~ CHAPTER 6c ~
WATER SUPPLIES FOR IRRIGATION (Continued)
Sections (6-A) and (6-B) of this chapter are in another file.
(6-A) ~ Global Overview ~ [A1]~Water Inventories, [A2]~Runoff, [A3]~Dam Construction, [A4]~Dam Inventories, [A5]~Water Use by Humans -Total, [A5a]~Non-Agricultural- and [A5b]~Agricultural, [A6]~Groundwater Supplies, [A7]~Desalinization, [A8]~Water Recycling, [A9]~Irrigation Water-Use Efficiency, [A10]~Surface Water Supplies, [A11]~Water Losses,
(6-B) ~ Regional Water Supplies and Use ~ Asia and Europe ~ [B1]~Asian Sub-continent, [B2]~Far East, [B3]~Middle East, [B4]~Southeast Asia, [B5]~Europe, [B6]~Russia and Central Asian Republics, ~
Table of Contents of this file:
SECTION (6-C) ~Regional Water Supplies and Use ~ Africa and Australia ~ [C1]~Africa, [C2]~Africa ~ Nile River Drainage, [C3]~Australia, ~
SECTION (6-D) ~Regional Water Supplies and Use ~ North and South America ~ [D1]~US, [D2]~US - Western, [D3]~US - Great Plains, [D4]~Northwestern US, [D5]~Southeastern US, [D6]~Midwestern US, [D7]~Central America, [D8]~South America,
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ir6cNOTE: The notation (su4) means that the adjacent data was used in the document analyzing the sustainability of the productivity of the world's systems for producing food, fiber and water.
SECTION (6-C) ~ Regional Water Supply and Use ~ Africa and Australia ~ [C1]~Africa, [C2]~Africa-Nile River Drainage, [C3]~Australia, ~
Part [C1] ~ Water Supply/ Use ~ Africa ~
Nearly 90% of Africa's water is used in agriculture. Some 40-60% of that water is lost to seepage (into aquifers?) and to evaporation (06I1).
Economic damages from water pollution and excessive extraction in the Middle East and North Africa (MENA) (the world's most water-stressed region) amounts to $9 billion/ year (2.1-7.4% of GDP) (09I1).
About 96% of agriculture in Africa is rain-fed, but soil nutrient depletion is a more pressing problem than drought in sub-Saharan Africa("Water Stress in Sub-Saharan Africa," Council on Foreign Relations (8/7/06).).
By the year 2025, 12 more African countries will join the 13 that already suffer from water stress or water scarcity (99S1).
Population growth and economic progress will, based on current trends, lead to nearly 50% of people in Africa living in countries facing water scarcity ('water stress') within 25 years (99S1).
In sub-Saharan Africa, farmers run the risk of total crop failure due to drought once every 5 years and severely reduced yields once every 2 years (04M1).
In sub-Saharan Africa more than 95% of crops are rain-fed, and 10-30% of the available rainfall is being used in a productive way (08E2). Comments: transpiration causes much of the rainfall to not serve a useful purpose.
Lake Songor in Ghana is being depleted as a result of salt production and as a result of the building of the Cabora Bassa Dam. In December of 1990 the lake's area was 74 km2. By December of 2000 the lake had been reduced to "a pale shadow of its former self (06I1)."
Lake Nakuru in Kenya declined in surface area from 43 km2 to 40 km2 during the year 2000 (06I1).
Niger has lost more than 80% of its freshwater wetlands during the past 2 decades (06I1).
Nine lakes in Africa's Rift Valley including Nakuru, Elementaita, Naivasha, Baringo, Magadi and Logopeis could be extinct within the next 15 years. All the rivers that drain into these lakes are threatened because they rely on the Mau forest as their catchment area and this forest is being stripped of forest cover by logging for charcoal burning.("Time to Act to Save Kenya's Dying Lakes," Kenya Times Newspaper (2/6/07).). (SU4)
Africa's Lake Victoria, which provides fishing and transport for 30 million people, has dropped by 1 meter in the past decade. The rapid shrinking of Lake Songor in Ghana is partly due to salt production, changes in the Zambezi river after the building of the Cahora Bassa dam site, and the near 90% shrinkage of Lake Chad. In the Volta river basin in West Africa, shared between Benin, Burkina Faso, Ivory Coast, Ghana, Mali and Togo, over the next two decades, population levels are set to double to 40 million, causing a rise in demand for water. Rainfall and river flows in the region have declined steadily in the past 30 years, partly linked to higher evaporation rates as a result of climate change("Africa Lakes Under Strain as Populations Rise", BBC News, 10/31/05).
Water levels in Lake Victoria (Africa's largest freshwater lake) have dropped by 1 meter since the early 1990s. The area around the lake supports 30 million people -- one of the world's poorest populations (06I1).
Lake Chad (in Cameroon, Chad, Nigeria and Niger) has shrunk by 90% (in area?) (06I1).
West Africa: Saving Lake Chad 3/21/03 [www.irinnews.org/wwd.asp]~
Lake Chad is now less than seven meters deep. A dryer climate and a higher demand for water for agriculture cause the decrease in surface area. Lake Chad's size decreased by 30% between 1966-1975, with irrigation accounting for only 5% of that reduction. However, irrigation demands increased four-fold between 1983-1994, accounting for half of the additional decrease in the lake's size. Failed rains and drought between 1992-1994, diversion of water from the River Chari to irrigation projects and construction of dams on the Jama'are and Hadeja rivers in northeastern Nigeria hastened the shrinking of the lake. (Continued below)
The Southern Chad Irrigation Project developed by Nigeria
was to irrigate 670 km2, but as water levels in the lake fell in the late 1980s, no irrigation could take place.
Cattle herders have been burning the sparse, coarse vegetation that is left in the hope that new plant life will sprout and provide a more palatable diet for livestock. Instead, the process loosens the dry soil and make it more susceptible to erosion. As areas dry up, farmers and cattle herders move southward, where they compete for land resources with host communities. This has led to conflicts between herders and farming communities in northeastern Nigeria. Some farmers, forced to migrate from the Lake Chad area, have gone to cities, as far south as Lagos, where they take up menial jobs or swell the ranks of the jobless, adding to the social crises there.
Africa's Lake Chad, which provides water to 20 million people in six countries, has shrunk by 80-95% in 38 years. (Environment News Service (3/22/01)) (su4)
Lake Chad in Africa has been reduced by climate change and irrigation to 20% of its 1960s size. (Financial Times (London), (8/14/01)).
Diversions for irrigation from the Logone and Chari Rivers have shrunk Africa's Lake Chad (in Cameroon, Chad, Nigeria and Niger by 75% over the last 3 decades (95P2).
Agriculture in Africa accounts for 88% of water use (99S1).
Africa's Sahel region, (south of the Sahara and includes parts of Ethiopia and Guinea), has seen precipitation fall 20-50% over past 30-40 years ("African Droughts "Triggered by Western Pollution", New Scientist (6/12/02)).
Morocco imports 50% of its grain (02B1). Comments: This due to lack of water to grow grain.
Algeria imports over 70% of its grain (02B1).
Africa (Egypt to Morocco) runs a water deficit of 10 km3/ year (99P1). Comments: Ref. (99P1) estimates a global deficit of 200 km3/ year.
According to a study published in Nature, Central Africa faces a "very high probability" of experiencing a "mega-drought" in the next 50-100 years. Scientists studying lakebed sediments representing 1100 years of history found evidence of long-lasting wet and dry periods more extreme than anything seen in the 20th century (Africa News (2/8/00)).
About 2/3 (of Africans) lack a sanitary means for excreta disposal, more people are today without water and adequate services than in 1990. Almost 50% of all Africans suffer from one of the six main water-related diseases (World Commission on Water for the 21st century data) (PanAfrican News Agency (2/9/00)).
Africa currently has 11 water-scarce countries - nations with renewable supplies of less than 725 gallons/ person/ day, a minimum benchmark for being able to meet food, industrial, and household water needs while maintaining a healthy aquatic environment. By 2000, four other countries will join that list, and the total number of Africans living in water-scarce countries will climb to 300 million, a third of Africa's projected population (97P3).
Collectively, the 20 countries comprising the Middle East and North Africa (MENA) face the worst water shortages. Today, annual per-capita water availability is 1,250 cubic meters, 60% less than in 1960. By 2025, the projected supply = 650 m3/ capita (98H1).
(Water Use Data) Africa's water use since 1950 has tripled (Wall Street Journal (4/24/97)). Comments: The population has probably tripled during that time also.
A map showing humid, sub-humid, and arid regions is in Ref. (76R1). A map of Africa showing number of months in which precipitation exceeds evapo-transpiration is also shown.
(Ground water Use Data) 10 km3/ year of water is being withdrawn from Northern Africa's aquifers (Ref. 13 of (94S1)). Removable aquifer volume = 600,000 km3 (94S1).
Growing demands for irrigation water in Tanzania's upper Pangani River basin caused the traditional system of water rationing to collapse in the mid-1980s (07M1). (Africa.doc)
The other major problem in Tanzania (besides pastoralist/ farmer conflicts) is water-availability. Population growth and human migration in northeastern Tanzania's Pangani River basin (the most water-stressed basin in Tanzania) (Total catchment area = 42,000 km2) have intensified local water conflicts. Tanzania's Pangani River's flow has decreased dramatically in recent years. Water demand is expected to double between 2003 and 2015 (IUCN, 2003) (07M1). (Africa.doc)
In Tanzania's Usangu Plains there has been concern over rising conflicts over water for irrigation among farmers and access to other water demands such as environmental and tourist demands in the Ruaha National Park, and demands for hydropower generation at Mtera Dam. One of the reasons for these conflicts is poor irrigation management in the Usangu plains, upstream of the Great Ruaha Basin. During the dry season most rivers dry up downstream, leaving only a few big rivers to maintain flow throughout the year. This has bought about many environmental, political and economic concerns (04M2).
