# Fresh water

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Naturally occurring water with low amounts of dissolved salts

This article is about a naturally occurring type of water. For all types of waters that are of potential use to humans, see [Water resources](/source/Water_resources). For other uses, see [Freshwater (disambiguation)](/source/Freshwater_(disambiguation)).

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Rivers, lakes, and marshlands, such as (from top) South America's [Amazon River](/source/Amazon_River), Russia's [Lake Baikal](/source/Lake_Baikal), and the [Everglades](/source/Everglades) in [Florida](/source/Florida) of the [United States](/source/United_States), are types of freshwater systems.

**Fresh water** or **freshwater** is any naturally occurring liquid or frozen [water](/source/Water) containing low [concentrations](/source/Concentration) of dissolved [salts](/source/Salt_(chemistry)) and other [total dissolved solids](/source/Total_dissolved_solids). The term excludes [seawater](/source/Seawater) and [brackish water](/source/Brackish_water), but it does include non-salty [mineral-rich waters](/source/Mineral_water), such as [chalybeate](/source/Chalybeate) springs. Fresh water may encompass [frozen](/source/Frozen_water) and [meltwater](/source/Meltwater) in [ice sheets](/source/Ice_sheet), [ice caps](/source/Ice_cap), [glaciers](/source/Glacier), [snowfields](/source/Snowfield) and [icebergs](/source/Iceberg), natural [precipitations](/source/Precipitation) such as [rainfall](/source/Rain), [snowfall](/source/Snowfall), [hail](/source/Hail)/[sleet](/source/Ice_pellets) and [graupel](/source/Graupel), and [surface runoffs](/source/Surface_runoff) that form inland [bodies of water](/source/Bodies_of_water) such as [wetlands](/source/Wetland), [ponds](/source/Pond), [lakes](/source/Lake), [rivers](/source/River), [streams](/source/Stream), as well as [groundwater](/source/Groundwater) contained in [aquifers](/source/Aquifer), [subterranean](/source/Subterranea_(geography)) [rivers](/source/Subterranean_river) and [lakes](/source/Underground_lake).

Water is critical to the survival of all living [organisms](/source/Organism). Many organisms can thrive on salt water, but the great majority of [vascular plants](/source/Vascular_plant) and most [insects](/source/Insect), [amphibians](/source/Amphibian), [reptiles](/source/Reptile), [mammals](/source/Mammal) and [birds](/source/Bird) need fresh water to survive.

Fresh water is the [water resource](/source/Water_resources) that is of the most and immediate use to humans. Fresh water is not always [potable water](/source/Drinking_water), that is, water safe to drink by [humans](/source/Human). Much of the [earth](/source/Earth)'s fresh water (on the surface and groundwater) is to a substantial degree unsuitable for human consumption without [treatment](/source/Water_treatment). Fresh water can easily become [polluted by human activities](/source/Water_pollution) or due to naturally occurring processes, such as erosion.

Fresh water makes up less than 3% of the world's water resources, and just 1% of that is readily available. About 70% of the world's freshwater reserves are frozen in [Antarctica](/source/Antarctica). Just 3% of it is extracted for human consumption. Agriculture uses roughly two thirds of all fresh water extracted from the environment.[1][2][3]

Fresh water is a renewable and variable, but finite [natural resource](/source/Natural_resource). Fresh water is replenished through the process of the natural [water cycle](/source/Water_cycle), in which water from seas, lakes, forests, land, rivers and [reservoirs](/source/Reservoirs) evaporates, forms [clouds](/source/Cloud), and returns inland as precipitation.[4] Locally, however, if more fresh water is consumed through human activities than is naturally restored, this may result in reduced fresh water availability (or [water scarcity](/source/Water_scarcity)) from surface and underground sources and can cause serious damage to surrounding and associated environments.[5] [Water pollution](/source/Water_pollution) also reduces the availability of fresh water. Where available water resources are scarce, humans have developed technologies like [desalination](/source/Desalination) and [wastewater recycling](/source/Wastewater_recycling) to stretch the available supply further. However, given the high cost (both capital and running costs) and - especially for desalination - energy requirements, those remain mostly niche applications.

A non-sustainable alternative is using so-called "[fossil water](/source/Fossil_water)" from underground [aquifers](/source/Aquifers). As some of those aquifers formed hundreds of thousands or even millions of years ago when local climates were wetter (e.g. from one of the [Green Sahara](/source/Green_Sahara) periods) and are not appreciably replenished under current climatic conditions - at least compared to drawdown, these aquifers form essentially non-renewable resources comparable to peat or lignite, which are also continuously formed in the current era but orders of magnitude slower than they are mined.

