ENSURE YOU UNDERSTAND THE FOLLOWING WHAT SURFACE WATER IS WHAT GROUNDWATER IS TAPPING THE WORLDS RELIABLE SURFACE WATER SUPPLY USES OF THE WORLDS FRESH WATER USES OF THE WORLDS FRESH WATER SUPPLYING MORE WATER (all subsections on how to do this) REDUCING WATER WASTE (all subsections on how to do this)

WATERS IMPORTANCE, USE, AND RENEWALImportance and Availability of Fresh WaterWater keeps us alive, moderates climate, sculpts the land, removes and dilutes wastes and pollutants, and is recycled by the hydrologic cycle.We live on the water planet, with a precious film of watermost of it salt watercovering about 71% of the earths surface. All organisms are made up of mostly water. Look in the mirror. What you see is about 60% water, most of it inside your cells.You could survive for several weeks without food but only a few days without water. It takes huge amounts of water to supply you with food, provide shelter, and meet your other needs and wants. Water also plays a key role in sculpting the earths surface, moderating climate, and removing and diluting water- soluble wastes and pollutants.Despite its importance, water is one of our most poorly managed resources. We waste it and pollute it. We also charge too little for making it available. This encourages still greater waste and pollution of this renewable resource, for which we have no substitute. As Benjamin Franklin said many decades ago, It is not until the well runs dry that we know the worth of water.Only a tiny fraction of the planets abundant water supply is readily available to us as fresh water. If the worlds water supply amounted to only 100 liters (26 gallons), our usable supply of fresh water would be only about 0.014 liter, or 2.5 teaspoons! Fortunately, the worlds freshwater supply is continuously collected, purified, recycled, and distributed in the solar-powered hydrologic cycle. This magnificent water recycling and purification system works well as long as we do not overload water systems with slowly degradable and non-degradable wastes or withdraw water from underground supplies faster than it is replenished. In parts of the world, we are doing both of these things.Differences in average annual precipitation divide the worlds countries and people into water haves and have-nots. Some places get lots of rain, whereas others get very little. For example, Canada, with only 0.5% of the worlds population, has one-fifth of the worlds fresh water. China, with one-fifth of the worlds people, has only 7% of the supply.Surface WaterWater that does not evaporate into the air or sink into the ground rums off the land into bodies of water is known as surface water. It is one of our most precious resources is fresh water that flows across the earths land surface and into rivers, streams, lakes, wetlands, and estuaries. The precipitation that does not return to the atmosphere by evaporation or infiltrate the ground is called surface runoff. The region from which surface water drains into a river, lake, wetland, or other body of water is called its watershed or drainage basin.Two-thirds of the worlds annual runoff is lost by seasonal floods and is not available for human use. The remaining one-third is reliable runoff: the amount of runoff that we can generally count on as a stable source of fresh water from year to year.GroundwaterSome precipitation infiltrates the ground and percolates downward through voids (pores, fractures, crevices, and other spaces) in soil and rock. The water in these spaces is called groundwaterand it is one of our most important sources of fresh water.Close to the surface, the spaces in soil and rock hold little moisture. Below a certain depth, in the zone of saturation, these spaces are completely filled with water. The water table is located at the top of the zone of saturation. It falls in dry weather or when we remove groundwater faster than it is replenished, and it rises in wet weather.Deeper down are geological layers called aquifers: porous, water-saturated layers of sand, gravel, or bedrock through which groundwater flows. They are like large elongated sponges through which groundwater seeps. Fairly watertight layers of rock or clay below an aquifer keep the water from escaping. About one of every three people on the earth depends on water pumped out of aquifers for drinking and other uses.Most aquifers are replenished naturally by precipitation that percolates downward through soil and rock, a process called natural recharge. Others are recharged from the side by lateral recharge from nearby streams. Most aquifers recharge extremely slowly.Groundwater normally moves from points of high elevation and pressure to points of lower elevation and pressure. This movement is quite slow, typically only a meter or so (about 3 feet) per year and rarely more than 0.3 meter (1 foot) per day.Some aquifers get very little, if any, recharge and on a human time scale are nonrenewable resources. They are found fairly deep underground and were formed tens of thousands of years ago. Withdrawals from them amount to water mining. If kept up, they will deplete these ancient deposits of natural capital.Tapping the Worlds Reliable Surface Water SupplyWe currently use more than half of the worlds reliable runoff of surface water and could be using 7090% by 2025.During the last century, the human population tripled, global water withdrawal increased sevenfold, and per capita withdrawal quadrupled. As a result, we now withdraw about 34% of the worlds reliable runoff. We leave another 20% of this runoff in streams to transport goods by boats, dilute pollution, and sustain fisheries and wildlife. In total, we directly or indirectly use about 54% of the worlds reliable runoff of surface water.To meet the demands of our growing population, global withdrawal rates of surface water could reach more than 70% of the reliable runoff by 2025 and 90% if per capita withdrawal of water continues increasing at the current rate. This is a global average. Withdrawal rates already exceed the reliable runoff in some areas.Uses of the Worlds Fresh WaterIrrigation is the biggest user of water (70%), followed by industries (20%) and cities and residences (10%).Worldwide, we use 70% of the water we withdraw each year from rivers, lakes, and aquifers to irrigate one-fifth of the worlds cropland. This land produces about 40% of the worlds food, including two-thirds of the worlds rice and wheat. Industry uses 20% of the water withdrawn each year, and cities and residences use the remaining 10%. Manufacturing and agriculture use large amounts of water. For example, it takes 400,000 liters (106,000 gallons) of water to produce an automobile, 9,000 liters (2,800 gallons) to produce 1 kilogram (2.2 pounds) of aluminum, and 7,000 liters (1,900 gallons) to produce 1 kilogram (2.2 pounds) of grain-fed beef. You could save more water by not eating a half a kilogram (1 pound) of grain-fed beef than by not showering for six months.

