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Chapter 2. Emerging Water Shortages: Falling Water Tables
Scores of countries are overpumping aquifers as they struggle to satisfy their growing water needs, including each of the big three grain-producing countries—China, India, and the United States. Their populations, along with those of other countries where overpumping will measurably reduce the food supply when aquifers are depleted, exceed 3 billion people, or half the world total. (See Table 2-1.)8
As noted in Chapter 1, falling water tables are already affecting harvests in some countries, including China, the world's largest grain producer. A little-noticed groundwater survey released in Beijing in August 2001 revealed that the water table under the North China Plain, which produces over half of China's wheat and a third of its corn, is falling faster than earlier reported. Overpumping has largely depleted the shallow aquifer, reducing the amount of water that can be pumped from it to the annual recharge from precipitation. This is forcing well drillers to turn to the region's deep aquifer, which, unfortunately, is not replenishable.9
The survey, conducted by the Geological Environmental Monitoring Institute (GEMI) in Beijing, reported that under Hebei Province in the heart of the North China Plain, the average level of the deep aquifer dropped 2.9 meters (nearly 10 feet) in 2000. Around some cities in the province, it fell by 6 meters. He Qingcheng, head of the GEMI groundwater monitoring team, notes that as the deep aquifer under the North China Plain is depleted, the region is losing its last water reserve—its only safety cushion.10
His concerns are mirrored in a World Bank report: "Anecdotal evidence suggests that deep wells [drilled] around Beijing now have to reach 1,000 meters [more than half a mile] to tap fresh water, adding dramatically to the cost of supply." In unusually strong language for a Bank report, it foresees "catastrophic consequences for future generations" unless water use and supply can quickly be brought back into balance.11
The U.S. embassy in Beijing reports that 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 translates into exorbitant costs and reduced profit margins that often force farmers to abandon irrigation and return to less productive dryland farming.12
Falling water tables, combined with reduced government grain support prices and the loss of farm labor in provinces that are rapidly industrializing, are shrinking China's grain harvest. The wheat crop, grown mostly in arid northern China, is particularly vulnerable to water shortages. After peaking at 123 million tons in 1997, the wheat harvest has fallen in five of the last six years, coming in at 87 million tons in 2003, a drop of nearly 30 percent.13
The U.S. embassy in Beijing also reports that the recent decline in rice production is partly the result of water shortages. After peaking at 140 million tons in 1997, the harvest has dropped in each of the five years since then, falling to an estimated 121 million tons in 2003. Only corn, China's third major grain, has thus far avoided a decline. This is because corn prices are stronger and because the corn crop is not as dependent on irrigation water as wheat and rice are.14
Overall, China's grain production has fallen from its historical peak of 392 million tons in 1998 to an estimated 338 million tons in 2003. (See Figure 2-1). For perspective, this drop of over 50 million tons is equal to the Canadian grain harvest. Thus far, China has covered the fall in production by drawing down its once vast stocks, but it can only do that for one or two more years. Then it will have to turn to the world market for imports. When it does so, we likely will see the effects in higher food prices at the supermarket checkout counter.15
A World Bank study indicates that China is overpumping three river basins in the north by 37 billion tons—the Hai, which flows through Beijing and Tianjin; the Yellow; and the Huai, the next river south of the Yellow. At 1,000 tons of water per ton of grain, this would produce 37 million tons of grain, enough to feed 111 million Chinese.16
The other country with extensive overpumping is India, which is depleting aquifers in Punjab (the country's breadbasket), Haryana, Gujarat, Rajasthan, Andhra Pradesh, and Tamil Nadu. The International Water Management Institute estimates that aquifer depletion could eventually reduce India's grain harvest by one fourth.17
The latest data indicate that under Punjab and Haryana, water tables are falling by up to a meter a year. Data for monitored wells in northern Gujarat suggest that the water table has fallen from a depth of 15 meters to 400 meters over the last three decades. At this point, the harvests of wheat and rice, India's principal food grains, are still increasing. But within the next few years, the loss of irrigation water could override technological progress and start shrinking the harvest, as it is already doing in China.18
In the United States, the USDA 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.19
Irrigated land accounts for about four fifths of the grain harvest in China and close to three fifths in India, but only one fifth in the United States. Of the leading grain producers, only China is currently experiencing a substantial decline in production. Even with a worldwide grain crunch and climbing grain prices providing an incentive to boost production, it would be difficult for China to regain earlier grain production levels given the loss of irrigation water. India can probably still expand its harvest somewhat before water shortages overwhelm the gains in production from advances in technology. For the United States, the ongoing irrigation water loss from aquifer depletion and diversion to cities does not appear to be large enough to reduce the grain harvest, but it will slow its growth.20
Pakistan, a country with 150 million people and growing by 4 million per year, is also overpumping its aquifers. 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 from 1982 to 2000 ranging from 1 to nearly 2 meters a year.21
In the province of Baluchistan, a more arid region, water tables around the provincial capital of 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, says that "within 15 years Quetta will run out of water if the current consumption rate continues."22
Future irrigation water cutbacks as a result of aquifer depletion will undoubtedly reduce Pakistan's grain harvest. In Pakistan, as in India, the harvest of wheat—the principal food staple—is continuing to grow, but more slowly.
