JAISY WATERS

BEFORE WE GO IN TO THE IMPORTANCE OF CONSERVING WATER JAISY I THINKK WE MUST KNOW
What is drought?
Drought is a natural part of our highly variable climate. Parched landscapes, dying livestock, empty farm dams and wilting gardens are images that we know all too well.
It is not a case of whether drought will occur, but when. The lessons of the past show clearly that it cannot be eliminated.
It is impossible to make WORLD drought-proof... in this sort of continent we will get (water) shortages periodically.
Drought is a prolonged, abnormally dry period when there is not enough water to meet normal or expected needs. It may include lower than expected water storage volumes and flows to reservoirs, and higher than expected demand for water caused by hot weather.
Drought may last a few months or many years.
The impact of a drought depends on the amount of water in storage (from rainfall in previous years). For example, the dry had little immediate impact because water storages were full after a wet YEAR.
Rainfall varies significantly across INDIA in its severity and frequency. For example, KERALA has more rainy days than MAHARSHTRA but its average annual rainfall is about 40 per cent less than KERALA
Even across KERALA, rainfall varies considerably, with averages for the past 20 years ranging from.....
Rainfall also varies significantly from year to year. For example,
Farms and agriculture are often the first to be hit by drought, but eventually everybody feels the impact. It causes environmental and economic damage, often resulting in loss of vegetation and soil erosion, reduced water quality, and increased risks of bushfires and dust storms as well as crop and stock losses.
The main cause of drought in Australia is El Niño - extensive warming of the central and eastern Pacific Ocean that leads to a major shift in weather patterns across the Pacific.

NOW HOW WE STARTS
Don’t let it run. We have all developed the bad habit of letting the faucet run while we brush our teeth or wait for a cold glass of water. Keeping a pitcher of water in the refrigerator or turning the faucet off while we brush our teeth can save several gallons of water each day! It’s
simple really, before you turn on the tap, think of ways you can use less water to accomplish

Fix the drip. There is no such thing as a little drip. A leaky faucet with a drip of just 1/16 of an inch in diameter (about this big –o–) can waste 10 gallons of water every day. You can turn off that drip by replacing worn washers or valve seats with the help of your parents


The silent leak.
Even worse than the careless hand on the faucet is the silent toilet bowl leak, probably the single greatest water waster in homes. A leak of 1 gallon every 24 minutes—an average amount—totals 2.5 gallons per hour or 60 gallons per day! To check your toilet for a leak, place a few drops of food coloring in the tank and wait. If the color appears in the bowl, then there’s a leak. Often these leaks can be fixed with a few minor adjustments, cleaning calcium deposits from the toilet ball in the tank, or by replacing worn valves.

Close the hose. Letting the garden hose run faster or longer than necessary while we water the lawn or wash the car often becomes a careless and wasteful habit. A ½ inch garden hose under normal water pressure pours out more than 600 gallons of water per hour and a ¾ inch hose delivers almost 1,900 gallons in the same length of time. If left on overnight, one garden hose can easily waste twice as much water as the average family uses in a month

Check the plumbing. Proper maintenance is one of the most effective water savers. Faucet washers are inexpensive and take only a few minutes to replace. At home, check all water taps, hoses, and hose connections (even those that connect to dishwashers and washing machines) for leaks. Check the garden hose too—it should be turned off at the faucet, not just at the nozzle.

Teach your community. Just as it is important to conserve water in your own home, it is important to help our towns and cities save water by teaching others to use water wisely. In agricultural areas, water may be saved by using more effective irrigation methods. In industrial areas, manufacturers can save water by reusing it and by treating industrial wastes. Cities and towns can save water by eliminating leaks and installing meters. Waste water can be treated and reused. As you conserve water at home and in your community, you will help insure that the water available now continues to meet the growing water needs of the future.
Water is essential to life on earth. We need water to grow food, keep clean, provide power, control fire, and last but not least, we need it to stay alive!
If water is constantly being cleaned and recycled through the earth’s water cycle, why do we need to conserve it? The answer is that people use up our planet’s fresh water faster than it can naturally be replenished.