Water body in Wallings, Antigua

SUPPLYING MORE WATERFreshwater ShortagesOne of every six people does not have regular access to an adequate and affordable supply of clean water. This number could increase to at least one of every four people by 2050. The two main factors causing water scarcity are a dry climate and too many people using the reliable supply of water. A 2003 study by the United Nations found that one of every six people does not have regular access to an adequate and affordable supply of clean water. By 2050, this number could increase to at least one of every four people. Poverty also governs access to water. Even when a plentiful supply of water exists, most of the worlds 1.1 billion poor people living on less than $1 (U.S.) per day cannot afford a safe supply of drinking water and so live in hydrological poverty. Most are cut off from municipal water supplies and must collect water from unsafe sources or buy wateroften taken from polluted riversfrom private vendors at high prices. In water- short rural areas in developing countries, many women and children must walk long distances each day, carrying heavy jars or cans, to get a meager and sometimes contaminated supply of water.Who Should Own and Manage Freshwater Resources?Controversy exists regarding whether water supplies should be owned and managed by governments or by private corporations.Most people believe that everyone should have access to clean water. But who will pay for making this water available to everyone?Most water resources are owned by governments and managed as publicly owned resources for their citizens. An increasing number of governments are retaining ownership of these public resources but are hiring private companies to manage them. In addition, three large European companiesVivendi, Suez, and RWEhave a long-range strategy to buy up as much of the worlds water supplies as possible, especially in Europe and North America.Currently, 85% of Americans get their water from publicly owned utilities. This may soon change. Within 10 years the three European-based water companies aim to control 70% of the water supply in the United States by buying up American water companies and entering into agreements with most cities to manage their water supplies.Some argue that private companies have the money and expertise to manage these resources better and more efficiently than government bureaucracies. Experience with this publicprivate partnership approach has yielded mixed results. Some water management companies have improved efficiency, done a good job, and in a few cases lowered rates.In the late 1980s, Prime Minister Margaret Thatcher placed Englands water management in private hands. The result: financial mismanagement, skyrocketing water rates, deteriorating water quality, and company executives who gave themselves generous financial compensation packages. In the late 1990s, Prime Minister Tony Blair brought the system under control by imposing much stricter government oversight. The message: Governments hiring private companies to manage water resources must set standards and maintain strict oversight of such contracts. Some government officials want to go even further and sell public water resources to private companies. Many people oppose full privatization of water resources because they believe that water is a public resource too important to be left solely in private hands. Also, once a citys water systems have been taken over by a foreign-based corporation, efforts to return the systems to public control can lead to severe economic penalties under the rules of the World Trade Organization (WTO). In the Bolivian town of Cochabamba, 60% of the water was being lost through leaky pipes. With no money to fix the pipes, the Bolivian government sold the towns water system to a subsidiary of Bechtel Corporation. Within 6 months, the company doubled water rates and began seizing and selling the houses of people who did not pay their water bills. A general strike ensued, and violent street clashes between protesters and government troops led to 10,000 injured people and 7 deaths. The Bolivian government ended up tearing up the contract. Todays the towns governmentprivate cooperative water management system is in shambles and most of the leaks persist.Some analysts point to two other potential problems in a fully privatized water system. First, because private companies make money by delivering water, they have an incentive to sell as much water as they can rather than to conserve it. Second, because of lack of money to pay water bills, the poor will continue to be left out. There are no easy answers for managing the water that everyone needs.

