Dictionary:

water

  (wô'tər, wŏt'ər)

1. A clear, colorless, odorless, and tasteless liquid, H₂O, essential for most plant and animal life and the most widely used of all solvents. Freezing point 0°C (32°F); boiling point 100°C (212°F); specific gravity (4°C) 1.0000; weight per gallon (15°C) 8.338 pounds (3.782 kilograms).
2. 1. Any of various forms of water: waste water.
   2. Naturally occurring mineral water, as at a spa. Often used in the plural.
3. 1. A body of water such as a sea, lake, river, or stream.
   2. waters A particular stretch of sea or ocean, especially that of a state or country: escorted out of British waters.
4. 1. A supply of water: had to turn off the water while repairing the broken drain.
   2. A water supply system.
5. 1. Any of the fluids normally secreted from the body, such as urine, perspiration, tears, or saliva.
   2. A fluid present in a body part in abnormal quantities as a result of injury or disease: water on the knee.
   3. The fluid surrounding a fetus in the uterus; amniotic fluid.
6. An aqueous solution of a substance, especially a gas: ammonia water.
7. A wavy finish or sheen, as of a fabric or metal.
8. 1. The valuation of the assets of a business firm beyond their real value.
   2. Stock issued in excess of paid-in capital.
9. 1. The transparency and luster of a gem.
   2. A level of excellence.

1. To pour or sprinkle water on; make wet: watered the garden.
2. 1. To give drinking water to.
   2. To lead (an animal) to drinking water.
3. To dilute or weaken by adding water: a bar serving whiskey that had been watered.
4. To give a sheen to the surface of (silk, linen, or metal).
5. To increase (the number of shares of stock) without increasing the value of the assets represented.
6. To irrigate (land).

1. To produce or discharge fluid, as from the eyes.
2. To salivate in anticipation of food: The wonderful aroma from the kitchen makes my mouth water.
3. To take on a supply of water, as a ship.
4. To drink water, as an animal.

water down

1. To reduce the strength or effectiveness of: “It seemed clear by late autumn that the ban would be significantly watered down or removed altogether before the trade bill became law” (George R. Packard).

above water

1. Out of difficulty or trouble.

1. A past occurrence, especially something unfortunate, that cannot be undone or rectified: All that is now just water under the bridge.

[Middle English, from Old English wæter.]

WORD HISTORY   Water is wet, even etymologically. The Indo-European root of water is *wed–, “wet.” This root could appear in several guises—with the vowel e, as here, or as *wod–, or with no vowel between the w and d, yielding *ud–. All three forms of the root appear in English either in native or in borrowed words. From a form with a long e, *wēd–, which by Grimm's Law became *wēt– in Germanic, we have Old English wǣt, “wet,” which became modern English wet. The form *wod–, in a suffixed form *wod-ōr, became *watar in Germanic and eventually water in modern English. From the form *ud– the Greeks got their word for water, hud-ōr, the source of our prefix hydro– and related words like hydrant. The suffixes *–rā and *–ros added to the form *ud– yielded the Greek word hudrā, “water snake” (borrowed into English as hydra), and the Germanic word *otraz, the source of our word otter, the water animal.

Background

Water is a chemical compound needed by most plants and animals on Earth in order to sustain life. Pure water is a tasteless, odorless, transparent liquid. In small amounts it is colorless, but it takes on a bluish tint in larger amounts. Water is an excellent solvent and as a result it usually contains a wide variety of dissolved minerals and other chemicals. It can also carry and support bacteria. Most of the water distributed through municipal water systems is treated to remove harmful substances. Some bottled waters undergo even further treatment to remove almost all impurities. The English word water is derived from the German word wasser, which in turn is derived from an ancient Indo-European word meaning to wet or wash.

The controlled use of water dates to at least 8,000 B.C. when farmers in Egypt and parts of Asia trapped floodwaters for crop irrigation. The concept of using irrigation canals to bring water to crops, rather than waiting for a flood, was first developed about 2,000 B.C. in Egypt and Peru. By about 1,000 B.C., the city of Karcho, in what is now Jordan, built two aqueducts to bring an adequate supply of water for the city's population. This is the first recorded instance of a planned municipal water supply.