To provide enough clean fresh water for people, water is cleaned at before it is used. And after water is used, it is cleaned again at plants or by a before being put back into the environment.
Saving water is good for the earth, your family, and your community

When you use water wisely, you help the environment. You save water for fish and animals. You help preserve drinking water supplies. And you ease the burden on wastewater treatment plants—the less water you send down the drain, the less work these plants have to do to make water clean again.
When you use water wisely, you save energy. You save the energy that your water supplier uses to treat and move water to you, and the energy your family uses to heat your water.
When you use water wisely, you save money. Your family pays for the water you use. If you use less water, you’ll have more money left to spend on other things
Using water wisely means conserving it when you can, and not wasting it.

The average person uses approximately 70 gallons of water per day. That’s more than enough to fill two big bathtubs! (You use less if your home has water-saving showerheads, faucets, toilets, and a water-saving washing machine.)
On a typical day, here’s where your 70 gallons goes:
20 gallons is used to flush the toilet.
15 gallons is used for laundry.
14 gallons is used for baths and showers.
10 gallons is used from faucets.
1 gallon is used for the dishwasher.
And last but not least, about 10 gallons isn’t used at all! It goes down the drain in the form of leaks.
After water leaves your home, it is treated at a wastewater treatment plant or by your septic system. The water is cleaned and then released into the environment.
You can reduce your water use a lot by becoming more efficient. The next page shows you how.

How YOU Can Conserve Water
Here are some ways you can use water more efficiently. Share these tips with your family.
1. Wash Hands Efficiently
Turn off the water while you soap your hands, and rinse briefly.
2. Brush Teeth Wisely
Turn off the water while you brush your teeth and save 4 gallons a minute. That’s 200 gallons a week for a family of four.
3. Flush Only When Necessary
Put paper, insects, hair, and other such waste in a trash can rather than in the toilet.
4. Don’t Waste Drinking Water
Instead of running water to make it cold, keep a pitcher of water in the fridge.
5. Use Less Water for Dishes
Scrape your dishes clean to reduce rinsing. Run the dishwasher only when it’s full.
6. Take Half-Full Baths
Try bathing in a tub that’s only half full to save water and the energy used to heat it.
7. Shorten Your Showers
Shorter showers save both energy and water—keeping your shower under 5 minutes can save up to 1,000 gallons a month!
8. Stop Leaks
Turn off water faucets tightly so they don’t drip. Tell an adult about any leak you find indoors or outside.
9. Wash Clothes Wisely
Make sure your clothes are truly dirty before putting them into the hamper. Wash clothes only when you have a full load, and use cold water whenever possible.
10. Don’t Overwater
Remind adults to water the lawn only every 3 to 5 days in the summer and avoid watering driveways, sidewalks, and gutters.
11. Sweep to Save
Use a broom, rather than a hose, to clean off sidewalks and driveways.
12. Wash Cars Wisely
Use a hose nozzle and turn the water off when soaping up your car. You can save over 100 gallons this way.
Examine Your Faucets
A leaky faucet can waste about 300 gallons of water per month. Check the faucets in your kitchen, bathroom, laundry room, and outdoors by turning them on briefly, then off. Do you see any leaks? If so, tell an adult. Tell your teacher or the custodian about any leaky faucets at your school.
Test Your Toilets
A leaky toilet can waste as much as 600 gallons of water per month. Ask an adult to help you check your toilets for leaks. Lift the top lid and add a few drops of blue food coloring to the tank. Then wait a few minutes. Does color appear in the toilet bowl? If so, water is leaking from the tank into the bowl. The flapper valve in the tank may need to be replaced
Conserving Water...Here?
Michigan has abundant water resources envied by people in less fortunate parts of the country. In those places, conservation by homeowners is often necessary, just to have enough water for basic needs. But why conserve here in water-rich Michigan?
The simplest answer is that conserving water saves money - in many cases, very significant amounts of money. If you depend on your own well and septic system, the hundreds of gallons of water released each day will, over a period of years, saturate the soil near the septic system absorption field to the point where extensive repair or replacement is necessary. Replacing a septic system costs $2,000 to $4,000. Conserving water can extend the life of the system and delay the need for repair.
