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Below is posted an interesting Washington Post article that is global in scope. This article is not specifically about this General Mills case, but is a good overview of water as a vital world resource. --- ds
MANAGING OUR PRECIOUS LIQUID ASSET
By: Ralph A. Wurbs
As water supplies are constrained by rising demands, uneven distribution, and pollution, effective management must integrate diverse factors, including water quality and availability, hydroelectric power, flood control, and ecosystem conservation.
'All rivers flow into the sea, yet the sea is never full. To the place the streams come from, there they return again.' -- Ecclesiastes 1:7
Water is a vital resource for all forms of life. It is not surprising, therefore, that the earliest civilizations developed along major rivers, such as the Tigris, Euphrates, Nile, and Indus. Today, water is used for personal consumption and cleaning, irrigating crops, sustaining livestock, running our industries, and generating hydroelectric power. In addition, bodies of water are used for navigation and recreation. Thus, human health and socioeconomic wellbeing are fundamentally linked to adequate supplies of suitable quality water. Moreover, the vitality of natural ecosystems depends on our stewardship of this natural resource.
Planet Earth has enormous water reserves, an estimated 1.4 billion cubic kilometers (336 million cubic miles). About 97 percent of that amount is bound up in the oceans, however, and more than half the remainder is contained in glaciers and permanent snow cover. Thus, our primary sources of freshwater--groundwater aquifers and surface water in streams, rivers, and lakes-- account for less than 1.5 percent of global water. When one considers such factors as population growth, rapid industrial development, and continuing expansion of irrigated agriculture, it is clear that dramatically increasing demands are being placed on our limited water resources.
A related problem is water pollution. More than a billion people in the developing world lack safe drinking water. About half the world's population of six billion lacks access to adequate sanitation systems that would reduce exposure to waterborne pathogens. During the past century, construction of water-supply and wastewater-treatment facilities has dramatically reduced or eliminated such water-related diseases as typhoid fever, cholera, and dysentery in the developed nations. But in the developing world, an estimated 14,000 to 30,000 people-mostly children and the elderly-die every day from illnesses caused by consuming contaminated water or food.
From this perspective, the effective management of water resources is a crucial issue that must be tackled by government and private sectors throughout the world. Comprehensive water resources development and management must deal with flood damage reduction, drainage, erosion control, water-quality management, and environmental protection, as well as supply of water for human use.
Water resources and uses.
We obtain water from various sources:
-- (1) precipitation (rain, snow, and so on);
-- (2) fresh and saline surface water in streams, rivers, lakes, and reservoirs;
-- (3) fresh and saline groundwater; and
-- (4) seawater.In the United States, the total amount of water withdrawn in 1995 was about 553 cubic kilometers (133 cubic miles) obtained in the following approximate proportions: 66 percent was fresh surface water, 19 percent was freshwater from aquifers, and 15 percent was saline surface water. Saline water is used primarily as a coolant for industrial processes.
While water's uses are numerous, they may be generally classified as either consumptive or in-stream. When water is withdrawn from but not returned to a stream, lake, or aquifer, that process is referred to as consumptive use. A major example is agricultural irrigation. Instream uses of water include such activities as navigation and hydroelectric power generation.
In terms of total withdrawals, the largest proportion of water usage in the United States and many other countries is for cooling at thermal electric power plants. But after the water is circulated through the cooling system, most of it -now warmer- is returned to the river from where it was taken. Thus the amount of consumptive use is low.
By contrast, agricultural irrigation accounts for more consumptive use than any other sector. Irrigation is important because it increases the area of land that can be productively farmed, raises crop yields, stabilizes productivity, facilitates crop diversity, enhances farm income and employment, helps alleviate poverty, and contributes to regional development. But after irrigation, typical return flows range from virtually nil to about half the water withdrawn. In recent years, given the depletion of groundwater reserves and competition from cities, the use of water for irrigation has leveled off and even decreased in regions of the United States and elsewhere.