Early water treatment was surprisingly advanced, although rarely practiced. An ancient Sanskrit manuscript, from what is now India, advises that drinking water should be kept in copper vessels, exposed to sunlight, and filtered through charcoal. Ancient Egyptian inscriptions give similar advice. Many of these methods are still used today. In about 400 B.C., the Greek medical practitioner Hippocrates suggested that water should be boiled and strained through a piece of cloth. Despite these early references, most people drank untreated water from flowing streams or subterranean wells. As long as there were no sources of contamination nearby, this was a satisfactory solution.

As the population of Europe and other parts of the civilized world grew, their sources of water became increasingly contaminated. In many cities, the rivers that served as the primary sources of drinking water were so badly contaminated with sewage that they resembled open cesspools. Cholera, typhoid, and many other water-borne diseases took their toll. In 1800, William Cruikshank of England demonstrated that small doses of chlorine would kill germs in water. By the 1890s, several municipalities found that slowly filtering water through beds of sand could also significantly reduce the incidence of disease. The public outcry for safe drinking water reached such a crescendo that by the early 1900s most major cities in the United States had installed some sort of water treatment system.

Even with water treatment, water contamination remained a serious concern as an increasing amount of industrial wastes poured into the nation's rivers and lakes. As the adverse health effects of lead, arsenic, pesticides, and other chemicals became known, the United States federal government was obliged to pass the Water Pollution Control Act of 1948. This was the first comprehensive legislation to define and regulate water quality. It was followed by a series of increasingly tougher requirements, culminating in the current Environmental Protection Agency (EPA) water quality standards. In addition to the federal standards, most states have their own water quality laws, and some state laws are more stringent than those specified by the EPA.

Types of Water

Pure water is an almost non-existent entity. Most water contains varying amounts of dissolved minerals and salts, plus an abundance of suspended particles such as silt and microscopic organic material. Different types of water are classified by the presence or absence of these impurities.

Tap water, or municipal water, has under-gone a series of treatments to kill harmful bacteria, remove sediments, and eliminate objectionable odors. It may also have had one or more chemicals added for a variety of reasons.

Hard water contains high amounts of calcium and magnesium salts. This causes soap to form curds. Hard water is further divided into temporarily hard water and permanently hard water. Temporarily hard water contains bicarbonates of calcium and/or magnesium, which react to form a hard substance called scale when the water is heated. Scale can clog hot water heaters and pipes and leave deposits on cooking utensils. Permanently hard water contains sulphates, chlorides, or nitrates of calcium and/or magnesium, which are not affected by heating. Soft water contains relatively low amounts of calcium and magnesium salts, although the definition of "low" varies. The term "softened water" refers to hard water that has had enough salts chemically removed to avoid forming soap curds. It is high in sodium chloride.

If water contains a large quantity of dissolved minerals, it is called mineral water. Mineral waters can be divided into five main classes: saline, alkaline, ferrunginous, sulphurous, and potable. Saline water has a high level of sodium or magnesium sulphate or sodium chloride. Alkaline water has a high concentration of salts which give it a pH in the range of about 7.2-9.5, where a pH of 7 is neutral and a pH of 14 is highly alkaline. Ferrungious water is rich in iron, which gives it a rusty color. Sulphurous water is rich in sulphur compounds and is distinguished by its rotten egg smell. Potable water has a mineral content of less than 500 parts per million and is most commonly bottled and sold as a specialty drinking water.

Carbonated water, soda water, and sparkling water all contain dissolved carbon dioxide. This may occur naturally where limestone or other carbonate rocks are present, or the carbon dioxide may be added artificially under pressure.

Spring water and artesian water are distinguished only by the fact that they flow from the ground naturally without the aid of drilling or pumping. Otherwise, there is nothing that makes them different than water from other sources.

Distilled water has been purified by an evaporation-condensation process that removes most, but not all, impurities. Deionized water has been purified by an ion-exchange process, which removes both positive ions, such as calcium and sodium, and negative ions, such as chlorides and bicarbonates. It is sometimes called de-mineralized water. Purified water is municipal water that has undergone carbon filtration, distillation, deionization, reverse osmosis, ultraviolet sterilization, or some combination of these processes to remove almost all minerals and chemical elements, both good and bad.

Raw Materials

A water molecule consists of two atoms of hydrogen bonded to one atom of oxygen. The chemical symbol is H₂O. Water usually also contains a wide range of organic and inorganic materials in solution or suspension.

In the process of treating water for use in a municipal system, several chemicals may be added. These include disinfectants like chlorine, chloramine, or ozone; coagulantants like aluminum sulfate, ferric chloride, and various organic polymers; acidity neutralizers like caustic soda or lime; and chemicals to help prevent tooth decay in the form of various fluoride compounds.