If you live in an area serviced by a municipal system, the greater your water use, the more you pay for water and sewer service. In some communities, costly sewage system expansion has been avoided by communitywide household water conservation.
In addition to saving money, water conservation helps tremendously in preventing water pollution. Old, leaky or poorly designed septic systems may cause nutrient and bacterial contamination of nearby lakes, streams and drinking water, even the water from your own well. Overloading municipal sewer systems can also cause untreated sewage to flow to lakes and rivers. The smaller the amount of water flowing through these systems, the lower the likelihood of pollution.
Pollution costs money, too. Excessive weed growth in a lake caused by nutrient enrichment from leaky septic systems often means costly
weed control measures paid for by you and your neighbors. Polluted home water wells cost thousands of dollars to fix... if they can be repaired at all.
Figure 1. Water use around the home
Figure 2. A toilet dam (below left) or a rock-filled container (below right) can reduce the amount of water flowing out of the toilet by up to 25%.
Water use around Your Home
The first step in understanding how to conserve water in your home is to know where water is used.
Most people use 50 to 70 gallons of water indoors each day and as much as the same amount outdoors, depending on the season. Indoors, three-quarters of all the water is used in the bathroom (Fig. 1). Outdoors, lawn and garden watering and car washing account for most of the water used.
How to Conserve Water Daily
Because such a huge percentage of the water you use is used in the bathroom, that's where water conservation efforts should focus. You can install a few simple, inexpensive devices in the bathroom that can save a lot of water with no change in your lifestyle or your present habits. Many hardware and plumbing supply stores stock these items. These are:
Toilet dams or rock-filled containers. These devices (one of which you can make yourself, Fig. 2) reduce the amount of water flowing out of the toilet by up to 25 percent. They do not affect its flushing ability. Never use a brick to accomplish the same effect-particles from it could harm your plumbing. Always be sure that at least 3 gallons of water remain in the tank so it will flush properly.
Low flow, water-saving shower heads. This piece of plumbing (Fig. 3) reduces the amount of water flowing through your shower by up to 50 percent, but increases its velocity so the shower feels the same. This also saves hot water. You may even be able to avoid buying a larger water heater, should the need arise.
Faucet aerators. These devices restrict the amount of water going through your faucet by up to 50 percent, but add bubbles so the flow of water appears the same. They could be installed on all of your faucets, not just the ones in your bathroom
Other relatively simple things you can do in your home to further reduce water use are:
Repair leaks in your faucets and toilets. A leaky faucet can waste 20 gallons or more per day. Leaky toilets, even though they are usually silent, can waste hundreds of gallons per day. To find out if your toilet has leaks, put a little food coloring in the tank. If, without flushing, color appears in the bowl, you have a leak that should be repaired. Repairing a faucet is usually as simple as changing an inexpensive washer. Leaky toilets can often be repaired by adjusting the float arm or plunger ball.
Use your dishwasher and clothes washer only when you have a full load. If you are purchasing a new clothes washer, choose one with variable load or suds-saver options. Many dishwashers are also now available with water-saving options. If you already have these options, use them whenever possible.
If you are building a new home or remodeling an old one, consider installing "low flush" toilets. These toilets use 1 to 2 gallons per flush instead of the 3 to 5 gallons used by conventional ones. They are readily available and, although they cost more, they can save you a lot of money in the long run through decreased water and energy use.
Outdoor uses of water are often high volume. Nevertheless, there are ways you can save water. Try these:
Attach a pistol-type sprayer to the end of your garden hose. In addition to enabling you to adjust the rate of flow, this device keeps water from continuing to run out during those short periods when you put down the hose without turning it off (while you are washing your car, for example).