## Definitions

Part of a series on Water salinity Salinity levels Fresh water (< 0.05%) Brackish water (0.05–3%) Saline water (3–5%) Brine (> 5% up to 26%–28% max) Bodies of water Seawater Salt lake Hypersaline lake Salt pan Brine pool Bodies by salinity v t e

### Numerical definition

Fresh water can be defined as water with less than 500 [parts per million](/source/Parts_per_million) (ppm) of dissolved [salts](/source/Salt_(chemistry)).[6]

Other sources give higher upper salinity limits for fresh water, e.g. 1,000 ppm[7] or 3,000 ppm.[8]

### Systems

Fresh water habitats are classified as either [lentic systems](/source/Lake_ecosystem), which are the stillwaters including [ponds](/source/Pond), lakes, [swamps](/source/Swamp) and [mires](/source/Bog); [lotic](/source/Lotic) which are running-water systems; or [groundwaters](/source/Groundwater) which flow in rocks and [aquifers](/source/Aquifer). There is, in addition, a zone which bridges between groundwater and lotic systems, which is the [hyporheic zone](/source/Hyporheic_zone), which underlies many larger rivers and can contain substantially more water than is seen in the open channel. It may also be in direct contact with the underlying underground water.

## Sources

Main articles: [Water cycle](/source/Water_cycle) and [Water resources](/source/Water_resources)

The original source of almost all fresh water is [precipitation](/source/Precipitation_(meteorology)) from the [atmosphere](/source/Earth's_atmosphere), in the form of [mist](/source/Mist), [rain](/source/Rain) and [snow](/source/Snow). Fresh water falling as mist, rain or snow contains materials dissolved from the [atmosphere](/source/Atmosphere) and material from the sea and land over which the rain bearing clouds have traveled. The precipitation leads eventually to the formation of [water bodies](/source/Body_of_water) that humans can use as sources of freshwater: [ponds](/source/Pond), [lakes](/source/Lake), [rainfall](/source/Rain), [rivers](/source/River), [streams](/source/Stream), and [groundwater](/source/Groundwater) contained in underground [aquifers](/source/Aquifer).

In coastal areas fresh water may contain significant concentrations of salts derived from the sea if windy conditions have lifted drops of seawater into the rain-bearing clouds. This can give rise to elevated concentrations of [sodium](/source/Sodium), [chloride](/source/Chloride), [magnesium](/source/Magnesium) and [sulfate](/source/Sulfate) as well as many other compounds in smaller concentrations.

In [desert](/source/Desert) areas, or areas with impoverished or dusty soils, rain-bearing winds can pick up [sand](/source/Sand) and [dust](/source/Dust) and this can be deposited elsewhere in precipitation and causing the freshwater flow to be measurably contaminated both by insoluble solids but also by the soluble components of those soils. Significant quantities of [iron](/source/Iron) may be transported in this way including the well-documented transfer of iron-rich rainfall falling in Brazil derived from sand-storms in the [Sahara](/source/Sahara) in [north Africa](/source/North_Africa).[9]

In Africa, it was revealed that groundwater controls are complex and do not correspond directly to a single factor. Groundwater showed greater resilience to climate change than expected, and areas with an increasing threshold between 0.34 and 0.39 aridity index exhibited significant sensitivity to climate change. Land-use could affect infiltration and runoff processes. The years of most recharge coincided with the most precipitation anomalies, such as during [El Niño](/source/El_Ni%C3%B1o) and [La Niña](/source/La_Ni%C3%B1a) events. Three precipitation-recharge sensitivities were distinguished: in super arid areas with more than 0.67 aridity index, there was constant recharge with little variation with precipitation; in most sites (arid, semi-arid, humid), annual recharge increased as annual precipitation remained above a certain threshold; and in complex areas down to 0.1 aridity index (focused recharge), there was very inconsistent recharge (low precipitation but high recharge). Understanding these relationships can lead to the development of sustainable strategies for water collection. This understanding is particularly crucial in Africa, where water resources are often scarce and climate change poses significant challenges.[10]

## Water distribution

Main article: [Water distribution on Earth](/source/Water_distribution_on_Earth)

Visualisation of the distribution (by volume) of water on Earth[a]

A graphical distribution of the locations of water on Earth[b]

Saline water in [oceans](/source/Ocean), [seas](/source/Sea) and saline [groundwater](/source/Groundwater) make up about 97% of all the water on [Earth](/source/Earth). Only 2.5–2.75% is fresh water, including 1.75–2% frozen in [glaciers](/source/Glacier), [ice](/source/Ice) and snow, 0.5–0.75% as fresh groundwater. The water table is the level below which all spaces are filled with water, while the area above this level, where spaces in the rock and soil contain both air and water, is known as the unsaturated zone. The water in this unsaturated zone is referred to as soil moisture.

