Water footprint

The water footprint is an indicator of water use that includes both direct and indirect water use of a consumer or producer. The water footprint of an individual, community or business is defined as the total volume of freshwater that is used to produce the goods and services consumed by the individual or community or produced by the business. Water use is measured in water volume consumed (evaporated) and/or polluted per unit of time. A water footprint can be calculated for any well-defined group of consumers (e.g. an individual, family, village, city, province, state or nation) or producers (e.g. a public organization, private enterprise or economic sector). The water footprint is a geographically explicit indicator, not only showing volumes of water use and pollution, but also the locations. [Definition taken from the Hoekstra, A.Y. and Chapagain, A.K. (2008) Globalization of water: Sharing the planet's freshwater resources, Blackwell Publishing, Oxford, UK. [http://www.blackwellpublishing.com/book.asp?ref=9781405163354&site=1] ]

History

The water footprint concept was introduced in 2002 by A.Y. Hoekstra from UNESCO-IHE as an alternative indicator of water use. [ A.Y. Hoekstra and Hung, P.Q. (2002) Virtual water trade: A quantification of virtual water flows between nations in relation to international crop trade [http://www.waterfootprint.org/Reports/Report11.pdf] ] . The concept was refined and accounting methods were established with a series of publications from two lead authors A.K. Chapagain and A.Y. Hoekstra from the UNESCO-IHE Institute for Water Education, now at WWF-UK and University of Twente respectively. The most elaborate publications on how to estimate water footprints are a 2004-report on the 'Water footprint of nations' from UNESCO-IHE [ [http://www.waterfootprint.org/Reports/Report16Vol1.pdf] ] and the 2008-book Globalization of Water by A.Y. Hoekstra and A.K. Chapagain, published by Blackwell, 2008. Cooperation between global leading institutions in the field has led to the establishment of the Water Footprint Network in 2008 that aims to coordinate efforts to further develop and disseminate knowledge on water footprint concepts, methods and tools.

Blue, green and grey water footprint

A water footprint consists of three components: the blue, green and grey water footprint. The blue water footprint is the volume of freshwater that evaporated from the global blue water resources (surface water and ground water) to produce the goods and services consumed by the individual or community. The green water footprint is the volume of water evaporated from the global green water resources (rainwater stored in the soil as soil moisture). The grey water footprint is the volume of polluted water that associates with the production of all goods and services for the individual or community. The latter can be estimated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains at or above agreed water quality standards.

Water footprint of individual consumers

The water footprint of an individual consumer refers to the sum of direct and indirect freshwater use by the consumer. The direct water use is the water used at home. The indirect water use relates to the total volume of freshwater that is used to produce the goods and services consumed by the consumer.

The global average Water Footprint is 1240 m³ water/person/year. The Chinese average is 700 m³ water/person/year one of the smallest in the world and the United States's 2480 m³ water/person/year is the largest in the world. [Water footprints of all nations for the period 1997 - 2001 have been first reported cite journal | title = Water footprints of nations| url = http://www.waterfootprint.org/Reports/Report16Vol1.pdf/| author = Chapagain, A.K. and Hoekstra, A.Y. | journal = Value of Water Research Report Series No. 16| publisher = UNESCO-IHE] which is published in a concise from in a journal [ cite journal | title = Water footprints of nations: Water use by people as a function of their consumption pattern | url = http://www.springerlink.com/content/t6264j8730051762/ | author = Hoekstra, A.Y. and Chapagain, A.K. | journal = Water Resources Management | publisher = Springer Netherlands | pages = 35-48 | volume = 21 | issue = 1 ] The Finnish average Water Footprint is 1730 m³ water/person/year. [Data obtained from the Finnish Wikipedia article page [http://fi.wikipedia.org/wiki/Vesijalanj%C3%A4lki Vesijalanjälki] ] . The water footprint of the UK is 1695 m³ water/person/year. [cite journal | title = UK Water Footprint: the impact of the UK's food and fibre consumption on global water resources, Volume 1| url = http://assets.wwf.org.uk/downloads/water_footprint_uk.pdf| author = Chapagain, A.K. and Orr, S.| journal = WWF-UK | publisher = WWF-UK and volume 2 cite journal | title = Volume 2| url = http://assets.wwf.org.uk/downloads/uk_waterfootprint_v2.pdf| author = Chapagain, A.K. and Orr, S. | journal = WWF-UK | publisher = WWF-UK]

Water footprint of businesses

The water footprint of a business, the 'corporate water footprint', is defined as the total volume of freshwater that is used directly or indirectly to run and support a business. It is the total volume of water use to be associated with the use of the business outputs. The water footprint of a business consists of two components: the direct water use by the producer (for producing/manufucturing or for supporting activities) and the indirect water use (in the producer’s supply chain).

Water footprints of nations

The water footprint of a nation shows the water that is used to produce the goods and services consumed by the inhabitants of the nation. It includes two components: the internal and the external water footprint. The first component refers to the appropriation of domestic water resources; the latter to the appropriation of water resources in other countries. About 65% of Japan's total water footprint comes from outside the country; about 7% of the Chinese water footprint falls outside China. [cite web | url = http://www.waterfootprint.org/?page=files/home | title = Waterfootprint.org Water footprint and virtual water.| accessdate = 2008-05-30 ]

ee also

*Carbon footprint
*Ecological footprint
*Virtual water
*Water crisis

*Water resources of China
*China water crisis

References

External links

Water footprint websites

* Water Footprint Network: [http://www.waterfootprint.org/]

* WWF-UK: [http://www.wwf.org.uk/what_we_do/safeguarding_the_natural_world/rivers_and_lakes/water_footprint/index.cfm]

* WWF-NL: [http://www.wnf.nl/nl/wat_wnf_doet/thema_s/water/waterfootprint/index.cfm]

* UNESCO-IHE : [http://www.unesco-ihe.org/Value-of-Water-Research-Report-Series]

Water footprint calculators

Online water footprint calculators are available:

* For most countries of the world (in English): [http://www.waterfootprint.org/index.php?page=cal/waterfootprintcalculator_indv_ext Individual water footprint calculator]

* For the USA (in English): [http://www.h2oconserve.org H2OConserve calculator]

* For Finland (in Finnish): [http://www.vesijalanjalki.org Vesijalanjälki]