The Treatment Process

The specific water treatment process depends on the intended application. Some water, such the water used to irrigate crops, receives no treatment. Other water, such as the water used to make pharmaceuticals, is highly purified.

Here is a typical series of operations used to treat municipal water for distribution to homes and businesses.

Collecting

• Most municipal water comes from two sources: ground water and surface water. Most ground water is tapped by drilling wells into the underground water-bearing layer called the aquifer. Some ground water rises naturally in the form of springs. Surface water is tapped by impounding rivers behind dams. The surrounding area that drains into the rivers is called the watershed. In many cases, access to and use of the watershed is limited to prevent contamination of the runoff water.
• From the well or dam, the water is carried to the water treatment plant in open canals or closed pipes. In some cases, the water supply is close to the municipality. In other cases, the water has to be transported many hundreds of miles (km) to reach its destination. Sometimes the water is stored in intermediate reservoirs along the way to ensure that there will always be an adequate supply available to meet a city's fluctuating needs.

Disinfecting

• In some water treatment plants, the water is initially disinfected by contact with ozone-rich air in a series of chambers. This step is used by most plants in Europe, but only a few plants in the United States. Ozone (03) is formed by passing compressed air through a high-voltage electric arc. This causes some of the oxygen (02) molecules in the air to split in half and reattach themselves to other oxygen molecules to form ozone. Ozone effectively kills most germs and also destroys compounds, which cause unpleasant tastes and odors. It has a relatively short life, however, and does not remain in the water to protect it during storage and distribution. For this reason, a small dose of chlorine or chloramine is added to the water at the end of the treatment process.

Coagulating/flocculating

• The water then passes through a flash mixer where chemicals known as coagulants are rapidly mixed with the water. The coagulants alter the electric charge around any suspended particles in the water and make them attract each other and clump together, or coagulate.
• The water moves slowly through a series of chambers where it is gently mixed by the swirling flow. As the water mixes, the charged particles continue to bump into each other and form even larger particles called flocs.

Settling

• The water flows into a settling basin or tank where the heavy flocs sink to the bottom. Some settling basins have two levels to double their capacity. The material that settles to the bottom is vacuumed out of the basin with a device like a pool vacuum and is deposited in a solids holding basin. The trapped material from the filter (step 7) is also added to the solids holding basin. These combined materials are sent through a gravity thickener and then a press where most of the water is squeezed out. The remaining solids are loaded into trucks and transported to a landfill for disposal.

Filtering

• The partially cleaned water passes through several layers of sand and pulverized coal, which trap any very small particles that remain in the water. Some harmful organisms are also trapped this way in those water treatment plants that do not use ozone as an initial disinfectant. The filter layers are back-flushed periodically to remove the trapped material.

Adsorpting

• In some plants, the water is passed through a bed of activated charcoal granules. Chemical contaminants in the water stick to the surface of the charcoal in a process known as carbon adsorption.

Aerating

• In some areas where the water contains undesirable amounts of iron and manganese or certain dissolved gases, the water is sprayed into the air from large basins to aerate it. When the water mixes with the air, it picks up oxygen, which causes some of the contaminants to settle out. Other contaminants are removed by evaporation.

Fluoridating

• In some water treatment plants, a fluoes ride compound is added to the water to help prevent tooth decay. Fluoride occurs naturally in some water supplies and additional amounts are not required. In the past, fluoridation has been a hotly debated subject, and not every municipality adds fluoride to their water.

Neutralizing

• Other chemicals may be added to the water to help reduce corrosion in pipes and plumbing fixtures. This is done by adding controlled amounts of certain chemicals to adjust the pH factor to a neutral level.

Distributing

• As the water leaves the treatment plant, it receives a small dose of chlorine or chloramine to kill any harmful bacteria that may have found their way into the distribution system. If the plant does not use ozone as an initial disinfectant, a larger amount of chlorine or chloramine is added to the water.
• After the water leaves the plant, it is usually stored in covered tanks or reservoirs to protect it from contamination. In some areas, these storage facilities are located at a higher elevation than the surrounding terrain, and the water is pumped up into the tank or reservoir. This elevated storage position provides the pressure necessary for adequate flow through the water mains and pipes within the city. In other cases, the water is stored in ground-level facilities, and the pressure is supplied by electric pumps that run on demand.

