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The cost of transporting water is determined largely by how far it has to be carried and how high it has to be lifted. Growing cities and towns may have to go hundreds of kilometers to find the water needed to satisfy their increasing thirst. California cities have long imported water from hundreds of kilometers away. And China is constructing three canals that are 1,156 kilometers, 1,267 kilometers, and 260 kilometers long to transfer water from the Yangtze River to Beijing and other rapidly growing areas in the northern provinces.
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Pumping water out of the ground or over land to higher elevations is energy-intensive. Pumping 480 cubic meters of water a height of 100 meters requires some 200 kilowatt-hours of electricity. At a price of 10¢ per kilowatt-hour, the cost is $20-not including the cost of the pump, the well, and the piping. One hundred meters is not an unusual lift for wells tapping falling supplies of groundwater. In Beijing and other areas in northern China, for instance, lifts of 1,000 meters are sometimes required.
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In most places water is not purchased or exchanged in a market. But formal water markets are developing in the western United States, Australia, and Chile. Where these water markets do exist, they provide examples of how high the scarcity value of the water-that is, the amount that other potential users would be willing to pay for it-can be. Water prices in Australia’s markets peaked at near 75¢ per cubic meter in December 2006, climbing 20-fold in a year in part due to prolonged drought. In the U.S. West, water prices typically range between 3 cents and 10 cents per cubic meter.
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In India, water scarcity has prompted some farmers to profit by selling their water instead of farming. The water they formerly used to irrigate their crops is instead pumped from their wells and trucked to nearby cities. The farmers are harvesting water rather than food and at the same time promoting a rapid drop in underground water tables.
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Another factor affecting how much people pay for water is the amount it is subsidized (补助). Water subsidies can be very large. For instance, water revenues in the city of Delhi are less than 20 percent of what it spends each year to provide water. On average worldwide, nearly 40 percent of municipal suppliers do not charge enough for water to meet their basic operation and maintenance costs.
第Ⅱ卷(共45分)