Below the water table, the entire region is known as the saturated zone, and the water in this zone is called groundwater.[12] Groundwater plays a crucial role as the primary source of water for various purposes including drinking, washing, farming, and manufacturing, and even when not directly used as a drinking water supply it remains vital to protect due to its ability to carry contaminants and pollutants from the land into lakes and rivers, which constitute a significant percentage of other people's freshwater supply. It is almost ubiquitous underground, residing in the spaces between particles of rock and soil or within crevices and cracks in rock, typically within 100 m (330 ft) of the surface,[12] and [soil](/source/Soil) moisture, and less than 0.01% of it as [surface water](/source/Surface_water) in [lakes](/source/Lake), [swamps](/source/Swamp) and [rivers](/source/River).[13][14]

Freshwater lakes contain about 87% of this fresh surface water, including 29% in the [African Great Lakes](/source/African_Great_Lakes), 22% in [Lake Baikal](/source/Lake_Baikal) in Russia, 21% in the [North American Great Lakes](/source/North_American_Great_Lakes), and 14% in other lakes. Swamps have most of the balance with only a small amount in rivers, most notably the [Amazon River](/source/Amazon_River). The atmosphere contains 0.04% water.[15] In areas with no fresh water on the ground surface, fresh water derived from [precipitation](/source/Precipitation_(meteorology)) may, because of its lower density, overlie saline ground water in lenses or layers. Most of the world's fresh water is frozen in [ice sheets](/source/Ice_sheet). Many areas have very little fresh water, such as [deserts](/source/Desert).

## Freshwater ecosystems

Water is a critical issue for the survival of all living organisms. Some can use salt water but many organisms including the great majority of higher plants and most [mammals](/source/Mammal) must have access to fresh water to live. Some terrestrial mammals, especially desert [rodents](/source/Rodent), appear to survive without drinking, but they do generate water through the [metabolism](/source/Metabolism) of [cereal](/source/Cereal) seeds, and they also have mechanisms to conserve water to the maximum degree.

This section is an excerpt from [Freshwater ecosystem](/source/Freshwater_ecosystem).[[edit](https://en.wikipedia.org/w/index.php?title=Freshwater_ecosystem&action=edit)]

Freshwater ecosystem

[Freshwater ecosystems](/source/Freshwater_ecosystem) are a subset of Earth's [aquatic ecosystems](/source/Aquatic_ecosystem) that include the [biological communities](/source/Biological_communities) inhabiting [freshwater](/source/Freshwater) [waterbodies](/source/Waterbodies) such as [lakes](/source/Lake_ecosystem), [ponds](/source/Pond), [rivers](/source/River_ecosystem), [streams](/source/Stream), [springs](/source/Spring_(hydrosphere)), [bogs](/source/Bogs), and [wetlands](/source/Wetland).[16] They can be contrasted with [marine ecosystems](/source/Marine_ecosystem), which have a much higher [salinity](/source/Salinity). Freshwater habitats can be classified by different factors, including temperature, light penetration, nutrients, and vegetation.

There are three basic types of freshwater ecosystems: [lentic](/source/Lentic_system_ecology) (slow moving water, including [pools](/source/Stream_pool), [ponds](/source/Pond), and [lakes](/source/Lakes)), [lotic](/source/Lotic_System_Ecology) (faster moving [streams](/source/Stream), for example [creeks](/source/Stream) and [rivers](/source/River)) and [wetlands](/source/Wetland) ([semi-aquatic](/source/Semi-aquatic) areas where the soil is saturated or inundated for at least part of the time).[17][16] Freshwater ecosystems contain 41% of the world's known [fish](/source/Fish) species.[18]

## Challenges

Main article: [Water resources § Challenges and threats](/source/Water_resources#Challenges_and_threats)

Further information: [Human impacts on the environment](/source/Human_impacts_on_the_environment) and [Freshwater ecosystem § Threats](/source/Freshwater_ecosystem#Threats)

The increase in the world population and the increase in per capita water use puts increasing strains on the finite resources availability of clean fresh water. The response by [freshwater ecosystems](/source/Freshwater_ecosystem) to a [changing climate](/source/Climate_change) can be described in terms of three interrelated components: water quality, water quantity or volume, and water timing. A change in one often leads to shifts in the others as well.[19]

