, universus) is all of space and time and their contents, including planets, stars, galaxy, galaxies, and all other forms of matter an ...
'' found that coastal groundwater in California would rise in many aquifers, increasing risks of flooding and
runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed (printing), bleed, printing that lies beyond the edges to wh ...
challenges.


Pollution

Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers and lakes. Groundwater pollution most often results from improper disposal of wastes on land. Major sources include industrial and household chemicals and garbage
landfill A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste Waste (or wastes) are unwanted or unusable materials. Waste is any substance which is discarded after primar ...

landfill
s, industrial waste lagoons, tailings and process
wastewater Wastewater is generated after the use of fresh water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the ...

wastewater
from mines, oil field brine pits, leaking underground oil storage tanks and pipelines,
sewage sludge Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of that is produced by a of people. It is typically transported through a . Sewage consists of wastewater discharged from residences and from commercial, instit ...
and septic systems. Polluted groundwater is mapped by sampling soils and groundwater near suspected or known sources of pollution, to determine the extent of the pollution, and to aid in the design of groundwater remediation systems. Preventing groundwater pollution near potential sources such as landfills requires lining the bottom of a landfill with watertight materials, collecting any leachate with drains, and keeping rainwater off any potential contaminants, along with regular monitoring of nearby groundwater to verify that contaminants have not leaked into the groundwater. Groundwater pollution, from
pollutant A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. A pollutant may cause long- or short-term damage by changing the growth rate of plant or animal spec ...
s released to the ground that can work their way down into groundwater, can create a contaminant plume within an aquifer. Pollution can occur from landfills, naturally occurring arsenic, on-site
sanitation Sanitation refers to public health Public health has been defined as "the science and art of Preventive healthcare, preventing disease", prolonging life and improving quality of life through organized efforts and informed choices of society ...

sanitation
systems or other point sources, such as
petrol station A filling station is a facility that sells fuel A fuel is any material that can be made to react with other substances so that it releases energy as heat energy or to be used for work. The concept was originally applied solely to thos ...

petrol station
s with leaking underground storage tanks, or leaking
sewer Sewer may refer to: * Part of sewerage, the infrastructure that conveys sewage *Sanitary sewer, a system of pipes used to transport sewage - several types of sanitary sewers can be distinguished *Storm drain, a collection and transportation system ...
s. Movement of water and dispersion within the aquifer spreads the pollutant over a wider area, its advancing boundary often called a plume edge, which can then intersect with groundwater wells or daylight into surface water such as seeps and
springs Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a heli ...
, making the water supplies unsafe for humans and wildlife. Different mechanism have influence on the transport of pollutants, e.g.
diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration In chemistry Chemistry is the study of the properties and behavior of . It is a that covers ...

diffusion
,
adsorption Adsorption is the adhesion Adhesion is the tendency of dissimilar Particle, particles or interface (matter), surfaces to cling to one another (Cohesion (chemistry), cohesion refers to the tendency of similar or identical particles/surfaces ...

adsorption
,
precipitation In meteorology Meteorology is a branch of the (which include and ), with a major focus on . The study of meteorology dates back , though significant progress in meteorology did not begin until the 18th century. The 19th century saw mod ...
, , in the groundwater. The interaction of groundwater contamination with surface waters is analyzed by use of
hydrology transport model relatively free of sediment load An hydrological transport model is a mathematical model used to simulate the flow of rivers, streams, groundwater movement or drainage front displacement, and calculate water quality Water quality refers to ...
s. The danger of pollution of municipal supplies is minimized by locating wells in areas of deep groundwater and impermeable soils, and careful testing and monitoring of the aquifer and nearby potential pollution sources.


Arsenic and fluoride

Around one-third of the world's population drinks water from groundwater resources. Of this, about 10 percent, approximately 300 million people, obtains water from groundwater resources that are heavily polluted with
arsenic Arsenic is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same num ...

arsenic
or
fluoride Fluoride (). According to this source, is a possible pronunciation in British English. is an inorganic In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds compose ...
. These trace elements derive mainly from natural sources by leaching from rock and sediments.