Increasing Freshwater SuppliesWe can increase water supplies by building dams, bringing in water from somewhere else, withdrawing groundwater, converting salt water to fresh water, wasting less water, and importing food.There are several ways to increase the supply of fresh water in a particular area. We can build dams and reservoirs to store runoff for release as needed. We can bring in surface water from another area. We can also withdraw groundwater and convert salt water to fresh water (desalination). Other strategies are to reduce water waste and import food to reduce water use in growing crops and raising livestock. In developed countries, people tend to live where the climate is favorable and bring in water from another watershed. In developing countries, most people (especially the rural poor) must settle where the water is and try to capture and use the precipitation they need.

Advantages and Disadvantages of Large Dams and Reservoirs.Large dams and reservoirs can produce cheap electricity, reduce downstream flooding, and provide year-round water for irrigating cropland, but they also displace people and disrupt aquatic systems. Large dams and reservoirs have both benefits and drawbacks. Their main purpose is to capture and store runoff and release it as needed to control floods, generate electricity, and supply water for irrigation and for towns and cities. Reservoirs also provide recreational activities such as swimming, fishing, and boating. The more than 45,000 large dams built on the worlds 227 largest rivers have increased the annual reliable runoff available for human use by nearly one- third. At the same time, a series of dams on a river, especially in arid areas, can reduce downstream flow to a trickle and prevent it from reaching the sea as a part of the hydrologic cycle. According to the World Commission on Water in the 21st Century, half of the worlds major rivers go dry part of the year because of flow reduction by dams, especially during drought years. This engineering approach to river management has displaced 4080 million people from their homes and flooded an area of mostly productive land roughly equal to the area of California. In addition, this approach often impairs some of the important ecological services rivers provide (Figure 11-9). In 2003, the World Resources Institute estimated that dams and reservoirs have strongly or moderately fragmented and disturbed 60% of the worlds major river basins. Since 1960, the Colorado River in the United States has rarely made it to the Gulf of California because of a combination of multiple dams, large-scale water withdrawal, and prolonged drought. Its dwindling water supply threatens the survival of species that spawn in the river, destroys estuaries that serve as breeding grounds for numerous aquatic species, and increases saltwater contamination of aquifers near the coast.

Advantages and Disadvantages of Water Transfersthe California ExperienceThe massive transfer of water from water-rich northern California to water-poor southern California has brought many benefits, but remains controversial.Tunnels, aqueducts, and underground pipes can transfer stream runoff collected by dams and reservoirs from water-rich areas to water-poor areas. They also create environmental problems. Indeed, most of the worlds dam projects and large-scale water transfers illustrate an important ecological principle: You cannot do just one thing. A number of unintended environmental consequences almost always occur.According to environmental economists, attaching even crudely estimated monetary values to these ecosystem services would help sustain them. One of the worlds largest water transfer projects is the California Water project, It uses a maze of giant dams, pumps, and aqueducts (cement-lined artificial rivers) to transport water from water-rich northern California to southern Californias heavily populated, arid and semiarid agricultural regions and cities. In effect, this project supplies massive amounts of water to areas that without such water would be mostly desert. For decades, northern and southern Californians have feuded over how the states water should be allocated under this project. Southern Californians want more water from the north to grow more crops and to support Los Angeles, San Diego, and other growing urban areas. Agriculture consumes three-fourths of the water withdrawn in California, much of it used inefficiently for water-thirsty crops growing in desert-like conditions. Northern Californians counter that sending more water south would degrade the Sacramento River, threaten fisheries, and reduce the flushing action that helps clean San Francisco Bay of pollutants. They also argue that much of the water sent south is wasted. They point to studies showing that making irrigation just 10% more efficient would provide enough water for domestic and industrial uses in southern California. According to a 2002 joint study by a group of scientists and engineers, projected global warming will sharply reduce water availability in California (especially southern California) and other water-short states in the western United States even under the best-case scenario. Some analysts project that sometime during this century, many of the people living in arid southern California cities (such as Los Angeles and San Diego), as well as farmers in this area, will have to move somewhere else because of a lack of water. Pumping out more groundwater is not the answergroundwater is already being withdrawn faster than it is replenished throughout much of California. Quicker and cheaper solutions would be to improve irrigation efficiency, stop growing water-thirsty crops in a desert climate, and allow farmers to sell cities their legal rights to withdraw certain amounts of water from rivers.

