CHAPTER 4 ~ SUSTAINABILITY  OF  OUTPUTS  OF  THE  WORLD'S  IRRIGATED  LANDS  AND  FRESHWATER  RESOURCES ~

Note: The data found below represent a sampling of a much larger collection of data compiled in "Irrigated Lands Degradation: A Global Perspective," found on this same website.

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Section [A] ~ ELEMENTS OF NON-SUSTAINABILITY ~

(Irrigation System Sustainability - Politics and History) "The major problems of irrigation system development and operation are not technical, but relate to the socio-political situation (74F1)." The author of that statement (a hydrologist) is reasonable certain that most, if not all, the water projects he designed will meet the same fate as the ancient Middle-Eastern irrigation projects that people now find buried in the sands, or sparkling with white salt crusts in the sun, totally vegetation-free. What that author is saying is that very few present-day irrigation systems are designed with protection against salt build-up (salinization), i.e. with systems of underground drainage tiles to: (1) carry off the salt that irrigation water accumulates as it percolates down through the soil, and (2) to prevent the water table, with or without its salt load, from rising up to the root zones of the plants being irrigated. Even the World Bank does not require drainage tiles in the irrigation systems it finances (95J1), nor does the world Bank require water conservation measures such as micro- or drip-irrigation to be installed. More than 50% of the world's irrigated soils are affected by secondary salinization, alkalization and waterlogging (Refs. 355, 356, p. 207 of Ref. (88S1)) (FAO and UNESCO data). The threat is greater in developing nations because they lack the financial capital required to: (1) invest in the drainage systems required to prevent salinization and water-logging, or (2) to build new irrigation systems or (3) to afford the water needed to restore degraded or abandoned irrigation systems (water that, in the short run, provides no crops). The world's semi-arid and arid landscapes are dotted with huge white, salt-encrusted patches that were once irrigation systems that have never recovered because restoration costs had become unaffordable.

(Irrigation and Subsidies) Modern societies not only ignore the lessons from the past, they also pay people to follow in the footsteps of their ancestors. Water obtained from surface water and groundwater is sold to irrigators at a price that is typically about 10-20% of the cost, to the taxpayer, of supplying water to irrigators, effectively subsidizing the consumption of water, encouraging waste (e.g. irrigating alfalfa fields in California) and making water conservation technologies like micro-irrigation non-competitive***. This is true virtually the world over. Developing nations pay an especially dear (but politically essential) price for subsidizing irrigation. The governments' income generated from irrigators is hence not sufficient to repay the loans the governments receive from external entities like the World Bank or the International Monetary Fund (IMF) to build the dams, water ducts and irrigation systems. The loss, instead, is added to their staggering external debt (now well over $2.5 trillion for the developing world as a whole). The result is economy-wrecking loan repayment costs and a drying up of financial capital for future investments in irrigation.

Subsidizing the consumption of a scarce and vital resource has serious consequences; yet few countries, if any, have a well-functioning system for allocating water between competing demands and needs (05F2). Non-sustainability is largely the result of a variety of expediencies (such as subsidies) that increase current food supplies while risking, and reducing, future food supplies. The principle expediencies are (1) neglecting to deal effectively with salinization and (2) water-logging, and consuming water supplies beyond their sustainable limits. Other expediencies are described below.

One need only examine the data below and elsewhere*** to see the problems looming for mankind as a result of not taking water supply/ demand/ conservation issues seriously - and they are not being taken seriously. At least this author has never run across any evidence of seriousness in seeking laws, policies and practices that ensure that water is used and consumed sustainably. Human pressures on freshwater resources focused first on surface waters until major rivers started to dry up before they reached the sea. Then they focused on dams of ever-increasing size and number (partly to keep ahead of the large and growing erosion sediment loads that keep filling up the backwaters of dams). This led to irrigation systems of ever increasing scale that fed initially on surface waters. Now the trend is to rely, to ever-increasing extents, on ground water aquifers that, in much of the world, are being drained dry.

(The role of Irrigated Lands in Producing the world's Food) Something on the order of 70% of the water "consumed" (for all intents and purposes) by man is irrigation water (97W1). (82% goes to agriculture as a whole.) That 70% figure for irrigation becomes 81% if one apportions reservoir evaporation losses among the other uses of water (00S4). The world's irrigation systems produce on the order of 40% (by weight) of the world's food supply (00W2). On a dollar basis they produce about 60% of the world's food supply. This is because higher-value crops are more likely to be irrigated (97C1), reflecting the huge financial capital investments that modern irrigation systems require. Productivities (in dollars worth of output per acre of irrigated lands) are about 7 times greater than those of rain-fed croplands, and 36 times greater than those of range lands (Ref. 18 of Ref. (97C1)) that are typically located on semi-arid or arid lands. In fact, the world's 2.7 million km² of irrigated land produce about 74% more than the world's 40-50 million km² of rangeland on a dollar-basis (97C1). Irrigation expansion contributed over 50% of the increase in global food production during 1965-85 (96G2). This illustrates the extreme effects of water on productivity and explains why irrigated lands are so crucial in the global food supply system.

(Salinity effects on Irrigation System Sustainability) The sustainability of irrigation systems rests largely on systems of drainage pipes a few feet below the soil surface to protect against salt build-up. (The drainage system also prevents the water table from rising up to the root zone of plants, starving them of oxygen.) The percentage of irrigation systems that contain such drainage systems is estimated to be extremely small. Salinity problems are couples with water supply problems. Increasing human pressures on the land, and diminishing water supplies force irrigators to try to increase production from each drop of water. But doing this increases salinity, resulting in an ever-steeper downward spiral of positive feedbacks. The lack of protection against salt build-up poses serious threats to most irrigated cropland in terms of decline and eventual abandonment - invariably permanent (74F1). (Only irrigation systems in monsoon climates do not require this protection.) Because salinity effects take some decades to become apparent, and because so many irrigation systems are so new, rates of productivity-degradation and abandonment of irrigated lands are certain to grow well beyond current rates in coming decades. As human (population) pressures on the land increase, and as the developing world's external debt spirals out of control, strategies for sustainability (fallowing, drainage tiles, drip irrigation) become increasingly hard to afford and to defend from the interests of short-term expediency. This hastens increased salinization, waterlogging, declining productivity, and abandonment.

(The Overall Water Supply Issue) The other major sustainability issue rests on the sustainability of water supplies for irrigation. Urban consumption of water is growing several times faster that human population growth, and urban users have the political and economic power to reallocate irrigation water to urban uses. In the late 1990s, at least 400 million people lived in regions with severe water shortages. By 2050, this number is expected to be 4 billion (98S1). Thus large-scale reallocations of irrigation water to household-, municipal- and industrial uses are virtually certain in coming decades. The International Food Policy Research Institute's (IFPRI's) "business-as-usual" scenario (02I1) forecasts that, by 2025, freshwater scarcity will cause annual global losses of 350 million metric tonnes of food production. For comparison, global cereal production in 1990 was 1921 million metric tonnes (98D1). Grains are the source of 2/3 of mankind's caloric food intake. Water consumption by agriculture (almost entirely for irrigation) accounts for 82% of human-based water consumption. If reservoir evaporation losses are apportioned among all other consumption categories, agriculture accounts for 93% of water consumption by humans (96P2). Thus irrigation is the primary reason why many of the world's major rivers no longer reach the oceans during at least parts of the year (99P1). It is also the primary reason why the number of lakes and the sizes of inland seas are shrinking so rapidly, and why the number of endangered lakes is now so large as to pose a threat to up to one billion people (01A1).

Water supply issues are best divided into two somewhat independent issues - surface water issues and groundwater issues. These two issues are taken up below.

(Surface Water) More than half the world's 500 largest rivers have been seriously depleted. Some have been reduced to a trickle in what the UN warned is a "disaster in the making" (06L1). Irrigation is the primary reason why these rivers no longer reach the oceans during parts of the year. It is also the primary reason why the number of lakes (and the sizes of inland seas) is shrinking so rapidly, and why the number of endangered lakes now poses a threat to up to one billion people ***.

(Aquifers [Ground Water]) As rivers, lakes, and inland seas, started to dry up due to over-extraction of water*** technological advances came along around 1950 in the form of sophisticated diesel- and electric-powered pumps that enabled the low-cost extraction of huge flows of "ground waters." Irrigation water now comes increasingly from aquifers. Predictably, what happened to surface waters is now happening to ground waters: As a result, groundwater tables are dropping globally, despite the fact that 97% of the earth's liquid freshwater is in aquifers (00S4). Often aquifers are joined to surface waters that supply water to the aquifers. Also aquifers are often joined to rivers, lakes and oceans that receive water from the aquifer. So in a way, it can be misleading to speak of surface water problems and ground water problems as separate issues. Draining a swamp, for example, can reduce flows to aquifers down below. Some aquifers ("fossil water") are not connected to surface water and have no way of replacing any water drawn from them. Once these aquifers are drained they are lost forever. If water is extracted from an aquifer near an ocean too rapidly, saltwater may flow from the ocean into the aquifer - reversing the normal flow pattern. When an aquifer becomes composed of 2-3% seawater or more, the aquifer becomes useless as a source of freshwater useful for human consumption or irrigation. This is a serious problem in many coastal nations***.

(Dams) Filling of dam backwaters with erosion sediments also threatens water supplies for irrigation-, urban-, and industrial use. The world's dam backwaters are filling with sediment at 1%/ year (87M1) and several times that in the world's more densely populated regions. Sedimentation rates are now 8 times higher than in the mid-1960s (UNEP release (12/4/01)) so the 1%/ year rate from the mid-1980s may now be too low. A US Geological Survey study notes that new dam construction might increase the (global) dam supply (storage capacity?) by 0.33%/ year over the next 30 years (98S3). This suggests that global dam-backwater storage per-capita should drop 2%/ year in coming decades - even as per-capita water consumption rises twice as fast as the world's population (98S1). The supply of suitable dam sites is also shrinking, greatly increasing the cost of new dams - costs that are already so high that developing nations must finance them largely by increasing their staggering external debt.