Water your lawn only when necessary. It takes 660 gallons of water to supply 1,000 square feet of lawn with 1 inch of water. This is nearly the same amount of water as you use inside the house in an entire week! Water your lawn when it begins to show signs of wilting - when the grass does not spring back when you step on it - rather than on a regular schedule
Saving Water in Special Situations
Sometimes it is necessary to use extra measures to reduce even further the amount of water you are using in your house. Although useful in any situation, these techniques may be especially helpful, or even necessary in some cases, when water levels are high around your house, your septic system shows signs of failing or your community water system temporarily loses capacity to supply adequate amounts of water.
Indoors, you should consider these changes:
Take short showers instead of baths. A four-minute shower can use as little as 8 gallons of water, while a bath needs 50 to 60 gallons.
Avoid unnecessarily flushing your toilet Never use it as a wastepaper basket to dispose of cigarette butts or tissue paper.
Turn off the faucet while you are shaving or brushing your teeth or hand washing dishes.
Avoid running water in the shower while you are shampooing or soaping. Most people step away from the water to do this anyway. Many water-saving shower heads come with a button to shut off the flow without changing the mix of hot and cold water.
Outdoors, try these:
Use mulch around trees and shrubs and in garden beds. This greatly reduces the amount of water lost through evaporation and so reduces the need for watering.
Consider using a drip irrigation system in your garden. This system supplies water only to the root zones of plants. In addition to saving water, it reduces weeding because it doesn't water the areas between rows and hills of crops.
Use only plant varieties that are well adapted to your locality and sell conditions. Poorly chosen varieties often need greater amounts of fertilizer and water just to stay alive.
Avoid watering the lawn. Your lawn may turn brown in the middle of the summer, but this doesn't mean that it's dead. Rather, the grass is dormant and will regrow when rain and cooler weather returns.
Use the water from your roof downspouts for watering your garden and flower beds

CONSERVING UDERGROUND WATER
Comprising over 70% of the Earth?s surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognize this fact, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our planet to the point where organisms are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution
According to the American College Dictionary, pollution is defined as: ?to make foul or unclean; dirty.? Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. When it is unfit for its intended use, water is considered polluted. Two types of water pollutants exist; point source and nonpoint source. Point sources of pollution occur when harmful substances are emitted directly into a body of water. The Exxon Valdez oil spill best illustrates a point source water pollution. A nonpoint source delivers pollutants indirectly through environmental changes. An example of this type of water pollution is when fertilizer from a field is carried into a stream by rain, in the form of run-off which in turn effects aquatic life. The technology exists for point sources of pollution to be monitored and regulated, although political factors may complicate matters. Nonpoint sources are much more difficult to control. Pollution arising from nonpoint soMany causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water. Pollution is also caused when silt and other suspended solids, such as soil, washoff plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respirationbecomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated. Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chainurces accounts for a majority of the contaminants in streams and lakes
Pathogens are another type of pollution that prove very harmful. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and particularly boats that dump sewage. Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness
Three last forms of water pollution exist in the forms of petroleum, radioactive substances, and heat. Petroleum often pollutes waterbodies in the form of oil, resulting from oil spills. The previously mentioned Exxon Valdez is an example of this type of water pollution. These large-scale accidental discharges of petroleum are an important cause of pollution along shore lines. Besides the supertankers, off-shore drilling operations contribute a large share of pollution. One estimate is that one ton of oil is spilled for every million tons of oil transported. This is equal to about 0.0001 percent. Radioactive substances are produced in the form of waste from nuclear power plants, and from the industrial, medical, and scientific use of radioactive materials. Specific forms of waste are uranium and thorium mining and refining. The last form of water pollution is heat. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms. These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs
Oil pollution is a growing problem, particularly devestating to coastal wildlife. Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, demonstrators with "oil-covered" plastic animals protest a potential drilling project in Key Largo, Florida. Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating
Workers use special nets to clean up a California beach after an oil tanker spill. Tanker spills are an increasing environmental problem because once oil has spilled, it is virtually impossible to completely remove or contain it. Even small amounts spread rapidly across large areas of water. Because oil and water do not mix, the oil floats on the water and then washes up on broad expanses of shoreline. Attempts to chemically treat or sink the oil may further disrupt marine and beach ecosystems.

