![Global Values of Water Resources and Water Use](https://upload.wikimedia.org/wikipedia/commons/2/22/Global_Values_of_Water_Resources_and_Water_Use.jpg)
Water resources are
natural resource
Natural resources are resources that are drawn from nature and used with few modifications. This includes the sources of valued characteristics such as commercial and industrial use, aesthetic value, scientific interest and cultural value. O ...
s of
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
that are potentially useful for humans, for example as a source of drinking
water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Thes ...
or
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
water. 97% of the water on the Earth is
salt water
Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish water, ...
and only three percent is
fresh water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
; slightly over two thirds of this is frozen in
glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...
s and
polar
Polar may refer to:
Geography
Polar may refer to:
* Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates
* Polar climate, the c ...
ice cap
In glaciology, an ice cap is a mass of ice that covers less than of land area (usually covering a highland area). Larger ice masses covering more than are termed ice sheets.
Description
Ice caps are not constrained by topographical features ...
s.
The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of
fresh water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
include
surface water
Surface water is water located on top of land forming terrestrial (inland) waterbodies, and may also be referred to as ''blue water'', opposed to the seawater and waterbodies like the ocean.
The vast majority of surface water is produced by prec ...
, under river flow,
groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...
and
frozen water
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opa ...
. Artificial sources of fresh water can include treated wastewater (
wastewater reuse
Water reclamation (also called wastewater reuse, water reuse or water recycling) is the process of converting municipal wastewater (sewage) or industrial wastewater into water that can be reused for a variety of purposes. Types of reuse include: ...
) and
desalinated seawater. Human uses of water resources include
agricultural
Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
,
industrial
Industrial may 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 city, a city dominate ...
,
household
A household consists of two or more persons who live in the same dwelling. It may be of a single family or another type of person group. The household is the basic unit of analysis in many social, microeconomic and government models, and is im ...
,
recreational
Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasure ...
and
environmental
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
activities.
Water resources are under threat from
water scarcity
Water scarcity (closely related to water stress or water crisis) is the lack of fresh water Water resources, resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water ...
,
water pollution
Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water ...
,
water conflict
Water conflict is a term describing a conflict between countries, states, or groups over water the rights to access water resources. The United Nations recognizes that water disputes result from opposing interests of water users, public or privat ...
and
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
. Fresh water is a
renewable resource
A renewable resource, also known as a flow resource, is a natural resource which will replenish to replace the portion resource depletion, depleted by usage and consumption, either through natural reproduction or other recurring processes in a ...
, yet the world's supply of
groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...
is steadily decreasing, with depletion occurring most prominently in Asia, South America and North America, although it is still unclear how much natural renewal
balances this usage, and whether
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 and energy flows. Energy enters the syste ...
s are threatened. The framework for allocating water resources to water users (where such a framework exists) is known as
water rights
Water right in water law refers to the right of a user to use water from a water source, e.g., a river, stream, pond or source of groundwater. In areas with plentiful water and few users, such systems are generally not complicated or contentious ...
.
Natural sources of fresh water
Natural sources of
fresh water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
include
surface water
Surface water is water located on top of land forming terrestrial (inland) waterbodies, and may also be referred to as ''blue water'', opposed to the seawater and waterbodies like the ocean.
The vast majority of surface water is produced by prec ...
, under river flow,
groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...
and
frozen water
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opa ...
.
Surface water
![Parinacota](https://upload.wikimedia.org/wikipedia/commons/4/49/Parinacota.jpg)
Surface water is water in a river,
lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
or fresh water
wetland
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
. Surface water is naturally replenished by
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
and naturally lost through discharge to the
oceans
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the worl ...
,
evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
,
evapotranspiration
Evapotranspiration (ET) is the combined processes by which water moves from the earth’s surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpi ...
and
groundwater recharge
Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in ...
. The only natural input to any surface water system is precipitation within its
watershed
Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to:
Hydrology
* Drainage divide, the line that separates neighbouring drainage basins
* Drainage basin, called a "watershe ...
. The total quantity of water in that system at any given time is also dependent on many other factors. These factors include storage capacity in lakes, wetlands and artificial
reservoirs
A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation.
Reservoirs can be created in a number of ways, including control ...
