The Desiccation of the Aral Sea

The Death of the Aral Sea

Source: NASA Earth Observatory

In the slide set on water footprints we used last session, there was a photo of fishing boats stranded in a desert, at the bottom of what was once a large saline lake, the Aral Sea. Similar to the Great Salt Lake in Utah or the Dead Sea, the Aral sea filled the lowest part of an interior basin with not outlets to the world ocean, but it was far less salty than those two inland seas because it received a much larger annual input of fresh water. Prior to the mid 1970s, it was an important supplier of fish to nearby areas and to the larger Soviet Union. As the lake has dried, the remaining water has become more saline, and many fish species that once flourished have been extinguished, unable to survive in the Aral Sea's remaining and increasingly briny waters.

During the Soviet era there was a huge push to increase crop production in the Central Asian republics, and in particular the production of cotton. The streams flowing from the Hindu Kush mountain range far to the south and east, in particular the exotic rivers the Amy Darya and the Syr Darya, were diverted to irrigate cotton fields.Most of that water has been lost to evapotranspiration, and the rivers now bring virtually no additional fresh water into the Aral Sea. The pictures above show the desiccation of the Sea, almost entirely due to diversion of streams feeding into it. The USGS has a good website describing the desiccation along with some additional photos. 

Source: Wordpress.com

Related articles

• Aral Sea Shrinking, Focus of UN Visit to Central Asia (brainz.org)

The Nile's Waters: Conflict Between Egypt and Upstream Countries

Nile Valley

Source: Wikipedia Commons

The Nile is the classic example of an exotic river, rising in the highlands of Ethiopia and Central Africa then flowing through the deserts of Sudan and Egypt toward the Mediterranean.  In all of the countries through which the river and its tributaries flow there is a demand for water in excess of easily obtainable supplies from sources other than the river. Egypt, with a population rapidly approaching 80 million, is almost totally dependent on the Nile for water. Agriculture, industry, and domestic users draw water from the river, while the Aswan Dam uses the flow of the river to produce a large fraction of the country's electric energy. With growing populations, demand for higher standards of living, and climate change, demand for the Nile's water is all but certain to generate conflict in the not too distant future.

There is an excellent article on the conflict in today's (Sunday 26 November 2010) New York Times by Thanassis Cambanis, "Egypt and Thirsty Neighbors Are at Odds Over Nile." As I had not planned to discuss in detail the Nile, or much of any other water conflict in Africa, the article is particularly interesting as a supplement to the course, and I strongly recommend reading it.

Climate Change - Glacial Retreat

Receding glacier, Upper Joffre Lake, British Columbia, Canada

©EOP

Any discussion of world water supplies over the next century must take into account climate change or what is frequently termed "global warming." The scientific consensus has long since concluded that an increase in global temperatures of several degrees over the next century is nearly certain. The only remaining debate is on how great and how fast the warming will be. That is an important debate, but a little outside our purview. What is important is the impact of increased temperatures on world water supplies. The worst case scenarios for that issue are, to use a very bad pun, chilling indeed.

One early sign of the increase in global temperatures is the recession of glacial ice in the Northern Hemisphere and of mountain glaciers in tropical areas. Glaciers are an important part of the water supply equation as well as a key variable in world climates. Glacial ice acts as a natural reservoir helping to keep runoff in streams constant over the year and from wet years to dry ones. Many perennial streams would run dry for several months a year, and for several years in succession in a severe drought, were it not for glacial melt. Exotic rivers in North America and Asia depend on glacial melt for a sizable part of their flow. The disappearing glaciers of the Rockies are major suppliers of water to the great American Rivers of the west. As a sad example, Glacier National Park is rapidly loosing its namesake features and may have no glacial ice in less than a century. In the Coast Range of British Columbia many glaciers are rapidly melting, like the one feeding Joffre Lakes, one of the most stunning sets of glacial lakes in the world. Not long ago that glacier reached the water of the upper lake. Now the melting glacier is more than 100 meters higher than the lake surface.