The major sources of water pollution can be classified as municipal, industrial, and agricultural. Municipal water pollution consists of waste water from homes and commercial establishments. For many years, the main goal of treating municipal wastewater was simply to reduce its content of suspended solids, oxygen-demanding materials, dissolved inorganic compounds, and harmful bacteria. In recent years, however, more stress has been placed on improving means of disposal of the solid residues from the municipal treatment processes. The basic methods of treating municipal wastewater fall into three stages: primary treatment, including grit removal, screening, grinding, and sedimentation; secondary treatment, which entails oxidation of dissolved organic matter by means of using biologically active sludge, which is then filtered off; and tertiary treatment, in which advanced biological methods of nitrogen removal and chemical and physical methods such as granular filtration and activated carbon absorption are employed. The handling and disposal of solid residues can account for 25 to 50 percent of the capital and operational costs of a treatment plant. The characteristics of industrial waste waters can differ considerably both within and among industries. The impact of industrial discharges depends not only on their collective characteristics, such as biochemical oxygen demand and the amount of suspended solids, but also on their content of specific inorganic and organic substances. Three options are available in controlling industrial wastewater. Control can take place at the point of generation in the plant; wastewater can be pretreated for discharge to municipal treatment sources; or wastewater can be treated completely at the plant and either reused or discharged directly into receiving waters
Raw sewage includes waste from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused; 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible
WTER TREATMENT
Agriculture, including commercial livestock and poultry farming, is the source of many organic and inorganic pollutants in surface waters and groundwater. These contaminants include both sediment from erosion cropland and compounds of phosphorus and nitrogen that partly originate in animal wastes and commercial fertilizers. Animal wastes are high in oxygen demanding material, nitrogen and phosphorus, and they often harbor pathogenic organisms. Wastes from commercial feeders are contained and disposed of on land; their main threat to natural waters, therefore, is from runoff and leaching. Control may involve settling basins for liquids, limited biological treatment in aerobic or anaerobic lagoons, and a variety of other methods
GROUND WATER
Ninety-five percent of all fresh water on earth is ground water. Ground water is found in natural rock formations. These formations, called aquifers, are a vital natural resource with many uses. Nationally, 53% of the population relies on ground water as a source of drinking water. In rural areas this figure is even higher. Eighty one percent of community water is dependent on ground water. Although the 1992 Section 305(b) State Water Quality Reports indicate that, overall, the Nation?s ground water quality is good to excellent, many local areas have experienced significant ground water contamination. Some examples are leaking underground storage tanks and municipal landfills
LEGISLATION
Several forms of legislation have been passed in recent decades to try to control water pollution. In 1970, the Clean Water Act provided 50 billion dollars to cities and states to build wastewater facilities. This has helped control surface water pollution from industrial and municipal sources throughout the United States. When congress passed the Clean Water Act in 1972, states were given primary authority to set their own standards for their water. In addition to these standards, the act required that all state beneficial uses and their criteria must comply with the ?fishable and swimmable? goals of the act. This essentially means that state beneficial uses must be able to support aquatic life and recreational use. Because it is impossible to test water for every type of disease-causing organism, states usually look to identify indicator bacteria. One for a example is a bacteria known as fecal coliforms.(Figure 1 shows the quality of water for each every state in the United States, click on the US link). These indicator bacteria suggest that a certain selection of water may be contaminated with untreated sewage and that other, more dangerous, organisms are present. These legislations are an important part in the fight against water pollution. They are useful in preventing Envioronmental catastrophes. The graph shows reported pollution incidents since 1989-1994. If stronger legislations existed, perhaps these events would never have occurred
It is an offence under the EP Act to pollute water.
Water not only includes reservoirs, tanks, billabongs, lakes, springs, swamps, natural and artificial watercourses, coastal waters as well as ground water but also the bed and subsoil beneath those waters, and the air lying above those waters and drains.
Water pollution will occur where any matter (gas, liquid or solid) gains access to any waters and makes those waters noxious, poisonous or potentially harmful to aquatic life, wildlife, vegetation, human beings or is in any way detrimental to any use of those waters. In other words, when the water becomes no longer safe for humans, fish, animals and plants, and not suitable for other important uses, such as swimming, drinking and for use by various industries.