(Glacier-Water) Half the world's population (about three billion people) depends on rivers starting from mountain glaciers as their freshwater source. Himalayan glaciers feed 7 major Asian rivers - the Ganges, Indus, Brahmaputra, Salween, Mekong, Yangtze and Huang He - ensuring a year-round water supply for two billion people (06H1). Shrinking glaciers, usually attributed to global warming, threaten the uniformity of the flows of these major rivers, and hence threaten the water supplies of these billions of people. The shrinking glaciers of the Andes Mountains in Latin America, the Rocky Mountains in the western US and the Alps of Europe probably account for the remaining one billion people whose water supplies are put at risk as a result of shrinking glaciers.

(Drip- or micro-irrigation) The water supply issue (and the salinity issue mentioned above) could be dealt with by greater use of "drip irrigation" and other "micro-irrigation" processes. They do not entail salt accumulation in the root zone (93P2) and, relative to furrow- or sprinkler irrigation, cut water use by 30-60% (96P1). One problem is the added capital required in developing nations where financial capital is already too scarce to even afford drainage tiles for avoiding salinity. Also, water supplies for irrigation are government-subsidized virtually worldwide, worsening the apparent (but not real) economics of drip irrigation. Typically on the order of 80-90% of the costs of "producing" water are government-subsidized. Perhaps for these two reasons, global use of drip irrigation accounts for less than 1% of the world's irrigated area (97P3).

(Water Conservation by using wastewater) Using wastewater is another water-conservation strategy. But salinity rises by 300-400 parts per million while passing through the urban circuit, and that salinity is not reduced by any of the usual sewage treatment processes (77A2). So more than once or twice through the urban circuit causes significant problems with salinization.

(Fallowing) Whether we are talking about the wheat fields of the US and Canadian Plains, the croplands run by shifting cultivators in most tropical rain forests, the grazing lands springing up all over the tropical portions of Latin America, or the irrigation systems threatened with salinization the world over, fallowing (idling) cropland for periods ranging from a year to several decades to permit the land to regain its past productivity is a common practice. Unfortunately fallow periods are shrinking in each of the environments listed above as a result of ever-increasing human pressures on the land to produce food and wood. The results are easily predictable. The land does not fully recover in the time allowed, so the long-term trend is toward ever-declining productivities. The name of the game is the same the world over - short-term gain, long-term pain.

(Desalination) Desalinated water costs about $800/ acre-foot, too expensive for irrigation by a factor of 10-30 or more (01R1). Also desalination plants are notoriously inefficient in terms of energy consumption. As a result they are very sensitive to increases in energy prices. Since irrigation uses (consumes) about 70% of the water that human-kind uses (consumes), it seems clear that desalination has little, if any, role to play in rendering water supplies sustainable unless there are major reductions in the cost of energy, or desalination technology can be made far more energy-efficient than it is today.

The above-mentioned sustainability problems are summarized below.

• Salinity-induced productivity declines;
• Salinity-induced irrigated land abandonment;
• Shrinking surface-water supplies;
• Shrinking groundwater supplies;
• Sea-water intrusion into shrinking coastal aquifers;
• Irrigation water reallocation to urban-, commercial and industrial uses;
• Growing problems with finding more dam sites, building dams and financing dams;
• Siltation of dam backwaters by erosion sediments from croplands and grazing lands;
• Threats to funding sources for government irrigation subsidies;
• Extreme scarcity of financial capital in developing nations;
• Wasteful uses of irrigation water and urban water - promoted by subsidies for consumption of water;
• Water-supply-salinity positive feedbacks.

The combined magnitude of all these threats make if quite clear that irrigation systems, their water supplies, and hence the food they produce are non-sustainable. Further, the degree of non-sustainability is certain to increase, particularly in developing nations where water supplies get increasingly precarious, the financial capital needed to reduce salinity problems and increase water supplies becomes scarcer, external debt increases by $1 trillion every 10-15 years, and where high and growing population pressures on the land worsen numerous positive feedbacks.

*** Additional data on the sustainability issues described above are given below. Much more data can be found in "Irrigated Land Degradation: A Global Perspective," found on this website.

Go to this Chapter's Table of Contents ~

• Once underground water with a salt content of 0.1% (1000 p.p.m.) (quite acceptable to crops) is within several feet of the surface, capillary evaporation residues raise the salt content of the top 3 ft. of soil to the intolerable level of 1% in 2 decades (76E1).
• The traditional method of dealing with salinization due to rising water tables is alternate-year fallowing. Details of the system are discussed in Ref. (77G1). The main problem with the fallowing approach to rejuvenating any kind of cropland is that, as population pressures on the land increase, the alternative of fallowing becomes increasingly difficult to justify from a near-term perspective. This is why the worldwide trend is toward shorter fallow periods, despite the long-term harmful effects of cropland productivity. This is true even in countries like Canada, where population pressures are minimal.
• Waterlogging starves plant roots of oxygen. This inhibits the plant's growth (90P1).
• Irrigation water sometimes contains sodium. So as water evaporates and transpires, Ca. and Mg. precipitate as carbonates, leaving Na+ dominant in the soil solution. Unless it is washed down in the water table, Na+ tends to be adsorbed by colloidal clay particles, deflocculating them and leaving the resultant structureless soil almost impervious to water (58J1).
• The upper limit (US EPA) for drinking water is 500 mg./ liter of total dissolved solids (Ref. 20 of Ref. (85E1)).
• Salinity of water rises by 300-400 p.p.m. every time it passes through the urban circuit. Salinity is not reduced by any of the usual urban sewage treatment processes (77A2). Eliminating dissolved salts from water requires expensive desalination processes that almost invariably have extremely low energy efficiencies. This makes such processes highly vulnerable to energy price increases.
• US Salinity Laboratory classification of the salinity hazard to crops of irrigated water (81S3):
  Low ~100- 250 p.p.m.~ Medium ~250-750 p.p.m.
  High ~750-2250 p.p.m.~ Very High~2250+ p.p.m. (81S3). (The salt content of sea water is 35,000 p.p.m.)
• Agricultural damage begins when salt contents of irrigation water reaches 700-850 mg./ liter, depending on soil condition and crop type (Ref. 20 of Ref. (85E1)).
• Ocean water averages about 35,000 parts per million (p.p.m.) (3.5%) dissolved solids (carbonates, chlorides and sulfates of calcium, magnesium and sodium) (81P1) (77M1).
• Because of its high salt content (35,000 p.p.m.), 2-3% of seawater mixed with freshwater, e.g. in a coastal aquifer, makes the water unusable for either drinking or irrigation (00S1).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~

Use of Drip- and Micro-Irrigation in selected countries around 2000 (05B1)
Col. 2 = Area Irrigated by Drip- and other Micro-irrigation Methods in units of km².
Col. 3 = Share (%) of Total Irrigated Area Under Drip or Micro-irrigation.

The implication of the above table is that only a small percentage of the world's irrigated lands are being irrigated by drip- and other micro-irrigation methods. That percentage is about 1%.

• Low-pressure sprinkler systems reduce water use by an estimated 30% relative to flood- or furrow irrigation. Drip irrigation typically reduces water use by 50% relative to flood- or furrow irrigation (Ref. 35 of (05B1)).
• Farmers began tapping ground water on a large scale after 1950, as powerful diesel and electric pumps became available (p. 255 of Ref. (99P1)). Prior to that they used surface waters for irrigation.
• Using drip irrigation is said to not entail salt accumulation in the root zone (93P2).
• Switching from furrow- or sprinkler irrigation to drip-irrigation systems cuts water use by 30-60% (96P1).
• Global use of drip irrigation accounts for less than 1% of world irrigated area (97P3). (Irrigation water is heavily government-subsidized virtually worldwide. This works against increased use of drip irrigation.)
• Dregne and Chou (Ref. 18 of Ref. (97C1)) estimate the value of production of irrigated cropland at $625/ ha/ year (as compared to $95/ ha/ year for rain-fed cropland, and $17.50/ ha/ year for rangelands). (36:5:1)
• Increases in irrigated area were the source of more than 50% of the increase in global food production during 1965-85 (Ref. 28 of Ref. (96G2)). The "Green Revolution" and increased use of chemical fertilizers provided the bulk of the remaining increase.
• More than 60% of the value of Asian food crops comes from irrigated land (98H1).
• Israel's irrigation system can feed 1000 people/ km² -compared to a global average of 250/ km² (77A2). (This data could be obsolete and mainly of historic interest.)
• Because of the high cost of new irrigation capacity in parts of Africa ($1-2 million/ km²), not even double-cropping of high-value crops can make such systems economical (90P1). Africans cannot afford adequate chemical fertilizers because infrastructure problems (poor roads) increase the price of chemical fertilizers to 6 times the price in the EU (60 times the price in the EU in terms of the number of hours that must be worked to buy 1 lb. of chemical fertilizer). This lack of chemical fertilizer makes the economics of both genetically improved plants and irrigation systems far worse in Africa than elsewhere in the world.
• Irrigated lands in monsoon climates do not require systems of underground drainage tiles to avoid salinity increases in the soil. Irrigated lands elsewhere do require such systems of drainage tiles to achieve sustainability of crop yields.
• Rejuvenating salt-covered fields costs $100,000-200,000/ km², and the efforts often fail. But salinization of irrigation systems can be prevented with a system of underground pipes to draw excess water off the field (95W1).
• Desalination (of sea water) around 2000 cost about $800/ acre-foot, but (California) farmers can lose money with water at $15/ acre-foot (01R1).
• Whereas homes and factories typically return a large portion of their used water to the environment after they use it, half to 2/3 of agriculture's (irrigation's) share is "consumed" through evaporation or transpiration and is thus not available for a second or third use (96P3). Irrigation water returned to the river is usually loaded with salt, making it less useful in downstream irrigation systems and less useful for homes and factories.