Advantages and Disadvantages of Withdrawing GroundwaterMost aquifers are renewable sources unless water is removed faster than it is replenished or becomes contaminated. Aquifers provide drinking water for about one-fourth of the worlds people. In the United States, water pumped from aquifers supplies almost all of the drinking water in rural areas, one-fifth of that in urban areas, and 43% of irrigation water. Relying more on groundwater has advantages and disadvantages. Aquifers are widely available and are renewable sources of water as long as the water is not withdrawn faster than it is replaced and as long as the aquifers do not become contaminated. But water tables are falling in many areas of the world because the rate of pumping out water (mostly to irrigate crops) exceeds the rate of natural recharge from precipitation. The worlds three largest grain-producing countriesChina, India, and the United States are over-pumping many of their aquifers. Saudi Arabia is as water-poor as it is oil-rich. It gets about 70% of its drinking water at a high cost from the worlds largest desalination complex on its eastern coast. The rest of the countrys water is pumped from deep aquifers, most as nonrenewable as the countrys oil. This water-short nation wastes much of its scarcest resource to grow irrigated crops on desert land and to fill large numbers of fountains and swimming pools that let precious water evaporate into the hot, dry desert air. Hydrologists estimate that because of the rapid depletion of its fossil aquifers, most irrigated agriculture in Saudi Arabia may disappear within 1020 years.In the United States, groundwater is being withdrawn at four times its replacement rate.

Withdrawing Groundwater Advantages DisadvantagesGood source of water for drinking and irrigation Aquifer depletion from over-pumpingAvailable year- round Sinking of land (subsidence) when water removedExists almost everywhere Polluted aquifers unusable for decades or centuriesRenewable if not over-pumped or contaminated Saltwater intrusion into drinking water supplies No evaporation losses near coastal areasCheaper to extract than most surface waters Reduced water flows into streams, lakes, estuaries, And wetlands Increased cost, energy use, and contamination From deeper wells

The most serious overdrafts in the US are occurring in parts of the huge Ogallala Aquifer, extending from southern South Dakota to central Texas, and in parts of the arid Southwest. Serious groundwater depletion is also taking place in Californias water-short Central Valley, which supplies half the countrys vegetables and fruits. Groundwater overdrafts near coastal areas can contaminate groundwater supplies by allowing salt water to intrude into freshwater aquifers used to supply water for irrigation and domestic purposes. This problem is especially serious in coastal areas in Florida, California, South Carolina, and Texas. Below is a list of ways to prevent or slow the problem of groundwater depletion.

Groundwater depletionPrevention Waste less waterSubsidize water conservationBan new wells in aquifers near surface watersBuy and retire groundwater withdrawal rights in critical areasDo not grow water-intensive crops in dry areasReduce birth rates

Control Raise price of water to discourage wasteTax water pumped from wells near surface watersSet and enforce minimum stream flow levels