Penalties will apply. If you pollute water or cause or allow waste to be placed or left in any position where it could reasonably be expected to access waters, you may be liable for a maximum fine of over $250,000. For continuing offences a daily fine of over $125,000 may apply.
It is also an offence if you discharge waste onto a dry water bed. Similar penalties will apply.
If you cause water pollution you may also be liable under water, health, fisheries and marine legislation as well as Commonwealth laws
GLOBALY
Estimates suggest that nearly 1.5 billion people lack safe drinking water and that at least 5 million deaths per year can be attributed to waterborne diseases. With over 70 percent of the planet covered by oceans, people have long acted as if these very bodies of water could serve as a limitless dumping ground for wastes. Raw sewage, garbage, and oil spills have begun to overwhelm the diluting capabilities of the oceans, and most coastal waters are now polluted. Beaches around the world are closed regularly, often because of high amounts of bacteria from sewage disposal, and marine wildlife is beginning to suffer
Perhaps the biggest reason for developing a worldwide effort to monitor and restrict global pollution is the fact that most forms of pollution do not respect national boundaries. The first major international conference on environmental issues was held in Stockholm, Sweden, in 1972 and was sponsored by the United Nations (UN). This meeting, at which the United States took a leading role, was controversial because many developing countries were fearful that a focus on environmental protection was a means for the developed world to keep the undeveloped world in an economically subservient position. The most important outcome of the conference was the creation of the United Nations Environmental Program (UNEP)
UNEP was designed to be ?the environmental conscience of the United Nations,? and, in an attempt to allay fears of the developing world, it became the first UN agency to be headquartered in a developing country, with offices in Nairobi, Kenya. In addition to attempting to achieve scientific consensus about major environmental issues, a major focus for UNEP has been the study of ways to encourage sustainable development increasing standards of living without destroying the environment. At the time of UNEP's creation in 1972, only 11 countries had environmental agencies. Ten years later that number had grown to 106, of which 70 were in developing countries
WATER QUALITTY
Water quality is closely linked to water use and to the state of economic development. In industrialized countries, bacterial contamination of surface water caused serious health problems in major cities throughout the mid 1800?s. By the turn of the century, cities in Europe and North America began building sewer networks to route domestic wastes downstream of water intakes. Development of these sewage networks and waste treatment facilities in urban areas has expanded tremendously in the past two decades. However, the rapid growth of the urban population (especially in Latin America and Asia) has outpaced the ability of governments to expand sewage and water infrastructure. While waterborne diseases have been eliminated in the developed world, outbreaks of cholera and other similar diseases still occur with alarming frequency in the developing countries. Since World War II and the birth of the ?chemical age?, water quality has been heavily impacted worldwide by industrial and agricultural chemicals. Eutrophication of surface waters from human and agricultural wastes and nitrification of groundwater from agricultural practices has greatly affected large parts of the world. Acidification of surface waters by air pollution is a recent phenomenon and threatens aquatic life in many area of the world. In developed countries, these general types of pollution have occurred sequentially with the result that most developed countries have successfully dealt with major surface water pollution. In contrast, however, newly industrialized countries such as China, India, Thailand, Brazil, and Mexico are now facing all these issues simultaneously.