, the permeability of the
soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...
beneath these storage bodies, the
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 that lies beyond the edges to which a printed sheet is trimmed
* Runoff or run-off, a stock market ...
characteristics of the land in the watershed, the timing of the precipitation and local evaporation rates. All of these factors also affect the proportions of water loss.
Humans often increase storage capacity by constructing reservoirs and decrease it by draining wetlands. Humans often increase runoff quantities and velocities by paving areas and channelizing the stream flow.
Natural surface water can be augmented by importing surface water from another watershed through a
canal
Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow un ...
or
pipeline
Pipeline may refer to:
Electronics, computers and computing
* Pipeline (computing), a chain of data-processing stages or a CPU optimization found on
** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...
.
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
is estimated to have the largest supply of fresh water in the world, followed by
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
and
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
.
Image:Sinclair Wetlands.jpg, ''Panorama of a natural wetland (Sinclair Wetlands
The Sinclair Wetlands (''Te Nohoaka o Tukiauau'') are an internationally renowned wetlands located to the south west of Dunedin, New Zealand, at the southern edge of the Taieri Plains. They are on the western side of Lake Waipori and approximatel ...
, New Zealand)''
Water from glaciers
Glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...
runoff is considered to be surface water. The Himalayas, which are often called "The Roof of the World", contain some of the most extensive and rough high altitude areas on Earth as well as the greatest area of glaciers and permafrost outside of the poles. Ten of Asia's largest rivers flow from there, and more than a billion people's livelihoods depend on them. To complicate matters, temperatures there are rising more rapidly than the global average. In Nepal, the temperature has risen by 0.6 degrees Celsius over the last decade, whereas globally, the Earth has warmed approximately 0.7 degrees Celsius over the last hundred years.
Groundwater
Under river flow
Throughout the course of a river, the total volume of water transported downstream will often be a combination of the visible free water flow together with a substantial contribution flowing through rocks and sediments that underlie the river and its floodplain called the
hyporheic zone
The hyporheic zone is the region of sediment and porous space beneath and alongside a stream bed, where there is mixing of shallow groundwater and surface water. The flow dynamics and behavior in this zone (termed hyporheic flow or underflow) is re ...
. For many rivers in large valleys, this unseen component of flow may greatly exceed the visible flow. The hyporheic zone often forms a dynamic interface between surface water and groundwater from aquifers, exchanging flow between rivers and aquifers that may be fully charged or depleted. This is especially significant in
karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...
areas where pot-holes and underground rivers are common.
Artificial sources of usable water
Artificial sources of fresh water can include
treated wastewater (
reclaimed water
Water reclamation (also called wastewater reuse, water reuse or water recycling) is the process of converting municipal wastewater
Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produce ...
) and
desalinated seawater. However, economic and environmental side effects of these technologies must also be taken into consideration.
Wastewater reuse
Desalinated water
Water uses
![Total Renewable Freshwater Resources in mm per year By WaterGAP Average 1961-1990](https://upload.wikimedia.org/wikipedia/commons/c/c2/Total_Renewable_Freshwater_Resources_in_mm_per_year_By_WaterGAP_Average_1961-1990.jpg)
The total quantity of water available at any given time is an important consideration. Some human water users have an intermittent need for water. For example, many
farm
A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is used fo ...
s require large quantities of water in the spring, and no water at all in the winter. To supply such a farm with water, a surface water system may require a large storage capacity to collect water throughout the year and release it in a short period of time. Other users have a continuous need for water, such as a
power plant
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Many pow ...
that requires water for cooling. To supply such a power plant with water, a surface water system only needs enough storage capacity to fill in when average stream flow is below the power plant's need. Nevertheless, over the long term the average rate of precipitation within a watershed is the upper bound for average consumption of natural surface water from that watershed.
Agriculture and other irrigation
It is estimated that 70% of worldwide water is used for
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
, with 15–35% of irrigation withdrawals being unsustainable.
It takes around 2,000 – 3,000 litres of water to produce enough food to satisfy one person's daily dietary need. This is a considerable amount, when compared to that required for drinking, which is between two and five litres. To produce food for the now over 7 billion people who inhabit the planet today requires the water that would fill a canal ten metres deep, 100 metres wide and 2100 kilometres long.