Tanzanian farmers cultivate only 63,000 km2 of the total 430,000 km2 of arable land. Only 1500 km2 of the 10,000 km2 with apparent potential for irrigation are under irrigation. A large proportion of irrigated area (850-1000 km2) is farmed by smallholders using diversion furrows (04K1).
Tanzania has 9330 km2 of potentially irrigatable land. This includes land for irrigation from surface water and ground water sources. By 1980 only 1440 km2 of this land were under irrigated agriculture, both partial and full-scale irrigation. Of this, the traditional small-scale agriculture accounted for 1204 km2, while 236 were under large-scale estate farms (04K1).
[C1a] ~ Water Supply/ Use ~ Africa ~ Libya ~
(Ground water Depletion) Libya's plan to extract 2.2 km3/ year from a desert aquifer will probably dry up the aquifer in 40-60 years (99P1).
(Ground water Resource data) In the Kufra region of southeastern Libya is a 140,000 km2 ground-water reserve of good quality that could irrigate a million acres (4000 km2) for 800 years (70P1).
(Salinization of Ground water) Salt water is displacing fresh water in Libya's water table (Ref. 11 of (92P1)).
(Ground water Depletion) The Kufra irrigation project in Libya mined fossil, underground water so fast that levels dropped 5-7 times faster than expected, jeopardizing the entire project (77A1).
(Ground water Depletion) Libya's fossil water will be depleted in a few decades, while others predict centuries (95G1).
Part [C2] ~ Water Supply/ Use ~ Africa ~ Nile River Drainage ~
Egypt and Sudan signed a treaty in 1959 allocating 75% of the Nile's water to the former and the remainder to Sudan, with no provisions for the other countries through which the river flows, and Egypt has threatened military action against any of those countries if their irrigation projects reduce the flow. [Elhadj, Elie. "Dry Aquifers in Arab Countries and the Looming Food Crisis." The Middle East Review of International Affairs, 12(3), (September 2008). http://www.meriajournal.com/en/asp/journal/2008/december/elhadj/index.asp ]
The water needed to produce the annual combined imports of grain by the Middle East and North Africa is equivalent to the annual flow of the Nile (99S1). Comments: The Nile does not reach the sea anymore (See below), so these grain imports could not be replaced by greater use of Nile water.
The combined population of the three countries the Nile runs through - Ethiopia, Sudan and Egypt - is expected to increase from 150 million in 1998 to 340 million in 2050, based on current trends (99S1).
With the Nile River now reduced to a trickle as it enters the Mediterranean, the three principal countries of the Nile River Basin - Egypt, Ethiopia, and Sudan - can each increase its take from the river only at the expense of the other two. The combined population of these countries is projected to climb from 167 million in 2002 to 264 million in 2025 (02B1).
About 90% of the flow of the Nile River is used for (consumed by?) irrigation, or is lost through evaporation from reservoirs by the time it reaches the Mediterranean Sea (USA Today (11/29/99)).
More than 85% of the Nile's water comes from the Blue Nile, which originates in Ethiopia (Postel 1992). Ethiopia has constructed more than 200 small dams that will use nearly 0.5 km3/ year of Nile water. Additional dams are planned (Marcus 1997). Ethiopia has 37000 km2 of land that could be irrigated (Postel 1996). Ethiopia's population is nearly the size of Egypt's and Ethiopia has a faster annual rate of population growth, 3.2%/ year for Ethiopia versus 2% for Egypt (UN Population Division 1996a). Irrigating half this potential Ethiopian cropland area with Nile water could reduce the river's flow to Egypt by 15% (Postel 1996) (98U2).
Egypt has begun a massive New Valley land-reclamation/ irrigation project in its western desert. When completed, a pipeline will carry up to 5 km3/ year of Nile water from Lake Nasser Reservoir to the New Valley site to facilitate new cities and irrigate more than 2000 km2
of desert (98U2).
Sources cited in the above paragraph:
Before the Aswan High Dam on the Nile was built, the Nile carried 32 km3 of water to the Mediterranean Sea annually (38% of the river's flow. After the dam and irrigation diversions were complete, 6 km3 reached the sea annually. In 1999, 1.8 km3 reaches the sea (99P1).
Some 85% of the Nile River is generated by rainfall in Ethiopia (93P1).
Egypt had 63.5 km3 of water available in 1990. In 2000 it will need 69.4 km3 (93P1).
Some 97% of Egypt's water comes from the Nile River (94G1). Over 95% of the Nile's runoff originates outside Egypt (94G1).
The Nile River irrigates 30,000 km2 of cropland (95P2). (la)
(Water Losses) Evaporation loss from the reservoir behind Aswan High Dam is 10 km3/ year (of 55.5 km3/ year entering the reservoir) (p. 146 of (99P1)).
Before the Nile River's Aswan Dam, 32 km3/ year of Nile River water reached the sea. After the dam, output dropped to 6 km3/ year and to 3 km3/ year in 1985, and to 1.8 km3/ year today (95P2).
About 37,000 km2 of Ethiopia are potentially irrigable. Irrigating half of this would reduce the Nile's flow through Egypt by 9 km3/ year (16%) (96P1).
Egypt has begun a "New Valley" project to pump up to 6.5 billion yd3 (4.97 km3/ year) from Lake Nassar (behind Aswan High Dam) for land reclamation in Egypt's Western Desert. The last Nile water agreement was between Egypt and Sudan in 1959. It gave Egypt 72.15 billion yd3/ year (55.2 km3/ year) and Sudan 20.04 (15.3 km3/ year). (Ethiopia got none, and has never recognized the treaty, but is now updating plans for dams and hydro-power projects.) (Amy Dockser Marcus, Wall Street Journal (8/22/97)).
Sudan's Jebel Aulia Dam (south of Khartoum) loses 2.8 km3/ year to evaporation (p. 159 of (99P1)).
Part [C3] ~ Water Supply/ Use ~ Australia ~
Australia's Great Artesian Basin is one of the largest groundwater basins in the world, covering 1.7 million km2 (656,370 sq. miles) and lying beneath 20% of Australia (08P1).
Australia's Great Artesian Basin holds 65 million gigaliters (65,000 km3) of water, about 820 times the amount of surface water in Australia (08P1).
Australia's Great Artesian Basin receives 1 million megaliters (0.001 million gigaliters) (1 km3) of water (from rainwater) per year (08P1).
Access to the waters of Australia's Great Artesian Basin is under threat from declining artesian pressures (the pressures that force the water in the aquifer up to the surface via bore holes and springs.) The declining pressures are due to excessive extraction of water from the surface. The Australia's Great Artesian Basin lies as much as 2 km. below ground. Some parts of the aquifer are 3 km below the surface (08P1).
The mining and petroleum industries extract 31 gigaliters (0.031 km3) of Australia's Great Artesian Basin water per year (08P1).
The pastoral industry extracts 500 gigaliters (0.5 km3) of water per year from Australia's Great Artesian Basin (08P1).
Since Australia's Great Artesian Basin waters were first tapped in 1878, 87,000 gigaliters (87 km3) of water have been extracted. Up to 90% of that was wasted. As a result of falling water pressure, more than 1000 natural springs have been lost, and a third of the original artesian bores have ceased flowing. Today there are 3000 bores that pour water into 34,000 km of open bore drains, with 90% of the water evaporating in the outback heat. But more than 1052 bores have now been controlled, and tens of thousands of km of open drains have been removed and pipelines laid, saving 272 gigaliters (0.272 km3) of water per year (08P1).
Australia is now in its 10th year of a drought that looks more like a long-term manifestation of climate change. (Paul Krugman, "Running out of Planet to Exploit," New York Times (4/21/08)).
Australia is in the midst of a 30-year dry spell (07S3).
South Australia's Irrigation System Allocation of Water among Various Outputs (1996-1997) (in km3) (01P1):
Pasture 0.72 / Grapes 0.13 / Citrus 0.08 / Remainder 0.11 / (Total 1.041).
Australia's Irrigation Water Allocations among Outputs in 1996-1997 (in km3) (01P1):
Australia's Irrigation Water Use Locations in 1996-1997 (in km3) (01P1):
"Degradation of land and water remains Australia's most critical environmental issue - much of it a direct result of population pressures, the nationalState of the Environment report for 2001 has concluded. The five-yearly report, which took a team of about 100 scientists to compile, warns that the environment has improved little since the first national report in 1996 and "in some critical aspects, has worsened". In 1999 Australia was the fourth largest land clearer in the world. Salinity and water quality were two of the most critical issues with the worst affected areas being the very agricultural land on which Australia depends. Between 1985-1997 water extracted for irrigation rose 75% and total water use rose 65% (Amanda Hodge, "Degradation is critical; Land clearing field of shame", The Australian (20/3/2002), p. 3.).
In South Australia, 20% of surface water is too saline for human consumption (6/25/99 PRNewswire).
Australia's Murray-Darling river system supplies about 75% of all water used nation-wide. About 70% of Australia's irrigated agriculture occurs within this river basin. Farms, cities and industries drain off 75-80% of the river's flow (99P1).
Water demands of Melbourne (Victoria) are likely to curtail any further expansion of irrigation in Victoria (83H1).
In Australia's Murray Valley, developed storage capacity exceeds annual flow (83H1).
Australia's arid zone has a mean annual runoff of less than 1.25 cm. (70P2). As a result, the only irrigation areas of any size are restricted to the Murrumbidgee River- and Murray River Systems in the far-southeast part of the arid zone (70P2).
Authorities in Australia's Murray-Darling Basin capped farmers' water withdrawals in 1995 when they learned that only 25% of the basin's water actually reached the sea (96G1).