Quality Control

The federal and state water quality standards set maximum contamination levels for more than 90 organic, inorganic, microbiological, and radioactive materials that may be found in water. These standards are further divided into primary standards, which cover materials that may be harmful to humans, and secondary standards, which cover materials and properties that may affect aesthetic qualities such as taste, odor, and appearance. A typical water district may perform more than 50,000 chemical and bacteriological analyses of the water supply each year to ensure the standards are being met.

The Future

The public's concern over safe drinking water is expected to result in even more stringent water quality standards in the future. Ironically, one of the most recent concerns is not about outside contamination, but about the effects of one of the substances commonly used to disinfect water—chlorine. Studies within the last 30 years have shown that chlorine forms certain compounds with the organic materials found in water. The most common compounds are called trihalomethanes, or THMs, which have a 1-in-10,000 risk of causing cancer when ingested or inhaled over a long period. One alternative to using chlorine is chloramine, which is a combination of ammonia and chlorine that does not form THMs as readily. Many water treatment plants have already switched to chloramine. Other alternative disinfectants include ozone, ultraviolet light, chlorine dioxide, and a hybrid of ozone and hydrogen peroxide called peroxone.

Where to Learn More

Books

von Wiesenberger, Arthur. H₂O: The Guide to Quality Bottled Water. Woodbridge Press, 1988.

Water Quality Standards Handbook, 2nd edition. United States Environmental Protection Agency, 1994.

Periodicals

Arrandale, T. "A Guide to Clean Water." Governing (December 1995): 57-60.

Wasik, J. F. "How Safe is Your Water?" Consumers Digest (May/June 1996): 63-69.

Other

"Alameda County Water District Water Treatment Facility." Pamphlet. Alameda County Water District, 1993.

"Layperson's Guide to Drinking Water." Pamphlet. Water Education Foundation, 1995.

Los Angeles Department of Water and Power. http://www.ladwp.com.

[Article by: Chris Cavette]

Water is the most abundant chemical in the body, making up roughly 60 per cent of body weight. It is an essential nutrient although it provides no energy. It has excellent solvent properties enabling it to act as a transport medium for many chemicals. It is involved in many chemical reactions including digestion of food.

Evaporation of water as sweat is essential for cooling the body. However, failure to replace water losses results in dehydration. This can adversely affect physical performance even if relatively slight. Each 1 per cent loss of water results in a 2 per cent reduction in aerobic capacity. Water loss causes the heart rate to spiral upwards. A loss of 6 per cent of total body water is serious; and loss of more than 10 per cent can be fatal. The amount of water an individual drinks depends on water losses (see water replacement).

Hardness of water varies with geographical location. There is statistical evidence that heart disease is more common in areas with soft drinking water than in those with hard water. However, the link between type of water and heart disease is not proven.

The quality of drinking water varies. In most areas of the USA and the UK, tap water is safe, but in some areas it can become contaminated with bacteria, nitrates, or other pollutants. Some people drink bottled water because they are worried about pollutants, but others drink it because they prefer the taste, or believe that bottled water has health-giving properties. Ironically, bottled water is not always healthy. Some contain high levels of sodium and the same pollutants as tap water.

verb

1. To lessen the strength of by or as if by admixture. attenuate, cut, dilute, thin, weaken. See strong/weak.
2. To fill with tears: tear². See dry/wet.

Idioms beginning with water:
waterfront
waterworks
water down
water over the dam

See also above water; backwater; blood is thicker than water; blow out (of the water); come on in (the water's fine); dead in the water; fish in troubled waters; fish out of water; head above water; hell or high water; high-water mark; hold water; hot water; in deep (water); keep one's head (above water); like water off a duck's back; make one's mouth water; muddy the waters; of the first water; pour cold water on; pour oil on troubled waters; still waters run deep; take to (like a duck to water); throw out the baby with the bath water; tread water; you can lead a horse to water.

Definition: dampen; put water in
Antonyms: dehydrate, dry

A tasteless, odorless, colorless compound made of hydrogen and oxygen (H₂O), which freezes at 32° F (0° C) and boils at 212° F (100° C). The autonomic nervous system regulates water balance in the body.

n. (waters) an area of sea regarded as under the jurisdiction of a particular country: Japanese coastal waters.

take a fresh supply of water on board (a ship or steam train): the ship was watered and fresh livestock taken aboard.

by water using a ship or boat for travel or transport:

make water (of a ship or boat) take in water through a leak.