An assessment of water management in agriculture sector was conducted in 2007 by the
International Water Management Institute
The International Water Management Institute (IWMI) is a non-profit international water management research organisation under the CGIAR with its headquarters in Colombo, Sri Lanka, and offices across Africa and Asia. Research at the Institute foc ...
in
Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
to see if the world had sufficient water to provide food for its growing population. It assessed the current availability of water for agriculture on a global scale and mapped out locations suffering from water scarcity. It found that a fifth of the world's people, more than 1.2 billion, live in areas of
physical water scarcity
Water scarcity (closely related to water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is wher ...
, where there is not enough water to meet all demands. A further 1.6 billion people live in areas experiencing
economic water scarcity, where the lack of investment in water or insufficient human capacity make it impossible for authorities to satisfy the demand for water. The report found that it would be possible to produce the food required in future, but that continuation of today's food production and environmental trends would lead to crises in many parts of the world. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficiently.
In some areas of the world, irrigation is necessary to grow any crop at all, in other areas it permits more profitable crops to be grown or enhances crop yield. Various irrigation methods involve different trade-offs between crop yield, water consumption and capital cost of equipment and structures. Irrigation methods such as
furrow
A plough or plow ( US; both ) is a farm tool for loosening or turning the soil before sowing seed or planting. Ploughs were traditionally drawn by oxen and horses, but in modern farms are drawn by tractors. A plough may have a wooden, iron or ...
and overhead
sprinkler
Sprinkler may refer to:
* Irrigation sprinkler, a device for watering lawns or crops
* Fire sprinkler, a device for fire suppression
* Sprinkler (dance), a dance move
See also
*
* Feynman sprinkler
A Feynman sprinkler, also referred to as a F ...
irrigation are usually less expensive but are also typically less efficient, because much of the water evaporates, runs off or drains below the root zone. Other irrigation methods considered to be more efficient include
drip or trickle irrigation,
surge irrigation, and some types of sprinkler systems where the sprinklers are operated near ground level. These types of systems, while more expensive, usually offer greater potential to minimize runoff, drainage and evaporation. Any system that is improperly managed can be wasteful, all methods have the potential for high efficiencies under suitable conditions, appropriate irrigation timing and management. Some issues that are often insufficiently considered are salinization of groundwater and contaminant accumulation leading to water quality declines.
As global populations grow, and as demand for food increases, there are efforts under way to learn how to produce more food with
less water, through improvements in irrigation methods and
technologies
Technology is the application of knowledge to reach practical goals in a specifiable and reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in medicine, science, ...
, agricultural
water management
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is salt water and only three percent is fresh water; slightl ...
, crop types, and water monitoring.
Aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
is a small but growing agricultural use of water. Freshwater commercial fisheries may also be considered as agricultural uses of water, but have generally been assigned a lower priority than irrigation (see
Aral Sea
The Aral Sea ( ; kk, Арал теңізі, Aral teñızı; uz, Орол денгизи, Orol dengizi; kaa, Арал теңизи, Aral teńizi; russian: Аральское море, Aral'skoye more) was an endorheic basin, endorheic lake lyi ...
and
Pyramid Lake).
Changing landscape for the use of agriculture has a great effect on the flow of fresh water. Changes in landscape by the removal of trees and
soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...
s changes the flow of fresh water in the local environment and also affects the cycle of fresh water. As a result, more fresh water is stored in the soil which benefits the agriculture. However, since agriculture is the human activity that consumes the most fresh water,
this can put a severe strain on local freshwater resources resulting in the destruction of local
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 and energy flows. Energy enters the syste ...
s.
In
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 ...
, over-abstraction of fresh water for intensive
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
activities has caused 33% of the land area to be at risk of
salination
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 be caused by natural processes such as mineral weathering or by the ...
.
Irrigation of green spaces and golf courses
Urban green space
In land-use planning, urban green space is open-space areas reserved for parks and other "green spaces", including plant life, water features -also referred to as blue spaces- and other kinds of natural environment. Most urban open spaces are ...
s and golf courses usually require some form of irrigation.
Golf course
A golf course is the grounds on which the sport of golf is played. It consists of a series of holes, each consisting of a tee box, a fairway, the rough and other hazards, and a green with a cylindrical hole in the ground, known as a "cup". Th ...
s are often targeted as using excessive amounts of water, especially in drier regions. Many golf courses utilize either primarily or exclusively treated effluent water, which has little impact on potable water availability.