Water shortages are common in Middle Eastern countries. Iran, a country of 68 million people, is overpumping its aquifers by an average of 5 billion tons per year, enough to produce 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. But, in 2001, the cumulative effect of a three-year drought and the new wells being drilled both for irrigation and to supply the nearby city of Mashad dropped the aquifer by an extraordinary 8 meters. Villages in eastern Iran are being abandoned as wells go dry, generating a flow of "water refugees."23
Saudi Arabia, a country of 24 million people, is as water-poor as it is oil-rich. It has tried to develop an extensive irrigated agriculture based largely on deep fossil aquifers. After several years of using oil money to support the price of wheat at five times the world market level to encourage farmers to develop an irrigated agriculture based on deep pumping, the government was forced to face fiscal reality and cut back on the program. Craig Smith writes in the New York Times, "From the air, the circular wheat fields of this arid land's breadbasket look like forest green poker chips strewn across the brown desert. But they are outnumbered by the ghostly silhouettes of fields left to fade back into the sand, places where the kingdom's gamble on agriculture has sucked precious aquifers dry." In some areas, farmers are now pumping water from 4,000-foot-deep wells-in other words, from nearly four fifths of a mile down.24
A 1984 Saudi national survey reports fossil water reserves at 462 billion tons. Half of that, Smith reports, has probably disappeared by now. This suggests that irrigated agriculture could last for another decade or so and then will largely disappear, limited to the small area that can be irrigated with water from the shallow aquifers that are replenished by the kingdom's sparse rainfall. The lush fields of thirsty alfalfa, grown to feed a recently created modern dairy industry, will also become history.25
In Yemen, a country of 19 million, the water table under most of the country is falling by roughly 2 meters a year as water use far exceeds the sustainable yield of aquifers. In the Sana'a basin in western Yemen, 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 by 6 meters per year. Projections by the World Bank indicate the Sana'a basin, home of the national capital and 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.26
With its population growing at a near-record 3.5 percent a year and with water tables falling everywhere, Yemen is fast becoming a hydrological basket case. Aside from the effect of overpumping on the capital, World Bank official Christopher Ward observes that "groundwater is being mined at such a rate that parts of the rural economy could disappear within a generation."27
Israel, a pioneer in raising irrigation water productivity, is depleting its two principal aquifers—the coastal aquifer and the mountain aquifer that it shares with the Palestinians. Conflicts between Israelis and Palestinians over the allocation of water in the latter are ongoing. Because of severe water shortages, Israel recently discontinued the irrigation of wheat.28
In Mexico—home to a population of 102 million that is projected to reach 140 million by 2050—the demand for water is outstripping supply. Mexico City's water problems are legendary. 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 coming from aquifers that are being overpumped.29
There are two types of aquifers: replenishable and nonreplenishable (fossil) aquifers. Most of the aquifers in India and the shallow aquifer under the North China Plain are replenishable. When a replenishable aquifer is depleted, the maximum rate of pumping is necessarily reduced to the rate of recharge.
For fossil aquifers, such as the vast Ogallala under the Great Plains of the United States, the deep aquifer under the North China Plain, or the aquifer under Saudi Arabia, 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 desert situations, however, such as the southwestern United States or the Middle East, the loss of irrigation water means the end of agriculture.
