[Vision2020] Fwd: Earth Policy Release - Water Tables Falling and Rivers Running Dry

[Tom Trail]

>Visionaires:


I thought the following report would be of interest to you.

Tom Trail

>Earth Policy Institute
>Plan B 2.0 Book Byte
>For Immediate Release
>July 24, 2007
>
>WATER TABLES FALLING AND RIVERS RUNNING DRY
>
>http://www.earthpolicy.org/Books/Seg/PB2ch03_ss2.htm
>
>Lester R. Brown
>
>As the world’s demand for water has tripled over 
>the last half-century and as the demand for 
>hydroelectric power has grown even faster, dams 
>and diversions of river water have drained many 
>rivers dry. As water tables fall, the springs 
>that feed rivers go dry, reducing river flows.
>
>Scores of countries are overpumping aquifers as 
>they struggle to satisfy their growing water 
>needs, including each of the big three grain 
>producers--China, India, and the United States. 
>More than half the world’s people live in 
>countries where water tables are falling.
>
>There are two types of aquifers: replenishable 
>and nonreplenishable (or fossil) aquifers. Most 
>of the aquifers in India and the shallow aquifer 
>under the North China Plain are replenishable. 
>When these are depleted, the maximum rate of 
>pumping is automatically reduced to the rate of 
>recharge.
>
>For fossil aquifers, such as the vast U.S. 
>Ogallala aquifer, the deep aquifer under the 
>North China Plain, or the Saudi aquifer, 
>depletion brings pumping to an end. Farmers who 
>lose their irrigation water have the option of 
>returning to lower-yield dryland farming if 
>rainfall permits. In more arid regions, however, 
>such as in the southwestern United States or the 
>Middle East, the loss of irrigation water means 
>the end of agriculture.
>
>The U.S. embassy in Beijing reports that Chinese 
>wheat farmers in some areas are now pumping from 
>a depth of 300 meters, or nearly 1,000 feet. 
>Pumping water from this far down raises pumping 
>costs so high that farmers are often forced to 
>abandon irrigation and return to less productive 
>dryland farming. A World Bank study indicates 
>that China is overpumping three river basins in 
>the north--the Hai, which flows through Beijing 
>and Tianjin; the Yellow; and the Huai, the next 
>river south of the Yellow. Since it takes 1,000 
>tons of water to produce one ton of grain, the 
>shortfall in the Hai basin of nearly 40 billion 
>tons of water per year (1 ton equals 1 cubic 
>meter) means that when the aquifer is depleted, 
>the grain harvest will drop by 40 million 
>tons--enough to feed 120 million Chinese.
>
>In India, water shortages are particularly 
>serious simply because the margin between actual 
>food consumption and survival is so precarious. 
>In a survey of India’s water situation, Fred 
>Pearce reported in New Scientist that the 21 
>million wells drilled are lowering water tables 
>in most of the country. In North Gujarat, the 
>water table is falling by 6 meters (20 feet) per 
>year. In Tamil Nadu, a state with more than 62 
>million people in southern India, wells are 
>going dry almost everywhere and falling water 
>tables have dried up 95 percent of the wells 
>owned by small farmers, reducing the irrigated 
>area in the state by half over the last decade.
>
>As water tables fall, well drillers are using 
>modified oil-drilling technology to reach water, 
>going as deep as 1,000 meters in some locations. 
>In communities where underground water sources 
>have dried up entirely, all agriculture is 
>rain-fed and drinking water is trucked in. 
>Tushaar Shah, who heads the International Water 
>Management Institute’s groundwater station in 
>Gujarat, says of India’s water situation, “When 
>the balloon bursts, untold anarchy will be the 
>lot of rural India.”
>
>In the United States, the U.S. Department of 
>Agriculture reports that in parts of Texas, 
>Oklahoma, and Kansas--three leading 
>grain-producing states--the underground water 
>table has dropped by more than 30 meters (100 
>feet). As a result, wells have gone dry on 
>thousands of farms in the southern Great Plains. 
>Although this mining of underground water is 
>taking a toll on U.S. grain production, 
>irrigated land accounts for only one fifth of 
>the U.S. grain harvest, compared with close to 
>three fifths of the harvest in India and four 
>fifths in China.
>
>Pakistan, a country with 158 million people that 
>is growing by 3 million per year, is also mining 
>its underground water. In the Pakistani part of 
>the fertile Punjab plain, the drop in water 