With global water shortages looming, scientists are evaluating deep aquifersfound at depths of 0.8 kilometer (0.5 mile) or moreas future water sources. Preliminary results suggest that some of these aquifers hold enough water to support billions of people for centuries. The quality of water in these aquifers may also be much higher than the quality of the water in most rivers and lakes. Two major concerns arise regarding tapping these mostly one-time deposits of water. First, little is known about the geological and ecological impacts of pumping water from deep aquifers. Second, no international water treaties exist governing rights to, and ownership of, water found under several different countries. Without such treaties, legal and physical conflicts could ensue over who has the right to tap into and use these valuable resources.DesalinationRemoving salt from seawater will probably not be done widely because of high costs and questions about what to do with the resulting salt. Desalination involves removing dissolved salts from ocean water or from brackish (slightly salty) water in aquifers or lakes. It represents another way to increase supplies of fresh water. One method for desalinating water is distillation heating salt water until it evaporates, leaves behind salts in solid form, and condenses as fresh water. Another method is reverse osmosispumping salt water at high pressure through a thin membrane with pores that allow water molecules, but not most dissolved salts, to pass through. In effect, high pressure is used to push fresh water out of salt water. Today about 13,500 desalination plants operate in 120 countries, especially in the arid, desert nations of the Middle East, North Africa, the Caribbean, and the Mediterranean. These plants meet less than 0.3% of the worlds water needs. There are two major problems with the widespread use of desalination. One is the high cost, because it takes a lot of energy to desalinate water. Currently, desalinating water costs two to three times as much as the conventional purification of fresh water, although recent advances in reverse osmosis have reduced the energy costs somewhat.The second problem is that desalination produces large quantities of briny wastewater that contain lots of salt and other minerals. Dumping concentrated brine into a nearby ocean increases the salinity of the ocean water, threatening food resources and aquatic life in the vicinity. Dumping it on land could contaminate groundwater and surface water.Bottom line: Currently, significant desalination is practical only for wealthy and water-short countries and cities that can afford its high cost. Scientists are working to develop new membranes for reverse osmosis that can separate water from salt more efficiently and under less pressure. If successful, this strategy could bring down the cost of using desalination to produce drinking water. Even so, desalinated water probably will not be cheap enough to irrigate conventional crops or meet much of the worlds demand for fresh water unless scientists can figure out how to use solar energy or other means to desalinate seawater cheaply and how to safely dispose of the salt left behind.

REDUCING WATER WASTEBenefits of Reducing Water WasteWe waste about two-thirds of the water we use, but we could cut this waste to 15%.Mohamed El-Ashrv of the World Resources Institute estimates that 6570% of the water people use throughout the world is lost through evaporation, leaks, and other losses. The United States, the worlds largest user of water, does slightly better but still loses about half of the water it withdraws. El-Ashry believes it is economically and technically feasible to reduce such water losses to 15%, thereby meeting most of the worlds water needs for the foreseeable future. This win-win solution would decrease the burden on wastewater plants and reduce the need for expensive dams and water transfer projects that destroy wildlife habitats and displace people. It would also slow depletion of groundwater aquifers and save both energy and money. According to water resource experts, the main cause of water waste is that we charge too little for water. Such under-pricing is mostly the result of government subsidies that provide irrigation water, electricity and diesel fuel for farmers to pump water from rivers and aquifers at below-market prices.Because these subsidies keep the price of water low, users have little or no financial incentive to invest in water-saving technologies. According to water resource expert Sandra Postel, By heavily subsidizing water, governments give out the false message that it is abundant and can afford to be wastedeven as rivers are drying up, aquifers are being depleted, fisheries are collapsing, and species are going extinct. Farmers, industries, and others benefiting from government water subsidies offer a counter-argument: They promote settlement and agricultural production in arid and semiarid areas, stimulate local economies, and help keep the prices of food, manufactured goods, and electricity low. Most water resource experts believe that when water scarcity afflicts many areas in this century, governments will have to make the unpopular decision to raise water prices. China did so in 2002 because it faced water shortages in most of its major cities, rivers running dry and falling water tables in key agricultural areas. Higher water prices encourage water conservation but make it difficult for low-income farmers and city dwellers to buy enough water to meet their needs. South Africa has found a novel solution to this problem. When the country raised water prices, it established lifeline rates that give each household a set amount of water at a low price to meet basic needs. When users exceed this amount, the price rises. The second major cause of water waste is lack of government subsidies for improving the efficiency of water use. A basic rule of economics is that you get more of what you reward. Withdrawing subsidies that encourage water waste and providing subsidies for efficient water use would sharply reduce water waste.

