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  • From: "TradingPostPaul" <tradingpost@riseup.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] WATER TABLES FALLING AND RIVERS RUNNING DRY
  • Date: Thu, 26 Jul 2007 11:53:12 -0600


(On this list, we've been promoting water-conserving practices for small
farmers and gardens. Building healthy organic soil, intensive planting,
mulching, and no-till are excellent methods of improving moisture retention
and raising production and profitability. They ignore these methods at
their peril.)

Earth Policy Institute
Plan B 2.0 Book Byte
For Immediate Release
July 24, 2007

WATER TABLES FALLING AND RIVERS RUNNING DRY

http://www.earthpolicy.org/Books/Seg/PB2ch03_ss2.htm

Lester R. Brown

As the world's demand for water has tripled over the last half-century and
as the demand for hydroelectric power has grown even faster, dams and
diversions of river water have drained many rivers dry. As water tables
fall, the springs that feed rivers go dry, reducing river flows.

Scores of countries are overpumping aquifers as they struggle to satisfy
their growing water needs, including each of the big three grain
producers--China, India, and the United States. More than half the world's
people live in countries where water tables are falling.

There are two types of aquifers: replenishable and nonreplenishable (or
fossil) aquifers. Most of the aquifers in India and the shallow aquifer
under the North China Plain are replenishable. When these are depleted, the
maximum rate of pumping is automatically reduced to the rate of recharge.

For fossil aquifers, such as the vast U.S. Ogallala aquifer, the deep
aquifer under the North China Plain, or the Saudi aquifer, depletion brings
pumping to an end. Farmers who lose their irrigation water have the option
of returning to lower-yield dryland farming if rainfall permits. In more
arid regions, however, such as in the southwestern United States or the
Middle East, the loss of irrigation water means the end of agriculture.

The U.S. embassy in Beijing reports that Chinese wheat farmers in some
areas are now pumping from a depth of 300 meters, or nearly 1,000 feet.
Pumping water from this far down raises pumping costs so high that farmers
are often forced to abandon irrigation and return to less productive
dryland farming. A World Bank study indicates that China is overpumping
three river basins in the north--the Hai, which flows through Beijing and
Tianjin; the Yellow; and the Huai, the next river south of the Yellow.
Since it takes 1,000 tons of water to produce one ton of grain, the
shortfall in the Hai basin of nearly 40 billion tons of water per year (1
ton equals 1 cubic meter) means that when the aquifer is depleted, the
grain harvest will drop by 40 million tons--enough to feed 120 million
Chinese.

In India, water shortages are particularly serious simply because the
margin between actual food consumption and survival is so precarious. In a
survey of India's water situation, Fred Pearce reported in New Scientist
that the 21 million wells drilled are lowering water tables in most of the
country. In North Gujarat, the water table is falling by 6 meters (20 feet)
per year. In Tamil Nadu, a state with more than 62 million people in
southern India, wells are going dry almost everywhere and falling water
tables have dried up 95 percent of the wells owned by small farmers,
reducing the irrigated area in the state by half over the last decade.

As water tables fall, well drillers are using modified oil-drilling
technology to reach water, going as deep as 1,000 meters in some locations.
In communities where underground water sources have dried up entirely, all
agriculture is rain-fed and drinking water is trucked in. Tushaar Shah, who
heads the International Water Management Institute's groundwater station in
Gujarat, says of India's water situation, "When the balloon bursts, untold
anarchy will be the lot of rural India."

In the United States, the U.S. Department of Agriculture reports that in
parts of Texas, Oklahoma, and Kansas--three leading grain-producing
states--the underground water table has dropped by more than 30 meters (100
feet). As a result, wells have gone dry on thousands of farms in the
southern Great Plains. Although this mining of underground water is taking
a toll on U.S. grain production, irrigated land accounts for only one fifth
of the U.S. grain harvest, compared with close to three fifths of the
harvest in India and four fifths in China.