Go toTop of this Chapter-Water Supplies for Irrigation
SECTION (6-D) ~ Regional Water Supply and Use~North and South America ~ [D1]~US, [D2]~US - Western, [D3]~US - Great Plains, [D4]~Northwestern US, [D5]~Southeastern US, [D6]~Midwestern US [D7]~Central America, [D8]~South America,~
See a listing of large databases in Chapter 8 Section (8-E) for sources of tabulations of:
A US Geological Survey Report of 8/1/05 "Estimated Withdrawals from Principal Aquifers in the US, 2000" provides details of ground-water withdrawals from principal aquifers in each state. It breaks the withdrawal data into major uses - irrigation, public water supplies, and self-supplied industrial uses. On a daily basis, 76.5 billion gallons are used for these three purposes, with irrigation accounting for nearly 75% of this amount. The full report is available online at http://pubs.water.usgs.gov/circ1279. It is 52 pages long and the pdf file is 12.8 MB in size.
Part [D1] ~ Water Supply/ Use ~ US ~
The cities of Las Vegas, and Phoenix were built in the middle of the desert. The Hoover Dam, built on the Colorado River near Las Vegas during the Great Depression, created Lake Mead, the country's largest artificial body of water. The lake provides water to Arizona, California, Nevada and northern Mexico - but after several recent years of drought, on top of ever-growing demand, it's dangerously depleted. Housing developments on the outskirts of these towns have been stopped dead in their tracks by lack of water supply(10Q1).
Mike Shedlock noted the difficulties facing the Southwestern US in a white paper that he wrote on the subject of peak water: "There is more water allocated to each user from the Colorado River than there is water to allocate. Chevron's water rights for its DeBeque, Colorado, shale oil project are leased, not sold, to the city of Las Vegas for drinking water. How will Las Vegas replace that in the future when Chevron won't extend the lease?"(10Q1)
The Ipswich River near Boston now "runs dry about every other year or so," according to Sandra Postel, director of the Global Water Policy Project. "Why? Heavy pumping of groundwater for irrigation of big green lawns." (10Q1)
On hot summer days Maryland, Virginia and the District of Columbia, combined, suck up 85% of the Potomac River's flow.(10Q1) Comments: That information probably dates back to the 1990s, so the situation currently is likely to be significantly worse.
About 20% of the grain harvest comes from irrigated land (08B1). Comments: Globally? US?
The US government projects that at least 36 US states will face water shortages within five years because of a combination of rising temperatures, drought, population growth, urban sprawl, waste and excess (07S3).
Experts estimate that just upgrading pipes to handle new supplies could cost the US $300 billion over 30 years (07S3).
The US used more than 148 trillion gallons of water in 2000, the latest figures available from the US Geological Survey. That includes residential, commercial, agriculture, manufacturing and every other use - almost 500,000 gallons/ person (07S3). Comments: What fraction is use and what fraction is consumption?
A US Geological Survey Report of 8/1/05 "Estimated Withdrawals from Principal Aquifers in the US, 2000" provides details of ground-water withdrawals from principal aquifers in each state. It breaks the withdrawal data into major uses - irrigation, public water supplies, and self-supplied industrial uses. On a daily basis, 76.5 billion gallons are used for these three purposes, with irrigation accounting for nearly 75% of this amount. The full report is available online at http://pubs.water.usgs.gov/circ1279. It is 52 pages long and the pdf file is 12.8 MB in size.
US irrigation consumes (uses?) 190 km3 of water/ year on 263,000 km2 of land (01T1).
The Ogallala Aquifer in the US supplies 22 km3 of water/ year to a land area of 53,000 km2. Aquifer mining of the Ogallala aquifer is 18 km3/ year (01T1). (su4)
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).
Rivers as unlikely as the Ipswich near Boston have been pumped dry (01R1).
The Rio Grande River is as over-committed as the Colorado River (01R1).
In the first 8 decades of the 20th century, growth in US water-use out-stripped population growth by 2.5 times. But US water use has declined by 20%/ person from 1980-95 (USGS data) (98S3).
Water used in the US for domestic purposes, both inside and outside the home, increased sharply in the 1960s and 1970s as the size of houses grew, along with the number of bathrooms, and homes were stocked with more water-using appliances. Since then, domestic use of water has stabilized at 100 gallons/ person/ day as more water-efficient dishwashers, clothes washers and toilets have been installed. Even so, domestic use increased as a share of the total, rising to 12% in 1995 from 10% in 1985 (98S2).
US use of public water - water withdrawn from natural sources by suppliers and conveyed to users rather than withdrawn directly by users like farmers and factories - is one of two categories in which the use has continued to increase. It grew by 18% from 1980-95. But because of greater efficiencies, per-person use in this category has stabilized at 180 gallons/ day (98S2).
Most US water is returned to rivers and streams after being used. Consumption of the rest by people, animals and crops dropped by 8% from 1980-1985, but has since rebounded to its 1980 level (98S2).
Irrigation is the top US freshwater use -134 billion gallons/ day in 1995. Next is thermoelectric power generation, which uses 132 billion gallons/ day of fresh water (98S2).
At any point in time, only 1% of the water in the Mississippi River System is in the part of the river that flows downstream to the Gulf of Mexico. The other 99% lies beneath the bottom, locked in strata of rock and sand (00S1).
(Water Use Trends) US water use by livestock and rural households has risen 58% since 1980 (98S2).
In the first 8 decades of this century, US growth in use of water was continuous, outstripping population growth by a ratio of about 2.5 to 1. Expansion of irrigation, industry and electrical power generation accounted for most of the increase. Then a number of factors combined to reverse the trend. The best sites for dams (the main means of gathering water for use) had been taken, and building new ones became more expensive (98S2).
Recycling of water and conservation measures, along with new technologies, reduced US industrial use of water by 35%, to the lowest level -29 billion gallons a day - since record keeping began in 1950. This does not include water used for cooling power plants, both nuclear and those powered by fossil fuels like coal. Water used for that purpose - the biggest single category of use, at 190 billion gallons a day in 1995 - fell by 5% in the 1980s and has remained about stable for several years (98S2).
(Water Quality Issues) About 60% of the US's liquid hazardous wastes (34 billion liters of solvents, heavy metals and radioactive materials) is directly injected into the ground. Though injected below the deepest current source of drinking water, some of these wastes have entered aquifers used for water supplies in parts of Florida, Texas, Ohio, and Oklahoma (00S1).
(Water Quality Issues) US businesses drain almost 2000 tonnes of assorted chemicals into septic systems annually, contaminating drinking water of 1.3 million people (00S1).
(Ground water Use Data) In a study of 54 US streams, the USGS found that ground water is the source for over 50% of the average flow (00S1).
(Water Supply Data) The 1.86 km3 (492 billion gallons) added to US surface waters daily is nearly equal to the daily flow of the Mississippi River (00S1).
Over 95% of the rural US population depends on ground water for drinking (00S1).
Americans' use of water declined by about 9% from 1980-1995 - even as the US population grew by 16% over the same period. The drop in water use, which came after decades of steady increase, is attributed by experts largely to a gradual shift in focus away from finding ways to capture more water - building dams, for instance - and toward devising ways of using it more efficiently. Most of the drop occurred in the 1980s, with a decline of only 2% reported from 1990-1995, the latest year for which numbers are available. Per-capita use of water declined, on average, by 20% from 1980, the all-time peak year, to 1995 (98S2).
Water used per acre of US irrigated land fell 16% from 1980-1995. The amount of US land under irrigation has remained about constant (98S2).
In 1994, Daniel P. Beard, Commissioner of the US Bureau of Reclamation, told an international gathering of water specialists that the dam-building era in the US is now over (95P2).
(Water Supply Inventory Data) 1260 billion gallons/ day (1742 km3/ year) reaches US streams. 315 billion (435 km3/ year) are withdrawn for all purposes. 100 billion (139 km3/ year) are consumed (Ref. 23 of (76P1)).
(Urban Water Uses) Shifting 7% of western US agriculture's water to cities could meet the growth in urban demand projected until 2000 (97P3).
Irrigation consumes 80% of all water withdrawn in the 17 western US states (Ref. 23 of (76P1)).
Agriculture accounts for 85% of US water consumption (97P1).
Ground water provides 31% of US agricultural water (97P1).
(Ground water Depletion) US ground water is being depleted 160% faster than its replenishment rate (97P1).
Water budget of the conterminous US (km3/ year) (83J1)
Precipitation ~ ~ ~ ~ ~ ~ ~ |5800
Evaporation ~ ~ ~ ~ ~ ~ ~ ~ |3800
Reservoir evaporation ~ ~ ~ | ~21
Consumption ~ ~ ~ ~ ~ ~ ~ ~ | 147
Stream flow to Canada ~ ~ ~ | ~ 8.6
Stream flow to Mexico ~ ~ ~ | ~ 2.2
Stream-flow to Atlantic ~ ~ | -
Ocean and Gulf of Mexico~ ~ |1270
Stream-flow to Pacific O. ~ | 420
Sub-surface flow to Pacific | ~35
Sub-surface flow to Atlantic| 104
US Water Supplies, Consumption, and Consumption for Irrigation in 1975 (Million Gallons/ day) (77F1) (multiply by 1.3832 to get m3/ year)
Region - - - - - - |Supplies*|Consumpt.|Irrigation
New England~ ~ ~ ~ | ~ 74,700| ~ 456.5 | ~ ~18.3
Middle Atlantic~ ~ | ~ 91,000| 1,826.2 | ~ 241.2
South Atlantic Gulf| ~227,800| 5,178.6 | 3,146.5
Great Lakes~ ~ ~ ~ | ~ 74,800| 2,544.7 | ~ 137.8
Ohio ~ ~ ~ ~ ~ ~ ~ | ~240,000| 1,784.2 | ~ ~44.5
Tennessee~ ~ ~ ~ ~ | ~ 68,900| ~ 307.7 | ~ ~12.4
Upper Mississippi~ | ~266,100| 1,039.1 | ~ 139.7
Lower Mississippi~ |1,196,700| 4,527.3 | 3,426.8
Souris-Red-Rainy ~ | ~ ~6,000| ~ ~87.0 | ~ ~25.7
Missouri ~ ~ ~ ~ ~ | ~156,800|14,376.7 |13,243.4
Arkansas-White-Red | ~778,000| 8,225.8 | 7,313.2
Texas-Gulf ~ ~ ~ ~ | ~ 33,900|11,406.9 | 9,847.0
Rio Grande ~ ~ ~ ~ | ~ 58,100| 6,133.3 | 5,840.9
Upper Colorado ~ ~ | ~ 24,600| 2,669.7 | 2,426.7
Lower Colorado ~ ~ | ~ 10,600| 3,626.4 | 4,144.5
Great Basin~ ~ ~ ~ | ~ 72,400| 4,289.6 | 3,692.8
Columbia-N.Pacific | ~611,400|13,773.6 |12,880.0
Columbia-S.Pacific | ~ 74,200|28,196.8 |26,128.9
Alaska ~ ~ ~ ~ ~ ~ | ~905,000| ~ ~79.3 | ~ ~ 3.6
Hawaii ~ ~ ~ ~ ~ ~ | ~ ~6,200| ~ 464.0 | ~ 415.8
* Supply figures are based primarily on adjusted natural runoff, which is the annual flow of water that would appear in surface streams, adjusted to account for upstream water development. In areas of surface/ground-water continuity, the adjusted natural runoff includes the perennial recharge or yield of ground water aquifers. Mean annual runoff in the contiguous US is 1660 km3/ year (=9") (=30% of precipitation) (77F1). The summary data in Col. 2 of the above table cannot be totaled to estimate total water supply for the U.S. because flows from upstream areas are included in down-stream estimates.