### Limited resource

This section is an excerpt from [Water scarcity](/source/Water_scarcity).[[edit](https://en.wikipedia.org/w/index.php?title=Water_scarcity&action=edit)]

[Water scarcity](/source/Water_scarcity) (closely related to water stress or [water crisis](/source/Water_crisis_(disambiguation))) is the lack of any, local or economically viably transportable, sources of fresh water [resources](/source/Water_resources) to meet the standard water demand in a region. There are two types of [water scarcity](/source/Water_scarcity). One is *physical.* The other is *economic water scarcity*.[20]: 560 Physical water scarcity is where there is not enough water to meet all demands. This includes water needed for [ecosystems](/source/Ecosystem) to function. Regions with a [desert climate](/source/Desert_climate) often face physical water scarcity.[21] [Central Asia](/source/Central_Asia), [West Asia](/source/West_Asia), and [North Africa](/source/North_Africa) are examples of arid areas. Economic water scarcity results from a lack of investment in infrastructure or technology to draw water from rivers, [aquifers](/source/Aquifer), or other water sources. It also results from weak human capacity to meet water demand.[20]: 560 Many people in [sub-Saharan Africa](/source/Sub-Saharan_Africa) are living with economic water scarcity.[22]: 11

There is and has always been enough physical supply of freshwater for current or near or distant future demand in a global scale. As such, water scarcity is caused by a mismatch between when and where people need water, and when and where it is available.[23] This can happen due to an [increase in the number of people](/source/Population_growth) in a region, changing living conditions and diets, and expansion of [irrigated agriculture](/source/Irrigation).[24][25][26] [Climate change](/source/Climate_change) (including [droughts](/source/Droughts) or [floods](/source/Floods)), [deforestation](/source/Deforestation), [water pollution](/source/Water_pollution) and wasteful use of water can also mean there is not enough water.[27] These variations in scarcity may also be a function of prevailing [economic policy](/source/Economic_policy) and planning approaches.

### Minimum streamflow

Further information: [Water scarcity § Environment](/source/Water_scarcity#Environment)

An important concern for hydrological ecosystems is securing minimum [streamflow](/source/Streamflow), especially preserving and restoring [instream water allocations](/source/Instream_use).[28] Fresh water is an important natural resource necessary for the survival of all [ecosystems](/source/Ecosystem).

### Water pollution

This section is an excerpt from [Water pollution](/source/Water_pollution).[[edit](https://en.wikipedia.org/w/index.php?title=Water_pollution&action=edit)]

[Water pollution](/source/Water_pollution) (or aquatic pollution) is the [contamination](/source/Contamination) of [water bodies](/source/Body_of_water), which has a negative impact on how they can be used.[29]: 6 It is usually caused by human activities. Water bodies include [lakes](/source/Lake), [rivers](/source/River), [oceans](/source/Ocean), [aquifers](/source/Aquifer), [reservoirs](/source/Reservoir) and [groundwater](/source/Groundwater). Water [pollution](/source/Pollution) results when [contaminants](/source/Contaminant) mix with these water bodies. [Contaminants](/source/Contamination) can come from one of four main sources. These are [sewage](/source/Sewage) discharges, industrial activities, agricultural activities, and urban runoff including [stormwater](/source/Stormwater).[30] Water pollution may affect either [surface water](/source/Surface_water) or [groundwater](/source/Groundwater_pollution). This form of pollution can lead to many problems. One is the [degradation](/source/Environmental_degradation) of [aquatic ecosystems](/source/Aquatic_ecosystems). Another is spreading [water-borne diseases](/source/Waterborne_diseases) when people use polluted water for drinking or [irrigation](/source/Irrigation).[31] Water pollution also reduces the [ecosystem services](/source/Ecosystem_service) such as [drinking water](/source/Drinking_water) provided by the [water resource](/source/Water_resources).

Sources of water pollution are either [point sources](/source/Point_source) or [non-point sources](/source/Non-point_source).[32] Point sources have one identifiable cause, such as a [storm drain](/source/Storm_drain), a [wastewater treatment plant](/source/Wastewater_treatment_plant), or an [oil spill](/source/Oil_spill). Non-point sources are more diffuse. An example is [agricultural runoff](/source/Surface_runoff).[33] [Pollution](/source/Pollution) is the result of the cumulative effect over time. Pollution may take many forms. One would be toxic substances such as oil, metals, plastics, [pesticides](/source/Pesticide), [persistent organic pollutants](/source/Persistent_organic_pollutant), and industrial waste products. Another is stressful conditions such as changes of [pH](/source/PH), [hypoxia](/source/Hypoxia_(environmental)) or anoxia, increased temperatures, excessive [turbidity](/source/Turbidity), or changes of [salinity](/source/Salinity)). The introduction of [pathogenic organisms](/source/Pathogen) is another. Contaminants may include [organic](/source/Organic_compound) and [inorganic](/source/Inorganic) substances. A common cause of [thermal pollution](/source/Thermal_pollution) is the use of water as a [coolant](/source/Coolant) by [power plants](/source/Power_plants) and industrial manufacturers.