Industries
![Poland Solina dam](https://upload.wikimedia.org/wikipedia/commons/4/41/Poland_Solina_dam.jpg)
It is estimated that 22% of worldwide water is used in
industry
Industry may refer to:
Economics
* Industry (economics), a generally categorized branch of economic activity
* Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery
* The wider industrial sector ...
.
Major industrial users include
hydroelectric
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...
dams,
thermoelectric power plants, which use water for
cooling
Cooling is removal of heat, usually resulting in a lower temperature and/or phase change. Temperature lowering achieved by any other means may also be called cooling.ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/as ...
,
ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...
and
oil refineries
An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, liquefie ...
, which use water in
chemical process
In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, and involves a chemical reaction of some ...
es, and manufacturing plants, which use water as a
solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
. Water withdrawal can be very high for certain industries, but consumption is generally much lower than that of agriculture.
Water is used in
renewable power
Renewable energy is energy that is collected from renewable resources that are naturally replenished on a human timescale. It includes sources such as sunlight, wind, the movement of water, and geothermal heat. Although most renewable energy ...
generation. Hydroelectric power derives energy from the force of water flowing downhill, driving a turbine connected to a generator. This hydroelectricity is a low-cost, non-polluting, renewable energy source. Significantly, hydroelectric power can also be used for
load following
A load-following power plant, regarded as producing mid-merit or mid-priced electricity, is a power plant that adjusts its power output as demand for electricity fluctuates throughout the day. Load-following plants are typically in between base lo ...
unlike most renewable energy sources which are
intermittent
Intermittency is a behavior of dynamical systems: regular alternation of phases of apparently periodic and chaotic dynamics.
Intermittent or intermittency may also refer to:
*Intermittent river or stream, the one that ceases to flow every year or ...
. Ultimately, the energy in a hydroelectric power plant is supplied by the sun. Heat from the sun evaporates water, which condenses as rain in higher altitudes and flows downhill.
Pumped-storage hydroelectric
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential ...
plants also exist, which use grid electricity to pump water uphill when demand is low, and use the stored water to produce electricity when demand is high.
Hydroelectric power plants generally require the creation of a large artificial lake. Evaporation from this lake is higher than evaporation from a river due to the larger surface area exposed to the elements, resulting in much higher water consumption. The process of driving water through the turbine and tunnels or pipes also briefly removes this water from the natural environment, creating water withdrawal. The impact of this withdrawal on wildlife varies greatly depending on the design of the power plant.
Pressurized water is used in water blasting and water jet cutters. Also, very high pressure water guns are used for precise cutting. It works very well, is relatively safe, and is not harmful to the environment. It is also used in the cooling of machinery to prevent overheating, or prevent saw blades from overheating. This is generally a very small source of water consumption relative to other uses.
Water is also used in many large scale industrial processes, such as thermoelectric power production, oil refining,
fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
production and other
chemical plant
A chemical plant is an industrial process plant that manufactures (or otherwise processes) chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transform ...
use, and
natural gas extraction
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbon di ...
from
shale rock
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially ...
. Discharge of untreated water from industrial uses is
pollution
Pollution is the introduction of contaminants 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). Pollutants, the ...
. Pollution includes discharged solutes (
chemical pollution
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...
) and increased water temperature (
thermal pollution
Thermal pollution, sometimes called "thermal enrichment", is the degradation of water quality by any process that changes ambient water temperature. Thermal pollution is the rise or fall in the temperature of a natural body of water caused by hum ...
). Industry requires pure water for many applications and utilizes a variety of purification techniques both in water supply and discharge. Most of this pure water is generated on site, either from natural freshwater or from municipal
grey water
Greywater (or grey water, sullage, also spelled gray water in the United States) refers to domestic wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from ...
. Industrial consumption of water is generally much lower than withdrawal, due to laws requiring industrial grey water to be treated and returned to the environment. Thermoelectric power plants using
cooling towers
A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat and ...
have high consumption, nearly equal to their withdrawal, as most of the withdrawn water is evaporated as part of the cooling process. The withdrawal, however, is lower than in
once-through cooling
Cooling tower and water discharge of a nuclear power plant
Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling. Water is inexpensive and non ...
systems.