(Ground water Depletion) Development of irrigation from ground-water sources in many parts of the world, including New Mexico, has lowered water tables and contaminated remaining ground-water resources by seawater intrusions (74F1).
(Ground water Use Data) Ground-water use (in the US) increased from 47 km3/ year in 1950 to 122 km3/ year now (85U1). Ground water provides 35% of US fresh-water withdrawals for municipal water supplies, 97% of rural drinking water, 40% of irrigation water, and 26% of water used in industry (85U1).
(Ground water Salinization) Salt-water intrusion into ground-water aquifers along the US Gulf- and Atlantic Coasts limits ground-water development there (77F1).
(Ground water Depletion) A map showing areas of ground-water over-drafts in the arid west is shown in Ref. (81S2), (81S1), (80C1), (80U1), and (87E1), based on US Water Resources Council data.
(Surface water Depletion) A map showing where US surface water supplies are inadequate is in Ref. (80C1). Irrigation consumes much of the water in the overdraft areas (Ref. 23 of (81S1)).
(Surface Water Depletion) A map of areas of inadequate surface water supply is on p. 23 of (80U1).
(Water Resource Inventory Data) A map of average annual precipitation is shown on p. 20 of Ref. (80U1) and on p. 182 of Ref. (82S1) based on US Water Resources Council, "The Nation's Water Resources", 1978. A plot of fresh water withdrawals by use (1955-1980) is on p. 21.
(Irrigated Land Inventory) A map of 1977 US irrigated areas is on p. 25 (one dot = 8000 acres) of Ref. (80U1).
(Ground water Depletion) A map of ground-water overdrafts is on p. 27 of Ref. (80U1). 40,000 km2 (20% of irrigated area) are watered by pumping in excess of recharge (90P1).
(Water Inventory Data) Ref. (80H1) gives an excellent chapter on US water resources, uses, precipitation, runoff, water quality, etc. with lots of data.
(Water Inventory Data) A detailed analysis of US water resources and withdrawals (state by state) is found in Ref. (85U1).
(Water Use Data) Irrigated agriculture in 1977 accounted for 82% of all US water consumption, 47% of all diversions, and 32% of all returned water (Ref. 22 of (85E1)).
Consumptive use of water by irrigation averages 85% of all consumptive uses of water in the US (77K2).
(Water Use Data) Some 98% of the water consumed in US agriculture is used to irrigate crops. The remainder is used for livestock (81B1).
(Water Use Data) Total US water withdrawals have increased 3.5%/ year over the past two decades (77K2). Between 1900-1970, water withdrawals for irrigation increased from 28 to 180 km3/ year (77K2).
(Ground water Depletion) Groundwater levels are falling by 0.15-1.2 meters/ year on over 25% of US irrigated lands. These lands account for 8% of total farm sales (86S1).
(Ground water Inventory Data) Groundwater, equivalent to 35 years of surface runoff, is 97% of the total US fresh-water supplies (81B1).
Groundwater withdrawals in the US have been estimated at 68-84 to 105 km3/ year (81B1). In Texas, Oklahoma, New Mexico, Colorado, Kansas, and Nebraska, irrigated area declined by 5920 km2 (7%) (85P1).
(Ground water Depletion) 40,000 km2 of US irrigated land are watered by over-pumping ground water (20% of US irrigated acreage) (Ref. 11 of (92P1)). (su4)
Some 79 km3/ year of water (over 2/3 of groundwater withdrawals) are used to irrigate 130,000 km2 of US crops (82W1).
(Ground water Depletion) Groundwater levels in the US are declining beneath at least 61,000 km2 (82W1).
(Ground water Use Data) Groundwater supplies 20% of total US water consumption nationwide (81S2) (81S1).
Irrigation water withdrawals (from rivers, etc.) range from 80% of total water use in Utah to 90% in New Mexico (Ref. 8 of (90L1)). Comments: Surface water? Ground water?
(Water Losses) Loss of water by seepage from canals was 1/3 of the amount delivered to irrigation farms (90L1). Comments: US? Global?
(Water Use Data - Western) Irrigation consumes 80% of all water withdrawn in 17 western US states (Ref. 23 of (76P2)).
Arizona, Colorado, Idaho and New Mexico no longer allow additional irrigation in problem areas. That still 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).
Some measured surface-subsidence data (due to ground-water) (56T1):
Las Vegas NV 1.5 ft. (1954)
San Jose CA 6.0 ft. (1940)
Texas City TX 3.0 ft. (1954)
Comments: Obsolete data - There are lots of additional data
A table is given of water resource sub-regions in the US with projected depletions of water supply greater than 35% in average- and dry years (1975, 1980, 1985, 1990, 2000) (79M1).
Ground-water Withdrawals in Excess of Recharge (USDA, RCA, 1980) (82S1)
(Col. 2 is withdrawal in excess of recharge in billion gallons/ day)
(Col. 3 is % withdrawal in excess of recharge)
(Col. 4 is withdrawal in excess of recharge in km3/ year)
Region - - - - |Col.2 |Col.3 |Col. 4
Missouri ~ ~ ~ | 2.557| (25%)| (3.537)
Arkansas ~ ~ ~ | 5.457| (62%)| (7.548)
Texas Gulf ~ ~ | 5.578| (77%)| (7.715)
Rio Grande ~ ~ | 0.657| (28%)| (0.909)
Upper Colorado | 0.000| ( 0%)| (0.000)
Lower Colorado | 2.415| (48%)| (3.340)
Great Basin~ ~ | 0.519| (42%)| (0.718)
Pacific NW ~ ~ | 0.627| ( 9%)| (0.864)
California ~ ~ | 2.197| (12%)| (3.039)
Western Region |20.079| - - -|(27.773)
Conterminous US|20.889| - - -|(28.894)
Areas Irrigated with Over-pumped Ground-water in 1982(89P1)
State -|-Irrigated|Area Irrigated
- - - -|Area (km2 )|by over-pumping
Texas ~ ~ | 21,440|15,430 | 72%
California| 32,210| 6,440 | 20
Kansas~ ~ | 10,600| 6,040 | 57
Nebraska~ | 24,230| 4,120 | 17
Colorado~ | 10,880| 1,960 | 18
Arizona ~ | ~4,260| 1,750 | 41
Arkansas~ | ~8,090| 1,210 | 15
New Mexico| ~2,810| 1,010 | 36
Florida ~ | ~5,280| 1,000 | 19
Idaho ~ ~ | 12,370| ~ 870 | ~7
Oklahoma~ | ~1,890| ~ 870 | 46
Other ~ ~ | 64,480| - - - | -
Total ~ ~ |198,540|40,700 | 21%
(A breakdown of these figures according to crops grown is shown in Ref. (88D1) based on data from its Ref. 4. Corresponding figures for 1977 and 1983 are shown in Ref. (88O1).)
(Ground water Use Data) In 1980, 90 billion gallons/ day (124 km3/ year) of ground water was pumped in the US. About 5% of this was used for rural water supplies; 13% for public supply, 67% for irrigation; 15% for industrial use (86S3).
(Ground water Use data) Groundwater contributes 20% of the US supply (450 billion gal/ day). 34% of water used for public supply and 79% of water used for rural domestic and livestock use in 1980 was supplied by ground water (See p. 1 of (86S3)).
(Ground water Depletion) In the US, 20% of irrigated lands depend on excessive pumping of ground water (93G1). In the US, over 25% of irrigated croplands (25% of 210,000 km2) is watered by drawing down underground water tables (6"-4'/ year) (Ref. 13 of (94B1)) (USDA data).
(Ground water Depletion) 21% of irrigated croplands in the US depend on drawing down aquifers (Ref. 43 of (95B1)).
Removable volume of the Southwest US aquifer = 3000 km3 (94S1). Removable volume for California's Central Valley aquifer = 10,000 km3 (94S1). The corresponding extraction rates are 12, 10 and 13 km3/ year (94S1). Three large aquifers in North America are associated with limited recharge and significant mining: the High Plains (including Ogallala) Aquifer, the Southwest Aquifer, and the Central Valley (CA) aquifer (94S1). Total recoverable ground water in these American aquifers is equivalent to 4.6 cm. in sea level (Ocean area = 360 million km2). They are being mined at a rate of 0.1 mm (sea level)/ year, and have contributed 3.2 mm. of sea-level rise to-date (See Table 1 of (94S1)). Recharge rate of these three North American aquifers is 6.75, 1.05 and 0.78 km3/ year (94S1).