Pakistan, a country with 158 million people that is growing by 3 million
per year, is also mining its underground water. In the Pakistani part of
the fertile Punjab plain, the drop in water tables appears to be similar to
that in India. Observation wells near the twin cities of Islamabad and
Rawalpindi show a fall in the water table between 1982 and 2000 that ranges
from 1 to nearly 2 meters a year.

In the province of Baluchistan, water tables around the capital, Quetta,
are falling by 3.5 meters per year. Richard Garstang, a water expert with
the World Wildlife Fund and a participant in a study of Pakistan's water
situation, said in 2001 that "within 15 years Quetta will run out of water
if the current consumption rate continues."

Iran, a country of 70 million people, is overpumping its aquifers by an
average of 5 billion tons of water per year, the water equivalent of one
third of its annual grain harvest. Under the small but agriculturally rich
Chenaran Plain in northeastern Iran, the water table was falling by 2.8
meters a year in the late 1990s. New wells being drilled both for
irrigation and to supply the nearby city of Mashad are responsible.
Villages in eastern Iran are being abandoned as wells go dry, generating a
flow of "water refugees."

Saudi Arabia, a country of 25 million people, is as water-poor as it is
oil-rich. Relying heavily on subsidies, it developed an extensive irrigated
agriculture based largely on its deep fossil aquifer. After several years
of using oil money to support wheat prices at five times the world market
level, the government was forced to face fiscal reality and cut the
subsidies. Its wheat harvest dropped from a high of 4 million tons in 1992
to some 2 million tons in 2005. Some Saudi farmers are now pumping water
from wells that are 1,200 meters deep (nearly four fifths of a mile).

In neighboring Yemen, a nation of 21 million, the water table under most of
the country is falling by roughly 2 meters a year as water use outstrips
the sustainable yield of aquifers. In western Yemen's Sana'a Basin, the
estimated annual water extraction of 224 million tons exceeds the annual
recharge of 42 million tons by a factor of five, dropping the water table 6
meters per year. World Bank projections indicate the Sana'a Basin--site of
the national capital, Sana'a, and home to 2 million people--will be pumped
dry by 2010.

In the search for water, the Yemeni government has drilled test wells in
the basin that are 2 kilometers (1.2 miles) deep--depths normally
associated with the oil industry--but they have failed to find water. Yemen
must soon decide whether to bring water to Sana'a, possibly by pipeline
from coastal desalting plants, if it can afford it, or to relocate the
capital. Either alternative will be costly and potentially traumatic.

Israel, even though it is a pioneer in raising irrigation water
productivity, is depleting both of its principal aquifers--the coastal
aquifer and the mountain aquifer that it shares with Palestinians. Israel's
population, whose growth is fueled by both natural increase and
immigration, is outgrowing its water supply. Conflicts between Israelis and
Palestinians over the allocation of water in the latter area are ongoing.
Because of severe water shortages, Israel has banned the irrigation of
wheat.

In Mexico--home to a population of 107 million that is projected to reach
140 million by 2050--the demand for water is outstripping supply. Mexico
City's water problems are well known. Rural areas are also suffering. For
example, in the agricultural state of Guanajuato, the water table is
falling by 2 meters or more a year. At the national level, 51 percent of
all the water extracted from underground is from aquifers that are being
overpumped.

Since the overpumping of aquifers is occurring in many countries more or
less simultaneously, the depletion of aquifers and the resulting harvest
cutbacks could come at roughly the same time. And the accelerating
depletion of aquifers means this day may come soon, creating potentially
unmanageable food scarcity.

While falling water tables are largely hidden, rivers that are drained dry
before they reach the sea are highly visible. Two rivers where this
phenomenon can be seen are the Colorado, the major river in the
southwestern United States, and the Yellow, the largest river in northern
China. Other large rivers that either run dry or are reduced to a mere
trickle during the dry season are the Nile, the lifeline of Egypt; the
Indus, which supplies most of Pakistan's irrigation water; and the Ganges
in India's densely populated Gangetic basin. Many smaller rivers have
disappeared entirely.