Drinking water and domestic use (households)
![Drinking water](https://upload.wikimedia.org/wikipedia/commons/a/ae/Drinking_water.jpg)
It is estimated that 8% of worldwide water use is for domestic purposes.
These include
drinking water
Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
,
bathing
Bathing is the act of washing the body, usually with water, or the immersion of the body in water. It may be practiced for personal hygiene, religious ritual or therapeutic purposes. By analogy, especially as a recreational activity, the term is ...
,
cooking
Cooking, cookery, or culinary arts is the art, science and craft of using heat to Outline of food preparation, prepare food for consumption. Cooking techniques and ingredients vary widely, from grilling food over an open fire to using electric ...
,
toilet flushing
A flush toilet (also known as a flushing toilet, water closet (WC) – see also toilet names) is a toilet that disposes of human waste (principally urine and feces) by using the force of water to ''flush'' it through a drainpipe to another loca ...
, cleaning, laundry and
gardening
Gardening is the practice of growing and cultivating plants as part of horticulture. In gardens, ornamental plants are often grown for their flowers, foliage, or overall appearance; useful plants, such as root vegetables, leaf vegetables, fruits ...
. Basic domestic water requirements have been estimated by
Peter Gleick
Peter H. Gleick (; born 1956) is an American scientist working on issues related to the environment. He works at the Pacific Institute in Oakland, California, which he co-founded in 1987. In 2003 he was awarded a MacArthur Fellowship for his work ...
at around 50 liters per person per day, excluding water for gardens.
Drinking water is water that is of sufficiently high quality so that it can be consumed or used without risk of immediate or long term harm. Such water is commonly called potable water. In most developed countries, the water supplied to domestic, commerce and industry is all of drinking water standard even though only a very small proportion is actually consumed or used in food preparation.
844 million people still lacked even a basic drinking water service in 2017.
Of those, 159 million people worldwide drink water directly from surface water sources, such as lakes and streams.
One in eight people in the world do not have access to safe water. Inappropriate use of water may contribute to this problem. The following tables provide some indicators of water use.
Environment
Explicit environment water use is also a very small but growing percentage of total water use. Environmental water may include water stored in impoundments and released for environmental purposes (held environmental water), but more often is water retained in waterways through regulatory limits of abstraction. Environmental water usage includes watering of natural or artificial wetlands, artificial lakes intended to create wildlife habitat,
fish ladder
A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as movemen ...
s, and water releases from reservoirs timed to help fish spawn, or to restore more natural flow regimes.
Environmental usage is non-consumptive but may reduce the availability of water for other users at specific times and places. For example, water release from a reservoir to help fish spawn may not be available to farms upstream, and water retained in a river to maintain waterway health would not be available to water abstractors downstream.
Recreation
Recreation
Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...
al water use is mostly tied to lakes, dams, rivers or oceans. If a
water reservoir
A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation.
Reservoirs can be created in a number of ways, including control ...
is kept fuller than it would otherwise be for recreation, then the water retained could be categorized as recreational usage. Examples are anglers, water skiers, nature enthusiasts and swimmers.
Recreational usage is usually non-consumptive. However, recreational usage may reduce the availability of water for other users at specific times and places. For example, water retained in a reservoir to allow boating in the late summer is not available to farmers during the spring planting season. Water released for whitewater rafting may not be available for hydroelectric generation during the time of peak electrical demand.
Challenges and threats
Threats for the availability of water resources include: Water scarcity, water pollution, water conflict and
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
.
Water scarcity
Water pollution
Water conflict
Climate change
Water resource management
Water resource management is the activity of planning, developing, distributing and managing the optimum use of water resources. It is an aspect of
water cycle management
Water cycle management is a multidisciplinary approach relating to all planning, development, operational and tactical decisions to influence the water cycle. Most importantly water cycle management is used to ensure availability of clean water for ...
. The field of water resources management will have to continue to adapt to the current and future issues facing the allocation of water. With the growing uncertainties of global
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
and the long-term impacts of past management actions, this decision-making will be even more difficult. It is likely that ongoing climate change will lead to situations that have not been encountered. As a result, alternative management strategies, including participatory approaches and
adaptive capacity Adaptive capacity relates to the capacity of systems, institutions, humans and other organisms to adjust to potential damage, to take advantage of opportunities, or to respond to consequences. In the context of ecosystems, adaptive capacity is deter ...
are increasingly being used to strengthen water decision-making.