>tables appears to be similar to that in India. 
>Observation wells near the twin cities of 
>Islamabad and Rawalpindi show a fall in the 
>water table between 1982 and 2000 that ranges 
>from 1 to nearly 2 meters a year.
>
>In the province of Baluchistan, water tables 
>around the capital, Quetta, are falling by 3.5 
>meters per year. Richard Garstang, a water 
>expert with the World Wildlife Fund and a 
>participant in a study of Pakistan’s water 
>situation, said in 2001 that “within 15 years 
>Quetta will run out of water if the current 
>consumption rate continues.”
>
>Iran, a country of 70 million people, is 
>overpumping its aquifers by an average of 5 
>billion tons of water per year, the water 
>equivalent of one third of its annual grain 
>harvest. Under the small but agriculturally rich 
>Chenaran Plain in northeastern Iran, the water 
>table was falling by 2.8 meters a year in the 
>late 1990s. New wells being drilled both for 
>irrigation and to supply the nearby city of 
>Mashad are responsible. Villages in eastern Iran 
>are being abandoned as wells go dry, generating 
>a flow of “water refugees.”
>
>Saudi Arabia, a country of 25 million people, is 
>as water-poor as it is oil-rich. Relying heavily 
>on subsidies, it developed an extensive 
>irrigated agriculture based largely on its deep 
>fossil aquifer. After several years of using oil 
>money to support wheat prices at five times the 
>world market level, the government was forced to 
>face fiscal reality and cut the subsidies. Its 
>wheat harvest dropped from a high of 4 million 
>tons in 1992 to some 2 million tons in 2005. 
>Some Saudi farmers are now pumping water from 
>wells that are 1,200 meters deep (nearly four 
>fifths of a mile).
>
>In neighboring Yemen, a nation of 21 million, 
>the water table under most of the country is 
>falling by roughly 2 meters a year as water use 
>outstrips the sustainable yield of aquifers. In 
>western Yemen’s Sana’a Basin, the estimated 
>annual water extraction of 224 million tons 
>exceeds the annual recharge of 42 million tons 
>by a factor of five, dropping the water table 6 
>meters per year. World Bank projections indicate 
>the Sana’a Basin--site of the national capital, 
>Sana’a, and home to 2 million people--will be 
>pumped dry by 2010.
>
>In the search for water, the Yemeni government 
>has drilled test wells in the basin that are 2 
>kilometers (1.2 miles) deep--depths normally 
>associated with the oil industry--but they have 
>failed to find water. Yemen must soon decide 
>whether to bring water to Sana’a, possibly by 
>pipeline from coastal desalting plants, if it 
>can afford it, or to relocate the capital. 
>Either alternative will be costly and 
>potentially traumatic.
>
>Israel, even though it is a pioneer in raising 
>irrigation water productivity, is depleting both 
>of its principal aquifers--the coastal aquifer 
>and the mountain aquifer that it shares with 
>Palestinians. Israel’s population, whose growth 
>is fueled by both natural increase and 
>immigration, is outgrowing its water supply. 
>Conflicts between Israelis and Palestinians over 
>the allocation of water in the latter area are 
>ongoing. Because of severe water shortages, 
>Israel has banned the irrigation of wheat.
>
>In Mexico--home to a population of 107 million 
>that is projected to reach 140 million by 
>2050--the demand for water is outstripping 
>supply. Mexico City’s water problems are well 
>known. Rural areas are also suffering. For 
>example, in the agricultural state of 
>Guanajuato, the water table is falling by 2 
>meters or more a year. At the national level, 51 
>percent of all the water extracted from 
>underground is from aquifers that are being 
>overpumped.
>
>Since the overpumping of aquifers is occurring 
>in many countries more or less simultaneously, 
>the depletion of aquifers and the resulting 
>harvest cutbacks could come at roughly the same 
>time. And the accelerating depletion of aquifers 
>means this day may come soon, creating 
>potentially unmanageable food scarcity.
>
>While falling water tables are largely hidden, 
>rivers that are drained dry before they reach 
>the sea are highly visible. Two rivers where 
>this phenomenon can be seen are the Colorado, 
>the major river in the southwestern United 
>States, and the Yellow, the largest river in 
>northern China. Other large rivers that either 
>run dry or are reduced to a mere trickle during 
>the dry season are the Nile, the lifeline of 
>Egypt; the Indus, which supplies most of 
>Pakistan’s irrigation water; and the Ganges in 
