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Regions in the world with water scarcity include Africa, Middle East, South Asia, and the North America. More specifically, North and East Africa, India, China, Mexico, Middle East, southern region of the former Soviet states and the western part of the United States are amongst the most directly affected regions. There is 1360 million cubic kilometers of water on Earth, but only 0.126 million cubic kilometers are easily available. This comes to a mere 0.009%. If we look at how we use this 0.009%, things become more clear.
Global use by sector per year:
- Cooling - 225 cubic kilometers
- Industrial - 200 cubic kilometers
- Domestic - 100 cubic kilometers
- Livestock - 40 cubic kilometers
- Total - 565 cubic kilometers
(Suzanne Schnek Mike Taylor,Westminister College)
Water scarcity can be defined either in terms of the existing and potential supply of water, or in terms of the present and future demands for water, or both. For example, in their pioneering study of water scarcity, Falkenmark et al. (1989) take a "supply-side" approach by ranking countries according to the per capita amount of Annual Water Resources in the country. One of the problems with the supply-side approach is that the criterion for water scarcity is based on a country’s water resources without reference to present and future demand or needs for water. The original study by Seckler et al (1998) and the subsequent work that led to the development of PODIUM, attempt to resolve these problems by simulating the demand for water in relation to the available water resources.
Three categories of water scarcity in the PODIUM:
Countries are grouped into three categories of water scarcity: 1. Physical water scarcity, 2. Economic water scarcity and 3. Little or no water scarcity.
1. Physical Water Scarcity: This is defined in terms of the magnitude of primary water supply (PWS) development with respect to potentially utilizable water resources (PUWR). Physical water scarce conditions are reached if primary water supply of country exceeds 60 percent of its PUWR. This means that even with the highest feasible efficiency and productivity, PUWR of a country is not sufficient to meet the demand of agriculture, domestic, industrial sectors while satisfying its environmental needs. Countries in this category will have to transfer water from agriculture to other sectors and import food or invest in costly desalinization plants.
2. Economic Water Scarcity: This is defined in terms of the magnitude of primary water. Economic water scarce countries have sufficient water resources to meet their additional PWS needs, but need to increase their PWS through additional storage and conveyance facilities by more than 25 percent. Most of these countries face severe financial and development capacity problems for increasing PWS to those levels.
3. Little or no water scarcity: This is defined in terms of the magnitude of primary water. These countries are not physically water scarce and also need to develop less than 25 percent of additional PWS to meet their 2025 needs.
Click on the link below and have a look into the model and water dependency (scarcity), related to sectors.
Use the model :http://podium.iwmi.org/
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