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~ Go to top of Section [C] (Irrigation System Basics) ~

Global irrigated area growth rate is down from 3%/ year during 1950 to the mid-70s, 2.0%/ year during 1970-82, and 1.3%/ year during 1982-94 (99P1). Per-capita irrigated area has declined 5% since 1978. Productivity of the world's irrigated land does not grow 1.3%/ year however. Yield degradation due to increasing salinization, water-logging, aquifer depletion, sea water intrusion into coastal aquifers, and water-supply reallocation to urban uses all detract significantly from the yields of irrigated lands. Growing financial demands on (and indebtedness of) developing nations, productivity losses to salinization, land abandonment due to salinization, aquifer depletion, surface water depletion, and reallocation of water to urban uses are all making it increasingly difficult to achieve net growth in irrigated area, output per unit area (yield) and dam storage capacity - not to mention per-capita growth. (Building and maintaining irrigation systems are heavily government-subsidized worldwide.)

• S. Postel ((99P1) (p. 255)) contends that, while official statistics still suggest that the world's irrigated area is still expanding, net growth actually might be closer to zero if the negative side of the ledger were counted properly.
• Losses of irrigated cropland has led David Seckler, Director General of the International Irrigation Management Institute, to conclude that such losses may be exceeding the gains, leading to a net shrinkage of global irrigated area (98H1).
• The FAO estimates that global irrigated area could theoretically increase 50% (Ref. 32 of Ref. (96G1)).
• One study projects a global irrigated-area growth rate of 0.3%/ year over the next 50 years (Ref. 42 of Ref. (96G2)).
• One projected expansion of irrigated land by 0.40 million km² (by 2030?) is an increase in net terms. It assumes that losses of existing irrigated land resulting from, e.g., water shortages or degradation due to salinity increases, will be compensated through rehabilitation or substitution by new areas for those lost (03B1).
• In developing countries, as in the past but even more so in the future, the mainstay of food production increases will be intensification of agriculture in the form of higher yields, more multiple cropping and reduced fallow periods rather than increases in irrigated area (03B1). Multiple cropping and reduced fallow periods usually produce sustainability problems of their own. Higher yields usually imply more intense use of chemical fertilizers - which also involved soil degradation problems unless manure and crop residue use is also increased. The problem is that in many developing nations, manure and crop residues are used for cooking because they cannot afford fossil fuels.
• Most expansion of irrigated land is currently achieved by converting land in use in rain-fed agriculture or land with rain-fed production potential but not yet in use, into irrigated land. Part of irrigation expansion, however, takes place on arid and hyper-arid land not suitable for rain-fed agriculture. It is estimated that, of the 2.02 million km² irrigated at present, 0.42 million km² are on arid and hyper-arid land, and of the projected increase of 0.40 million km², about 0.02 million km² will be on such land. In some regions and countries, irrigated arid and hyper-arid land form an important part of total irrigated land at present in use: 18 out of 26 million ha in the Near East/ North Africa, and 17 out of 81 million ha in South Asia (03B1). These figures apparently pertain to the expansions expected by 2030. The figure 2.02 million km² for current global irrigated area seems low. 2.7 million km² seems more likely.
• Two-thirds of African countries have realized less than 20% of their potential irrigation area (PanAfrican News Agency (2/9/00)). Large external debts preclude borrowing for irrigation projects. The high cost of irrigation systems in Africa (90P1), the lack of both chemical and organic fertilizers and the low fertility of most tropical soils also work against expansion of irrigation in Africa.
• The GAP project in eastern Turkey aims to irrigate an added 17,000 km² (p. 151 of Ref. (99P1)). It will also reduce the already scarce water supplies of Syria and Iraq.

Annual Renewable Water Resources (RWR) and Irrigation Water Requirements (03B1)

Note: RWR for all developing countries exclude regional net incoming flows to avoid double counting.
* km³

For the 93 countries used in the table above, irrigation water withdrawals are expected to grow by 14%, from the current 2128 km³/ year to 2420 km³/ year in 2030. The region expected to contribute the most to this increase is South Asia, e.g. India. This increase is low compared to the 33% increase projected in harvested irrigated area, from 2.57 million km² in 1997/99 to 3.41 million km² in 2030 (Table 4.8 in Ref. (03B1)) (03B1).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~ Go to top of Section [C] (Irrigation System Basics) ~ Go to top of Section [D] (Irrigation System Growth) ~

Section [E] ~ WATER SUPPLIES AND URBANIZATION LIMITING IRRIGATION ~ [E1]~ Global Data, [E2]~ Middle East and North Africa, [E3]~ U.S. [E4]~ Southern and Eastern Asia, [E5]~ Europe and Northern Asia, ~

• The International Water Management Institute, a CGIAR laboratory in Sri Lanka, projects that by 2025 as many as 39 countries - including northern China, eastern India, and much of Africa - will be forced to reduce irrigation rather than expand it due to a lack of water (99M1).
• 5-8% of global irrigated area depends on non-renewable water or on renewable sources that are pumped faster than they are replenished (Ref. 32 of Ref. (96G2)) (Ref. 49 of Ref. (97G1)). Much other irrigation water is subject to being reallocated to urban areas.
• On average, a ton of water (about 1 m³) used in industry generated roughly $14,000 worth of output. A ton of water used to produce grain generated about $200 worth of output (00S1). This suggests that, as water supplies grow scarcer, irrigation water is highly vulnerable to being reallocated to urban/ industrial uses.
• Whereas homes and factories return a large portion of their water to the environment after they use it, half to 2/3 of agriculture's share is "consumed" through evaporation or transpiration and is thus not available for a second or third use (96P3). Also Irrigation water returned to the river is usually loaded with salt, making it less useful in downstream irrigation systems.
• The FAO said that two-thirds of the world's population could be threatened by water shortages by 2025. Today 1.2 billion people live in areas with insufficient water. An additional 0.5 billion could soon face shortages. (07F1).

Major categories of Global Freshwater Flows at a Glance:
Global precipitation rate: 110,000 km³/ year. 2/3 of this precipitation is evaporated (transpired) into the atmosphere, leaving 40,000 km³/ year to flow to the sea via rivers, streams and underground aquifers ("groundwater"). in northern North America, Europe and Asia, 55 rivers (with a combined flow of 5% of global runoff) are so remote that they have no dams on them. About 75% of the global runoff (i.e. 30,000 km³/ year) is in the form of floodwater. Large dams, which can hold 14% of the world's annual runoff, have increased the stable supply of water provided by underground aquifers and year-around river flow by nearly 1/3. This brings the world's total stable, renewable supply of freshwater to 14,600 km³/ year. Of this total supply, 12,500 km³/ year is within reach, geographically. So it is accessible for irrigation, industrial and household use (96P3).

• In a survey of irrigation and water resources in the Near East region, it was estimated that the amount of water required to produce the net amount of food imported in the region in 1994 would be comparable to the total annual flow of the Nile River at the Aswan Dam (03B1).
• 10% of Israel's wells in its coastal aquifer yield water that is too salty for irrigation of crops (Ref. 38 of Ref. (96G2)).
• Israel, faced with dwindling water supplies, is no longer irrigating its small remaining area of wheat, which means that dependence on imported grain, already over 90%, will climb still higher (04B1).
• 37,000 km² of Ethiopia are potentially irrigable. Irrigating even half of this area would reduce the Nile's flow through Egypt by 9 km³/ year (16%) (96P1). Very little of the Nile River's waters currently reach the sea.
• The Kufra irrigation project in Libya mined fossil, ground water so fast that levels dropped 5-7 times faster than expected, jeopardizing the entire project (77A1). Libya's fossil water will be depleted in a few decades, while others predict centuries (95G1).
• Agricultural production threatens to drain Saudi Arabia's underground water resources within the next 10-20 years (90W1).
• Evaporation loss from reservoir behind Aswan High Dam: 10 km³/ year (of the 55.5 km³/ year entering the reservoir) (p. 146 of Ref. (99P1)).
• 75% of groundwater used in agriculture on the Arabian Peninsula is not replenished (Ref. 33 of Ref. (96G2)).
• 33% of Iran's cultivated area depends on over-drafted groundwater (96G1).
• Syria's over-pumping of aquifers for irrigation has caused saltwater intrusions into the coastal plains (96M2).