Since 1950, the number of large dams, those over 15 meters high, has
increased from 5,000 to 45,000. Each dam deprives a river of some of its
flow. Engineers like to say that dams built to generate electricity do not
take water from the river, only its energy, but this is not entirely true
since reservoirs increase evaporation. The annual loss of water from a
reservoir in arid or semiarid regions, where evaporation rates are high, is
typically equal to 10 percent of its storage capacity.

The Colorado River now rarely makes it to the sea. With the states of
Colorado, Utah, Arizona, Nevada, and, most important, California depending
heavily on the Colorado's water, the river is simply drained dry before it
reaches the Gulf of California. This excessive demand for water is
destroying the river's ecosystem, including its fisheries.
A similar situation exists in Central Asia. The Amu Darya--which, along
with the Syr Darya, feeds the Aral Sea--is diverted to irrigate the cotton
fields of Central Asia. In the late 1980s, water levels dropped so low that
the sea split in two. While recent efforts to revitalize the North Aral Sea
have raised the water level somewhat, the South Aral Sea will likely never
recover.

China's Yellow River, which flows some 4,000 kilometers through five
provinces before it reaches the Yellow Sea, has been under mounting
pressure for several decades. It first ran dry in 1972. Since 1985 it has
often failed to reach the sea, although better management and greater
reservoir capacity have facilitated year-round flow in recent years.
The Nile, site of another ancient civilization, now barely makes it to the
sea. Water analyst Sandra Postel, in Pillar of Sand, notes that before the
Aswan Dam was built, some 32 billion cubic meters of water reached the
Mediterranean each year. After the dam was completed, however, increasing
irrigation, evaporation, and other demands reduced its discharge to less
than 2 billion cubic meters.

Pakistan, like Egypt, is essentially a river-based civilization, heavily
dependent on the Indus. This river, originating in the Himalayas and
flowing westward to the Indian Ocean, not only provides surface water, it
also recharges aquifers that supply the irrigation wells dotting the
Pakistani countryside. In the face of growing water demand, it too is
starting to run dry in its lower reaches. Pakistan, with a population
projected to reach 305 million by 2050, is in trouble.

In Southeast Asia, the flow of the Mekong is being reduced by the dams
being built on its upper reaches by the Chinese. The downstream countries,
including Cambodia, Laos, Thailand, and Viet Nam--countries with 168
million people--complain about the reduced flow of the Mekong, but this has
done little to curb China's efforts to exploit the power and the water in
the river.

The same problem exists with the Tigris and Euphrates Rivers, which
originate in Turkey and flow through Syria and Iraq en route to the Persian
Gulf. This river system, the site of Sumer and other early civilizations,
is being overused. Large dams erected in Turkey and Iraq have reduced water
flow to the once "fertile crescent," helping to destroy more than 90
percent of the formerly vast wetlands that enriched the delta region.

In the river systems just mentioned, virtually all the water in the basin
is being used. Inevitably, if people upstream use more water, those
downstream will get less. As demands continue to grow, balancing water
demand and supply is imperative. Failure to do so means that water tables
will continue to fall, more rivers will run dry, and more lakes and
wetlands will disappear.

# # #

Adapted from Chapter 3, "Emerging Water Shortages" in Lester R. Brown, Plan
B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble (New
York: W.W. Norton & Company, 2006), available free of charge on-line at
www.earthpolicy.org/Books/PB2/index.htm

The next Plan B 2.0 Book Byte will cover Reducing Urban Water Use.

Additional data and information sources at www.earthpolicy.org

For information contact:

Media Contact:
Reah Janise Kauffman
Tel: (202) 496-9290 x 12
E-mail: rjk (at) earthpolicy.org

Research Contact:
Janet Larsen
Tel: (202) 496-9290 x 14
E-mail: jlarsen (at) earthpolicy.org

Earth Policy Institute
1350 Connecticut Ave. NW, Suite 403
Washington, DC 20036
Web: www.earthpolicy.org






  • [Livingontheland] WATER TABLES FALLING AND RIVERS RUNNING DRY, TradingPostPaul, 07/26/2007

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