Wasting Less Water in IrrigationAlthough 60% of the worlds irrigation water is currently wasted, improved irrigation techniques could reduce this proportion to 520%.About 60% of the irrigation water applied throughout the world does not reach the targeted crops and does not contribute to food production. Most irrigation systems obtain water from a groundwater well or a surface water source. The water then flows by gravity through unlined ditches in crop fields so the crops can absorb it. This flood irrigation method delivers far more water than is needed for crop growth and typically loses 40% of the water through evaporation, seepage, and runoff. More efficient and environmentally sound irrigation technologies can greatly reduce water demands and waste on farms by delivering water more precisely to crops. For example, the center-pivot low- pressure sprinkler uses pumps to spray water on a crop. Typically, it allows 80% of the water to reach crops. Low-energy precision application (LEPA) sprinklers, another form of center-pivot irrigation, put 9095% of the water where crops need it by spraying the water closer to the ground and in larger droplets than the center-pivot, low-pressure system. Another method is to use soil moisture detectors to Water crops only when they need it. Drip irrigation or micro-irrigation is the most efficient way to deliver small amounts of water precisely to crops. It consists of a network of perforated plastic tubing installed at or below the ground level. Small holes or emitters in the tubing deliver drops of water at a slow and steady rate, close to the plant roots. Drip irrigation is very efficient, with 9095% of the water input reaching the crops. The flexible and lightweight tubing system can easily be fitted to match the patterns of crops in a field and left in place or moved around. Currently, drip irrigation is used on slightly more than 1% of the worlds irrigated crop fields and 4% of those in the United States. This percentage rises to 90% in Cyprus, 66% in Israel, and 13% in California. Unfortunately, the capital cost of conventional drip irrigation systems remains too high for most poor farmers and for use on low-value row crops. As noted earlier, irrigation water is under-priced. Raise water prices enough and drip irrigation would quickly be adopted to irrigate most of the worlds crops. .Reducing Irrigation Water Waste Lining canals which bring water to irrigation ditches Leveling fields with lasers Irrigating at night to reduce evaporation Using soil and satellite sensors and computer systems to monitor soil moisture and add water only when necessary Use of polyculture and other forms of organic farming Growing water-efficient crops using drought- resistant and salt-tolerant crop varieties Irrigating with treated urban waste water Importing less water-intensive crops and meatThe above list outlines methods for reducing water waste in irrigation.

Wasting Less Water in Industry, Homes, and BusinessesWe can save water by changing to yard plants that need little water, using drip irrigation, raising water prices, fixing leaks, and using water-saving toilets and other appliances.Below is a list of ways to use water more efficiently in industries, homes, and businesses. Many homeowners and businesses in water-short areas are replacing green lawns with vegetation adapted to a dry climate. This win-win approach, called xeriscaping (pronounced ZER-i-scaping), reduces water use by 3085% and sharply reduces inputs of labor, fertilizer, and fuel. It also reduces polluted runoff, air pollution, and yard wastes.About one-fifth of all U.S. public water systems do not have water meters and charge a single low rate for almost unlimited use of high-quality water. In Boulder, Colorado, introducing water meters reduced water use by more than one-third. Many apartment dwellers have little incentive to conserve water because water use is included in their rent. We can also save water by replacing the current system in which we use large amounts of water good enough to drink to dilute and wash or flush away industrial, animal, and household wastes with one that mimics the way nature deals with wastes. According to the FAQ, if current trends continue, within 40 years we will need the worlds entire reliable flow of river water just to dilute and transport the wastes we produce. One potential solution is to ban the discharge of industrial toxic wastes into municipal sewer systems. Another is to rely more on waterless composting toilets that convert human fecal matter into a small amount of dry and odorless soil-like humus material that can be removed from a composting chamber every year or so and returned to the soil as fertilizer. We can also return the nutrient-rich sludge produced by conventional waste treatment plants to the soil as a fertilizer. Banning the input of toxic industrial chemicals into sewage treatment plants will make this feasible. Redesign manufacturing processes Landscape yards with plants that require little water Use drip irrigation Fix water leaks Use water meters and charge for all municipal water use Raise water prices Use waterless composting toilets Require water conservation in water-short cities Use water-saving toilets, showerheads, and front- loading clothes washers Collect and reuse household water to irrigate lawns and non-edible plants Purify and reuse water for houses, apartments, and office buildings