• Arizona, Colorado, Idaho and New Mexico no longer allow additional irrigation in problem areas. That leaves 83% of all ground-water-irrigated land in the US free of restrictions (86S1). Within the next 40 years, farmers on over 35% of ground-water-irrigated land in the US will have to drastically reduce ground-water extraction, find a surface water supply, or abandon irrigated farming (86S1).
• 21% of irrigated US cropland is fed by drawing down water tables (USDA data) (91B3) (Ref. 43 of Ref. (95B1)).
• 40,000 km² of US irrigated land (20% of US irrigated acreage) are fed by drawing down water tables (Ref. 11 of Ref. (92P1)).
• The US High Plains aquifer underlies nearly 20% of all US irrigated lands. Net depletion to date = 325 km³; Current depletion rate = 12 km³/ year.
• US irrigated area has shrunk 11% since 1978 (Ref. 8 of Ref. (88B1)). Water tables are falling 6-48"/ year beneath 25% of irrigated croplands in the US (Ref. 8 of Ref. (88B1)).
• In west-central Kansas, irrigation wells numbered 250 in 1950, and 2850 in 1980. The Ogallala Aquifer was 58 ft. thick in 1930. Around 1980 it was less than 8 ft. (Ref. 101 of Ref. (81S1)).
• About 4000 miles of Kansas's streams and rivers, strangled by irrigation, now run only intermittently (89F1).
• In west-central Kansas, the number of irrigation wells in 1950 was 250. Today there are 2850. Within the Ogallala Aquifer the water-saturated area was 17.7 meters thick in 1930. Around 1980 it was less than 2.4 meters thick (81S2).
• Depletion of the Ogallala Aquifer in the southern Great Plains of the US has caused cutbacks in irrigation. Texas has lost 1% of its irrigated land per year since 1980 (99U1). By some estimates, more than 50% of the Ogallala Aquifer's water is gone (02U3). The Ogallala Aquifer supports irrigated agriculture on more than 44,500 km² of arid land in the US (Ref. 24 of Ref. (81S2)). About 40,500 km² of irrigated land are threatened by Ogallala Aquifer overdrafts in western Texas and eastern New Mexico (80C1).
• About 8100 km² in Texas have been taken out of ground-water irrigation since the mid-1970s, a 23% drop (due to falling water tables and rising costs of natural gas used to pump water) (86S1).
• San-Pedro Basin (CA?) water over-draft is 0.304 km³/ year. San-Pedro Basin's 600 km² of irrigated lands consume 0.537 km³/ year. The over-draft could effectively exhaust the aquifer by 2020 (Ref. 263 of Ref. (81S1)). Tucson and mining companies have bought up to 81 km² of irrigated farms for the water, and plan to acquire an additional 146 km² by 1985. These purchases will effectively end irrigated agriculture in Avra and upper Santa Cruz Valleys (Ref. 248 of Ref. (81S1)).
• Of the 2223 km² of irrigated land in the Santa Cruz-San Pedro area, 215 km² have been abandoned due to lack of water (Ref. 33 of Ref. (81S3)). The 15-20% decrease in water supply projected for 2000 will cause abandonment of an additional 332-445 km² of irrigated cropland (Ref. 35 of (81S3)). (Obsolete data, mainly of historical interest)
• In the lower Santa Cruz Valley, ground-water overdrafts total 0.68 km³/ year (mainly for irrigation) (81S3). Upper Santa Cruz River Valley ground-water overdrafts total 0.29 km³/ year, 27% to mining, 29% to urban uses, and 41% to agriculture (Ref. 20 of Ref. (81S3)). Avra Valley aquifers will be depleted within 100 years at current consumption rates (81S1).
• Ground-water overdrafts are now the major desertification force at work in the 42,700 km² Santa Cruz-San Pedro Basin. Abandonment of irrigation projects is spreading (Refs. 223 and 224 of Ref. (81S1)).
• Between the late 1950s and the early 1970s, irrigated area in Maricopa County fell from 2240 to 1779 km² due to water diversion to Phoenix. Water tables in Maricopa County continue to drop 3-6 meters/ year (Ref. 31 of Ref. (78B2)). (Obsolete data - Of historical interest only)
• In Pinal County, irrigated cropland area fell from 1380 to 930 km² between the late 1950s and the early 1970s (78B2) (79W1) (presumably due to water diversions).
• Saltwater has moved over 7 miles inland in the aquifer under Salinas Valley (93M1). (65 km² there produce $1.7 billion/ year worth of vegetables.) In 1980, seawater had moved 4 miles inland from the coast. Intrusion is due to over-pumping of ground water for agriculture, since 85% of aquifer-pumping is used for agriculture (93M1).
• 1620 km² of irrigated farmlands in San Joaquin Valley are affected by high, brackish water tables (81S3), (81S1), (83B1) resulting in a 10% reduction in productivity since 1970. (Average rainfall = 14" in the north, and 5" in the south.) By 2080, 4500 km² of San Joaquin farmlands will become unproductive unless sub-surface drainage systems are installed to carry away the salty water (81S1).
• The amount of water-storage capacity lost through aquifer compaction in California's Central Valley is over 40% of the combined storage capacity of all human-made reservoirs in California (00S1).
• California's irrigated area peaked in 1981 at 39,000 km². Net irrigated area fell by more than 1210 km² during the 1980s. Officials project a net decline of nearly 1620 km² between 1990 and 2020, with most of the loss due to urbanization as the population expands from 30 to a projected 49 million (Ref. 13 of Ref. (96P1)).
• Falling groundwater tables and rising energy costs during 1978-1984 caused irrigation to be halted on 367,000 acres (1486 km²) of the Texas High Plains (95G1).
• Constraints on irrigation water supplies in the Rio Grande River basin are causing food production to fall. In 1996 the Mexican government was forced to import almost $2 billion worth of grain to alleviate growing hunger, with much of the grain going to northern Mexico (Ref. 24 of Ref. (02K2)).
• Urban areas (Colorado Springs, Pueblo) are buying water rights, so irrigation systems in Colorado are being abandoned (Ref. 331 of Ref. (81S1)).
• Since 1982, irrigated area in Texas has shrunk 11% (95B2). The irrigated area in Texas has declined 30% in the past 15 years. This is due mainly to depletion of the Ogallala Aquifer (Ref. 17 of Ref. (95B3)).
• During the late 1980s, Saudi Arabia launched a plan to become self-sufficient in wheat. By tapping a deep underground aquifer, the Saudi's raised grain output from 0.3 million tons in 1980 to 5.0 million tons in 1994. The aquifer could not sustain large-scale pumping and, by 2003, the wheat harvest had fallen to 2.2 million tons (04B1).
• Between 1978-82, irrigated land area in New Mexico dropped 9% (85P1).
• Walla River (Oregon/ Washington): Irrigated farmland diverts literally all the Walla River's flow from its channel and leaves the river-bed dry ("America's Most Endangered Rivers of 1998", American Rivers, Washington DC, 4/98 See http://www.amrivers.org).

• Of 1.33 million km² of land in India being cropped, 240,000 km² are irrigated, but only 50% of this has an assured supply of water (70T1). (Obsolete data of mainly historic interest)
• In China between 1950-80, 543 large- and medium-sized lakes disappeared when their water was diverted for irrigation. Remarks were made at the International Conference on Conservation and Management of Lakes in Japan, in preparation for the Third World Water Forum to be held in the city of Kyoto, Japan in 2003 (01A1).
• 10% of China's cultivated area depends on over-drafted groundwater (96G1).
• Half of China's irrigation water now comes from wells (50% from dams). Water tables are falling in much of China (94B2).
• As much as 20% of China's river water is too polluted for irrigation use (Wall Street Journal (8/2/96)).

• In Spain, irrigation of fields of wheat, maize and vegetables has reduced groundwater levels by five meters; the La Mancha aquifer in Spain is being consumed at a rate 2-3 times its rate of recharge (01U1).
• Russia's entire irrigation program is threatened because the southern half of Russia is running short of water (Ref. 30 of Ref. (78B2)).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~ Go to top of Section [C] (Irrigation System Basics) ~ Go to top of Section [D] (Irrigation System Growth) ~ Go to top of Section [E] (Water Supplies and Urbanization-Limited Irrigation) ~

Section [F] ~ SALINITY AND WATERLOGGING EFFECTS LIMITING IRRIGATION ~ [F1]~ Global, [F2]~ Asian Sub-Continent, [F3]~ North America, [F4]~ Middle East - North Africa, [F5]~ Central Asia, [F6]~ Far East, [F7]~ Australia and Oceania, [F8]~ Latin America,

Part [F1] ~ Global ~
Large irrigated regions with serious salinity problems (85D1):

• lower Yellow River Plain - - (China)
• San Joaquin Valley - - - - - (California)
• Kara Kum Canal project - - (Turkmenistan)
• Indus Plain - - - - - - - - - - - (Pakistan)
• Tigris-Euphrates Plain - - - (Iraq)
• Murray-Murrumbidgee Area- (Australia)
• lower Nile Valley - - - - - - - (Egypt)

Irrigated Land Damaged by Salinization ((89P1), Table 2) (90P1)
(Areas in Column 2 are in units of 1000 km².)

* (by extrapolation)

Globally, the areas most affected by seawater intrusion into freshwater aquifers include Mexico, the northern portions of the Pacific and Atlantic coastlines (of the US), Chile, Peru and Australia. (07S2).