= New method of identifying substances that are hazardous to health

= In 2008, the Swiss Aquatic Research Institute, Eawag, presented a new method by which hazard maps could be produced for geogenic toxic substances in groundwater. This provides an efficient way of determining which wells should be tested. In 2016, the research group made its knowledge freely available on the Groundwater Assessment Platfor
GAP
This offers specialists worldwide the possibility of uploading their own measurement data, visually displaying them and producing risk maps for areas of their choice. GAP also serves as a knowledge-sharing forum for enabling further development of methods for removing toxic substances from water.


Regulations


United States

In the United States, laws regarding ownership and use of groundwater are generally state laws. Regulation of groundwater to minimize pollution of groundwater is addressed in both state and federal law; in the latter case, through regulations issued by the U.S. Environmental Protection Agency (EPA). * The
Rule of Capture The rule of capture or law of capture is common law from England, adopted by a number of U.S. jurisdictions, that establishes a rule of non-liability for captured natural resources including groundwater, Petroleum, oil, Natural gas, gas, and game a ...
, based on English common law, provides each landowner the ability to capture as much groundwater as they can put to a beneficial use, but they are not guaranteed any set amount of water. As a result, well-owners are not liable to other landowners for taking water from beneath their land. State laws or regulations will often define "beneficial use", and sometimes place other limits, such as disallowing groundwater extraction which causes
subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope move ...
on neighboring property. * Limited private ownership rights similar to
riparian rights Riparian water rights (or simply riparian rights) is a system for allocating water among those who possess land along its path. It has its origins in English common law. Riparian A riparian zone or riparian area is the interface between la ...
in a surface stream. The amount of groundwater right is based on the size of the surface area where each landowner gets a corresponding amount of the available water. Once adjudicated, the maximum amount of the water right is set, but the right can be decreased if the total amount of available water decreases as is likely during a drought. Landowners may sue others for encroaching upon their groundwater rights, and water pumped for use on the overlying land takes preference over water pumped for use off the land. * The Reasonable use rule in American
drainage law Drainage law is a specific area of water law related to drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils ...
does not guarantee the landowner a set amount of water, but allows unlimited extraction as long as the result does not unreasonably damage other wells or the aquifer system. Usually this rule gives great weight to historical uses and prevents new uses that interfere with the prior use. * EPA published its "Ground Water Rule", applicable to
public water system Water towers are used to store water at a height sufficient to pressurize a water supply distribution system Public water system is a regulatory term used in the United States and Canada, referring to certain utilities A public utility company ...
s, in 2006. The rule focuses on groundwater-supplied systems that may be subject to contamination from fecal bacteria, and requires such systems to take corrective action. * In real estate property transactions both groundwater and soil are the subjects of scrutiny. For
brownfields In urban planning Urban planning, also known as regional planning, town planning, city planning, or rural planning, is a technical and political process that is focused on the development and design of land use and the built environment, ...
sites (formerly contaminated sites that have been remediated), EPA requires preparation of Phase I Environmental Site Assessments, to investigate and disclose potential pollution issues. In the
San Fernando Valley The San Fernando Valley, known locally as "the Valley", is an urbanized valley A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other ...

San Fernando Valley
of California,
real estate contract A real estate contract is a contract A contract is a legally binding document between at least two parties that defines and governs the rights and duties of the parties to an agreement. A contract is legally enforceable because it meets the re ...
s for property transfer below the
Santa Susana Field Laboratory The Santa Susana Field Laboratory is a complex of industrial research and development facilities located on a portion of the Southern California Simi Hills in Simi Valley, California. It was used mainly for the development and testing of Liquid-p ...
(SSFL) and eastward have clauses releasing the seller from
liability Liability may refer to: Law * Legal liability, in both civil and criminal law ** Public liability, part of the law of tort which focuses on civil wrongs ** Product liability, the area of law in which manufacturers, distributors, suppliers, retai ...
for groundwater contamination consequences from existing or future pollution of the Valley Aquifer.