## Society and culture

Annual freshwater withdrawals

### Human uses

Main article: [Water resources § Water uses](/source/Water_resources#Water_uses)

Uses of water include [agricultural](/source/Agricultural), [industrial](/source/Industrial_sector), [household](/source/Household), [recreational](/source/Recreational) and [environmental](/source/Natural_environment) activities.

### Global goals for conservation

The [Sustainable Development Goals](/source/Sustainable_Development_Goals) are a collection of 17 interlinked global goals designed to be a "blueprint to achieve a better and more [sustainable](/source/Sustainability) future for all".[34] Targets on fresh [water conservation](/source/Water_conservation) are included in [SDG 6](/source/Sustainable_Development_Goal_6) (Clean water and sanitation) and [SDG 15](/source/Sustainable_Development_Goal_15) (Life on land). For example, Target 6.4 is formulated as "By 2030, substantially increase [water-use efficiency](/source/Water-use_efficiency) across all sectors and ensure sustainable withdrawals and [supply of freshwater](/source/Water_supply) to address water scarcity and substantially reduce the number of people suffering from [water scarcity](/source/Water_scarcity)."[34] Another target, Target 15.1, is: "By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland [freshwater ecosystems](/source/Freshwater_ecosystem) and their services, in particular forests, [wetlands](/source/Wetland), [mountains](/source/Mountain) and [drylands](/source/Drylands), in line with obligations under international agreements."[34]

## See also

- [Limnology](/source/Limnology) – Science of inland aquatic ecosystems

- [Properties of water](/source/Properties_of_water) – Physical and chemical properties of pure water

## Notes

1. **[^](#cite_ref-13)** Each tiny cube[i] (such as the one representing biological water) corresponds to approximately 1400 cubic km of water, with a mass of approximately 1.4 trillion tonnes (235000 times that of the [Great Pyramid of Giza](/source/Great_Pyramid_of_Giza) or 8 times that of [Lake Kariba](/source/Lake_Kariba), arguably the heaviest human-made object).[11]

1. **[^](#cite_ref-14)** Only 3% of the Earth's water is fresh water. Most of it is in icecaps and glaciers (69%) and groundwater (30%), while all lakes, rivers and swamps combined only account for a small fraction (0.3%) of the Earth's total freshwater reserves.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

*Subnotes*

1. **[^](#cite_ref-11)** The entire block comprises 1 million tiny cubes.

## References

1. **[^](#cite_ref-:68_1-0)** ["Wastewater resource recovery can fix water insecurity and cut carbon emissions"](https://www.eib.org/en/essays/wastewater-resource-recovery). *European Investment Bank*. [Archived](https://web.archive.org/web/20220829150040/https://www.eib.org/en/essays/wastewater-resource-recovery) from the original on 29 August 2022. Retrieved 29 August 2022.

1. **[^](#cite_ref-2)** ["Competing for Clean Water Has Led to a Crisis"](https://web.archive.org/web/20210219192438/https://www.nationalgeographic.com/environment/article/freshwater-crisis). *Environment*. 26 January 2010. Archived from [the original](https://www.nationalgeographic.com/environment/article/freshwater-crisis) on 19 February 2021. Retrieved 29 August 2022.

1. **[^](#cite_ref-3)** ["Freshwater Resources | National Geographic Society"](https://education.nationalgeographic.org/resource/freshwater-resources/). *education.nationalgeographic.org*. [Archived](https://web.archive.org/web/20220526195118/https://education.nationalgeographic.org/resource/freshwater-resources) from the original on 26 May 2022. Retrieved 29 August 2022.

1. **[^](#cite_ref-4)** ["The Fundamentals of the Water Cycle"](https://web.archive.org/web/20191127053410/https://www.usgs.gov/special-topic/water-science-school/science/fundamentals-water-cycle?qt-science_center_objects=0#qt-science_center_objects). *www.usgs.gov*. Archived from [the original](https://www.usgs.gov/special-topic/water-science-school/science/fundamentals-water-cycle?qt-science_center_objects=0#qt-science_center_objects) on 27 November 2019. Retrieved 17 September 2021.