The hydrologic cycle is the central concept of the science of hydrology. As energy from the sun causes water to evaporate from both land and ocean surfaces, it also produces differential heating and movement of air masses. Water vapor is transported with the air masses and, under the right conditions, converted to precipitation.
From the perspective of a global water budget, precipitation on land surfaces provides more than adequate volumes of water for human and environmental needs. But the availability of water at the place and time of need is often hampered by the uneven distribution of precipitation, along with regional variations in surface water and groundwater resources. For instance, in Cheerapunji, India, annual rainfall often exceeds 10 meters (394 inches), but it all occurs during the short monsoon season. By contrast, regions of the Sahara Desert of Africa and the Atacama Desert of South America receive little or no rain in many years. When one considers the average global runoff, the Amazon River accounts for about 20 percent, while the entire continent of Australia contributes just 1 percent.
The construction of dams and water-conveyance facilities is generally governed by the characteristics of precipitation and demands of the population. For example, California's precipitation occurs mainly in the northern third of the state. Yet California's Central Valley, which receives essentially no precipitation during the growing season (May through September), is among the world's most productive agricultural regions as a result of the massive Central Valley and State Water Projects.
Problems with water supplies are also caused by contamination from natural sources, such as salinity, and from human activities, including municipal and industrial wastewater discharges, agricultural pesticides and fertilizers, disposal of solid and chemical wastes, and accidental spills of hazardous materials. Additional problems, occurring in regions of the United States and other countries, have been caused by decades of pumping water from aquifers at rates far exceeding natural recharge. The results have included watersupply depletion, salt-water encroachment, land subsidence, and greater reliance on surface water.
Development and management
Water is typically viewed as a public resource owned by the state and used by the people. Consequently, development and management of water resources have to be addressed on both the political level and technical plane.
The water-management community includes government entities (from the local to the international level); private water suppliers; engineering firms, construction companies, and equipment suppliers; industries that use water; environmental and other interest groups; and individual water users. The survival and prosperity of people everywhere depend on the ability of the complex water-management community to deal with the uneven geographic and temporal distribution of water resources and protect water from pollution.
The development and management of water resources include the following key dimensions: (1) facilities, (2) demand management, (3) desalination, (4) water allocation, and (5) comprehensive integrated water management. Let us consider each in turn.
Facilities.
Water supply facilities include wells, dams, storage reservoirs, pipelines and pump stations, water treatment plants, municipal distribution pipe networks, wastewater collection and treatment systems, and irrigation equipment. While the history of dam construction stretches at least 5,000 years into the past, most of today's dams were built between the 1930s and 1970s.
Over half the world's major dams are in China, with the United States placing a distant second. In terms of reservoirs, the United States has about 2,700 with storage capacities of at least 5,000 acre-feet (6,167,000 m^sup 3^) and thousands more that are smaller.
Dams, reservoirs, and associated structures play a key role in water supply and multiple-purpose water management. Most of the world's rivers are characterized by highly variable flows, with seasonal fluctuations aggravated by severe droughts and extreme floods. Reservoir storage is therefore necessary to regulate streamflow fluctuations and develop reliable water supplies.
In the United States and other nations where rivers are already highly regulated by dams and associated structures, building major dams is severely constrained by environmental and economic considerations. As a result, the construction era of the 1940s-1970s has been replaced by an emphasis on optimal operations, maintenance, and rehabilitation of existing facilities.
In various other countries, however, major projects are still being undertaken. Turkey's plan to develop the upper TigrisEuphrates River Basin during the 1980s-2000s includes a number of dams, hydroelectric power plants, and irrigation projects. The recently constructed Atatirk Dam on the Euphrates River is the largest in the system and fifth-largest in the world. In China, the Three Gorges Project on the Yangtze River is currently under construction, with completion scheduled for 2009. As the largest such project in the world, it will provide critically needed flood control, hydroelectric energy, and water supply. But it has generated enormous international controversy because of its massive size, serious environmental impacts, and displacement of over a million people.