India

In India, 65% of the PM Launches Rs 6,000 Crore Groundwater Management Plan
NDTV, 25 December 2019.
and about 90% of extracted groundwater is used for irrigation. The groundwater regulation is controlled and maintained by the central government and four organizations; 1) Central Water Commission, 2) Central Ground Water, 3) Central Ground Water Authority, 4)
Central Pollution Control Board The Central Pollution Control Board (CPCB) of India is a statutory organisation under the Ministry of Environment, Forest and Climate Change (Mo.E.F.C.C.). It was established in 1974 under the Water (Prevention and Control of pollution) Act, 1 ...
. Laws, regulations and scheme regarding India's groundwater: * 2019 Atal Bhujal Yojana (Atal groundwater scheme), a 5 years (2020-21 to 2024-25) scheme costing INR 6 billion (US$854 million) for managing demand side with village panchayat level water security plans, was approved for implementation in 8,350 water-stressed villages across 7 states, including Haryana, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan and Uttar Pradesh.Centre approves Rs 6,000 crore scheme to manage groundwater
Times of India, 24 December 2019.
* 2013 National Water Framework Bill ensures that India's groundwater is a public resource, and is not to be exploited by companies through privatization of water. The National Water Framework Bill allows for everyone to access clean drinking water, of the right to clean drinking water under Article 21 of 'Right to Life' in . The bill indicates a want for the states of India to have full control of groundwater contained in aquifers. So far
Andhra Pradesh Andhra Pradesh (English: Telugu: ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Andhra Pradesh
,
Assam Assam (, ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to ...

Assam
,
Bihar Bihar (; ) is a states and union territories of India, state in eastern India. It is the list of states and union territories of India by population, third-largest state by population and list of states and union territories of India by area ...

Bihar
,
Goa Goa () is a state on the southwestern coast of India India (Hindi: ), officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by population, second-most populous country, the ...

Goa
,
Himachal Pradesh Himachal Pradesh (; ; "Province of the Snow-laden Mountains") is a States and union territories of India, state in the northern part of India. Situated in the Western Himalayas, it is one of the eleven Indian Himalayan Region, mountain states ...

Himachal Pradesh
, Jammu & Kashmir,
Karnataka Karnataka (; ISO The International Organization for Standardization (ISO; ) is an international standard are technical standards developed by international organizations (intergovernmental organizations), such as Codex Alimentarius in f ...

Karnataka
,
Kerala Kerala ( ; ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper ...

Kerala
,
West Bengal West Bengal (, Bengali Bengali or Bengalee, or Bengalese may refer to: *something of, from, or related to Bengal, a large region in South Asia * Bengalis, an ethnic and linguistic group of the region * Bengali language, the language they sp ...

West Bengal
,
Telangana Telangana (, , ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspape ...

Telangana
,
Maharashtra Maharashtra (; , abbr. MH or Maha, is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper) ...

Maharashtra
,
Lakshadweep Lakshadweep (), also known as Laccadives (), is a union territory #REDIRECT Union territory#REDIRECT Union territory A union territory ( hi, script=latn, kendraśāsit pradeś, , centrally administered province) is a type of administrative d ...

Lakshadweep
,
PuducherryPuducherry or Pondicherry may refer to: * Puducherry (union territory) Puducherry (), also known as Pondicherry (), is a States and union territories of India, union territory of India. It was formed out of four territories of former French India, ...
,
Chandigarh Chandigarh () is a city, district and union territory in India that serves as the capital of the two neighbouring states of Punjab and Haryana. Chandigarh is bordered by the state of Punjab to the north, the west and the south, and by the s ...

Chandigarh
, Dadra & Nagar Haveli are the only ones using this bill. * In 2012, National Water Policy was updated, which had previously been launched in 1987 and updated in 2002 and later in 2012. * In 2011, the Indian Government created a Model Bill for Groundwater Management; this model selects which state governments can enforce their laws on groundwater usage and regulation. * 1882 Easement Act gives landowners priority over surface and groundwater that is on their land and allows them to give or take as much as they want as long as the water is on their land. This act prevents the government from enforcing regulations of groundwater, allowing many landowners to privatize their groundwater instead accessing it in community areas. 1882 Easement Act's Section 7(g) states that every landowner has the right to collect within his limits, all water under the land and on its surface which does not pass in a defined channel.