Irrigated Land Damaged by Salinization in the late 1980s (95G3)

• Yields on 50% of the world's irrigated land -- 1.2 million km² -- have fallen in recent years (98H1).
• A Soviet soil scientist estimates that 60-80% of the world's irrigated lands are becoming saline and hence infertile (76E1). (Obsolete data - Of historical interest only)
• 250,000 km² (over 10% of the world's irrigated area) are suffering from salt buildup sufficient to reduce yields (Ref. 10 of Ref. (92P1)).
• 10% of the world's irrigated area appears to be suffering from salinization serious enough to reduce yields. Another 30% may be moderately affected (Ref. 20, Chapter 8 of Ref. (94B1)). Additional areas suffer from waterlogging (Ref. 9, Chapter 11 of Ref. (94B1)).
• 20% of the world's irrigated area (about 500,000 km²) suffers from salinization (97G1).
• 26% of the world's irrigated area (624,000 km²) suffers from some degree of waterlogging and salinity (91B3).
• Over 100,000 km² (globally?) are estimated to be affected by waterlogging (91O1) (03N1).
• 250,000 km² of irrigated lands appear to suffer from salt buildup enough to lower crop yields (Ref. 12 of Ref. (96P1)).
• A 1995 study, drawing on the global data of the 1980s, estimated that 20% of the world's irrigated area suffers from salinization (Ref. 52 of Ref. (96G2)).
• Oldeman, Hakkeling and Sombroek (91O1) estimate the total global area affected by salinization to be over 760,000 km², but they do not differentiate between irrigated and rain-fed areas. It seems possible that 20% of the total irrigated area is affected, and 120,000 km² of once-irrigated land may have gone out of production (01N1) (03N1).
• 20% of the world's irrigated land is losing productivity because of increasing salinity (99P1). Because such a large fraction (60%??) of the world's irrigation systems is younger than 50 years, and because the growth of irrigation has slowed so dramatically, and because it takes some decades for salinization (and waterlogging) to begin degrading productivity, the fraction of irrigated lands losing productivity is sure to climb in coming decades.
• The UNEP estimates irrigated area damaged by salinization at 400,000 km² (Ref. 15 of Ref. (89P3)).
• Salinity seriously affects productivity on 200,000 km² of the world's irrigated lands (Ref. 14 of Ref. (85E1)).
• 200,000-300,000 km² of the world's irrigated area suffer serious salinization (94P2).
• 600,000-800,000 km² (globally) are moderately affected by salinization (Ref. 5 of Ref. (94P2)).
• More than 50% of the world's irrigated soils are affected by secondary salinization, alkalization and waterlogging (Refs. 355, 356, p. 207 of Ref. (88S1)) (FAO and UNESCO data).
• Productivity on at least 1/3 of the world's irrigated land is being undermined by salinity problems (76E1). (Obsolete data - Of historical interest only)
• A third of the world's irrigated lands have serious salination problems (79S1).
• A 1977 UN report indicated that 210,000 km² of irrigated land (10% of the total) were waterlogged, and productivity on these lands has dropped 20% (78B3) (81B2) (Ref. 23 of Ref. (78B2)). 200,000 km² were affected mainly by salinization, and productivity has been reduced by a similar amount (Ref. 14 of Ref. (78B3)) (81B2). These data imply an overall reduction in productivity in the world's irrigated lands of 4% (cumulative) (78B2), (78B3). (50% of global irrigation capacity has been developed since 1950 (81B2)).
• Waterlogging and salinization are reducing yields to varying degrees in virtually all of the 30 or so countries with over 5000 km² of land under irrigation (76E1). (Obsolete data - Of historical interest only)
• 150,000 km² in developing countries are experiencing serious reductions in crop yields because of salt buildup in irrigated soil (Ref. 9 of Ref. (92P1)).
• The FAO estimates that salt build-up in soil has severely damaged 300,000 km² of the world's 2.4 million km² of irrigated land. Another 800,000 km² are affected by a combination of salinization and waterlogging (98H1). In some semi-arid countries, 10-50% of the irrigated area is affected (by salinization) to a greater or lesser degree (93U1) (97F1), with average yield decreases of 10-25% for many crops (93F1) (93U1). Unfortunately there are little or no time series data to allow reliable estimates of the rates of change in salinity damage or the area being degraded by salinity. It could be 10,000 -15,000 km²/ year and increasing (93U1) but it is difficult to quantify (03N1).
• Soil salinization is spreading at a rate of up to 20,000 km²/ year (globally), offsetting a significant portion of the increased productivity achieved by expanding irrigation. (93U1) (Ref. 12 of Ref. (96P1)).
• Globally, more than 770,000 km² of land is salt-affected by secondary salinization: 20% of irrigated land, and about 2% of dryland agricultural land (FAO, AGL, 2000 data) (05S1).
• Nearly 16,000 km²/ year are lost globally due to salinization ("How to Feed the World", Christian Science Monitor (2/20/03)).
• Waterlogging and salinity have reduced yields of major crops (globally?) by 30% (92P1).
• 50% of the 400 km² irrigated in the 19th century are undergoing salinization (88S1).
• Salinization is spreading at a rate of 10-15,000 km²/ year. This is about half the rate at which new land is being bought under irrigation (Ref. 10 of Ref. (92P1)) (Ref. 7 of Ref. (94P2)).

• Nonexistent or inadequate drainage seriously limits irrigated agriculture in India. About 85,000 km² (of irrigated land) are damaged by salinity in India (70T1). (Obsolete data of historic interest only)
• Over 60,000 km² have been severely damaged by waterlogging and salinity in India, out of a total irrigated area of 400,000 km² (76E1). (Obsolete data - Of historical interest only)
• 60,000 to 70,000 km² of India's irrigated lands are affected by waterlogging, salinity and alkalinity (Refs. 45 and 54 of (81G1)).
• In India, 20% of irrigated land suffers from salinization (99P1) (00W2).
• About 25,000-35,000 km² in Pakistan have severe salinity problems. Another 25,000-45,000 km² are moderately affected by salinity. The provinces of Sind and Punjab are areas most damaged (Ref. 62 of Ref. (81G1)). Yields on tens of thousands of km² of Pakistan's irrigated cropland have been substantially reduced. Water tables are within 3 meters of the surface in more than 50% of Pakistan's irrigated area, and within 1.5 meters in some regions (Ref. 62 of Ref. (81G1)).
• Pakistan has 32,000 km² of saline and alkaline agricultural land (90P1).
• Over 16% of Pakistan's agricultural land suffers from salinization (96G2).
• Extent of degraded land in India, circa 1980 (88B1): 70,000 km² are saline or alkaline, as compared to 130,000 km² that are wind-eroded, 740,000 km² that are water-eroded, and 350,000 km² that are degraded forest land (out of India's total land base of 3,290,000 km²).
• Salinity has cut yields on 21% of Pakistan's irrigated land (98H1).
• In some districts in Pakistan, virtually all irrigated land is plagued with waterlogging and salinity (Ref. 28 of Ref. (78B2)) (76E1).
• By 1960, waterlogging and salinity were severely affecting more than 20,000 km² of the Indus Plain. As many as 400 km²/ year of new areas were being affected (76E1). (Obsolete data - Of historical interest only)
• Of 138,000 km² of irrigated land in Pakistan, 21,000 km² are salinized after a few years of irrigation (Ref. 387 of Ref. (88S1)).
• About 25% of the 121,000 km² of irrigated land in the Indus River Basin are encountering serious drainage- and salinity problems (74F1). (Obsolete data - Of historical interest only)
• Salinity reduces crop yields on 200,000 km² in India (90P1). This probably includes some non-irrigated cropland.

• In the US, 20% of irrigated land suffers from salinization (99P1) (00W2).
• About 25% of US irrigated land suffers from some degree of salinization or waterlogging (78D1) (82S1).
• Salt accumulation is lowering crop yields on 25-30% (50,000 km²) of US irrigated land (92P1).
• Bower and Foreman estimated that 25% of irrigated soils in the US were salty or alkaline to the point where productivity was lowered (71R1). (Obsolete data - Of historical interest only)
• Dry cropland areas in the western US where production has ceased or is significantly reduced due to increased salinity: 600-800 km². This area is growing at 10%/ year (80C1).
• About 20-25% of all US irrigated land (40,000 km²) suffers from salt-caused yield reductions (Ref. 2 of Ref. (85E1)).
• About 25-35% of irrigated western US croplands have excessive salinity (83B1). Salt buildup lowers crop yields on 25-30% of irrigated lands (90P1).
• About 25% of California's irrigated land suffers from moderate- to heavy salt build-up (91B2).
• Of California's 34,800 km² of irrigated land, 18,200 km² are affected by salinity or sodicity (85G1). Croplands damaged by salinity are expected to increase from 18,200 to 21,000 km² by 2000 (Ref. 8 of Ref. (85G1)).
• Trends in salinity in irrigated lands in San Joaquin Valley indicate that, in two decades, 3,000 km² will be affected (82S1). San Joaquin Valley crop yields have declined 10% ($31.2 million) since 1970 because of high saline water tables. Losses are expected to increase to $321 million/ year if action is not taken (Ref. 19 of Ref. (85E1)).
• Not far below the surface of California's San Joaquin Valley and Imperial Valley (like the Tigris-Euphrates Valley) is a tight layer of material that blocks water passage. Hence saltwater builds up. When it meets the roots of plants, salt is drawn up to the surface, destroying the irrigation system (81S1).
• Imperial Valley (Southern California) experienced about 90% of the agricultural damage from salinity in the US portion of the Colorado River Basin. Imperial Valley is under pressure to give some of its water to nearby cities (87P1). The Imperial Dam on the Lower Colorado River sends about 95% of the water flowing into it to California and to Wellton-Mohawk (Arizona) for irrigation. When Wellton-Mohawk opened in 1961, the average salinity of the water delivered by the Colorado to Mexico doubled to 1,500 p.p.m., causing Mexican crop failures and protests (87P1).
• A study in the Grand Valley (which puts 0.5 million tons of salt into the Colorado River yearly) found that 85% of the water reaching rivers was irrigation water, carrying salt from marine shales that lie under local farms (87P1).
• In Crowley County Colorado, salt crusts are visible on a number of irrigated fields (Ref. 331 of Ref. (81S1)).
  Arkansas River salinity in Colorado increases from a trace to 2200 mg./ liter over 120 miles (85E1). (This is usually due to seepage and return-flow from irrigated land.)
• Salt content of the Colorado River as it flows into Mexico: 800 p.p.m. in 1960, 1500 p.p.m. in 1962 (81S3). (Little if any water in the Colorado River now makes it into Mexico.)