See the Introduction, Abbreviations and Pronunciation for further details.

For more information on water, visit Britannica.com.

Classical ornament such as the Vitruvian scroll may represent waves, while the Ancient Egyptians used parallel zig-zag lines to suggest water. Sculpted representations of flowing water are associated with grottoes, nymphaea, etc., and are found in rustication, often frozen, or congelated.

A clear, colourless, tasteless liquid composed of hydrogen and oxygen. Despite having no value as an energy source, water is our most important nutrient. It constitutes about 60% of the total adult body weight. Losses of as little as 9-10% of body weight can be fatal. Smaller losses result in a significant impairment of physical performance. The speed of distance runners, for example, is reduced by about 2% for each per cent of body weight lost by dehydration. Among its important functions during exercise, water provides the main transport medium for nutrients and respiratory gases, regulates body temperature, and maintains blood pressure for efficient cardiovascular function.

Because of its scarcity, water plays a central role in Middle Eastern politics and society.

Nowhere in the world is water more important than in the Middle East and North Africa. In no other region do so many people strive so hard for economic growth on the basis of so little water: here is found 5 percent of the world's population but only 1 percent of its fresh water. Of the ten nations with the least water per capita, six are in this region. No wonder that both Jewish and Muslim scriptures are full of references to water.

Role of Climate

The more heavily populated parts of the Middle East are semiarid, with rainfall of 10 to 29 inches (250 to 750 mm) per year. However, low rainfall is less of a problem than variability in rainfall. The great bulk of the rain falls in four winter months, with none falling during the rest of the year. Rainfall also changes rapidly with distance, from more than 20 inches (500 mm) on the coast of Lebanon to 8 inches (200 mm) in the Biqa, only an hour away by road but across the Lebanon mountains.

Seasonal and spatial variations in rainfall are sharp but predictable. What makes planning difficult is the sharp variation from one year to the next. Reliable flow in the rivers (the flow that can be expected nine years out of ten) is only 10 percent of the average. In northern latitudes, water planning can be built around statistical averages; here, it must be built around extremes.

This already difficult water situation will likely get worse. Population growth rates are high, and most climate change models suggest higher temperatures, lower rainfall, and more frequent droughts for the region.

Role of History

Development in the Middle East and North Africa has always been more dependent on water than on any other resource, including oil. By the fourth millennium B.C.E., the Sumerians had built a paradise in what is now Iraq through intricate canals for irrigating crops; two millennia later it had largely collapsed because of salinization of the soil. Ancient cities, such as Palmyra in Syria, were possible only because of carefully engineered tunnels, called qanats (foggaras in Iran), to bring water from springs tens of kilometers away.

Over the years, the peoples of the Middle East have made water a preoccupation, and each nation has a central agency, typically a full ministry, to deal with water. Many of the principles for good water management were worked out in the Middle East - although just as often they were ignored for political, financial, or social reasons.

Water Sources

The Middle East includes two of the mightiest river systems in the world. The Nile has two main branches: The White Nile originates in Uganda, and the larger Blue Nile (together with the Atbara) originates in Ethiopia; they join near Khartoum and flow northward through Egypt to the Mediterranean. The Tigris and Euphrates both originate in Turkey and flow south-southeastward through Syria and Iraq before joining and flowing into the Persian Gulf via the Shatt al-Arab, at the Iranian border.

The region also includes numerous mediumsized rivers, such as the Jordan, which flows from three springs through the Sea of Galilee (one of the few natural lakes in the region) and into the Dead Sea, 415 meters below sea level. Only Turkey has an
abundance of river water, but its big rivers are only found in the eastern part of the nation. Finally, there are small coastal rivers (many of them ephemeral), and a few major wetlands, such as the marshlands in southern Iraq and the Sudd swamp in southern Sudan.

The construction of new dams and pipelines to deliver water from major rivers in the Middle East will cost two or three times as much per unit of water as current supplies, and if construction occurs in upstream countries, such as Ethiopia and Turkey, it will reduce flows downstream. Therefore, the region will increasingly shift toward the use of underground water, which has the great advantage of not evaporating. (Lakes and reservoirs in the region lose meters of water per year to evaporation.)

Historically, underground water was tapped by shallow wells dug in unconsolidated materials to get small flows of water. Today, much larger volumes of water are extracted from wells drilled tens to hundreds of meters into aquifers, which are rock layers with pores that contain water. Renewable aquifers are replenished (generally slowly) by rainfall; non-renewable, or fossil, aquifers contain water trapped in sediments laid down millions of years ago.

