Water footprint

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Hello, as we distinguish between blue, green and gray water. Do we have to measure blue, green and gray water foot print? I am curious to know this.....:)

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  1. Dear Marcus, what are your views on this report. Virtual Water: some reservation,,http://www.globalwaterforum.org/2012/05/14/virtual-water-some-reservations/

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    1. Dear Parimal, an excerpt from the text you are referring to: quoting Ramaswamy R. Iyer, Steering Committee on Water, Government of India from his text on "Virtual Water: some reservations" (http://www.globalwaterforum.org/2012/05/14/virtual-water-some-reservations/)"...I am not arguing against the concept of ‘virtual water’ as a means of promoting an awareness of the water implications of the production or export of certain commodities or products. It is indeed very useful for that purpose. The concept is also a useful adjunct to that of ‘water footprint’." Here my comment: I am first stating the definition that describes the relationship between virtual water and water footprint, which aids in this discussion: The virtual-water content of a product is the freshwater ‘embodied’ in the product, not in real sense, but in virtual sense. It refers to the volume of water consumed or polluted for producing the product, measured over its full production chain. If a nation exports/imports such a product, it exports/imports water in virtual form. The ‘virtual-water content of a product’ is the same as ‘the water footprint of a product’, but the former refers to the water volume embodied in the product alone, while the latter term refers to that volume, but also to which sort of water is being used and to when and where that water is being used. The water footprint of a product is thus a multidimensional indicator, whereas virtual-water content refers to a volume alone. The concept of virtual water has been developed by Prof Allan in the early 90's and ever since there was a strong evolution of the concept. Prof. Hoekstra developed the water footprint concept in 2002. Prof. Allan uses the data that were derived by Prof. Hoekstra's research group in his book "Virtual Water: Tackling the treat to our planet's most precious resource" (Allan, 2011). (link to publisher website: bit.ly/mo1Hyn) The water footprint concept has developed to water footprint assessment, which is described in the water footprint assessment manual in full detail: http://www.waterfootprint.org/?page=files/WaterFootprintAssessmentManual This assessment comprises three steps: (i) setting goals and scope; (ii) quantify and locate the water footprint of a process, product, producer or consumer or to quantify in space and time the water footprint in a specified geographic area; (iii) assess the environmental, social and economic sustainability of this water footprint; and (vi) formulate a response strategy. The range of applications is broad. But uptake of new insight is a slow process. The potential of Water Footprint Assessment in policy making is grossly underestimated. The argument often used: it has not been demonstrated. The strength of the concept in awareness raising has been proven and acknowledged, there are numerous applications in assessing product and business water footprint, water footprint of regions, nations, etc., its contribution to improved policy making not yet fully - but in some countries the process has begun. It requires governments to adopt the idea and explore. There is sufficient evidence that Water Footprint Assessment will be a powerfull tool to enrich policy making. A few references to illustrate this: Zeng, Z., Liu, J., Koeneman, P.H., Zarate, E. and Hoekstra, A.Y. (2012) Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China, Hydrology and Earth System Sciences, 16: 2771-2781. Mekonnen, M.M., Hoekstra, A.Y. and Becht, R. (2012) Mitigating the water footprint of export cut flowers from the Lake Naivasha Basin, Kenya, Water Resources Management, 26: 3725–3742. Hoekstra, A.Y. and Mekonnen, M.M. (2012) From water footprint assessment to policy, Proceedings of the National Academy of Sciences, 109(22): E1425. Ercin, A.E., Mekonnen, M.M and Hoekstra, A.Y. (2012) The water footprint of France, Value of Water Research Report Series No. 56, UNESCO-IHE. Fader, M., Gerten, D., Thammer, M., Heinke, J., Lotze-Campen, H., Lucht, W. and Cramer, W. (2011) Internal and external green-blue agricultural water footprints of nations, and related water and land savings through trade, Hydrology and Earth System Sciences, 15(5): 1641-1660. Aldaya, M.M., Martinez-Santos, P. and Llamas, M.R. (2010) Incorporating the water footprint and virtual water into policy: Reflections from the Mancha Occidental Region, Spain, Water Resources Management 24(5): 941-958. Hoekstra, A.Y. (2013) The water footprint of modern consumer society, Routledge, London, UK. All those references and more information can be found at: http://www.waterfootprint.org/?page=files/Publications The next steps require visionary people in governments taking the ideas further in practice. The richness of the science of Water Footprint Assessment as it stands today should be applied. There is no time to waste. Prof. Allan also calls in his book for action. You may also be interested in the upcoming publication of Prof. Hoekstra related to this ("The water footprint of modern consumer society": http://www.routledge.com/books/details/9781849713030/). The Water Footprint Network (www.waterfootprint.org) is very active and maybe you can also contribute - or maybe you are already contributing in various ways. If so, then please share your experiences. It is fabulous to read about the work that is ongoing worldwide and to possibly collaborate on sustainable appropriation of the globe's freshwater resources. Best regards, Markus