(Ground water Inventory Data) The Northern Great Plains Aquifer System covers 250,000 mi.2 (648,000 km2) (p. 50 of (86S3)). (la)
(Ground water Inventory Data) The Northern Midwest Regional Aquifer System (Cambrian-Ordovician Aquifer System) covers 161,000 mi.2 in the US (p. 72 of (86S3)). (la)
Part [D2] ~ Water Supply/ Use ~ US ~ Western ~ [D2a]~Arizona, [D2b]~California, [D2c]~Nevada, [D2d]~New Mexico, [D2e]~Oregon, [D2f]~Utah,~
In the western US, the Sierra Nevada snow-pack melts faster each year (07S3).
Experts also say the Colorado River, which provides freshwater to seven Western states, will probably provide less water in coming years as global warming shrinks its flow (07S3).
Aurora (a suburb of Denver, Colorado) has purchased water rights that were previously used to irrigate 96 km2 of cropland in the Arkansas River valley (Ref. 34 of (05B1)).
Farming, ranching, mining and agricultural and mineral processing account for 6% of employment in the western US (west of the 100th meridian excluding Hawaii and Alaska) (Western Water Policy Review Advisory Commission, "Water in the West: the Challenge for the next Century" Denver, Colorado (1992), p. 2-18).
Western US irrigated agricultural lands are responsible for 45% of the value of US crop commodity exports (Western Water Policy Review Advisory Commission, "Water in the West: the Challenge for the next Century" Denver, Colorado, 1992, p.2-18 and 2-29).
In 1960, water withdrawals in the western US totaled 135 million acre-ft. (maf), vs. 179 maf in 1990. During the same timeframe, agricultural water withdrawals declined, as a percent of the total, from 86% to 78% with increases in the relative shares of thermoelectric and domestic consumption (Western Water Policy Review Advisory Commission, "Water in the West: the Challenge for the next Century" Denver, Colorado (1992) p. 2-22, 2-23, Fig. 2-10).
Irrigation water represents 90% of water use in the Western US (Western Water Policy Review Advisory Commission, "Water in the West: the Challenge for the next Century" Denver, Colorado (1992) p. 2-24).
Overdrafts amount to 50% of withdrawals in the Lower Colorado region of the Western US (82S1).
The Colorado River Compact of 1922 allocated 16.5 million acre-ft. of water among 7 states and Mexico. The long-term average flow of the Colorado is about 90% of that (95P2).
Tree-ring studies show that the period of time during which Colorado River flows were studied for allocating water in the Colorado River Compact of 1922 was much wetter than the long-term historical average flow. A report released in February of 2007 by a committee of the National Research Council documents this. It also notes that the 240,000 square-mile Colorado River basin has experienced staggering population growth in recent decades and points out that the only way to allocate more water to residential and commercial growth is to reduce the allocation of water to agriculture (mainly irrigation) (Editorial, "A Pattern of Normal Drought," New York Times (3/3/07)).
The Colorado River, controlled by 10 major dams, irrigates 8000 km2 of farmland in the Western US (95P2).
[D2a] ~ Water Supply/ Use ~ US ~ Western ~ Arizona ~
Robert A. Witzeman, M.D. Conservation Chair, Maricopa Audubon Society, 4619 E. Arcadia Lane Phoenix, AZ 85018 tel. 602 840-0052,email@example.com in a 7/16/01 email to RangeNet@yahoogroups.com.
In central Arizona, ground-water levels are declining at a rate of 2.1-3.0 meters/ year (82S1).
Groundwater supplies 62% of total water consumption in Arizona (81S2) (81S1).
Arizona's ground-water over-draft is 2700 km3/ year (Note: probably an error - 2.7 km3/ year seems more likely) - 46% of total water consumption (79S2).
Arizona's population grew by 40% in a decade. Two decades doubled Arizona's population to 5.13 million. In Phoenix, where urban canals still flood home gardens, water use is 250 gallons/ person/ day (01R1).
San-Pedro Basin 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 (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 (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)). (la)
(Groundwater Depletion) Tucson draws its water from the upper Santa Cruz- and Avra Valley Basin's groundwater. At present pumping rates, the Santa Cruz aquifer will be exhausted within 100 years (over-draft = 0.29 km3/ year) (81S1).
(Groundwater Depletion) In the lower Santa Cruz Valley, ground-water overdrafts total 0.681 km3/ year (mainly for irrigation) (81S3). Upper Santa Cruz River Valley ground-water overdrafts total 0.291 km3/ year, 27% to mining, 29% to urban uses, and 41% to agriculture (Ref. 20 of (81S3)). Avra Valley aquifers will be depleted within 100 years at current consumption rates (81S1).
(Groundwater Depletion) Some Tucson wells have dropped 110 ft. (34 meters) in the past decade (Ref. 6 of (81S3)), (81S1).
(Groundwater Depletion) Water tables in some areas around Tucson have dropped over 50 meters (85P1). Tucson pumps water at five times the rate nature replaces it (Ref. 7 of (81S3)), (81S1).
(Groundwater Depletion) Groundwater over-drafts 0.681 km3/ year in the Santa Cruz Basin are as severe as anywhere in the US. Even more water coming from the Central Arizona Project won't keep 2020 over-drafts under 0.617 km3/ year (81S1).
(Groundwater Depletion) 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 (81S1)). (la)
(Groundwater Depletion) 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, and water tables continue to drop 3-6 meters/ year (Ref. 31 of (78B2)).
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).
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).
In aquifers of southern and central Arizona, 900 million acre-ft. (1110 km3) of recoverable water was stored in the upper 1200 ft. of sediments before development. 2.5 million acre-ft. (3.085 km3) of water enter and leave this aquifer yearly. From the beginning of development through 1980, 184 million acre-ft. (227 km3) of water has been pumped. Though part of this volume has been balanced by recharge, water levels have dropped by more than 400 ft. in some basins (p. 129 of (86S3)).
[D2b] ~ Water Supply/ Use ~ US ~ Western ~ California ~
About 18 million Californians expect water rationing in mid-2008 - the first one in years (08C1).
Californians use nearly 23 trillion gallons (1 million gallons = 3785 m3) of water a year, much of it coming from Sierra Nevada snowmelt. But climate change is producing less snow-pack and causing it to melt prematurely, jeopardizing future supplies (07S3).
California irrigated land, in 1986, consumed (used?) 32 km3 of water (5 on pasture, 5 on Lucerne hay, 4 on cotton, 3 on rice, 2 on grapes) (01T1). This water went onto 37,000 km2 of irrigated land (3000 km2 was salt-affected.) Aquifer mining in California is 2.4 km3/ year which has caused a cumulative loss of aquifer storage of 25 km3 which is 47% of California's man-made storage of 53 km3 (01T1).
(Groundwater Depletion) California over-drafts ground water at a rate of 1.6 km3/ year (15% of California's ground water use) (99P1). (su4)
Groundwater supplies 40% of total water consumption in California (81S2) (81S1).
According to the California Department of Water Resources, if more supplies aren't found by 2020, residents will face a shortfall nearly as great as the amount consumed today ("California Water Shortage", Village Voice (8/27/02)).
Southern Californians' water consumption has dropped from 205 gallons/ person/ day in 1980 to 170 in 2002. Los Angeles' water use has grown 7% since 1970 despite a population increase of 35% (02K1).
Los Angeles is a coastal desert able to support at most 1 million people on its own water; the Los Angeles basin now is the core of a megalopolis that spans 220 miles from Santa Barbara to the Mexican border. The region's population of 16 million is expected to reach 22 million by 2020. The 1440-mile Colorado River supplies 30% of coastal Southern California's water. The Colorado River system is the major water source for 25 million people (02K1).
By 2000, the water-supply deficiency for California's urban and agricultural demands will total over 2.47 km3/ year (Gertsch, 1977, in Ref. (82S3)).
Desalinization now costs about $800/ acre-foot, but (California) farmers can lose money with water at $15/ acre-foot (01R1). (su4)
Orange County (CA) Water District has a revolutionary project to triple-filter wastewater and recharge the substantial Santa Ana aquifer. This also helps to block encroaching seawater (01R1).
Early in the 20th century, Los Angeles-area water authorities purchased the third-largest body of water in the state, Owens Lake. Today it is called Owens Dry Lake, because Los Angeles sucked it dry. People in the area want Los Angeles to fill the lake again, but city officials say that would require 10% of their water, something they cannot afford (98S1).
Farmers in California's San Joaquin Valley began tapping the area's groundwater in the late 19th century. By 1912, the water table had fallen by as much as 400 ft. (00S1).
Some 35 km. of San Joaquin River (California) have been so permanently dewatered that developers have proposed building houses in the river-bed (95P2).
(Groundwater Depletion) In San J oaquin Valley's Westlands Water District, ground-water levels are dropping 3-6 meters/ year in 291 km2 (Ref. 108 of (81S3)).
(Groundwater Depletion) In western San Joaquin Valley, some irrigation water is pumped from 1067 meters below the surface (81S1). About 1.85 km3 more water is pumped from the basin's aquifer than is naturally replenished (81S1) (79S2).
(Groundwater Depletion) In Antelope Valley (north of Los Angeles, and on the edge of Mojave Desert), ground-water levels are dropping 0.9 meters/ year, due mainly to urban demands (81S2), Ref. 99 of (81S1).
(Surface Water Depletion) Mono Lake's level is dropping as water is drawn off to supply Los Angeles, 300 miles away (Ref. 100 of (81S1)).
(Ground water Depletion) Stockton (pop. 190,000) draws 90% of its water from depleting wells (89C1).
(Ground water Salinization) 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).