1. **[^](#cite_ref-5)** Alviar, Rene (1998). ["Laguna de Bay drying up fast, says task force"](https://tuklas.up.edu.ph/Record/IPN-00000053237?sid=961997). *UP collection of Inquirer*. Retrieved 30 December 2024.

1. **[^](#cite_ref-6)** ["Groundwater Glossary"](https://web.archive.org/web/20060428102341/http://www.groundwater.org/gi/gwglossary.html#F). 27 March 2006. Archived from [the original](http://www.groundwater.org/gi/gwglossary.html#F) on 28 April 2006. Retrieved 14 May 2006.

1. **[^](#cite_ref-7)** ["Freshwater"](https://web.archive.org/web/20110606104533/http://amsglossary.allenpress.com/glossary/search?p=1&query=freshwater). *Glossary of Meteorology*. [American Meteorological Society](/source/American_Meteorological_Society). June 2000. Archived from [the original](http://amsglossary.allenpress.com/glossary/search?p=1&query=freshwater) on 6 June 2011. Retrieved 27 November 2009.

1. **[^](#cite_ref-8)** ["Freshwater"](https://web.archive.org/web/20060511182717/http://www.practicalfishkeeping.co.uk/pfk/pages/glossary.php?entry_name=Freshwater). *Fishkeeping glossary*. [Practical Fishkeeping](/source/Practical_Fishkeeping). Archived from [the original](http://www.practicalfishkeeping.co.uk/pfk/pages/glossary.php?entry_name=Freshwater) on 11 May 2006. Retrieved 27 November 2009.

1. **[^](#cite_ref-9)** Rizzolo, Joana A.; Barbosa, Cybelli G. G.; Borillo, Guilherme C.; Godoi, Ana F. L.; Souza, Rodrigo A. F.; Andreoli, Rita V.; Manzi, Antônio O.; Sá, Marta O.; Alves, Eliane G.; Pöhlker, Christopher; Angelis, Isabella H.; Ditas, Florian; Saturno, Jorge; Moran-Zuloaga, Daniel; Rizzo, Luciana V. (22 February 2017). ["Soluble iron nutrients in Saharan dust over the central Amazon rainforest"](https://www.researchgate.net/publication/314247273). *Atmospheric Chemistry and Physics*. **17** (4): 2673–2687. [Bibcode](/source/Bibcode_(identifier)):[2017ACP....17.2673R](https://ui.adsabs.harvard.edu/abs/2017ACP....17.2673R). [doi](/source/Doi_(identifier)):[10.5194/acp-17-2673-2017](https://doi.org/10.5194%2Facp-17-2673-2017). [hdl](/source/Hdl_(identifier)):[10536/DRO/DU:30091978](https://hdl.handle.net/10536%2FDRO%2FDU%3A30091978) – via ResearchGate.

1. **[^](#cite_ref-10)** ["Global climate change impacts on Sub-Sahara Africa: The case of Nigeria's shorelines"](https://dx.doi.org/10.3726/978-3-653-04584-0/15), *The Impact of Climate Change on Sub-Sahara Africa*, Peter Lang, 2015, [doi](/source/Doi_(identifier)):[10.3726/978-3-653-04584-0/15](https://doi.org/10.3726%2F978-3-653-04584-0%2F15), [ISBN](/source/ISBN_(identifier)) [978-3-653-04584-0](https://en.wikipedia.org/wiki/Special:BookSources/978-3-653-04584-0), retrieved 19 December 2023{{[citation](https://en.wikipedia.org/wiki/Template:Citation)}}: CS1 maint: work parameter with ISBN ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN))

1. **[^](#cite_ref-12)** [USGS – Earth's water distribution](https://ga.water.usgs.gov/edu/waterdistribution.html) [Archived](https://web.archive.org/web/20120629055146/http://ga.water.usgs.gov/edu/waterdistribution.html) 29 June 2012 at the [Wayback Machine](/source/Wayback_Machine). Ga.water.usgs.gov (11 December 2012). Retrieved on 29 December 2012.

