Water for the Future The West Bank and Gaza Strip, Israel, and Jordan (1999) / Chapter Skim
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3 Factors Affecting Patterns of Water Use
3 Factors Affecting Patterns of Water Use
Pages 54-65
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From page 54... ...
The 1996 UN report assessing the freshwater resources of the world concludes that "water use has been growing at more than twice the rate of the population increase during this century and already a number of regions are chronically water short. About one-third of the world's population lives in countries that are experiencing moderate to high water stress, resulting in part from increasing demands fueled by population growth and human activity.
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From page 55... ...
The chapter's discussion begins with the difficulties of projections and the problems associated with identifying specific disparities between water supply and demand. PROJECTED SUPPLY-DEMAND DISPARITIES AND WATER RESOURCES PLANNING Water resource planners frequently focus on identifying potential gaps between water demand and water supply at some future date.
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From page 56... ...
Where existing levels of water use are extremely low compared with the levels needed to avoid high economic and social costs, attention understandably focuses on closing the water supply "gap" between current and minimally acceptable levels of use. In addition, where current levels of supply include sources that cannot be sustained over the long-run "mined" ground water, for example it will not be possible to maintain a balance between supply and existing patterns of use indefinitely.
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From page 57... ...
In developing and assessing strategies to manage scarce water supplies, it will be important to identify the variables that have a large influence on the level of water use. It will be equally important to understand the extent to which these variables can be managed and controlled, or be changed by further research and development.
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From page 58... ...
On the other hand, failure to employ modern technology may mean lower quantities and higher costs of available supply. While improvements in technology have sometimes dramatically increased the availability of water supplies, technology can also produce unwanted and unforeseen side effects.
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From page 59... ...
Increases in temperature or decreases in vegetated area or biological diversity are likely to diminish available supplies and increase the water demanded in many water using sectors. Water quality deterioration due to increased contamination levels reduces the available supply of water as surely as drought.
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From page 60... ...
While instream uses do not render water unavailable for additional use, where water supplies are scarce, instream and withdrawal uses tend to compete. The importance of water in supporting the instream uses to maintain biodiversity and environmental quality is explored in the next chapter.
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From page 61... ...
Changes in technology or behavior that alter levels of water withdrawn and consumed may have significant impacts on the total levels used and the proportion returned as waste. It would be useful to investigate the effects of drought on water use; reductions on outdoor uses of water and economizing on indoor uses reduced total domestic water use by 25 percent in California during the drought of 1987-1993.
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From page 62... ...
In most instances, water that deep percolates from irrigated areas constitutes ground-water recharge, and water that runs off from fields is a source of supply for someone else. As a consequence, agricultural water conservation programs need to be carefully tailored to ensure they result in true water savings and not simply savings at the farm level that reduce someone else's supply (Council for Agricultural Science and Technology, 1988~.
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From page 63... ...
Other things being equal, options that have relatively large positive impacts on available water supply, whether individually or in aggregate, will be more desirable than those that have more modest effects. In many circumstances, programs of demand management that induce economizing on water use may have very significant impacts on the available supply of water.
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From page 64... ...
For purposes of analysis, the notion of intergenerational equity can be defined in terms of three principles. The principle of future options requires that actions taken now do not unduly restrict the opportunities for future generations to satisfy their own needs and advance their own welfare.
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From page 65... ...
1996. Middle East Regional Study on Water Supply and Demand Development, Phase I, Reional Overview.
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