The overpumping of aquifers is occurring in many countries more or less simultaneously. This means that the depletion of aquifers and the resulting harvest cutbacks will come in many countries at roughly the same time. And the accelerating depletion of aquifers means this day may come sooner than expected, creating a potentially unmanageable situation of food scarcity.
|Table 2-1. Countries with Extensive Overpumpting of Aquifers in 2002|
|Source: See endnote 8.|
8. Grain production from USDA, Production, Supply, and Distribution, electronic database, updated 13 May 2003; Table 2-1 from United Nations, World Population Prospects: The 2002 Revision (New York: February 2003).
9. Michael Ma, "Northern Cities Sinking as Water Table Falls," South China Morning Post, 11 August 2001; share of China's grain harvest from the North China Plain based on Hong Yang and Alexander Zehnder, "China's Regional Water Scarcity and Implications for Grain Supply and Trade," Environment and Planning A, vol. 33 (2001), and on USDA, op. cit. note 8.
10. Ma, op. cit. note 9.
11. World Bank, op. cit. note 1, pp. vii, xi.
12.John Wade, Adam Branson, and Xiang Qing, China Grain and Feed Annual Report 2002 (Beijing: USDA, 21 February 2002).
13. China's grain production from USDA, op. cit. note 8.
14. Wade, Branson, and Qing, op. cit. note 12; grain production from USDA, op. ct. note 8; 2003 rice production is Earth Policy Institute estimate.
15. Figure 2-1 from USDA, op. cit. note 8.
16. World Bank, op. cit. note 1, p. viii.
17. Tushaar Shah et al., The Global Groundwater Situation: Overview of Opportunities and Challenges (Colombo, Sri Lanka: International Water Management Institute, 2000); Seckler cited in David Seckler, David Molden, and Randolph Barker, "Water Scarcity in the Twenty-First Century," Water Brief 1 (Colombo, Sri Lanka: International Water Management Institute, 1999), p. 2.
18. Shah et al., op. cit. note 16.
19. USDA, op. cit. note 1, Chapter 2.1, p. 6.
20. Irrigated area from U.N. Food and Agriculture Organization, FAOSTAT Statistics Database, at apps.fao.org, updated 9 January 2003; grain harvest from USDA, op. cit. note 8.
21. Population from United Nations, op. cit. note 8; fall in water table from "Pakistan: Focus on Water Crisis," U.N. Integrated Regional Information Networks, 17 May 2002.
22. "Pakistan: Focus on Water Crisis," op. cit. note 21; Garstang quoted in "Water Crisis Threatens Pakistan: Experts," Agence France-Presse, 26 January 2001.
23. Population from United Nations, op. cit. note 8; overpumping from Chenaran Agricultural Center, Ministry of Agriculture, according to Hamid Taravati, publisher, Iran, e-mail to author, 25 June 2002.
24. Craig S. Smith, "Saudis Worry as They Waste Their Scarce Water," New York Times, 26 January 2003.
26. Population from United Nations, op. cit. note 8; Yemen's water situation from Christopher Ward, "Yemen's Water Crisis," based on a lecture to the British Yemeni Society in September 2000, July 2001; Ward, op. cit. note 1; Marcus Moench, "Groundwater: Potential and Constraints," in Ruth S. Meinzen-Dick and Mark W. Rosegrant, eds., Overcoming Water Scarcity and Quality Constraints (Washington, DC: International Food Policy Research Institute, October 2001).
27. Population from United Nations, op. cit. note 8; Ward, op. cit. note 26.
28. Deborah Camiel, "Israel, Palestinian Water Resources Down the Drain," Reuters, 12 July 2000.
29. Population from United Nations, op. cit. note 8; water table fall from Shah et al., op. cit. note 17; percentage of water extracted from underground from Karin Kemper, "Groundwater Management in Mexico: Legal and Institutional Issues," in Salman M.A. Salman, ed., Groundwater: Legal and Policy Perspectives, Proceedings of a World Bank Seminar (Washington, DC: World Bank, 1999), p. 117.
Copyright © 2003 Earth Policy Institute