Ideally, water resource management planning has regard to all the competing
demands for water and seeks to allocate water on an equitable basis to satisfy all uses and demands. As with other
resource management
In organizational studies, resource management is the efficient and effective development of an organization's resources when they are needed. Such resources may include the financial resources, inventory, human skills, production resources, or i ...
, this is rarely possible in practice so decision-makers must prioritise issues of sustainability, equity and factor optimisation (in that order!) to achieve acceptable outcomes. One of the biggest concerns for water-based resources in the future is the
sustainability
Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...
of the current and future water resource allocation.
Sustainable Development Goal 6
Sustainable Development Goal 6 (SDG 6 or Global Goal 6) is about "clean water and sanitation for all". It is one of 17 Sustainable Development Goals established by the United Nations General Assembly in 2015, the official wording is: "Ensure ava ...
has a target related to water resources management: "Target 6.5: By 2030, implement integrated water resources management at all levels, including through transboundary cooperation as appropriate."
[Ritchie, Roser, Mispy, Ortiz-Ospina (2018]
"Measuring progress towards the Sustainable Development Goals." (SDG 6)
''SDG-Tracker.org, website''[United Nations (2017) Resolution adopted by the General Assembly on 6 July 2017, Work of the Statistical Commission pertaining to the 2030 Agenda for Sustainable Development]
A/RES/71/313
Sustainable water management
At present, only about 0.08 percent of all the world's fresh water is accessible. And there is ever-increasing demand for
drinking
Drinking is the act of ingesting water or other liquids into the body through the mouth, proboscis, or elsewhere. Humans drink by swallowing, completed by peristalsis in the esophagus. The physiological processes of drinking vary widely among o ...
,
manufacturing
Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a r ...
,
leisure
Leisure has often been defined as a quality of experience or as free time. Free time is time spent away from business, work, job hunting, domestic chores, and education, as well as necessary activities such as eating and sleeping. Leisure ...
and
agriculture
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
. Due to the small percentage of water available, optimizing the fresh water we have left from
natural resources
Natural resources are resources that are drawn from nature and used with few modifications. This includes the sources of valued characteristics such as commercial and industrial use, aesthetic value, scientific interest and cultural value. O ...
has been a growing challenge around the world.
Much effort in water resource management is directed at optimizing the
use of water and in minimizing the
environmental impact
Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on t ...
of water use on the natural environment. The observation of water as an integral part of the
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 and energy flows. Energy enters the syste ...
is based on
integrated water resources management
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is salt water and only three percent is fresh water; slight ...
, based on the 1992
Dublin Principles The Dublin Statement on Water and Sustainable Development, also known as the Dublin Principles, was a meeting of experts on water related problems that took place on 31 January 1992 at the International Conference on Water and the Environment (ICWE) ...
(see below).
Sustainable water management requires a holistic approach based on the principles of
Integrated Water Resource Management, originally articulated in 1992 at the Dublin (January) and Rio (July) conferences. The four Dublin Principles, promulgated in the
Dublin Statement The Dublin Statement on Water and Sustainable Development, also known as the Dublin Principles, was a meeting of experts on water related problems that took place on 31 January 1992 at the International Conference on Water and the Environment (ICWE) ...
are:
# Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment;
# Water development and management should be based on a participatory approach, involving users, planners and policy-makers at all levels;
# Women play a central part in the provision, management and safeguarding of water;
# Water has an economic value in all its competing uses and should be recognized as an economic good.
Implementation of these principles has guided reform of national water management law around the world since 1992.
Further challenges to sustainable and equitable water resources management include the fact that many water bodies are shared across boundaries which may be international (see
water conflict
Water conflict is a term describing a conflict between countries, states, or groups over water the rights to access water resources. The United Nations recognizes that water disputes result from opposing interests of water users, public or privat ...
) or intra-national (see
Murray-Darling basin).