CONCLUSION
Clearly, the problems associated with water pollution have the capabilities to disrupt life on our planet to a great extent. Congress has passed laws to try to combat water pollution thus acknowledging the fact that water pollution is, indeed, a seriousissue. But the government alone cannot solve the entire problem. It is ultimately up to us, to be informed, responsible and involved when it comes to the problems we face with our water. We must become familiar with our local water resources and learn about ways for disposing harmful household wastes so they don?t end up in sewage treatment plants that can?t handle them or landfills not designed to receive hazardous materials. In our yards, we must determine whether additional nutrients are needed before fertilizers are applied, and look for alternatives where fertilizers might run off into surface waters. We have to preserve existing trees and plant new trees and shrubs to help prevent soil erosion and promote infiltration of water into the soil. Around our houses, we must keep litter, pet waste, leaves, and grass clippings out of gutters and storm drains. These are just a few of the many ways in which we, as humans, have the ability to combat water pollution. As we head into the 21st century, awareness and education will most assuredly continue to be the two most important ways to prevent water pollution. If these measures are not taken and water pollution continues, life on earth will suffer severely. Global environmental collapse is not inevitable. But the developed world must work with the developing world to ensure that new industrialized economies do not add to the world's environmental problems. Politicians must think of sustainable development rather than economic expansion. Conservation strategies have to become more widely accepted, and people must learn that energy use can be dramatically diminished without sacrificing comfort. In short, with the technology that currently exists, the years of global environmental mistreatment can begin to be reversed

Methods
Twelve intact cylindrical (250 cm long, 74 cm in diameter) monoliths each of two soil types were extracted during the summer of 1998-99. The two soils were a light clay kandosol, with 0-20 cm A, 20-55 cm B and 55+ cm C horizons, and a medium clay, high bulk density sodic (SAR >15%) vertisol, with 0-25 cm A and 25+ cm B horizons. The cores were enclosed in cylindrical steel casing and had a sand-filled base where water could be applied to form a watertable. Seed of two lucerne cultivars with contrasting winter dormancy’s (winter-dormant Pioneer L34, and winter-active Pioneer L90) were inoculated and sown in May 1999. Minirhizotron tubes (740 mm long and 38 mm outside diameter), each scribed with lines in the 10 o’clock and 2 o’clock positions and scaled in 1 cm increments, had been fitted to all cores at 60, 85, 145 and 200 cm depths in January 2000. These tubes represented ~6% of the cross-sectional area of the cores. All cores were fitted with neutron moisture meter (NMM) access tubes using the kaolin slurry technique (4).
At the start of this experiment in January 2001, the plants were 20 months old. A watertable was imposed at 2.5 m depth in all cores. Tensiometers were installed horizontally at 210 cm, which was 40 cm above the imposed watertable. Readings from these tensiometers stabilised at water potentials of between -4and -10 kPa, indicating that soil water was readily available to roots at this depth.
When all plants in the cores were visibly water-stressed (day 0), half of them were surface watered (+sw) with 125 mm of simulated rainfall applied through a drip irrigation system over 48 hours. The remaining cores received no surface water (-sw). All cores were protected from summer rainfall by a clear polythene rain shelter fixed on a metal frame. NNM readings were taken weekly at nine depths in each core using a 16-second count. Root density was scanned along the 130 cm of scribed line in each tube with a bore scope and recorded by a mounted video camera. Functional roots that intersected the line were counted on a screen.
The total number of stems that had extended above the stubble in each core was counted every 5 days prior to and after watering. Shoot dry matter production was assessed by hand cutting to a height of ~3 cm at early flowering (day 29). Roots were first counted on day 4. Data were analysed as a factorial ANOVA.
Results
There was no statistical difference between the lucerne cultivars for each parameter (shoot number, shoot dry matter and root growth). As a result, the shoot number and dry matter data for each cultivar, but not the root growth data, were treated as replicates and these data re-analysed.
There was little evidence of increased shoot growth in the no surface water (-sw) treatments, where water was available from the 2.5 m deep watertable only. Shoot counts increased markedly where surface water was applied (+sw) in contrast to the –sw plants (Figure 1). By day 14 the growth response of the +sw plants was clearly established and shoot counts were discontinued.
The absence of a shoot growth response to water supplied to the base of the root system is shown in Figure 2. Dry matter production for the period showed very little response to the lower part of the root system being in moist subsoil whereas dry matter accumulated rapidly when the upper part of the root system was in moist soil. Dry matter production after 29 days by the +sw plants averaged 1.9 t/ha compared with an average of 0.09 t/ha from the –sw plants (P<0.05) (Figure 2). The plants growing in the kandosol producing significantly (P< 0.05) more dry matter in each treatment than those growing in the vertisol (Figure 2).