>India’s densely populated Gangetic basin. Many 
>smaller rivers have disappeared entirely.
>
>Since 1950, the number of large dams, those over 
>15 meters high, has increased from 5,000 to 
>45,000. Each dam deprives a river of some of its 
>flow. Engineers like to say that dams built to 
>generate electricity do not take water from the 
>river, only its energy, but this is not entirely 
>true since reservoirs increase evaporation. The 
>annual loss of water from a reservoir in arid or 
>semiarid regions, where evaporation rates are 
>high, is typically equal to 10 percent of its 
>storage capacity.
>
>The Colorado River now rarely makes it to the 
>sea. With the states of Colorado, Utah, Arizona, 
>Nevada, and, most important, California 
>depending heavily on the Colorado’s water, the 
>river is simply drained dry before it reaches 
>the Gulf of California. This excessive demand 
>for water is destroying the river’s ecosystem, 
>including its fisheries.
>A similar situation exists in Central Asia. The 
>Amu Darya--which, along with the Syr Darya, 
>feeds the Aral Sea--is diverted to irrigate the 
>cotton fields of Central Asia. In the late 
>1980s, water levels dropped so low that the sea 
>split in two. While recent efforts to revitalize 
>the North Aral Sea have raised the water level 
>somewhat, the South Aral Sea will likely never 
>recover.
>
>China’s Yellow River, which flows some 4,000 
>kilometers through five provinces before it 
>reaches the Yellow Sea, has been under mounting 
>pressure for several decades. It first ran dry 
>in 1972. Since 1985 it has often failed to reach 
>the sea, although better management and greater 
>reservoir capacity have facilitated year-round 
>flow in recent years.
>The Nile, site of another ancient civilization, 
>now barely makes it to the sea. Water analyst 
>Sandra Postel, in Pillar of Sand, notes that 
>before the Aswan Dam was built, some 32 billion 
>cubic meters of water reached the Mediterranean 
>each year. After the dam was completed, however, 
>increasing irrigation, evaporation, and other 
>demands reduced its discharge to less than 2 
>billion cubic meters.
>
>Pakistan, like Egypt, is essentially a 
>river-based civilization, heavily dependent on 
>the Indus. This river, originating in the 
>Himalayas and flowing westward to the Indian 
>Ocean, not only provides surface water, it also 
>recharges aquifers that supply the irrigation 
>wells dotting the Pakistani countryside. In the 
>face of growing water demand, it too is starting 
>to run dry in its lower reaches. Pakistan, with 
>a population projected to reach 305 million by 
>2050, is in trouble.
>
>In Southeast Asia, the flow of the Mekong is 
>being reduced by the dams being built on its 
>upper reaches by the Chinese. The downstream 
>countries, including Cambodia, Laos, Thailand, 
>and Viet Nam--countries with 168 million 
>people--complain about the reduced flow of the 
>Mekong, but this has done little to curb China’s 
>efforts to exploit the power and the water in 
>the river.
>
>The same problem exists with the Tigris and 
>Euphrates Rivers, which originate in Turkey and 
>flow through Syria and Iraq en route to the 
>Persian Gulf. This river system, the site of 
>Sumer and other early civilizations, is being 
>overused. Large dams erected in Turkey and Iraq 
>have reduced water flow to the once “fertile 
>crescent,” helping to destroy more than 90 
>percent of the formerly vast wetlands that 
>enriched the delta region.
>
>In the river systems just mentioned, virtually 
>all the water in the basin is being used. 
>Inevitably, if people upstream use more water, 
>those downstream will get less. As demands 
>continue to grow, balancing water demand and 
>supply is imperative. Failure to do so means 
>that water tables will continue to fall, more 
>rivers will run dry, and more lakes and wetlands 
>will disappear.
>
>#     #     #
>
>Adapted from Chapter 3, “Emerging Water 
>Shortages” in Lester R. Brown, Plan B 2.0: 
>Rescuing a Planet Under Stress and a 
>Civilization in Trouble (New York: W.W. Norton & 
>Company, 2006), available free of charge on-line 
>at www.earthpolicy.org/Books/PB2/index.htm
>
>The next Plan B 2.0 Book Byte will cover Reducing Urban Water Use.
>
>Additional data and information sources at www.earthpolicy.org
>
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>---
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-- 
Dr. Tom Trail
International Trails
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