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Water Works!Water works for us in many ways, making our lives easier and more enjoyable. But we must take great care not to overuse and abuse this precious resource. Water is a basic necessity of life, not only for people but for every type of plant and animal as well. Water accounts for about 65% of our body weight. If we lost as little as 12% of it, we would soon die. Water is essential not only for survival but also contributes immeasurably to the quality of our lives. Since the dawn of time, human beings have harnessed water to improve their lives. In some ways, the history of civilization is the story of how we have made water work for us in ever more ingenious ways. As early as 5000 B.C., our predecessors used irrigation to increase crop production. Archaeologists have found masonry sewers dating back to 2750 B.C. and water-flushed toilets dating back almost as far. Water played and continues to play a special role in the growth of our nation. The fur trade, which stimulated the exploration of Canada's vast interior, was totally dependent on water for transportation. Water powered the grist mills and sawmills along small and large rivers in the Maritimes and Upper Canada, making possible the production and export of grain and lumber, two early economic staples. As Canadian industry diversified, water was put to new uses: as a coolant, a solvent, a dispersant, and a source of hydroelectric energy. Water transportation is still the most efficient way to move bulk goods. Water is also the basis of cheap energy. It is a raw material in the manufacture of chemicals, drugs, beverages, and hundreds of other products. It is an essential part of the manufacturing processes that produce everything from airplanes to zippers. In other words, we depend on water for most of our technology, comforts and conveniences, and of course for personal hygiene and to flush away our waste products. Many people think it makes no difference how much water we use or what we use it for. Actually, the way we use water is very important. Some uses are incompatible with others. Some uses remove water from the natural cycle for longer periods than others. Worst of all, most uses actually lower the quality of the water. Water quality is everybody's business because ultimately we all draw from the same supply of water. Most Canadians live downstream from somebody else, not to mention the fact that the same basic supply of water, replenished over and over again through the hydrologic cycle, has been used millions of times over in the long history of the earth. We are now aware of limits to the reuse of water, when and where it is returned to nature diminished in quantity and quality. Therefore, we must learn to understand water use much better: where we use it, what to measure, what the main uses are, how they compete and interfere with each other, and how to manage the growing competition.
Withdrawal usesWithdrawal use is directly measurable as quantities of intake, discharge, and consumption. Water intake is the amount withdrawn from the source for a particular activity over a specific period of time. This measure is important because it represents the demand imposed by that particular use on the water source at a given location. Usually, however, most of the water taken out is returned at or near the source. This is called water discharge. Water consumption is the difference between water intake and water discharge. Consumption removes water from a river system and makes it unavailable for further use downstream. The irrigation of crops is by far the largest consumptive use, followed by evaporation in large open water reservoirs and cooling ponds. However, because evaporation is difficult to measure, it is seldom recognized as water consumption. In the global hydrologic cycle, water is never actually lost. For example, the water evaporated from industrial cooling towers or an irrigated field simply returns to the atmosphere, later to fall again as precipitation somewhere else on earth. We determine how efficiently we use water in a particular process or economic sector with the help of two additional measurements: gross water use and the amount of water that is recirculated. Gross water use represents the total amount of water used during a process. This would normally be equal to the water intake, except that more and more users (especially industries) reuse the same water one or more times. In such cases, the gross water use could be equal to several times the water intake. The difference between gross water use and water intake is the amount recirculated, which can be expressed as a recycling rate. This is the number of times that the water is recirculated and indicates how efficient a particular water use is. In 1996, five main withdrawal uses are estimated to have accounted for a gross water use in Canada of 64 421 million cubic metres (MCM), made up of intake (44 611 MCM) and recirculation (19 810 MCM in industrial uses). About 10% of the intake was consumed (mostly industrial uses and agriculture), while the rest was discharged back to receiving waters. The following is a closer look at these withdrawal uses, starting with the largest.
Instream useUnlike withdrawal uses, instream uses cannot be measured quantitatively because the water is not removed from its natural environment. Instead, instream uses are described by certain characteristics of the water or by the benefits they provide to us and the ecosystem. Flow rates and water levels are very important factors for instream uses. When these conditions are changed by a dam, for example, it is easy for conflicts to arise. The most common conflict is between hydroelectric development and other uses with respect of aquatic life, wildlife, water supply and water transportation. Storage of the spring freshet (a high river flow caused by rapidly melting snow) removes the natural variability of streamflows on which many life processes depend, in particular, the highly productive ecosystems of deltas, estuaries and wetlands. To make the best use of our water, all needs must be carefully assessed and taken into account.