Canada

A significant portion of
Canada Canada is a country in the northern part of North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean, Atlantic to the Pacific Ocean, Pacific and northward into the Arctic Oce ...

Canada
’s
population Population typically refers the number of people in a single area whether it be a city or town, region, country, or the world. Governments typically quantify the size of the resident population within their jurisdiction by a process called a ...

population
relies on the use of groundwater. In
Canada Canada is a country in the northern part of North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean, Atlantic to the Pacific Ocean, Pacific and northward into the Arctic Oce ...

Canada
, roughly 8.9 million people or 30% of Canada's population rely on groundwater for domestic use and approximately two thirds of these users live in
rural area A rural landscape in Lappeenranta, South Karelia, Finland. 15 July 2000.">South_Karelia.html" ;"title="Lappeenranta, South Karelia">Lappeenranta, South Karelia, Finland. 15 July 2000. In general, a rural area or a countryside is a geographic ...

rural area
s. * The
Constitution Act, 1867 The ''Constitution Act, 1867'The Constitution Act, 1867'', 30 & 31 Victoria (U.K.), c. 3, http://canlii.ca/t/ldsw retrieved on 2019-03-14. (french: Loi constitutionnelle de 1867, originally enacted as ''The British North America Act, 1867' ...
, does not give authority over groundwater to either order of Canadian government; therefore, the matter largely falls under provincial
jurisdiction Jurisdiction (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be i ...
* Federal and Provincial governments can share responsibilities when dealing with
agriculture Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary Image:Family watching television 1958.jpg, Exercise trends, Increases in sedentary behaviors su ...

agriculture
, health, inter-provincial waters and national water-related issues. * Federal jurisdiction in areas as boundary/trans-boundary waters, fisheries, navigation, and water on federal lands,
First Nations The First Nations (french: Premières Nations ) are groups of Canadian indigenous peoples, who are classified as distinct from the Inuit Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally s ...
reserves and in Territories. * Federal jurisdiction over groundwater when
aquifer An aquifer is an underground layer of -bearing , rock fractures or unconsolidated materials (, , or ). can be extracted using a water . The study of water flow in aquifers and the characterization of aquifers is called . Related terms include a ...

aquifer
s cross inter-provincial or international boundaries. A large federal government groundwater initiative is the development of the multi-barrier approach. The multi-barrier approach is a system of processes to prevent the deterioration of drinking water from the source. The multi-barrier consists of three key elements: * Source water protection, * Drinking water treatment, and * Drinking water distribution systems.


By country

Groundwater is an important
water resource Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all ...
for the supply of drinking water, especially in
arid A region is arid when it is characterized by a severe lack of available water, to the extent of hindering or preventing the growth and development Development or developing may refer to: Arts *Development hell, when a project is stuck in d ...

arid
countries.


Extraterrestrial groundwater

Groundwater may not be confined only to Earth. The formation of some of the
landforms A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body A planet is an astronomical body Astronomy (from el, ἀστρονομία, literally meaning the science that studies the laws o ...
observed on
Mars Mars is the fourth planet A planet is an astronomical body orbiting a star or Stellar evolution#Stellar remnants, stellar remnant that is massive enough to be Hydrostatic equilibrium, rounded by its own gravity, is not massive enough to ...

Mars
may have been influenced by groundwater. There is also evidence that liquid water may also exist in the subsurface of
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant A gas giant is a giant planet composed mainly of hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and at ...

Jupiter
's moon
Europa Europa may refer to: Places *Europe Europe is a continent A continent is one of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven regions are commonly regard ...
.


See also

* * * * *


References


External links


USGS Office of Groundwater

IAH, International Association of Hydrogeologists

The Groundwater Project
- Online platform for groundwater knowledge {{Authority control * Hydrology Hydraulic engineering Soil mechanics Liquid water Water and the environment Water Lithosphere