The four federal agencies that control much of the federal water policy issued standards for San Francisco Bay Delta that will require less pumping from the Delta. Most reductions are likely to come from farms -agriculture uses 80% of the water used in California (93M2).
In California's Palm Desert, large-scale desalinization will be essential within 50 years (01R1).
In Central Valley CA (precipitation= 14-20"/ year, making it arid to semi-arid), irrigated croplands require 36"/ year including delivery losses (86S3). In Central Valley CA, water is used at 22 million acre-ft./ year (27 km3/ year) (1961-1977). 50% was supplied by surface water, 50% by ground-water (including delivery losses) (86S3). In parts of San Joaquin Valley and Tulare Basin (CA), ground-water levels have declined nearly 400 ft. (86S3).
In 2002, 450,000 irrigated acres of vegetables earn the Imperial Valley's 400 farms $1 billion/ year in revenue. California has long used more water from the Colorado River than it's legally entitled to. Now, the federal government is threatening to cut the state's water from the river on Jan. 1/03(?) by an amount equivalent to the needs of 1.5 million families. That could kill lawns from San Diego to Santa Barbara and force 16 million people in a six-county coastal region to ration showers and laundry loads (02K1).
[D2c] ~ Water Supply/ Use ~ US ~ Western ~ Nevada ~
Pyramid Lake in western Nevada has dropped 70 ft. since 1906 due to overdrafts from Truckee Valley Aquifer and the Truchee River (81S2).
In western Nevada, the Newlands irrigation project and the Reno-Sparks urban water diversion from Truckee River and the Truckee Valley Aquifer have dropped the level of Pyramid Lake 70 ft. since 1906, and in the past two decades, salinity and turbidity have increased markedly (Ref. 95 of (81S1)).
[D2d] ~ Water Supply/ Use ~ US ~ Western - New Mexico ~
Between 1978-1982, irrigated land area in New Mexico dropped 9% (85P1).
(Groundwater Depletion) Albuquerque NM, whose underground reserves were until recently vastly overestimated, could dry up by 2050 (01R1).
[D2e] ~ Water Supply/ Use ~ US ~ Western ~ Oregon ~
"Even in a normal year, the water in the Klamath Basin (Oregon) cannot meet the current, and growing, demands for tribal, agricultural, industrial, municipal and fish and wildlife needs," Oregon Governor Kitzhaber said commenting the feud over the basin's resources between farmers and the Ecological Society of America. He further commented "the current water crisis in the Klamath Basin has been 150 years in the making and serves as a reminder to us all that we are stretching our natural resources beyond their limits." ("Oregon US: Water Crisis 150 Years in the Making", Greenlines/ Environment & Energy Daily (6/11/01)).
[D2f] ~ Water Supply/ Use ~ US ~ Western ~ Utah ~
In Utah a $400-million pipeline is being proposed that would take water out of Lake Powell - one of the nation's premier recreation areas - and channel it 120 miles west to St. George, Utah, home to Sun Belt retirees. Los Angeles, Las Vegas, and Phoenix are well known as expanding desert capitals. University of Colorado law professor and water-policy expert Charles Wilkinson says the Lake Powell project is the "prototype" of water projects that will give rise to new instant cities, representing environmental challenges profoundly affecting the future of the wild and arid West. Western US interior states have increased their population by 4 times since World War II, from 8 to 34 million. Southern California is proposing pipelines to carry water from distant basins to suburbs pushing deeper into the Mojave Desert. For example, a pipeline across northern Arizona has been proposed, to bring water from the Colorado River to Flagstaff Arizona. St. George's pipeline would take 70,000 acre-feet/ year. St. George has grown from a population of 13,669 in 1970 to 90,354 at the latest census. A report projects that St. George-Washington County could reach 525,000 residents by 2050. A pipeline opponent, commissioned a separate study that said that the population will only reach 340,000. Utah has the highest per-capita rate of water use in the West - and water rates that are among the lowest in the nation. The state is trying to reduce consumption by 25%. Another plan calls for building a dam along the Bear River, which provides 60% of the freshwater entering Great Salt Lake, and then channeling water into metropolitan Salt Lake City, where 80% of Utah's 2.2 million residents live. The Bear River Pipeline would carry 2-3 times the volume of water of the Lake Powell Pipeline and cost up to $1 billion (Christian Science Monitor (5/3/01)).
Part [D3] ~ Water Supply/ Use ~ US Great Plains ~ [D3a]~Kansas, [D3b]~Ogallala Aquifer, [D3c]~High Plains Aquifer, [D3d]~Texas, ~
In the US, the USDA reports that in parts of Texas, Oklahoma, and Kansas the underground water table has dropped by more than 30 meters. As a result, wells have gone dry on thousands of farms in the southern Great Plains (07B1).
The Oklahoma Legislature was motivated to update the state's 1995 water plan because of dwindling reservoirs and aquifers. Since 1973, the number of water wells in Oklahoma have increased tenfold. Current Oklahoma law allows the OWRB to issue groundwater use permits based on an assumed 20-year lifetime for the aquifer("Development of 50-Year State Water Plan Discussed," (7/20/07) Norman Transcript website http://www.normantranscript.com/).
The state of Texas covers 7 major and 16 minor aquifers that underlie 75% of the state. The Ogallala Aquifer accounts for about 90% of water in all of Texas aquifers. Pumping of water from many aquifers in Texas has resulted in a significant lowering of the water table. Maps of the major and minor aquifers of Texas are found in Ref.
The Ogallala Aquifer, the largest aquifer in North America, covers 174,000 square miles in 8 states and incorporates some of the most important aquacultural land in the US. The Ogallala irrigates more than 140,000 km2 of land (in North America?). In Texas, 79.4% of groundwater usage is for irrigation. 6.2 million acre-feet of water were pumped out of the Ogallala Aquifer in Texas in 1997 (08M1). (The average recharge rate of the entire Ogallala Aquifer is 0.3 million acre-feet per year.) Comments: The Ogallala Aquifer is thinnest at its outer edges. These outer edges (perimeter) run through Texas. This is why some parts of the Ogallala Aquifer in western Texas have dried up. The thickest portion of the lens-shaped Ogallala Aquifer is in Nebraska.
The US Department of Agriculture (USDA) reports that in parts of (three leading grain-producing states) the underground water table has dropped by more than 30 meters (100 feet) (08B1).
[D3a] ~ Water Supply/ Use ~ US Great Plains ~ Kansas ~
(Groundwater Depletion) In west-central Kansas, irrigation wells numbered 250 in 1950, and 2850 in 1980. The Ogallala Aquifer was 58 ft. thick in 1930. Today it is less than 8 ft. (Ref. 101 of (81S1)).
(Surface Water Depletion) 4000 miles of Kansas's streams and rivers, strangled by irrigation, now run only intermittently (89F1).
(Groundwater Depletion) 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. Today it is less than 2.4 meters thick (81S2).
By 2000, irrigation in western Kansas will have dried up (US Dept. of the Interior Study) (80F1).
In the SW corner of Kansas are 10,000 wells on 8000 mi2 (20,700 km2). They withdraw 3.5 million acre-ft/ year (4.32 km3/ year) from the Ogallala (82M1). Since 1940 the saturated thickness in half of the SW Kansas Ogallala has declined 11% or more (82M1). The Arkansas River dries up permanently somewhere between the Colorado state line and Deerfield, 50 miles to the east (82M1). In Groundwater Management District 3 along the western reaches of the Kansas Ark River, it has been decided that a 40% depletion of the Ogallala Aquifer in the next 25 years is acceptable, and permits are granted accordingly (82M1).
[D3b] ~ Water Supply/ Use ~ US Great Plains - Ogallala Aquifer ~
(Ground water Depletion) The Ogallala Aquifer depletion rate: 12 km3/ year (99P1).
The Ogallala aquifer waters 20% of US irrigated land (99P1).
(Ground water Depletion) The Ogallala Aquifer is being depleted at a rate 20 times the rate of natural replenishment (93G1).
(Ground water Depletion) Depletion of the Ogallala Aquifer in the southern Great Plains of the US has caused cutbacks in irrigation. Texas has lost 1%/ year since 1980 (99U1).
(Ground water Inventory Data) The Ogallala Aquifer, which stretches from the Texas Panhandle to South Dakota, is believed to have contained 4 trillion tons of pristine water. It is now mined by over 200,000 wells that pull out 6838 billion gallons/ year, 14 times faster than the recharge rate. Since 1991 the Ogallala Aquifer's water table has dropped three feet/ year. By some estimates, more than 50% of the Ogallala Aquifer's water is gone (02U3).
The USGS estimates that there are more than 6000 mi3 (25,000 km3) of gravel in the Ogallala Aquifer (O. A.) (laid down during the Miocene by glacial melt from the Rockies) (82M1).
The Ogallala Aquifer is a lens-shaped gravel bed, formerly up to 91 meters thick. A map of the Ogallala Aquifer showing the saturated thickness is shown on the front cover of Ref. (82S2).
Rain recharges the Ogallala Aquifer at 0.006 meter / year. Water is being pumped from the aquifer at 1.5 meters/ year (80J1).
(Ground water Depletion) The Ogallala Aquifer is being drawn down 15-18 times faster than nature is replacing it (80F1). The Ogallala Aquifer supports irrigated agriculture on more than 44,500 km2 of arid land (Ref. 24 of (81S2)). Mean thickness of the Ogallala Aquifer is 700 ft. (p. 31 of (86S3)). (la)
Over 50% of the 93,000 km2 of irrigated farmland in the Great Plains depend on the Ogallala Aquifer (84U1).
(Groundwater Depletion) Over 20,000 km2 now irrigated will have no remaining ground water by 2000 (84U1). 20% of US irrigated croplands is supported by water mined from the Ogallala Aquifer (85P1).
(Groundwater Depletion) The Ogallala Aquifer is now half depleted under 9,000 km2 of Kansas, New Mexico, and Texas (85P1).