Demand management.
Hydrologic, environmental, and economic conditions have led to heightened constraints on developing additional water supplies. Consequently, demand management-in the form of reducing waste and increasing efficiency of use-has become a major focus in the United States and elsewhere during the past 20 years.
Many cities waste much of their water through undetected pipeline leaks in aging water-distribution systems. Agricultural irrigation systems are notorious for losses due to seepage and evaporation. People use more water than they really need with water-inefficient landscaping and plumbing.
Such problems may be addressed by short- and longterm measures. Rationing of water during droughts is an emergency, short-term measure. Long-term measures include the use of water-efficient toilets, irrigation equipment, and landscaping, along with water-pricing incentives and efforts to detect and repair leaks.
Desalination.
Until recently, the high salt content of the oceans, inland seas, and certain segments of rivers and groundwater has severely restricted our ability to use their waters. Now, however, desalination technology is well established and readily available. Plants constructed from 1950 to 1980 are based on thermal distillation technology Since then, the technology has shifted to membrane processes known as reverse osmosis and electrodialysis. Even so, the primary limiting factor in using this approach is the cost relative to other water-supply options.
The world's total desalination plant capacity is distributed as follows: Saudi Arabia (30 percent), other Middle Eastern nations (30 percent), United States (10 percent), and over 100 other countries (30 percent). Plants in the Middle East primarily desalt seawater, using thermal distillation processes. In the United States, most plants employ membrane processes to treat brackish water (primarily groundwater), and most of the desalted water is used in the industrial sector.
The largest seawater desalination plant in the United States is currently being constructed to supply municipalities in the Tampa Bay region of Florida. This project is the result of growing demands and the lack of other, less-expensive alternatives. Due to overdrafting of the groundwater system, large areas of wetlands were being permanently damaged, lakes were drying up, and domestic wells for hundreds of families were being lost. The region's surface water is already totally committed. This type of scenario here and abroad will lead to increased use of desalination technology, but the challenge for future research and development is to continue to minimize cost.
Water allocation.
Water rights systems and interstate and international agreements allocating water resources are becoming increasingly important. Around the world, 261 river basins are shared by two or more countries, often leading to disputes and conflicts related to water supply. As a result, methods of cooperation and conflict mitigation need to be brought into play.
From the perspective of legal agreements, the Colorado River is perhaps the most regulated river in the world. Its waters are shared by Mexico and seven U.S. states. The allocation system is governed by a series of international and interstate negotiations, legislative acts, U.S. Supreme Court decisions, compacts, and treaties, collectively called the Law of the River.
The Texas Natural Resource Conservation Commission (TNRCC) currently administers a massive, surface-water allocation system in which 7,000 permits are held by river authorities, water districts, cities, private companies, and individual citizens. Moreover, this author is participating in the development and implementation of a statewide computer modeling system to support planning and water-rights regulatory activities. The system is being developed by the TNRCC, its partner agencies, and contractors pursuant to comprehensive water-management legislation enacted by the Texas legislature in 1997.
Integrated water management.
As noted above, water resources are tapped by multiple users for a variety of purposes. Effective water management therefore requires a systems approach, with comprehensive integration of a number of factors.
In particular, attention must be given to both water quality and quantity. Conjunctive management of groundwater and surface water resources is required, and the water needs to be appropriately allocated to the various users. Human needs must be balanced with ecosystem needs, economic development with environmental protection. Efforts have to be made toward optimizing the mix of demand management programs, new facilities construction, and improved operation and maintenance of existing facilities.
Furthermore, water-management approaches need to incorporate ongoing advances in water-supply technologies- such as desalination processes and efficient irrigation techniques-and the technologies chosen have to be appropriate for the particular country, region, and local culture. In addition, computer technology can be used to assist with data collection, analysis, systems modeling, and management.