The above list outlines methods of reducing water waste in industries, homes, and businesses. Using Water More SustainablyWe can use water more sustainably by cutting waste, raising water prices, preserving forests in water basins, and slowing population growth.Sustainable water use is based on the commonsense principle stated in an old Inca proverb: The frog does Not drink up the pond in which it lives. Below is a list of ways to implement this principle.The challenge in encouraging such a blue revolution is to implement a mix of strategies. One strategy involves using technology to irrigate crops more efficiently and to save water in industries and homes.A second approach uses economic and political policies to remove subsidies that cause water to be under- priced and thus wasted, while guaranteeing low prices for low-income consumers and adding subsidies that reward reduced water waste. A third component is to switch to new waste-treatment systems that accept only nontoxic wastes, use less or no water to treat wastes, return nutrients in plant and animal wastes to the soil, and mimic the ways that nature decomposes and recycles organic wastes. A fourth strategy is to leave enough water in rivers to protect wildlife, ecological processes, and the natural ecological services provided by rivers. We can all help bring about this blue revolution by using and wasting less water. We can also support government policies that result in more sustainable use of the worlds water and better ways to treat our industrial and household wastes.

Sustainable Water Use Preserving ecological health of aquatic systems Agreements among regions and countries sharing surface water resources Outside party mediation of water disputes between nations Marketing of water rights Raising water prices Wasting less water Decreasing government subsidies for supplying water Increasing government subsidies for reducing water waste Slowing population growthWhat individuals can do Use water-saving toilets, showerheads, and faucet aerators. Shower instead of taking baths, and take short showers. Repair water leaks. Turn off sink faucets while brushing teeth, shaving, or washing. Wash only full loads of clothes or use the lowest possible water-level setting for smaller loads. Wash a car from a bucket of soapy water, and use the hose for rinsing only. If you use a commercial carwash, try to find one that recycles its water. Replace your lawn with native plants that need little if any watering. Water lawns and gardens in the early morning or evening. Use drip irrigation and mulch for gardens and flowerbeds. Use recycled (gray) water for watering lawns and houseplants and for washing cars.

TOO MUCH WATERHeavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.Whereas some areas have too little water, others sometimes have too much because of natural flooding by streams, caused mostly by heavy rain or rapid melting of snow. A flood happens when water in a stream overflows its normal channel and spills into the adjacent area, called a floodplain. Floodplains, which include highly productive wetlands, help provide natural flood and erosion control, maintain high water qua1it and recharge groundwater. To reduce the threat of flooding and thus to allow people to live in floodplains, rivers have been narrowed and straightened (channelized), equipped with protective levees and walls, and dammed to create reservoirs that store and release water as needed. In the long run, however, such measures can greatly increase flood damage because they can be overwhelmed by prolonged rains, as happened along the Mississippi River in the Midwestern United States during the summer of 1993. People settle on floodplains because of their many advantages, including fertile soil, ample water for irrigation, availability of nearby rivers for transportation and recreation, and flat land suitable for crops, buildings, highways, and railroads. Floods are a natural phenomenon and have several benefits. They provide the worlds most productive farmland thanks to the nutrient-rich silt left behind after floodwaters recede. They also recharge groundwater and help refill wetlands. Unfortunately, each year floods kill thousands of people and cause tens of billions of dollars in property damage. Floods, like droughts, usually are considered natural disasters. Since the 1960s, however, human activities have contributed to the sharp rise in flood deaths and damages. One such activity is removal of water-absorbing vegetation, especially on hillsides another is draining wetlands that absorb floodwaters and reduce the severity of flooding. Living on floodplains increases the threat of damage from flooding. Flooding also increases when we pave or build, and replace water-absorbing vegetation, soil, and wetlands with highways, parking lots, and buildings that cannot absorb rainwater. In developed countries, people deliberately settle on floodplains and then expect dams, levees, and other devices to protect them from floodwaters. When heavier-than-normal rains occur, these devices can be overwhelmed. In many developing countries, the poor have little choice but to try to survive in flood-prone areas.