(Ground water Depletion) Depletion of the Ogallala Aquifer in the southern Great Plains, and diversion of irrigation water to sunbelt cities in Arizona, California and Florida have led to a 3% decline in US irrigation area since 1978 (85B1).
(Ground water Depletion) In western Texas, 63,000 irrigation wells pump 4900-9800 m3/ year of water from the Ogallala Aquifer from depths of 30-90 meters to irrigate 21,000 km2 (70P1). Since 1949, average pumping lift in Hale Co. Texas has increased from 12 to 30 meters (70P1).
(Ground water Depletion) In Gaines Co. TX water is consumed at twice the rate of natural recharge. The entire billion-$ agricultural economy of the Texas High Plains is built on the over-draft of water from the Ogallala Aquifer (Ref. 362 of (81S1)).
(Ground water Depletion) As of 1990, 24% of the Texas portion of the Ogallala Aquifer had been depleted - a loss of 164 km3 (92P1).
(Water Use Data) Nearly 12% of the nation's corn, cotton, grain sorghum and wheat, valued as high as $2.8 billion are watered by the Ogallala Aquifer (80F1).
(Water Inventory Data) The Ogallala Aquifer holds 4000 km3 of water (95G1).
(Ground water Depletion) Ogallala groundwater levels in Kansas and Western Nebraska have dropped as much as 60 ft Water levels dropped 16 ft. during 1952-1975. If all water developments planned for the Platt River are carried out, the Platt River will be dry in 35 years (79A1).
During 1982-1992, farmers drawing water from the Ogallala Aquifer lost three times more irrigated area than they gained. Five High-Plains states and 3 in the western US cut irrigated area by nearly 10% over 1982-92 (Ref. 11 of (96G1)).
(Ground water Depletion) Sidney Nebraska groundwater levels dropped 22 ft. during 1970-1978 (79A1).
(Ground water Depletion) In the High-Plains-Ogallala Aquifer study, experts predicted the aquifer has about 30 years of life remaining at the present rate of development (Ref. 12 of (79A1)).
(Water Use Data) Nebraska irrigates 6 million of its 18 million acres (73,000 km2) of cultivated lands - a 5-fold increase since 1959 (Ref. 1 of (79A1)). A projection to 2000 gives 10-12 million acres -mainly center-pivot technology (3000 units in 1973, 15,000 in 1979) (79A1).
Average discharge (to lakes and streams) from the Ogallala Aquifer is 2.3 million acre-ft./ year (2.8 km3/ year). 85% of this occurs north of 39o latitude (p. 34 of (86S3)).
[D3c] ~ Water Supply/ Use ~ US Great Plains - High Plains Aquifer ~
The High Plains Aquifer underlies 174,000 mi2 (451,000 km2) in CO, KS, NB, NM, OK, SD, TX and WY. 134,000 (347,000 km2) of this is the Ogallala Aquifer (86S3). (la)
Between 1978-1982, irrigated land dropped 18% in Oklahoma (85P1)).
(Groundwater Depletion) In Oklahoma, the water table has dropped more than 100 feet ("Ecological Deficits Taking Economic Toll", Earth Policy Institute (10/8/02)).
(Groundwater Depletion) In Kansas, the water table has dropped more than 100 feet ("Ecological Deficits Taking Economic Toll", Earth Policy Institute (10/8/02)).
Recharge rate of the US High Plains Aquifer is 0 to 41 mm./ year (Ref. 9 of (94S1)).
Removable volume of the US High Plains Aquifer estimated to be 4000 km3 (94S1).
About 20% of the irrigated land in the US, and 30% of the groundwater used for irrigation, comes from the High Plains Aquifer. In 1980, 18 million acre-ft. (22.2 km3) were pumped from this aquifer to irrigate 14 million acres (p. 30 of (86S3)).
Average recharge of the High Plains Aquifer System is 5.7 million acre-ft/ year (7.03 km3/ year). 80% of this recharge occurs north of 39o latitude (p. 31 of (86S3)). Average saturated thickness of the High Plains Aquifer System is 200 ft.; 46% has less than 100 ft.; 5% has over 600 ft. (p. 34 of (86S3)). Total volume of drainable water in the High Plains Aquifer in 1980 was 3.25 billion acre-ft. (4011 km3) -65% in Nebraska, 12% in TX, 10% in KS, 4% in Colorado, 3.5% in OK; 2% in SD, and 1.5% in NM (86S3).
Some 95% of water pumped from the High Plains Aquifer system is used for irrigation (p. 34 of (86S3)). Some 13 million acres (5.3 million km2) were irrigated by the High Plains Aquifer System in 1978 (p. 35 of (86S3)). 23 million acre-ft. of water were pumped then (p. 37 of (86S3)). This pumping rate is growing at 1.2 million acre-ft./ year (86S3). (A breakdown by state is on p. 38 of (86S3).) 166 million acre-ft. of water have been removed from the High Plains Aquifer System since pumping began in the mid-1940s (p. 40 of (86S3)).
[D3d] ~ Water Supply/ Use ~ US Great Plains ~ Texas ~
In the El Paso/ Far West Texas region of the Rio Grande River Basin, irrigation accounts for 2/3 of water use. In the Lower Rio Grande Valley of Texas it is closer to 85%; in the Conchos River basin (a tributary of the Rio Grande River) irrigation water accounts for over 90% of water use (02K2).
In some areas of the Rio Grande River Basin, groundwater pumping has reduced or even eliminated spring flow or allowed the infiltration of saline water into the fresh water zones. Many observers have predicted that, at current pumping rates, the Hueco Bolson aquifer (under El Paso Texas and Cd. Juarez Mexico) may run dry for all practical purposes in 2022 (02K2).
Recent Population History of major Metropolitan Areas of the Texas portion of the Rio Grande Basin (02K2).
Metropolitan S. Area - - - - - -| 1990~ | ~2000~ |%Change
McAllen-Edinburg-Mission~ ~ ~ ~ |383,545| 569,463| 48.5
El Paso ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ |591,610| 679,622| 14.9
Brownsville-Harlingen-San Benito|260,120| 335,227| 28.9
Laredo~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ |133,239| 193,117| 44.9
Totals ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ |1368,514|1777,429| 29.9
Recent population history of major Metropolitan Areas of the Mexico portion of the Rio Grande Basin(02K2).
Municipal Area| 1990~ ~ | 2000~ ~ |% Change
Cd. Juarez~ ~ | ~798,500|1,217,818| 53%
Cd. Chihuahua | ~609,059| ~670,208| 10%(5-year)
Cd. Acuna ~ ~ | ~ 41,947| ~110,388|163%
Piedras Negras| ~ 80,291| ~127,898| 59%
Nuevo Laredo~ | ~203,285| ~310,277| 53%
Monterrey ~ ~ |1,069,238|1,108,499| ~4%
Reynosa ~ ~ ~ | ~211,411| ~471,651| 98%
Matamoros ~ ~ | ~238,839| ~416,428| 74%
Totals~ ~ ~ ~ |3,252,570|4,433,167| 36%
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 River 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)).
The Rio Grande River basin (mainly in Texas) contains 180,000 miles2 (02K2).
(Groundwater Depletion) The underground aquifer supplying the Juarez Mexico-El Paso Texas area will be exhausted in 15-25 years ("The Border" (http://www.pbs.org/kpbs/border/) A two-hour documentary, aired on PBS 9/23-24/99).
(Surface Water Depletion) For the first time in history, a "sandbar has silted shut the mouth" of the Rio Grande. Thus, the Rio Grande River 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)).
From 1930-80, water-use in Texas increased twice as fast as population (98S1).
(Groundwater Depletion) In Texas, the water table has dropped more than 100 feet ("Ecological Deficits Taking Economic Toll", Earth Policy Institute (10/8/02)).
Ciudad Juarez (Mexico), across from El Paso, Texas, has soared beyond a million inhabitants, typical of northern Mexico's growth. It could run out of water as early as 2006 (01R1).
(Groundwater Depletion) 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).
(Groundwater Depletion) In areas such as the high plains of West Texas, underground water supplies are being steadily depleted ((76E1) p. 135).
(Groundwater Depletion) In parts of Ft. Worth-Dallas Metro-area of Texas, water tables have fallen over 120 meters in the last 25 years (Ref. 23 of (85P1)).
(Groundwater Depletion) In Texas, water tables are falling 15 cm./ year beneath 15,400 km2 - 72% of the irrigated area of Texas (90P1). (la)
(Groundwater Depletion) In the Texas high plains, irrigated area is expected to drop 45% by 2000 even if conservation cuts water use by 20% (80F1). Some 40,500 km2 of irrigated land are threatened by Ogallala Aquifer overdrafts in western Texas and eastern New Mexico (80C1).
Groundwater supplies 75% of total water consumption in western Texas (81S2) (81S1).
Over-drafts in Texas amount to 78% of groundwater withdrawals, 30% in the Rio Grande River Region (82S1). (su4)
Between 1978-1982, irrigated land area in Texas dropped 20% (85P1).
Part [D4] ~ Water Supply/ Use ~ Northwestern US ~
Walla River (Oregon/ Washington): Irrigated farmland diverts literally all the river's flow from its channel and leaves the riverbed dry ("America's Most Endangered Rivers of 1998", American Rivers, Washington DC, 4/98 See http://www.amrivers.org).
The Columbia Plateau Basalt regional aquifer system has experienced declining water levels of as much as 20 ft./ year (86S3). It has also experienced sodium enrichment of its waters (86S3). Comments: Sodium enrichment probably comes from irrigation system drainage.
Part [D5] ~ Water Supply/ Use ~ Southeastern US ~
Lake Lanier is the major freshwater source for the majority of people living in the urban sprawl surrounding Atlanta Georgia (09H1).
(Groundwater Salinization) Along the Atlantic coast of the US, seawater seeps into aquifers from Cape Cod to the tip of Florida (01R1).