Water extraction from the surface of the +sw treatment was rapid with a return to the initial soil water content after 30 days, whereas the profiles of the –sw remained static (Figure 3). When all of the applied water was taken up, the plants showed visible indications of water stress, and all treatments were harvested for dry matter.
The average number of root intersections over the 130 cm length of inscribed minirhizotron tube is shown in Table 1. No significant differences (P<0.05) were found between treatments at 200 cm depth, which is in the vicinity of the capillary fringe of the watertable. There were significantly (P<0.05) fewer roots at the 60cm depth in the surface watered cores than in the non-watered cores but this did not prevent the rapid extraction of water and accumulation of dry matter.
Table 1. Number of roots intersecting 130 cm of scribed line on bore scope tubes at four depths on 26 March 2001.
Depth (cm)
+sw =surface watered, -sw=no surface water; 90=Pioneer L90 winter active lucerne, 34=Pioneer L34 winter dormant lucerne;K=Kandosol, V=Vertisol;1 LSD = least significant difference for ± surface water comparisons within each cultivar/soil type combination.
Figure 3. Volumetric water contents (m3/m3) to 200 cm depth of two soil profiles under lucerne prior to, and on three occasions after the application of 0 mm (-sw) and 125 mm (+sw) of simulated rain to the soil surface.
Discussion
Lucerne apparently produces foliage for extended periods after summer rain by drawing on subsoil water (5). These rates of foliage production are small compared with the potential of the plant, but very significant to the livestock industries they support (6). When foliage production is minimal during extended dry periods, it suggests that roots have extracted all the available soil water from their root zone and have not extended into moist subsoil or a watertable below, or that roots were unable to extend rapidly enough into moist subsoil to meet plant transpiration demands. When these limitations were addressed in this experiment, lucerne still produced very little dry matter, indicating that processes other than subsoil water availability were restricting water extraction. We conclude that despite being well watered at 2.5 m depth, the –sw plants failed to produce additional foliage because the upper layers of the soil profile were dry. This suggests that lucerne may be able to discriminate when the upper layers of the soil profile are dry and initiate processes to conserve water that is held deeper in the soil.
It is not uncommon for plants to restrict their water losses when the water content of the soil is decreasing. Hormones produced in roots growing in drying soil have been shown to regulate the plants’ water losses independently of the water status of other roots (7). Abscisic acid is implicated in the increased extension of roots, and decreased shoot growth when plant roots occupy drying soil (8). Hormone signals from roots in drying soil would be expected to fade over time with the gradual physiological separation of the roots from the plants as water uptake ceased, or actual separation as the roots senesced. It is likely therefore that over time the plants would adapt to the supply of water at the base of the root system (at 2.5 m depth in our cores) as hormone signals from roots in the dry soil ceased to suppress shoot production. This was not observed in our experiment. Shoot production continued to be severely restricted in the -sw treatments throughout the experiment. It has been suggested (9) that the restriction in radial flow of water from the soil to the xylem may be a significant restriction, but why it should be different for deeper roots is not clear. The deeper roots may themselves be morphologically or functionally different in a way that we cannot identify at this time.
Our observations support the suggestion that lucerne evolved under arid or semi-arid conditions prior to domestication (10). The rapid breaking of dormancy and extraction of water by lucerne after rainfall that we see in temperate Australia is a common feature of desert plants. When water is available to desert plants they extract it rapidly and return to conservative growth when it is exhausted. It would be an evolutionary advantage for such plants to sense the dwindling supplies of surface water and have mechanisms to restrict growth and conserve subsoil water for survival. It appears that such mechanisms prevent the subsoil roots of lucerne from extracting water at high rates.
Conclusion
The hypothesis that lucerne would use subsoil water primarily for growth was not confirmed. When the principal source of water for lysimeter-grown lucerne was an abundant supply of fresh water at 2.5 m depth, the plant used this water conservatively and growth was limited. Survival mechanisms resulting from the plant’s adaptation to a water-limited environment may to prevent the rapid extraction of subsoil water by lucerne. The upper limits to subsoil water extraction will be set by these survival mechanisms