Just more than 10 percent of the water supply for the region comes from aquifers, but in Israel and Jordan the share approaches 50 percent, and in Kuwait and parts of the Arabian Peninsula it approaches 100 percent (apart from desalination). Libya's Great Man-Made River pumps water from fossil aquifers in the south of the country and moves it 930 miles (1,500 km) to farms and cities in the north.

The third most important source of water in the Middle East is recycled sewage, which is treated and reused, mainly for irrigation. Despite common
belief (shared by both Muslims and non-Muslims), there is no objection in Islamic law to the reuse of sewer water provided it is properly treated.

More than half of the world's desalination capacity is found in the region, mainly in the oil-producing nations of the Arabian peninsula with lots of by-product natural gas that was formerly flared. (Desalination is an energy-intensive process.) Costs for desalination have fallen to a level that makes it feasible as a source of potable water but still too expensive for irrigation.

Other sources of water are individually small but collectively provide sizable amounts of water. Water harvesting gathers rain that falls over a wide area and directs it to one field through small channels and micro-barrages. The technique can allow crops in areas where rainfall is only 4 inches (100 mm) per year. Rainwater is also collected from rooftops and stored in cisterns. If handled carefully, rooftop water can be used for drinking.

Uses of Water

By far the largest share of water in the region goes to agriculture - as much as 90 percent of total water use in some countries, and 60 percent in the more industrialized countries.

Drinking requires only a relatively small volume of water, but it must meet higher standards than that used for irrigation. Thirty liters of potable water per person-day is generally regarded as the minimum for drinking, cooking, and washing.

Industrial water use is low. Food and beverage processing are the largest industrial consumers. More is withdrawn for cooling but most of this water is recycled or returned to the watercourse.

A hidden but critical amount of water must be left in place to support fisheries and hydropower, as well as to protect habitat. This use is typically neglected by governments when they drain swamps, canalize rivers, or extend land. As a result, not only has the environment been degraded, but fish catches have declined and the salinity of groundwater has increased.

Problems

The nations of the Middle East all face three overlapping sources of stress in their water management: 1) quantity, which has been a source of stress since history began; 2) quality, which is a newer stress but increasingly important; and 3) equity, which occurs when the same water is subject to competing demands.

Quantity.Iran, Iraq, Lebanon, Sudan, Syria, and Turkey are fairly well endowed with water, with more than 1 million cubic meters (Mcm) per capita; Algeria, Egypt, Israel, Morocco, and Palestine form a middle group; and Jordan, Libya, Tunisia, and the countries of the Arabian Peninsula are least well endowed, with less than 500 Mcm per capita. However, water availability is declining in every nation, which means that current patterns of water use are not sustainable. Some projections for the Jordan River basin suggest that by 2025 household and industrial uses will require all the fresh water, leaving none for farmers. Most nations are also drawing down their renewable aquifers and mining fossil ones. Some have annual water deficits of several thousand Mcm.

Water quantity problems in the region can be resolved in small part by exploiting additional

sources of supply but in much larger part by better use of the water that is already available. People in the region use less water than those elsewhere in the world, but as a result of poor management and misguided economic policies conservation here (as in most other parts of the world) remains far short of its potential. Many nations lose half the water put into municipal systems to leaks, and they typically deliver piped water at low (or no) price. Cost-effective savings of 25 to 50 percent are possible in most uses.

Moreover, every country in the region provides water to farmers at highly subsidized prices. Under the influence of higher prices, Israeli scientists developed drip irrigation systems that have cut water use per hectare by 40 percent. However, drip irrigation is expensive and not appropriate for all crops. Lower-cost sprinkler systems, used at night to minimize evaporation, can also increase irrigation efficiency, as can irrigating only at times critical to plant growth.

Most analysts find that water is tens of times more valuable in industrial or household uses than in agriculture. Therefore, crops grown in the region will gradually be replaced by imports. It takes roughly a thousand tons of water to produce one ton of wheat. Using that ratio, Middle Eastern nations already import grains with a virtual water content equal to the flow of the Nile.