(Groundwater Extraction) 3 billion gallons/ day (4.15 km3/ year) are withdrawn from Florida's aquifer system in 1980 for all uses. It's recharge area is 67,000 mi.2 (174,000 km2) which contributes 4.4"/ year (86S3).
In the US Southeastern Coastal Plain Regional Aquifer System, precipitation = 50"/ year (p. 206 of (86S3)). Over-land runoff = 7"/ year; evapo-transpiration = 35"/ year; recharge to aquifers = 8"/ year (1" of that to the deeper aquifers). In places, municipal and agricultural use has resulted in local water level declines of up to 100 ft. of pre-development levels (p. 206 of (86S3)).
Across the southern US are water shortages that, in some instances, approach crisis proportions (Ref. 12 of (85H1)).
In several of the Southeast's 11 states, water pumping for irrigation has lowered sub-surface water levels by 50 to several hundred feet. In the Grand Prairie area of eastern Arkansas, irrigation pumping since the 1930s has caused water level declines of more than 18 meters in the Mississippi River Alluvial aquifer (Ref. 27 of (85H1)).
Part [D6] ~ Water Supply/ Use ~ Midwestern US ~
Some 53% of the new water entering the Great Lakes is ground water; 24% is surface water; 20% is over-lake precipitation subtracting evaporation losses (02R2).
Alarmed by increasing reports of suburban wells running dry, the Northeastern Illinois Planning Commission looked into the problem, releasing a report earlier this year forecasting water shortfalls by 2020. The 6-county Chicago metro area is projected to add 1.3 million people by 2020. The lesson from Chicago, say water experts, is that the days of cheap, easy water are over in the US. If Chicago has to scramble for water, then fierce competition over water can break out anywhere (Joan Lowy, "Chicago Area Will Run Short of Water by 2020", Scripps Howard News Service/NPG (12/12/01)).
Part [D7] ~ Water Supply/ Use ~ Central America ~
Mexico City is sinking into the old lakebed it was built upon at the rate of 3 inches per year(09G1)
Mexico'swater system pipes lose about 40% of liquid before ever reaching homes (09G1)
The average Mexico City resident uses 300 liters of water per day, compared to 180 liters per day in some European cities(09G1)
In Mexico - (population: 107 million and projected to reach 140 million by 2050) -- In Mexico's agricultural state of Guanajuato, the water table is falling by 2 meters or more a year. At the national level (in Mexico), 51% of all of Mexico's water extracted from underground is from aquifers being over-pumped (07B1). (SU4)
In the Gulf of California's states of Sonora, Sinaloa and Nayarit, agriculture consumes 80% of the fresh water available in the region, wasting 60% of that. The National Water Commission categorizes 41% of the region's aquifers as over-exploited (07N1). (SU4)
Over-exploitation of the aquifers in the states of Baja California, Baja California Sur, and Sonora has caused saline seepage so bad that it has rendered formerly productive lands useless (07N1). (SU4)
Farming on the Coast of Hermosillo (Gulf of California Region) is almost a lost cause. The level of the water table here, as well in the other coastal aquifers of Caborca and Guaymas, has dropped to 50 meters below sea level, so all these reservoirs are contaminated by salt-water intrusion. In some places, nothing grows (07N1). (SU4)
[D7a] ~ Water Supply/ Use ~ Central America ~ Mexico ~
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 (02K2)).
Guadalajara (in Mexico) faces water rationing and a growing crisis. For more than a decade, Mexico has not invested in water development, and now the aquifers are polluted or dry, municipal drainage systems waste 40% of the water and every city with a population over 100,000 has problems finding clean water. Water was rationed after Guadalajara's main water source, Lake Chapala, fell to low levels. Guadalajara added no new water sources for 13 years but the population increased by 1 million. Every city of 100,000 population has a drinking-water problem. The 97 aquifers that supply half of Mexico's drinking water are overexploited and in decline. One-sixth of Mexico's population has no running water. The president pledged to spend $250 million to preserve the Lake Chapala-Rio Lerma basin. But still Guadalajara stands out. It added no sources to its supply since 1991 while the population grew 30%, drinking water is increasingly fouled by industrial pollution. The Rio Santiago River is among Mexico's most polluted and opponents say the government is underestimating the cost of purifying the water. An engineer with the water commission, says that the water can be made potable and the construction and operating cost of the Arcediano dam, a projected $300 million is 40% less than the Rio Verde alternative ("Mexico: Fight Over Dam Points Up Water Woes", Los Angeles Times (5/29/04)).
Since 1970 Lake Chapala in Mexico's state of Jalisco has lost 80% of its water. The 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 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 (Jim Carlton, "A Lake Shrinks, Threatening Mexican Region", Wall Street Journal (9/3/03)).
Salt content of lower Colorado River leaving the US (entering Mexico) nearly doubled after 1961 (76E1).
The third of Mexico's croplands that is irrigated provides 5.3% of the total agricultural production (76W1).
The Rio Conchos is being diverted for agricultural use in Mexico. Soon in Big Bend National Park it will be dry during part of the year (03K1).
(Groundwater Depletion) In Mexico's state of Guanajuato, the water table is falling by 1.8-3.3 meters/ year (02E1).
(Groundwater Depletion) In Alamos, Mexico, ancient aquifers are pumped at five times the sustainable (recharge) rate (02R1). (su4)
(Groundwater Salinization) In 25 years, Mexico's total number of areas of over-exploited aquifers has tripled to 96. Seawater has polluted 17 other aquifers because of over-pumping. Toxic seepage is spreading fast (02R1). Hydrologists estimate that only 27% of Mexico's surface water is clean enough for simple treatment. Some 49% requires complex and expensive equipment. The rest (24%) is too poisonous for any practical use (02R1). Outmoded and neglected water systems in Mexico are crippled further by theft from illegal connections. In most cities, more than 50% of piped water is lost to leakage (02R1). Well over half of Mexico's irrigation water is lost to evaporation or seepage. Water-sharing systems often fall apart in Mexico because local officials flout the rules for bribes or personal ties (02R1). Under agreements worked out decades ago, Mexico receives a fixed minimum of the Colorado's normal flow, more in rare years of excess. But the Rio Grande requires complex negotiation. Mexico can borrow extra Rio Grande water, but must pay it back. President Vicente Fox has promised to pay the debt, which amounts to enough to put the state of Delaware under a foot of water. But with Mexico already so short of water, it is not clear how he might do that (02R1). Meanwhile, because of drought and rising demand, farmers on both sides are demonstrating on country lanes and in city streets with a hostility not seen before (02R1).
Mexico City, built eight centuries ago atop vast lagoons, cannot supply water for its 22 million inhabitants. Less than half of Mexico City's wastewater is treated. The rest sinks into underground lakes or flows to the Gulf of Mexico, turning rivers into sewers (02R1).
Mario Cantu Suarez, a deputy director of Mexico's National Water Commission, said 35 Mexican cities must shrink dramatically unless more water can somehow be found. Parts of Mexico are dying, with fields poisoned by salt and village wells running dry. 85% of Mexico's economic growth, and 75% of its 100 million people, are in the north, and the water is far to the south. It costs too much to pipe over mountains or to desalinate far from the sea. To supply Northern Mexico's new industries and farms, Mexico depends on much of the same water that is needed in California, Arizona, New Mexico and Texas (02R1).
How the US and Mexico share the water of the Rio Grande River has become a thorny issue in US-Mexican relations (02B1).
In Mexico - home to 104 million people and with its population growing by 2 million/ year - demand for water has outstripped supply in many Mexican states. In the agricultural state of Guanajuato, for example, the water table is falling by 1.8-3.3 meters/ year (02B1).
Practically all surface- and ground- water are already being used. In some irrigated regions of the central highlands (of Mexico), water shortages are increasing, and ground-water levels are falling (76W1).
Mexico's total cropland covers 167,000 km2, its irrigated cropland covers 53,000 km2 (76W1). (la)
Some measured surface-subsidence data (56T1):
(Groundwater Depletion) Ground water pumping in Mexico City exceeds recharge by 50-80% (Ref. 11 of (93P2)). (su4)
Part [D8] ~ Water Supply/ Use ~ South America ~
Latin America and the Caribbean covers 15% of the earth's land surface and are home to 8.5% of the world's population. It receives 29% of global rainfall and one-third of renewable water resources. South America receives 30% of global runoff. But 4.5 million km2 face severe water shortages including Barbados, Haiti, western Peru, northeastern Brazil, parts of northern Mexico, the Pacific coastal region of Central and South America, as well as parts of the Andean highlands and the southern Argentine and Chilean region of Patagonia. In Bolivia, water management includes the reforestation of river basins. Chile is focusing on reforestation, incentives for irrigation systems, and the recuperation of degraded and desertified areas. About 30,000 km2 have been recovered since the late 1990s, but there are more than 45,000 km2 to be recuperated("Latin America: the Struggle for Water Amidst a Vast Abundance", InterPress Service (12/22/04)). Comments: The reason for the water-scarce areas in a continent with lots of water is that much of the rainfall is in the Amazon River basin where populations are low.
[D8a] ~ Water Supply / Use ~ South America ~ Peru ~
Ref. (70C2) cites evidence of serious over-drafts of groundwater (mainly for irrigation) in Ica Valley, Piura, Chicama, Ilo, and La Yarada. (All of these areas are along Peru's arid Pacific coast.)
[D8b] ~ Water Supply / Use ~ South America ~ Colombia ~
Colombia's water supply could be reduced by up to 40% within 50 years. In Colombia's paramo, the Andean mountain moorland, over-farming has reduced the soil's ability to hold water that later drains into lowland rivers. Comments: This typically translates into erosion and a loss of soil organic matter content.
Some 58% of the Colombian paramo is gone.
Some 75% of the rest of Colombia's paramo could disappear in 15 years.
Some 27% of high Andean forests (in Colombia) have been cut down ("
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