Highland glaciers are found in several tropical areas where there is clear evidence of rapid melting. Much of highland tropical South America, including populated parts of Ecuador, Peru, and Bolivia, has permanent streams only because of the water released when glaciers in the high mountains melt. Urban water supplies and irrigation are dependent on that water, for the region is characterized by a division between a wet season and a dry season. There is disturbing evidence of glacial retreat in that area as there is in New Guinea. Kilimanjaro has one of the few glaciers in Africa, and the debate is not if the glacier will disappear but when with the best guess being in about 10 years.

Outside the tropics there is rapid glacial melting in the Himalaya. An unfortunate error in a major climate report concerning glacial melting in the Himalayas has been used as "evidence" by those opposed to the idea of global warming, persons who believe, against all evidence, that global warming is a myth being perpetrated by greedy scientists to get more research funding. The elected Attorney General of the antediluvian Commonwealth of ole Virginny is among those anti-scientific Luddites. Almost all of them are slavishly repeating the propaganda generated by the coal and petroleum industry, an industry which does not want to have any limits placed on coal and oil consumption, the major source of the most important greenhouse gas carbon dioxide. It is clear the glaciers are less important as sources of water in major Asian rivers than the report indicated, and the rate of melting is slower than the alarmist information in the report. But glacial melt in the world's highest mountains is crucial to the flow of the Indus and significant in several other streams. The retreat of those glaciers portends catastrophe in an area where water supplies are already seen as inadequate to meet increasing demands.

Related articles by Zemanta

• Melting ice (news.bbc.co.uk)
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Hidrovia and Water in South America I

Evening view of the junction of Rio Iguazú (right) with Río Paraná from Argentinian Bank, Brasil to right and Paraguay left (Ciudad del Este high rises in distant background), 2007

©EOP

Water transportation is not going to be a topic for discussion in the course, nor will wildlife conservation issues be emphasized, but they are both related to human water use. At the moment I am also preparing to lead a course on the Southern Cone of South America where the Paraná and its tributaries are important for transportation, for wildlife, and for water supply. The Paraná is navigable for small ocean going ships upstream as far as the Argentinian city of Corrientes, and its branches can be navigated further upstream into Brasil and Paraguay by shallower draft vessels. Landlocked Paraguay has long been dependent on the river for transportation access, and inland Argentinian cities including Corrientes and Rosario are also dependent on river transportation for access to world markets. More recently the commodity production boom in Brasil has greatly increased transportation demand as that country extends its ecumene into the interior.

The Rio de la Plata river system, including the Paraná its largest single stream, is one of the world's great river systems with a flow second only to the Amazon in the Americas.Its flow comes mainly from rainfall in the humid zones of subtropical and tropical southern Brasil, though it is not an exotic river for there is an excess of precipitation over evapo-transpiration in normal years along much of its length. Several huge hydroelectric projects on the Paraná provide much of the power used by Brasil, Argentina and Paraguay and have converted large segments of its upstream basin into slackwater lakes. As yet the Paraguay, a major tributary to the Paraná and navigable in some years into Brasil, has not been dammed.

A problem for navigation is the uneven flow across the year and from year to year. Hidrovia is a project to even out the flow of the Parana by manipulating water in the Pantanal, the immense marshland on the boundary between Brasil and Bolivia. While the project is apparently moribund at the moment, it is likely to be revived. The problem is the Pantanal is one of the world's great wetlands, and one of the largest still largely untouched by human activity. Known for the diversity and density of its wildlife, conservationists argue that it should be preserved in its current state.

In future postings I shall examine Hidrovia in greater detail and look at other aspects of water availability and use in South America.

Columbia Basin Project I

Grand Coulée Dam, 2005, © EOP

The Tennessee Valley Authority (TVA) is perhaps the most famous water project in the United States, but during the Depression years and the New Deal of the 1930s, several huge water projects were initiated or expanded under the control of the Bureau of Reclamation. As today is my birthday, I thought I might indulge myself and write a little about the one I know the best and with which my family has had close connections, the Columbia Basin Project an irrigation and hydroelectric scheme using the huge flow of the Columbia River, an exotic river flowing across the northern and central parts of Washington State. Its centerpiece is Grand Coulée Dam (shown above and again at the end of this posting) for many years the largest hydroelectric facility on earth and still the largest in the United States.