As we look to the future, we can expect that the planning and management of water resources will move toward a holistic systems approach, which will coordinate and integrate various aspects, including water supply (for domestic, industrial, and agricultural needs), hydroelectric power, flood control, and ecosystem conservation. The reduction of waste and enhancement of efficiency will be increasingly stressed. And the decisionmaking process will have to consider the views of various people, including scientists, engineers, political officials, interest groups, and the public at large. The success of this approach will depend on how well the diverse factors are blended to make up the larger picture.
Water Usage - (Sidebar)
Basic domestic water supply and sanitation are fundamental to economic and social development and prevention of many diseases. According to the World Health Organization, World Bank, and U.S. Agency for International Development, the minimum amount of water required for drinking, cooking, cleaning, and sanitation ranges from 20 to 40 liters/day (5.3-10.6 gallons/day) per person. In the United States, the average per capita use of water for household purposes-including lawn watering and indoor use-is about 300 liters/day (80 gallons/day).
Total freshwater withdrawn from surface and groundwater sources worldwide in 1990 has been estimated to be about 3,000 cubic kilometers (km^sup 3^) [1 cubic kilometer = 0.24 cubic mile]. In the United States, withdrawals in 1995 amounted to about 469 km^sup 3^ of freshwater and 84 km^sup 3^ of saline water. The total amount (553 km^sup 3^) withdrawn was used for the following purposes: public supply (10 percent), rural domestic (2 percent), irrigation (34 percent), thermoelectric power cooling water (47 percent), and other industrial uses (7 percent).
Agricultural irrigation accounts for approximately 65 percent of total withdrawals worldwide and about 75 percent in developing countries. Only about 16 percent of cultivated land is irrigated, but it contributes roughly 36 percent of total food production. In 1940, 1970, and 1995, the land areas being irrigated globally were about 76, 242, and 256 million hectares, respectively. Fifty-four percent of the irrigated land is in four countries: China (20 percent), India (19 percent), United States (8 percent), and Pakistan (7 percent). -- R.A.W.
Water Salinity - (Sidebar)
Seawater is too saline for most uses. Though rivers, lakes, and aquifers consist of mostly freshwater, their salinity levels vary, occasionally surpassing that of seawater. In seawater, the concentration of total dissolved solids (TDS) averages about 35,000 milligrams/liter (mg/1), of which about 85 percent is common salt (sodium chloride). For freshwater, the upper limit of salt concentration is typically defined in the range of 500-1,000 mg/l, which is also the generally accepted quality standard for drinking water. If the TDS concentration falls between that of freshwater and seawater, the water is often referred to as brackish. For irrigation, tolerable TDS concentrations vary greatly, depending on the crop and mix of precipitation and supplemental irrigation, but they are generally much lower than 10,000 mg/l. -R.A.W.
Author note
Ralph A. Wurbs is professor and division head of the Environmental and Water Resources Engineering Division, Department of Civil Engineering, A&M University (TAMU). He worked in the water resources development program of the U.S. Army Corps of Engineers for nine years prior to joining the TAMU faculty in 1980. Since then, he has worked closely with local, state, federal, and international water management agencies through his research and consulting.
Additional Reading / Reference
Mahesh Chaturvedi, "Water for Food and Rural Development: Developing Countries," Water International, Journal of the International Water Resources Association, vol. 25, no. 1, 2000.
Mostafa Dolatyar and Tim Gray, Water Politics in the Middle East: A Context for Conflict or Cooperation? St. Martin's Press, New York, 2000.
Peter Gleick, The World's Water, 2000-2001: The Biennial Report on Freshwater Resources, Island Press, Washington, D.C., 2000.
Igor Shiklomanov, "Appraisal and Assessment of World Water Resources," Water International, Journal of the International Water Resources Association, vol. 25, no. 1, 2000.
Ralph blurbs, Modeling and Analysis of Reservoir System Operations, Prentice Hall, Upper Saddle River, N.J., 1996.
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The World & I
Volume 15, Issue 10
Copyright: Washington Times Corporation, Oct 2000
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