1. ^ [***a***](#cite_ref-:0_15-0) [***b***](#cite_ref-:0_15-1) ["Natural Quality of Water and Groundwater Contamination"](https://dx.doi.org/10.1201/9781482278934-9), *Groundwater Contamination, Volume I*, CRC Press, pp. 35–56, 14 April 2000, [doi](/source/Doi_(identifier)):[10.1201/9781482278934-9](https://doi.org/10.1201%2F9781482278934-9), [ISBN](/source/ISBN_(identifier)) [978-0-429-18165-8](https://en.wikipedia.org/wiki/Special:BookSources/978-0-429-18165-8), retrieved 19 December 2023{{[citation](https://en.wikipedia.org/wiki/Template:Citation)}}: CS1 maint: work parameter with ISBN ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN))

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1. **[^](#cite_ref-Water_scarcity_Rijsberman-2006a_24-0)** Rijsberman, Frank R. (2006). ["Water scarcity: Fact or fiction?"](https://linkinghub.elsevier.com/retrieve/pii/S0378377405002854). *Agricultural Water Management*. **80** (1–3): 5–22. [Bibcode](/source/Bibcode_(identifier)):[2006AgWM...80....5R](https://ui.adsabs.harvard.edu/abs/2006AgWM...80....5R). [doi](/source/Doi_(identifier)):[10.1016/j.agwat.2005.07.001](https://doi.org/10.1016%2Fj.agwat.2005.07.001).

1. **[^](#cite_ref-Water_scarcity_IWMI-2007_25-0)** IWMI (2007) *[Water for Food, Water for Life: A Comprehensive Assessment of Water Management in Agriculture](https://www.iwmi.cgiar.org/assessment/files_new/synthesis/Summary_SynthesisBook.pdf)*. London: Earthscan, and Colombo: International Water Management Institute.

1. **[^](#cite_ref-Water_scarcity_Mekonnen-2016_26-0)** Mekonnen, Mesfin M.; Hoekstra, Arjen Y. (2016). ["Four billion people facing severe water scarcity"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4758739). *Science Advances*. **2** (2) e1500323. [Bibcode](/source/Bibcode_(identifier)):[2016SciA....2E0323M](https://ui.adsabs.harvard.edu/abs/2016SciA....2E0323M). [doi](/source/Doi_(identifier)):[10.1126/sciadv.1500323](https://doi.org/10.1126%2Fsciadv.1500323). [ISSN](/source/ISSN_(identifier)) [2375-2548](https://search.worldcat.org/issn/2375-2548). [PMC](/source/PMC_(identifier)) [4758739](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4758739). [PMID](/source/PMID_(identifier)) [26933676](https://pubmed.ncbi.nlm.nih.gov/26933676).

1. **[^](#cite_ref-Water_scarcity_Vorosmarty-2000_27-0)** Vorosmarty, C. J. (14 July 2000). ["Global Water Resources: Vulnerability from Climate Change and Population Growth"](https://www.science.org/doi/10.1126/science.289.5477.284). *Science*. **289** (5477): 284–288. [Bibcode](/source/Bibcode_(identifier)):[2000Sci...289..284V](https://ui.adsabs.harvard.edu/abs/2000Sci...289..284V). [doi](/source/Doi_(identifier)):[10.1126/science.289.5477.284](https://doi.org/10.1126%2Fscience.289.5477.284). [PMID](/source/PMID_(identifier)) [10894773](https://pubmed.ncbi.nlm.nih.gov/10894773). [S2CID](/source/S2CID_(identifier)) [37062764](https://api.semanticscholar.org/CorpusID:37062764).

1. **[^](#cite_ref-28)** Ercin, A. Ertug; Hoekstra, Arjen Y. (2014). ["Water footprint scenarios for 2050: A global analysis"](https://doi.org/10.1016%2Fj.envint.2013.11.019). *Environment International*. **64**: 71–82. [Bibcode](/source/Bibcode_(identifier)):[2014EnInt..64...71E](https://ui.adsabs.harvard.edu/abs/2014EnInt..64...71E). [doi](/source/Doi_(identifier)):[10.1016/j.envint.2013.11.019](https://doi.org/10.1016%2Fj.envint.2013.11.019). [PMID](/source/PMID_(identifier)) [24374780](https://pubmed.ncbi.nlm.nih.gov/24374780).

1. **[^](#cite_ref-Water_scarcity_Liu-2017_29-0)** Liu, Junguo; Yang, Hong; Gosling, Simon N.; Kummu, Matti; Flörke, Martina; Pfister, Stephan; Hanasaki, Naota; Wada, Yoshihide; Zhang, Xinxin; Zheng, Chunmiao; Alcamo, Joseph (2017). ["Water scarcity assessments in the past, present, and future: Review on Water Scarcity Assessment"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6204262). *Earth's Future*. **5** (6): 545–559. [doi](/source/Doi_(identifier)):[10.1002/2016EF000518](https://doi.org/10.1002%2F2016EF000518). [PMC](/source/PMC_(identifier)) [6204262](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6204262). [PMID](/source/PMID_(identifier)) [30377623](https://pubmed.ncbi.nlm.nih.gov/30377623).