• Egypt's Aswan Dam made possible the cultivation of over 3644 km² of former desert, but nearly 810 of these are once again barren (due to salinity?), and the remaining area is cultivated at a loss (77U1).
• Over 10,000 km² of irrigated land in the Arab states region suffer from salinization (96M2).
• The majority of irrigated lands in Iran are saline, and crop yields are depressed as a result (Ref. 13 of Ref. (76E1)).
• More than 50% of irrigated soils in Iraq and Iran are affected by secondary salinization (Ref. 388 of Ref. (88S1)).
• Salinization affects 160,000 km² of Iran's agricultural land (96G2).
• In 1970, less than 10 years after Jordan initiated irrigation agriculture in the Jordan River Valley, salt and sogginess were affecting 12% of the project area, and the extent of the damage was increasing every year (76E1).
• The FAO reports of salinity in the Euphrates Valley of Syria note that crop yields have decreased 50% on 300 km², and 20% on 600 km² (Ref. 20 of Ref. (88S1)):
• More than 25% of Turkey's alluvial soils are affected by salinity (88S1). This probably includes more than just irrigated lands.
• Irrigated agriculture is rather non-productive in the 2000 km² of irrigated croplands of the arid- and desert zones of North Africa. Lack of drainage causes excessive salt deposits or hydro-morphology (waterlogging?) or both (70L1).
• Over 10,000 km² of Egypt's irrigated land suffer from the effects of salinity (96M2).
• Half of all irrigated land in Egypt is salty enough to show reduced yields (90P1).
• Egypt's Aswan Dam made possible the cultivation of over 3,600 km² of former desert, but 810 km² of this are once again barren (due to salt buildup?), and the rest of the area is cultivated at a loss (77U1).
• Before Aswan Dam, annual flooding washed salt away. After Aswan Dam, irrigation replaced annual flooding, so Nile Delta salt levels are rising rapidly. Before dams, seasonal floods carried salts to the sea. Today the salt is being stored within river basins, and salt levels in irrigated soils are rising (87P1). The reason why Egypt was one of only 3-4 civilizations to last much longer than all the rest in a progressive state was that annual floods replenished the soils.
• Ref. (76E1) describes salinization problems of Egyptian irrigation systems outside the Nile flood plain. Waterlogging and salinity are becoming major problems in Egypt. The Aswan Dam has contributed to that salinization problem (76E1).
• Waterlogging and salinization have reduced yields of major crops (in Egypt) by 30% (92P1). Cultivated land in the Nile Delta (100% irrigated) grows increasingly saline, since annual flooding no longer flushes out evaporitic salt (Ref. 40 of Ref. (93S1)).
• Nearly 50% of Egypt's Delta is affected by salinity, alkalinity, and waterlogging. Rising water tables in Egypt's Western Desert are causing salinization (89E1).
• About 75% of Egypt's Delta topsoil is non-saline, 15% moderately-to-highly saline; 10% is very highly saline (89E1).
• In the Euphrates Valley of eastern Syria, above the Euphrates entry into Iraq, 25-50% of the total agricultural area has been rendered unfit for cultivation by soil salinity and "saturation" (waterlogging?). Average cotton yields in the valley's remaining farmland dropped from 250 tonnes/ km²/ year in the early 1950s to about 150 by 1966. Over 50% of the combined irrigatable land of the Euphrates and Khabour Valleys (2200 km²) had been harmed or destroyed by salinity as of 1970. Nearly all damage has occurred in the past 25 years, since the introduction of perennial cotton production (p. 125 of Ref. (76F1)).

• In the Central Asian republics, salinization reduced cotton yields from 280 to 230 tonnes/ km² between the late 1970s and late 1980s, despite increasing use of fertilizer during this period (Ref. 52 of Ref. (96G2)).
• The share of irrigated land that is moderately to heavily salinity is 35% in Tajikistan and 80% in Turkmenistan (all in the Aral Sea Basin) and 60% for the entire Aral Sea basin (Ref. 25, Chapter 8 of Ref. (94B1)) (91B2).
• Land productivity in the Area Sea basin (in terms of cotton yields) has fallen 15% since its peak year in 1979 (Ref. 26, Chapter 8 of Ref. (94B1)).
• About 21% of Kazakhstan's irrigated area is undergoing salinization (93M3). 13% of Kazakhstan's irrigated area is waterlogged (93M3). (Kazakhstan's total area of irrigated cropland is 18,560 km²)
• Yield losses due to salinity: 30% in Uzbekistan, 40% in Turkmenistan, 30-33% in Kazakhstan, 18% in Tadjikistan, and 20% in Kirghizia (89K1).
• Mainguet quotes Khakimov in her book as saying that the percent of moderate-to-severe salinity of irrigated areas in Central Asia are: Uzbekistan-60%, Turkmenistan-80%, Tadjikistan-35%, Kirghizia-40%, Kazakhstan-60-70% (89K1).
• About 25,000 km² of the former USSR are undergoing salinization, Most of this area is in the irrigated deserts of central Asia (Ref. 10 of Ref. (92P1)) (90P1).
• Egorov et al found that, in the USSR cotton belt, weakly- and medium-saline soils increased from 49.6% to 85% during 1945-61 (71R1). (Obsolete date of mainly historic interest)
• 12% of irrigated farmland (25,000 km²) (in central Asia) is contaminated with salt or salt compounds due to poor drainage systems (89P1) (91F1).
• Between 1975-85 (in central Asia), salinized land area nearly doubled (89P1) (Ref. 31 of Ref. (91F1)).
• Nearly all of Karakalpakia's agricultural land is either salinized or waterlogged. (Karakalpahia is the republic around the southern portion of the Aral Sea (Population: 1.2 million)). The process began around 1958, therefore no more than 37 years were required to start the salinization process (95H1).
• In 1994, 28% of the Aral Sea Basin had salt buildup severe enough to lower crop yields by 20-50%, compared to 23% about 4 years earlier (99P1).

• Salinity has cut yields on nearly 25% of China's irrigated land (98H1).
• In China, 20% of irrigated land suffers from salt build-up (99P1) (00W2).
• Waterlogging and salinity have reduced productivity on 15% of China's irrigated land (p. 71 of Ref. (95B3)).
• About 20% of cropland suffers from salinity in northwest China (Baotou and Tarim Basin) and along the China coast (89H1).
• Yields on at least 20% of the irrigated area of some major regions of China are reduced by salinity (76E1)
  During the 1950s and 1960s, salt-affected soil occurred in over 40,000 km² of the North China Plain (85X1).
• Waterlogging and salinization are reducing productivity on 15% of China's irrigated land (94B2).
• China has 70,000 km² of saline and alkaline agricultural land (90P1).

• In irrigation systems in the Ord River basin of Western Australia, the water table has risen 15 meters and is rising by 0.5 meter/ year (01P1). The system apparently lacks a system of underground drainage tiles to carry off the water. Once underground water with a salt content of 0.1% (1000 p.p.m.) (Which is quite acceptable to crops) is within several feet of the surface, capillary evaporation residues raise the salt content of the top 3 ft. of soil to the intolerable level of 1% in 2 decades (76E1).
• Problems with dry-land salinity in Australia affect 25,000 km², with 170,000 km² of the 300,000 km² likely to be destroyed by salinity by 2050 based on current trends (01F1) (02C1). The majority of Australia is hot desert (01F1). Total Australian land stock is 7.7 million km². Less than 300,000 km² (less than 4%) of Australia's land are of good, or very good, quality in terms of broad scale cropping potential (02C1).
• Salinity ravages key waterways and agricultural zones in Australia, according to the new Australian State of the Environment report by over 100 scientists, government agencies and private sector groups. The Committee chairman said, "Although there has been some improvement since 1996, as a nation Australia is not sustainable in environmental concerns." Salinity is increasing in the Murray-Darling basin, which provides 40% of Australia's agricultural value. Salinity posed a risk to 57,000 km² of land in 2001, and is expected to impact 170,000 km² by 2050 (02U5).
• In Southwestern Australia, 4400 km², once used as cropland or pasture, are now salt-affected -- a +500% increase in salinized area since 1955. Virtually all secondary soil salinity is found in the rain-fed wheat belt of Western Australia where 130,000 km² of indigenous woodlands were cleared in the 20th Century (90C1).
• About 800 km² in the valley of Australia's River Murray and in northern Victoria are affected by secondary salinity and alkalinity (Ref. 389 of (88S1)).
• Over 45,000 km² of Australia's drylands -- 10% of all croplands and more than 8% of irrigated area -- are affected by salinization. The area affected by dryland salting doubled in size during 1975-89 (96G2).
• A UN survey found that 20,000 km² of irrigated land in Argentina have declined in productivity due to salinization and alkalinization (78B2).

• 20-30% of agricultural lands in Argentina's Patagonia region have been damaged by salt accumulation (76E1).
• In Northeast Brazil, at least 50% of irrigated land is affected by waterlogging and salinity. Yields on some irrigated fields are lower than before irrigation (76E1). (Obsolete data of mainly historic interest)
• In Sertao (nearly 3/4 of the area of Northeast Brazil), irrigation leads rapidly to salinization of soils. Water supplies there have an average salinity of 500+mg./ liter (85L1).
• The lack of complete studies for irrigation projects in Peru has caused increased drainage and salinity problems on the coast. This is the main problem facing irrigation agriculture on the coast, and affects 2500 km². In all irrigation projects on the coast, drainage- and salinity problems have developed within a few years after the beginning of irrigation (70C2). (Obsolete data of mainly historic interest)
• A UN survey found that, of 8000 km² of irrigated land in the coastal desert of Peru, 3000 km² are affected by poor drainage and salinization (Ref. 27 of Ref. (78B2)).
• Over 2000 km² along Peru's coast (almost a third of the cultivated area) suffers from salinity and rising water tables (76E1).
• Nearly all of Peru's irrigated alluvial soils show the effects of salinity and alkalinity (Ref. 64 of Ref. (88S1)).
• Salinization reduces Mexico's crop output by one million tons of grain/ year (90P1).
• 10% of Mexico's irrigated area suffers from salinization (03K1).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~ Go to top of Section [C] (Irrigation System Basics) ~ Go to top of Section [D] (Irrigation System Growth) ~ Go to top of Section [E] (Water Supplies and Urbanization-Limited Irrigation) ~ Go to top of Section [F] (Salinity and Waterlogging Limiting Irrigation) ~

About 70,000 km² have been abandoned as salty wasteland in India (90P1).