  2. Markus, very well illustrated.

  3. The water footprint is an indicator of freshwater use that looks at 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 used to produce the goods and services consumed by the individual or community or produced by the business. Water use is measured in terms of water volumes consumed (evaporated or incorporated into a product) and/or polluted per unit of time. A water footprint can be calculated for a particular product, for any well-defined group of consumers (for example, an individual, family, village, city, province, state or nation) or producers (for example, a public organization, private enterprise or economic sector). The water footprint is a multi-dimensional indicator (three colors: green, blue and grey - see definitions below) geographically explicit indicator, showing not only volumes of water use and pollution, but also the locations and time of use and pollution. The WaterStat database (URL: www.waterfootprint.org/?page=files/WaterStat), a comprehensive database on water statistics maintained by the Water Footprint Network, may be of help. There you can find: - Product water footprint statistics Find here statistics on green, blue and grey water footprints of crops, derived crop products, biofuels, and farm animal products. All data are available at national and sub-national level. - National water footprint statistics Download here statistics on green, blue and grey water footprints of national production and consumption. - International virtual water flow statistics Here you find detailed statistics on international virtual water trade flows and on water savings related to international trade. - Water scarcity statistics This is the only database in the world providing data on blue water scarcity per river basin on a monthly basis. - Water pollution level statistics Download here statistics on water pollution level per river basin. [Visit: www.waterfootprint.org/?page=files/WaterStat] If you mean to carry out a water footprint assessment, which refers to the full range of activities to: (i) setting goals and scope of the assessment, (ii) quantify and locate the water footprint of a process, product, producer or consumer or to quantify in space and time the water footprint in a specified geographic area (i.e. wf accounting); (iii) assess the environmental, social and economic sustainability of this water footprint; and (iv) formulate a response strategy, then in the accounting phase it is necessary to collect factual, empirical data on water footprints with a scope and depth as defined earlier. Again, there the WaterStat database may be of help, depending on the goals and scope of the study. A comprehensive and sound set of equations exists on how to determine green, blue and grey water footprint (see Hoekstra et al., 2011). Full information on water footprint assessment can be found in the Water Footprint Assessment Manual (Hoekstra et al., 2011), freely available at: http://www.waterfootprint.org/?page=files/WaterFootprintAssessmentManual Some definitions that may help: * Blue water footprint – Volume of surface and groundwater consumed as a result of the production of a good or service. Consumption refers to the volume of freshwater used and then evaporated or incorporated into a product. It also includes water abstracted from surface or groundwater in a catchment and returned to another catchment or the sea. It is the amount of water abstracted from groundwater or surface water that does not return to the catchment from which it was withdrawn. * Green water footprint – Volume of rainwater consumed during the production process. This is particularly relevant for agricultural and forestry products (products based on crops or wood), where it refers to the total rainwater evapotranspiration (from fields and plantations) plus the water incorporated into the harvested crop or wood. * Grey water footprint – The grey water footprint of a product is an indicator of freshwater pollution that can be associated with the production of a product over its full supply chain. It is defined as the volume of freshwater that is required to assimilate the load of pollutants based on natural background concentrations and existing ambient water quality standards. It is calculated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains above agreed water quality standards. Reference: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint assessment manual: Setting the global standard, Earthscan, London, UK. Hope this helps!

  4. non l'eau reste toujours de l'Eau. c'est l'usage que l'on en a fait qui va déterminer comment la nettoyer et l'épurer si tant est que l'on veuille le faire avant de la rejeter dans la nature. l'usage qui en ajura été fait détermine aussi sa qualité au niveau biologique, qui elle détermine le moyen d'épuration le plus approprié