Water quality is everybody's problemHow water recovers from pollution and the limits to what nature can do by itself are discussed in detail in Freshwater Series No. A-3, "Clean Water Life Depends on It!" An understanding of how water is used helps us to predict and anticipate shortages of clean water even where there seem to be sufficient quantities. Using water entails the responsibility to clean it up after use, and before it passes on to the next user downstream. We must do unto others what we would have them do unto us. We take our water for grantedBecause we undervalue this precious resource, we tend to overuse it and, in fact, abuse it. The apparent abundance of water is deceptive, and the capacity of our lakes and rivers and even of the oceans to purify the wastes we dump into them is much more limited than we once thought it was. There is a price for it: billions and billions of dollars to clean up or prevent pollution. It is becoming abundantly clear that water is not a free good. Sooner or later it presents us with a bill: the price of neglect. In many cases we pay less than the actual cost of processing and delivery. For example, irrigation water charges only recover about 10% of the actual costs of the service. The same is true, to a less extreme extent, for water costs to householders. Our overuse of water begins at home. Compared to other countries, we pay very little to have water delivered to our kitchen and bathroom faucets. Nevertheless, we use more water per person than most other countries. Typical municipal water prices in Canada and other countries: Average daily domestic water use: What is a fair price?Consider for a moment the great contribution water makes to our quality of life indeed to life itself. Most of us rely on municipal water service, and our health depends on the quality of the water supplied. Most Canadians have been putting this service inadvertently at serious risk by not paying a sufficient price for its provision. According to the National Round Table on the Environment and Economy, unmet water and wastewater infrastructure needs in Canada were $38-49 billion in 1996, and capital costs for the following 20 years will be in the order of $70-90 billion. There is one clear way to deal with this problem. We need to pay realistic rates for water service which are sufficient to cover their true cost. In other words, we should pay a fair price that will recover the full cost of water delivered to the tap, one that is based on actual quantity used. Those who use more water should pay more and those who use less should pay less. Experience has shown that one important result will be users recognize the real value of this resource, and will use it more efficiently and wisely. The price Canadians pay for water varies significantly across the country. Analysis of the 1999 Municipal Water Pricing Survey prepared in 2001 indicates that the average domestic water user (assuming 25 000 litres per month) pays $1.14 for 1000 litres. This value has increased substantially in recent years from about 82 cents per 1000 litres in 1991, and nationally, now includes a waste treatment component of about 39%. Correcting the problem of the undervalued water resource would involve minimal change. However, in some cases, economically rational pricing would also require an increase in water metering, which in turn would reduce demand enough to postpone the need for new facilities for years, with significant savings for each year of postponement. Even with the price, water would still be the best bargain going, compared with other liquids we consume and which, unlike water, are not delivered at our taps year-round. Bottled water, for example, is in great demand at $1500 for 1000 litres, or 1000 times the price for the same volume of high quality tap water! Typical prices for popular beverages: In 2001, the average Canadian daily domestic use of fresh water was 335 litres per person. At least half of this amount is unnecessary and wasteful. Common causes of waste at home are leaking faucets, faulty plumbing, and over-use of water for watering the lawn and washing the car. Much of this waste would be reduced if we had to pay a fair price for water. As our usage becomes more efficient, we would not only produce less wastewater, we could also afford better treatment for it. In fact, wastewater usually becomes easier to treat if it is less diluted at the treatment plant, as there is less water to be removed from the sludge. The result would be multiple savings and a better environment. The same principle applies to industrial, agricultural, and commercial users. If major industries with their own water supplies were also charged for the amount they withdraw from their source of water, reuse would increase and a more efficient use of water would result. In fact, recycling has been called an automatic solution to the water quality problem. The cleaner the discharge required by regulations, the easier and more economical it is to reuse that same water instead of pumping in fresh supplies. Realistic pricing of water for large-volume agricultural uses such as irrigation would tend to lead to greater efficiency in its use, and therefore to conservation.
Water use in the futureAs time goes on, more and more water users will compete for what remains the same finite supply. This implies increases in water efficiency and conservation and doing even more to restore its quality after use. Nor is conservation restricted to only the uses of water: energy conservation, a desirable goal in itself, also contributes to water conservation. The reason is that reduced energy consumption lessens the need for electric power generation, which outranks all other water uses many times. We must learn to use only what we need, and need what we use. In the words of one conservation slogan: "Let's keep it on tap for the future." Paying for the accumulated deterioration of water supply and sewerage systems, and making up for the years of indifference and neglect our water resources have suffered is very much a part of the challenge to conserve water for our own use and for that of future generations. But if we do not learn from our past mistakes now, we will add to an already large environmental mortgage.
Freshwater Series A-4Note: A resource guide, entitled Let's Not Take Water For Granted, is available to help classroom teachers of grades 5-7 use the information from the Water Fact Sheets.
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