Salinization has caused the abandonment of over 20,000 km² of India's land (96G2). (Note the disparity between this estimate and the one above.)

India has abandoned a cumulative total of about 70,000 km² of once-irrigated area (93U1) (94F1) (99F2).

Nearly 4 million acres (16,000 km²) of irrigated farmland is lost to excessive salt every year (01W2).

Research in the early 1990s puts the current loss of world farmland due to salinization at 15,000 km²/ year (Ref. 60 of (94K1)).

About 20-30,000 km²/ year of irrigated lands may be coming out of production due to salinization. (Average irrigated-area expansion in recent years has been about 20,000 km²/ year) (Ref. 12 of Ref. (96P1)).

David Seckler, Director General of International Irrigation Management Institute, believes that losses in irrigated areas may now exceed gains (97B2).

A Soviet soil scientist estimates that 200-250,000 km² have been laid to waste over the centuries by mismanaged irrigation systems (76E1) (1978 Aspen Institute study in Ref. (82S1)).

A Soviet soil scientist estimates that 2000-3000 km²/ year out of a total world-wide irrigated area of nearly 2 million km² pass from cultivation due to waterlogging and salinity (76E1) (1978 Aspen Institute study in Ref. (82S1)). More recent estimates are considerably higher.

Salinization severe enough to remove (irrigated?) land from production claims 15-25,000 km²/ year. (Ref. 52 of Ref. (96G2)).

Soviet agronomist Victor Kovda estimates a global rate of irrigation system abandonment of 10,000-15,000 km²/ year (Ref. 12 of Ref. (90B1)).

Waterlogging and salinization are sterilizing 10-15,000 km²/ year (85P1).

Aerial views of abandoned irrigation lands in the world's dry regions reveals vast expanses of glistening white salt-encrustation -- useless land (Ref. 21 of Ref. (89P1)).

Ref. (87P2) references a study (not named) claiming that as much irrigated land is being taken out of production due to salinization and waterlogging as is being bought into production by new irrigation schemes.

About 20,000 km²/ year of irrigated land are lost to salinity (Ref. 29 of Ref. (94P1)).

In Uzbekistan, 15,000 km² of land were abandoned between 1950 and 1980 (500 km²/ year) due to high salinity (81F1). (To grow 1.0 kg. of cotton requires 660 gallons of water in Uzbekistan (81F1).) Some of this land may not have been irrigated.

Irrigation ceased on 29,000 km² in central Asia during 1971-85 (2100 km²/ year) (Ref. 14 of Ref. (89P1)). This was 25% of the new area bought under irrigation in that same period (Ref. 11 of Ref. (90P1)).

Over 9300 km² of irrigated farmland in China have come out of production since 1980 (1160 km²/ year) (Ref. 14 of (89P1)) (90P1). About 46% of China's 970,000 km² of croplands are irrigated (90W1).

About 20-30% of Iraq's potentially irrigable land is unusable (76E1), i.e. has been converted to desert by salinization of irrigation projects (79S1).

Viewed from the air, vast areas of southern Iraq glisten with salt like new-fallen snow (85S1) (76E1).

Salt build-up has forced over 80,000 km² in Iran out of production (96G2).

The FAO reports of salinity in the Euphrates Valley of Syria note that, on over 200 km², salinity has caused the soil to be taken out of cultivation (Ref. 20 of Ref. (88S1)).

Hundreds of thousands of km² throughout China are barren because of salinization. Some of it is natural. Some of it comes from old abandoned irrigation systems of the past (76E1).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~ Go to top of Section [C] (Irrigation System Basics) ~ Go to top of Section [D] (Irrigation System Growth) ~ Go to top of Section [E] (Water Supplies and Urbanization-Limited Irrigation) ~ Go to top of Section [F] (Salinity and Waterlogging Limiting Irrigation) ~ Go to top of Section [G] (Irrigation System Abandonment) ~

Section [H] ~ SURFACE WATER PROBLEMS ~[H1]~ Asian Sub-Continent, [H2]~ Eastern Asia, [H3]~ Middle East - North Africa, [H4]~ North America, [H5]~ Central Asia, [H6]~ Africa,

Some of the Major Rivers of the world that no longer reach the sea for at least parts of the year (99P1)

** See elsewhere in this review document

The data below is from a Table of Disappearing Lakes and Shrinking Seas http://www.earth-policy.org/Indicators/Water/2006_data.htm#fig4)

• The Dead Sea surface has dropped 25 meters (82 feet) in the past 40 years.
• Mono Lake's surface in California fell 11 meters since 1941 (when Los Angeles first began to draw water from its tributaries).
• Lake Chad once spanned 23,000 km² in Nigeria, Niger, Cameroon, and Chad. It now covers 900 km² and exists entirely within Chad.
• China's Hebei Province lost 969 of its 1052 lakes.

In developing countries, 90-95% of all sewage and 70% of all industrial wastes are dumped untreated into surface waters where they pollute usable water supplies (Ref. 15 of Ref. (02B2)).

• Bangladesh Inland Water Transport Authority says 80% of Bangladesh's 235 rivers are drying up (Pittsburgh Post Gazette (2/17/02)).
• Farmers in India are leaving little water in the Ganges River for farmers in Bangladesh (99U1).
• Almost all of the 44 rivers in Kerala India face extinction through deforestation, sand mining, river-bank brick-making and water pollution (WorldWatch, 9(3) (1996)).

Both India and China rely heavily on major river systems that have their sources from the glacial melt of the Himalaya that is now under threat of global warming. Rapid glacial melt will not only cause short term flooding problems, but more importantly it will result in decrease of future water supplies for both nations (06H2).

Around 25% of India's agricultural production comes from land irrigated from over-exploited aquifers. Millions of wells have already gone dry (06P1).

The Gangotri glacier, which provides up to 70% of the water in the Ganges River during the dry summer months, is shrinking at a rate of 40 yards/ year, nearly twice as fast as two decades ago. According to a UN climate report, the Himalayan glaciers that are the source of the Ganges could disappear by 2030 as temperatures rise. In India, the Ganges River provides more than 500 million people with water for drinking and farming (07W1).

• All but a few of the 300 tributaries that feed into the Hai River in China are now dry. (120 million people live in the Hai River basin.) (03U3).
• About 7% of China's glaciers are vanishing annually. By 2050, as many as 64% of China's glaciers will have disappeared. An estimated 300 million Chinese live in China's arid west. These people depend on the continuous flow of water from glaciers for their survival (05U3).
• In China between 1950-80, 543 large- and medium-sized lakes disappeared when their water was diverted for irrigation. Remarks were made at the International Conference on Conservation and Management of Lakes in Japan, in preparation for the Third World Water Forum to be held in the city of Kyoto, Japan in 2003 (01A1).
• Thousands of lakes in northern China have disappeared (US satellite data over the past 30 years) (01B2).
• So much water is siphoned off Northern China's rivers that the amount of China's surface water reaching the sea has dropped by 93% since the 1950s (88P1).
• The number of Indian villages without any water source increased from 750 in 1985 to 65,000 in 1996. (02W1).

The Jordan River flows at 25% of the 1950 level, and is becoming increasingly saline (93L1).

• The growing population in Syria's capital, Damascus (now 3 million), has sucked the Baroda River nearly dry (91W1).
• The Euphrates River supplies about 60% of Syria's water. The Turkish GAP dam-building project in eastern Turkey has cut the Euphrates River's flow into Syria by over 50% during 1986-1990 (91W1).

The Rio Grande River (second largest river in the US), by the time it reaches the Gulf of Mexico, has been reduced to a trickle compared to the pre-1962 average flow of 2.4 million acre-ft./ year. In February 2001 the Rio Grande River failed to reach the Gulf of Mexico (02K2). It still hadn't reached the Gulf of Mexico as of June 28, 2001. The Rio Grande used to be large enough for ocean-going ships for at least 10 miles from its mouth (Lynn Brezosky, Pittsburgh Post Gazette (6/28/01)).

• For the first time in history, a "sandbar has silted shut the mouth" of the Rio Grande. Thus, the Rio Grande joins the Colorado as the second great Western river whose waters no longer flow into the ocean. Although "water weeds" and the worst drought since the 1950s are blamed, a biologist with Texas Parks and Wildlife says the "aquatic weeds are a convenient scapegoat for state water policy that over controls the river and allocates virtually every drop to municipal, industrial and agricultural users." (Dallas Morning News (5/10/01)).
• Leading the West's growth are rainless inland cities such as Las Vegas, Phoenix, Denver, Albuquerque and Salt Lake City. They will run out of water to sustain new residents as soon as 2030 if they can't squeeze more water from the Colorado (02K1).
• Use of water within Gila River Basin has been so intense that practically no outflow has gone into the Colorado River for 13 years (56T1).
• 35 km. of San Joaquin River (CA) have been so permanently dewatered that developers have proposed building houses in the river's bed (95P2).
• The Arkansas River dries up permanently somewhere between the Colorado state line and Deerfield, 50 miles to the east (82M1).
• Walla River (Oregon/ Washington): Irrigated farmland diverts literally all the Walla River's flow from its channel and leaves the river-bed dry ("America's Most Endangered Rivers of 1998", American Rivers, Washington DC (April 1998) See http://www.amrivers.org).
• Since 1970 Lake Chapala in Mexico's state of Jalisco has lost 80% of its water volume. That lake is fed by Rio Lerma that passes through several hundred miles of (semi)arid farmland supporting 11 million people in its watershed. Most of the water in that river is diverted to irrigation systems that use water-wasteful techniques. Also the manufacturing center, Guadalajara, draws on the lake as its principal source of water (03C2).