Quality.Much of the limited fresh water in the Middle East is polluted from growing volumes of human, industrial, and agricultural waste. Three problems stand out: 1) Overpumping of wells causes a decline in the water table - by as much as a meter a year in some areas. This decline adds to pumping costs and permits lower-quality water (or, if near the coast, seawater) to flow inward and contaminate the aquifer. The only way to avoid the problem is to match pumping rates to inflow. 2) Agricultural runoff is the major non-point source of water pollution - mainly sediment, phosphorus, nitrogen, and pesticides. Better farming methods, such as conservation tillage, contour planting, and terracing can control soil erosion and cut pollution by half or more. 3) Urban sewage systems have either begun to deteriorate or cannot handle the growing loads placed on them. Large investments are needed to improve their physical infrastructure.

Equity.Most of the larger rivers in the region cross an international border - some cross several borders - or form a border. No tabulation exists for aquifers that underlie national borders, but there are many.

Despite many statements suggesting that the next war in the Middle East will be over fresh water, there is little evidence for this. Not a single war has been fought over water for hundreds of years, but many treaties dealing with water have been signed. Water will be a source of conflict, but the conflicts will mainly be intranational rather than international. Likely sources of conflict include rural and urban users contending for the same water and rising demands from poor farmers, who are often disadvantaged in their access to water, and from women, who typically want more water for their households while men prefer to use it to grow cash crops. Israeli control of water in the West Bank is contentious, but even here experts have shown that compromise is feasible.

None of the three stresses on water in the Middle East will be easily resolved. Most of the nations in the region have already reached or are fast approaching the limits of their indigenous water supplies. Although higher prices for water and technological advances may defer the crisis, the only long-term solutions involve much greater efficiency in use, full reuse of wastewater, and gradual shifts of water from agriculture to other sectors. All of the nations of the Middle East and North Africa must revise their water policies to provide for a sustainable future, and they must find equitable ways to share water within and between nations.

Bibliography

Amery, Hussein A., and Wolf, Aaron T., eds. Water in theMiddle East: A Geography of Peace. Austin: University of Texas Press, 2000.

Beaumont, Peter. "Water Policies for the Middle East in the Twenty-first Century: The New Economic Realities." International Journal of Water Resources Development 18, no. 2 (2002): 315 - 334.

Brooks, David B., and Mehmet, Ozay, eds. Water Balances in the Eastern Mediterranean. Ottawa: International Development Research Centre, 2000.

Kolars, John. "The Spatial Attributes of Water Negotiation: The Need for a River Ethic and River Advocacy in the Middle East." In Water in the Middle East: A Geography of Peace, edited by Hussein A. Amery and Aaron T. Wolf. Austin: University of Texas Press, 2000.

Lonergan, Stephen C., and Brooks, David B. Watershed:The Role of Fresh Water in the Israeli-Palestinian Conflict. Ottawa: International Development Research Centre, 1994.

Postel, Sandra. Pillar of Sand: Can the Irrigation Miracle Last? New York: Norton, 1999.

Rogers, Peter, and Lydon, Peter, eds. Water in the ArabWorld: Perspectives and Prognoses. Cambridge, MA: Division of Applied Sciences, Harvard University, 1994.

Shapland, Greg. Rivers of Discord: International Water Disputes in the Middle East. New York: St. Martin's Press; London: Hurst, 1997.

Waterbury, John. The Nile Basin: National Determinants of Collective Action. New Haven, CT: Yale University Press, 2002.

Wolf, Aaron T. "Transboundary Fresh Water Database." Department of Geosciences, Oregon State University. Available from http://www.transboundarywaters.orst.edu.

— DAVID B. BROOKS

This entry contains three subentries:
Water As a Beverage and Constitutent of Food
Water As a Resource
Safety of Water

The giving of water to animals.

• w. devices — includes, troughs, ball-cock float valves, hydraulic rams, windmills, drinking nipples.
• preslaughter w. — ad. lib. water facilitates electrical stunning and hide removal and reduces danger of fecal contamination.

Quotes:

"When the water of a place is bad it is safest to drink none that has not been filtered through either the berry of a grape, or else a tub of malt. These are the most reliable filters yet invented." - Samuel Butler

"A pool is, for many of us in the West, a symbol not of affluence but of order, of control over the uncontrollable. A pool is water, made available and useful, and is, as such, infinitely soothing to the western eye." - Joan Didion

"In the world there is nothing more submissive and weak than water. Yet for attacking that which is hard and strong nothing can surpass it." - Lao-Tzu

"So let man consider of what he was created; he was created of gushing water issuing between the loins and the breast-bones." - Qur'an