1. **[^](#cite_ref-Water_scarcity_WWF-2013_30-0)** ["Water Scarcity. Threats"](http://worldwildlife.org/threats/water-scarcity). *WWF*. 2013. [Archived](https://web.archive.org/web/20131021012358/http://worldwildlife.org/threats/water-scarcity) from the original on 21 October 2013. Retrieved 20 October 2013.

1. **[^](#cite_ref-31)** [Peter Gleick](/source/Peter_Gleick); Heather Cooley; David Katz (2006). [*The world's water, 2006–2007: the biennial report on freshwater resources*](https://books.google.com/books?id=Lttb1qPh4Z8C). Island Press. pp. 29–31. [ISBN](/source/ISBN_(identifier)) [978-1-59726-106-7](https://en.wikipedia.org/wiki/Special:BookSources/978-1-59726-106-7). [Archived](https://web.archive.org/web/20220317181510/https://books.google.com/books?id=Lttb1qPh4Z8C) from the original on 17 March 2022. Retrieved 12 September 2009.

1. **[^](#cite_ref-Water_pollution_Von_Sperling_32-0)** Von Sperling, Marcos (2007). ["Wastewater Characteristics, Treatment and Disposal"](https://doi.org/10.2166%2F9781780402086). *Water Intelligence Online*. Biological Wastewater Treatment. **6**. IWA Publishing. [doi](/source/Doi_(identifier)):[10.2166/9781780402086](https://doi.org/10.2166%2F9781780402086). [ISBN](/source/ISBN_(identifier)) [978-1-78040-208-6](https://en.wikipedia.org/wiki/Special:BookSources/978-1-78040-208-6).

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1. **[^](#cite_ref-35)** Schaffner, Monika; Bader, Hans-Peter; Scheidegger, Ruth (15 August 2009). "Modeling the contribution of point sources and non-point sources to Thachin River water pollution". *Science of the Total Environment*. **407** (17): 4902–4915. [Bibcode](/source/Bibcode_(identifier)):[2009ScTEn.407.4902S](https://ui.adsabs.harvard.edu/abs/2009ScTEn.407.4902S). [doi](/source/Doi_(identifier)):[10.1016/j.scitotenv.2009.05.007](https://doi.org/10.1016%2Fj.scitotenv.2009.05.007). [ISSN](/source/ISSN_(identifier)) [0048-9697](https://search.worldcat.org/issn/0048-9697). [PMID](/source/PMID_(identifier)) [19501876](https://pubmed.ncbi.nlm.nih.gov/19501876).

1. **[^](#cite_ref-Water_pollution_Moss2008_36-0)** Moss B (February 2008). ["Water pollution by agriculture"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2610176). *Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences*. **363** (1491): 659–666. [doi](/source/Doi_(identifier)):[10.1098/rstb.2007.2176](https://doi.org/10.1098%2Frstb.2007.2176). [PMC](/source/PMC_(identifier)) [2610176](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2610176). [PMID](/source/PMID_(identifier)) [17666391](https://pubmed.ncbi.nlm.nih.gov/17666391).

1. ^ [***a***](#cite_ref-:17_37-0) [***b***](#cite_ref-:17_37-1) [***c***](#cite_ref-:17_37-2) 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](https://en.wikipedia.org/wiki/File:A_RES_71_313_E.pdf) ([A/RES/71/313](https://undocs.org/A/RES/71/313) [Archived](https://web.archive.org/web/20201023121826/https://undocs.org/A/RES/71/313) 23 October 2020 at the [Wayback Machine](/source/Wayback_Machine))

## External links

Wikimedia Commons has media related to [Freshwater](https://commons.wikimedia.org/wiki/Category:Freshwater).

- [The World Bank's work and publications on water resources](http://water.worldbank.org/water/)

- [U.S. Geological Survey](https://ga.water.usgs.gov/edu/mearth.html) [Archived](https://web.archive.org/web/20120806000058/http://ga.water.usgs.gov/edu/mearth.html) 6 August 2012 at the [Wayback Machine](/source/Wayback_Machine)

- [Fresh Water National Geographic](http://environment.nationalgeographic.com/environment/freshwater/) [Archived](https://web.archive.org/web/20161127175917/http://environment.nationalgeographic.com/environment/freshwater) 27 November 2016 at the [Wayback Machine](/source/Wayback_Machine)

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Adapted from the Wikipedia article [Fresh water](https://en.wikipedia.org/wiki/Fresh_water) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Fresh_water?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.