Integrated water resources management
Integrated water resources management (IWRM) has been defined by the
Global Water Partnership (GWP) as "a process which promotes the coordinated
development
Development or developing may refer to:
Arts
*Development hell, when a project is stuck in development
*Filmmaking, development phase, including finance and budgeting
*Development (music), the process thematic material is reshaped
*Photographi ...
and management of water, land and related resources, in order to maximize the resultant
economic
An economy is an area of the Production (economics), production, Distribution (economics), distribution and trade, as well as Consumption (economics), consumption of Goods (economics), goods and Service (economics), services. In general, it is ...
and
social welfare
Welfare, or commonly social welfare, is a type of government support intended to ensure that members of a society can meet Basic needs, basic human needs such as food and shelter. Social security may either be synonymous with welfare, or refe ...
in an equitable manner without compromising the
sustainability
Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...
of vital
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 and energy flows. Energy enters the syste ...
s".
IWRM is a paradigm that emerged at international conferences in the late 1900s and early 2000s, although participatory water management institutions have existed for centuries.
Discussions on a holistic way of managing water resources began already in the 1950s leading up to the 1977 United Nations Water Conference. The development of IWRM was particularly recommended in the final statement of the ministers at the International Conference on Water and the Environment in 1992, known as the
Dublin Statement The Dublin Statement on Water and Sustainable Development, also known as the Dublin Principles, was a meeting of experts on water related problems that took place on 31 January 1992 at the International Conference on Water and the Environment (ICWE) ...
. This concept aims to promote changes in practices which are considered fundamental to improved
water resource management
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is Saline water, salt water and only three percent is fresh ...
. IWRM was a topic of
the second World Water Forum, which was attended by a more varied group of stakeholders than the preceding conferences and contributed to the creation of the GWP.
In the
International Water Association
The International Water Association (IWA) is a nonprofit organization and knowledge hub for the water sector, connecting water professionals and companies to find solutions to the world's water challenges. The IWA is headquartered in London, UK, ...
definition, IWRM rests upon three principles that together act as the overall framework:
# Social equity: ensuring equal access for all users (particularly marginalized and poorer user groups) to an adequate quantity and quality of water necessary to sustain human
well-being
Well-being, or wellbeing, also known as wellness, prudential value or quality of life, refers to what is intrinsically valuable relative ''to'' someone. So the well-being of a person is what is ultimately good ''for'' this person, what is in th ...
.
# Economic efficiency: bringing the greatest benefit to the greatest number of users possible with the available financial and water resources.
# Ecological sustainability: requiring that
aquatic ecosystem
An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The tw ...
s are acknowledged as users and that adequate allocation is made to sustain their natural functioning.
In 2002, the development of IWRM was discussed at
the World Summit on Sustainable Development held in Johannesburg, which aimed to encourage the implementation of IWRM at a global level.
The third World Water Forum recommended IWRM and discussed information sharing, stakeholder participation, and gender and class dynamics.
IWRM practices depend on context; at the operational level, the challenge is to translate the agreed principles into concrete action.
Operationally, IWRM approaches involve applying knowledge from various disciplines as well as the insights from diverse stakeholders to devise and implement efficient, equitable and sustainable solutions to water and development problems. As such, IWRM is a comprehensive,
participatory
Citizen Participation or Public Participation in social science refers to different mechanisms for the public to express opinions—and ideally exert influence—regarding political, economic, management or other social decisions. Participato ...
planning and implementation tool for managing and developing water resources in a way that balances social and economic needs, and that ensures the
protection of ecosystems for future generations. In addition, in light of contributing the achievement of
Sustainable Development goals (SDGs), IWRM has been evolving into more sustainable approach as it considers the Nexus approach, which is a cross-sectoral water resource management. The Nexus approach is based on the recognition that "water, energy and food are closely linked through global and local water, carbon and energy cycles or chains."
Water’s many different uses — for agriculture, for healthy ecosystems, for people and livelihoods — demands coordinated action. An IWRM approach is consequently cross-sectoral, aiming to be an open, flexible process, and bringing all stakeholders to the table to set policy and make sound, balanced decisions in response to specific water challenges faced.
An IWRM approach focuses on three basics and aims at avoiding a fragmented approach of water resources management by considering the following aspects:
# Enabling Environment: A proper enabling environment is essential to both ensure the rights and assets of all stakeholders (individuals as well as public and private sector organizations and companies), and also to protect public assets such as intrinsic environmental values.