In the rain shadow of the Cascade Mountains, the Great Columbia Plain (pace Donald Meinig) was a vast steppe or high desert atop one of the more geologically interesting bits of the United States, the Columbia basalt flow. In the early years of settlement, after the Northern Pacific Crossed that steppe at a diagonal with its route from Spokane to Pasco, there was some settlement and dryland agriculture, wheat farming and ranching, but the area was lightly populated. Only water was necessary for an agricultural bonanza, it was claimed. The Columbia Basin Project, long a goal of Chambers of Commerce and other civic booster groups in the central and eastern part of Washington State, was intended to provide that water in a scheme similar, though not identical, to the TVA, with the dual goals of long term regional development and stimulus spending in a depression.

A make-work project to employ some of the large number of unemployed, Grand Coulée Dam was begun in 1933 and completed 9 years later, one of the largest engineering projects ever undertaken up to that time, though in publicity it was somewhat overshadowed by construction of Boulder Dam in a dramatic canyon of the Colorado River ongoing at the same time. When it was being built there was no clear idea of how or where the vast amount of electricity Grand Coulée Dam could produce would be consumed, though sale of electricity was to help fund the project and pay for the more than 1000 km of irrigation canals and drainage ditches the project would require if carried to completion. World War II defense industries, including Boeing's Seattle plants, rendered the issue of where to sell the electricity moot until 1945, after which a series of aluminum smelters purchased much of the electricity produced.

Meanwhile the irrigation scheme was constructed, albeit at a slower pace. Several of the major canals and drainage works were not completed until the 1960s and 1970s. Irrigation has transformed the sere steppe into an immense green expanse, at least in Spring and early summer. Areas where the distance between trees was measured in kilometers in the 1930s or even as late as the 1960s, have become orchards and vinyards. Dryland wheat or barley has been replaced by water intensive field crops including corn (maize). Sounds wonderful, the bonanza promised by early boosters, but the change has come at some environmental costs to be examined in a later posting.

Grand Coulée Dam, 2005, © EOP

International Water Wars?

Indus Valley, Source: NASA Earth Observatory

A potential for water war between India and Pakistan has long been feared by outside observers. An article in today's right-wing Washington Post suggests that possibility is growing greater. The partition of the Raj in the waning hours of British control creating the predominantly Muslim Pakistan and the mostly Hindu India (though India also has a huge Muslim population making it one of the largest Muslim nations) is usually discussed in religious terms. In the bloody aftermath of the partition, Kashmir with a largely Muslim population, remained a major point of contention between the two mostly unfriendly states with Hindu India controlling the crucial eastern section. There have been almost ceaseless and frequently bloody confrontations between Hindus and Muslims and between India and Pakistan, with China later added to the toxic mix, but more frequently than not, the conflict has been discussed in religious and political terms.

In fact the conflict is also over water, for India and China control the crucial headwaters where the Indus River gets the bulk of its flow from melting snowfall and glaciers in the Himalaya. The Indus is a classic example of what the geographer Edward Ullman many years ago termed an exotic river, a stream that after gathering significant flow in a humid zone passes for much of its length through arid areas where rates of evaporation exceed rainfall and little if any water is added to the flow. In the arid zone the river becomes the major, if not the only, source of water and allows human occupation.

One of the oldest areas of agriculture and urban settlement on earth, the Indus Valley, now largely contained within Pakistan, has an almost total dependence on the flow of the Indus. The larger towns and cities use river water for urban and industrial purposes, and agriculture would be impossible were not for withdrawals of Indus water. The critical headwaters, most of the primary sources of the Indus's flow, are controlled by India (and to a much smaller extent by China). India has the ability, and the facilities, to cut off the flow into Pakistan. There is ample demand for the water within India, for its western portions are nearly as dry as most of Pakistan.

A water blockade with most or all of the flows cut off by India would in very short order lead to a collapse of agriculture in Pakistan and intense privation. It could also lead to open warfare between the nuclear armed states. More on this in later postings.