The Aral Sea in Russia was once the fourth largest inland sea in the world. The sea will dry up by 2015 due to the damning of the rivers that feed it - all to grow cotton in arid Soviet Central Asia. The Aral Sea is a quarter of the size it was 50 years ago. It suffers from increased salinity that dry into huge salt plains that cause dust storms and spread disease and severely damage neighboring agriculture. Fishing has been wiped out, and agriculture is close to following it ("Russia's Aral Sea to Disappear Within 15 Years", News24.com (7/23/03)). Four decades ago, 60 km³/ year of water flowed into the Aral Sea. Now only 1-5 km³/ year trickles through. If no measures to save the Aral are taken, its area will decrease to 9,000 km² (3500 mi²) from 41,000 km² (16,000 mi²) in the mid-1990s. Shrinking of the Aral Sea might lead to large-scale migration. Given today's population explosion in the region, people may be unable to feed themselves from the remaining allotments of (fertile) land. Uzbekistan (24 million people, population growth 2%/ year) shares the dying sea with Kazakhstan. At least 10 million people might be involved in chaotic migration early in the 21st century (98B2). About 37 km³/ year of water are being withdrawn from the Aral Sea and surrounding ground water. Removable volume = 2500 km³ (94S1). The Amu Darya and Syr Darya Rivers once fed fresh water to the Aral Sea at 50 km³/ year. Irrigation diversions have reduced this input to 2-3 km³/ year, shrinking the Aral Sea from 64,500 km² to under 30,000 km² (95H1).

• Kyrgyz Republic ran its hydroelectric dam all winter to heat its cities, depriving Uzbekistan and Kazakhstan of most of their water needed for spring cotton planting (Wall Street Journal (11/20/97)).

• Africa's Lake Chad, which provides water to 20 million people in six countries, has shrunk (in volume?) by 80-95% in 38 years (Environment News Service (3/22/01)).
• Before Aswan Dam was constructed, 32 km³/ year of Nile River water reached the Mediterranean sea. After the dam was complete, output to the sea dropped to 6 km³/ year and to 3 km³/ year in 1985, and to 1.8 km³/ year in 1995 (95P2).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Water-Soil-Salt Systems) ~ Go to top of Section [C] (Irrigation System Basics) ~ Go to top of Section [D] (Irrigation System Growth) ~ Go to top of Section [E] (Water Supplies and Urbanization-Limited Irrigation) ~ Go to top of Section [F] (Salinity and Waterlogging Limiting Irrigation) ~ Go to top of Section [G] (Irrigation System Abandonment) ~ Go to top of Section [H] (Surface Water Problems) ~

Section [I] ~ AQUIFER DEGRADATION ~ [I1]~ Global, [I2]~ Asian Sub-Continent, [I3]~ Eastern Asia, [I4]~ Middle East - North Africa, [I5]~ Sub-Saharan Africa, [I6]~Southeast Asia, [I7]~ North America, [I8]~ South America, [I9]~ Europe,

More than half the world's people live in countries where water tables are falling (07B1).

Average recharge rate for the world's aquifers: 0.007%/ year (Ref. 62 of Ref. (94K1)).

China, India, Saudi Arabia, North Africa, and the US over-pump and deplete aquifers at a rate of 160 billion cubic meters (tons?) annually. Since it takes it takes 1000 tons of water to produce 1 ton of grain (wheat), this 160-billion-ton water deficit is equal to 160 million tons of grain or one half the US grain harvest. 480 million of the world's 6 billion people are being fed with grain produced with unsustainable use of water. About 70% of the water consumed worldwide is used for irrigation, 20% by industry, and 10% for residential purposes. Migration to cities means that residential use of water triples due to indoor plumbing. If we decided abruptly to stabilize water tables everywhere by simply pumping less water, the world grain harvest would fall by 160 million tons, or 8% (World Watch (6/21/00)).

Scores of countries are running up regional water deficits, including nearly all of those in Central Asia, the Middle East, and North Africa, plus India, Pakistan, and the US. Historically, water shortages were local, but shortfalls can cross national boundaries via the international grain trade. Water-scarce countries often satisfy growing needs of cities and industry by diverting water from irrigation and importing grain to offset resulting loss of production. Since a ton of grain equals (requires) 1000 tons of water, importing grain is the most efficient way to import water (02B1).

Groundwater over-pumping is widespread in central and northern China, northwest and southern India, parts of Pakistan, much of the western US, Northern Africa, the Middle East and the Arabian Peninsula. Ref. (99P1) believes that groundwater over-pumping may now be a bigger threat to irrigated agriculture than the buildup of salt in the soil.

Groundwater Depletion in Major Regions of the World, Circa 1990 (96P1):
US High Plains: This aquifer underlies nearly 20% of all US irrigated lands. Net depletion to date = 325 km³; Current depletion rate = 12 km³/ year.
California: Current overdraft = 1.6 km³/ year (About 2/3 of this overdraft is in Central Valley.)
Southwestern US: Water tables have dropped over 120 meters east of Phoenix. At current rate, water table will drop an added 20 meters by 2020.
Mexico City and Valley of Mexico: Pumping exceeds natural recharge by 50-80%.
Arabian Peninsula: Groundwater use nearly 3 times greater than recharge. Estimated reservoir lifetime at extraction rate projected for the 1990s = 50 years.
African Sahara: Current groundwater depletion rate is 10 km³/ year (3.8 km³/ year in Libya alone).
Israel and Gaza: Pumping from the coastal plain aquifer bordering the Mediterranean Sea exceeds recharge by 60%. Salt water has invaded the aquifer.
Spain: 20% of total groundwater use (1 km³/ year) is not sustainable.
India - Punjab (India's breadbasket): Water tables are falling 20 cm./ year across 2/3 of the Punjab.
India - Gujarat: groundwater levels declined in 90% of observation wells during the 1980s.
North China: Water table beneath Beijing has dropped 37 meters during the past 4 decades. North China's region of groundwater overdraft covers 15,000 km².
Southeast Asia: Significant overdrafts have occurred in and around Bangkok, Manila and Jakarta. Over-pumping has caused land subsidence beneath Bangkok at a rate of 5-10 cm./ year for the past two decades.

Use of Drip- and micro-irrigation in selected countries around 2000 (05B1)
Col. 2 = Area Irrigated by Drip- and other Micro-irrigation Methods in units of thousands of ha.
Col. 3 = Share (%) of Total Irrigated Area Under Drip or Micro-irrigation.

The implication of the above table is that only about 1% percent of the world's irrigated lands are being irrigated by drip- and other micro-irrigation methods.

Farmers are driving Asian countries towards catastrophe, using tube wells that suck groundwater reserves dry, New Scientist says. Tens of millions of tube wells have been drilled over the past decade, many of them beyond any official control, and powerful electric pumps are being used to haul up the water at a rate that far outstrips replenishment by rainfall. In the case of India, smallholder farmers have driven 21 million tube wells into their fields and the number is increasing by a million wells per year. Half of India's traditional hand-dug wells have run dry, as have millions of shallower tube wells (04U3).

Villages in northwestern India have been abandoned because over-pumping depleted their aquifers (04U1).

In India's Indus basin as a whole, the rate of groundwater pumping is estimated to exceed the rate of recharge by 50% (p. 97 of Ref. (99P1)).

An estimated 25% of India's grain harvest could be in jeopardy from groundwater depletion (98S5).

In the north Indian state of Uttar Pradesh the number of water-short villages increased from 17,000 to 70,000 in two decades (98H1). Of 2700 water wells (tub wells?) supplied by the Uttar Pradesh government, 2300 wells have dried up (98H1).

Between 1946-86 the water table in parts of Karmataka in India dropped 40 meters (Ref. 20 of Ref. (92P1)). In portions of the southern state of Tamil Nadu, ground-water levels have dropped 25-30 meters in a decade (Ref. 12 of Ref. (92P1)) (85B1) (90P1).

In Ludhiana District, one of 12 in India's Punjab where water tables have been carefully studied, the water table is dropping nearly 1 meter/ year (Ref. 18, Chapter 8 of Ref. (94B1)). Water tables are dropping by less than one to several meters/ year in much of India's Punjab (India's breadbasket), Haryana, Uttar Pradesh, Gujurat, and Tamil Nadu - states that contain a total of 250 million people (Ref. 16 of Ref. (95B1)).

65% of Haryana India sits over salty groundwater (Ref. 38 of Ref. (96G2)).

In India's North Gujarat, the water table is falling by 6 meters/ year (07B1).

The Central Ground Water Board in New Dehli (India) reports that India's water table was lowered by over 25 ft. during 1983-95 (Pittsburgh Post Gazette (5/20/96)).

Delhi, India, is expected to run out of groundwater by 2015 at current rates of extraction (Environment News Service (3/22/01)).

India's 21 million water wells are powered by heavily subsidized electricity, yet they are lowering water tables at an accelerating rate. In some Indian states, half of all electricity is used to pump water (Ref. 9 of (05B1)).

In India's Tamil Nadu, (Population: 62 million people in southern India), falling water tables have dried up 95% of the wells owned by small farmers, reducing the irrigated area in Tamil Nadu by 50% over the last decade (0