# Roles of Institutions: Institutional development is critical to the formulation and implementation of IWRM policies and programmes. Failure to match responsibilities, authority and capacities for action are all major sources of difficulty with implementing IWRM.
# Management Instruments: The management instruments for IWRM are the tools and methods that enable and help decision-makers to make rational and informed choices between alternative actions.
Some of the cross-cutting conditions that are also important to consider when implementing IWRM are:
* Political will and commitment
* Capacity development
* Adequate investment,
financial stability
Financial stability is a property of a financial system that dissipates financial imbalances that arise endogenously in the financial markets or as a result of significant adverse and unforeseeable circumstances. When stable, the system absorbs ...
and sustainable cost recovery
* Monitoring and evaluation
IWRM should be viewed as a process rather than a one-shot approach - one that is long-term and iterative rather than linear in nature. As a process which seeks to shift water development and management systems from their currently unsustainable forms, IWRM has no fixed beginnings or endings.
Furthermore, there is not one correct administrative model. The art of IWRM lies in selecting, adjusting and applying the right mix of these tools for a given situation.
Managing water in urban settings
By country
Water resource management
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is Saline water, salt water and only three percent is fresh ...
and governance is handled differently by different countries. For example, in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, the
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
(USGS) and its partners monitor water resources, conduct research and inform the public about groundwater quality.
Water resources in specific countries are described below:
See also
*
Holistic management
Holistic Management (from ''holos'', a Greek word meaning ''all'', ''whole'', ''entire'', ''total'') in agriculture is an approach to managing resources that was originally developed by Allan Savory. Holistic Management is a registered tradema ...
*
International trade and water International trade and water is the relationship between international trade and the water being used by humans. The substantial increase in human population during the 20th century combined with rapid increases in overall global economic developme ...
*
List of countries by freshwater withdrawal
This is a list of countries by freshwater withdrawal mostly based on The World Factbook
''The World Factbook'', also known as the ''CIA World Factbook'', is a reference resource produced by the Central Intelligence Agency (CIA) with almanac ...
*
List of countries by total renewable water resources
This is a list of countries by total renewable water resources mostly based on The World Factbook. This entry provides the long-term average water availability for a country in cubic kilometers from precipitation, groundwater recharge, and surface ...
*
Peak water
Peak water is a concept that underlines the growing constraints on the availability, quality, and use of freshwater resources.
Peak water was defined in a 2010 peer-reviewed article in the ''Proceedings of the National Academy of Sciences'' by ...
*
Socio-hydrology
Socio-hydrology; socio (from the Latin word ''socius,'' meaning ‘companion) and hydrology (from the Greek: ὕδωρ, "hýdōr" meaning "water"; and λόγος, "lógos" meaning "study") is an interdisciplinary field studying the dynamic interac ...
*
Virtual water
The virtual water trade (also known as embedded or embodied water) is the hidden flow of water in food or other commodities that are traded from one place to another. The virtual water trade is the idea that when goods and services are exchanged, s ...
*
Water security
Water security is the focused goal of water policy and water management. A society with a high level of water security makes the most of water's benefits for humans and ecosystems and limits the risk of destructive impacts associated with water. T ...
*
Water storage Water storage is a broad term referring to storage of both potable water for consumption, and non potable water for use in agriculture. In both developing countries and some developed countries found in tropical climates, there is a need to store po ...
References
External links
Renewable water resources in the world by countryPortal to international hydrology and water resourcesCap-Net, Network for Capacity Building in Sustainable Water ManagementCKnet-INA, Indonesian Integrated Water Resource Management SecretariatSustainable Sanitation and Water Management Toolbox
{{DEFAULTSORT:Water Resources
Aquatic ecology
Hydrology
Irrigation
Natural resources
Resources
Resource refers to all the materials available in our environment which are technologically accessible, economically feasible and culturally sustainable and help us to satisfy our needs and wants. Resources can broadly be classified upon their a ...
Water and the environment
Water management
Resources
Resource refers to all the materials available in our environment which are technologically accessible, economically feasible and culturally sustainable and help us to satisfy our needs and wants. Resources can broadly be classified upon their a ...
Water resources management
Water industry
Sanitation