Introduction A New Era Of Water Scarcity Or An Old Error Of Water Waste
The discovery from tree rings of ancient drought cycles, the emergence of centuries-old shipwrecks on drying riverbeds, and the forecasts of unruly climate change and variability can easily stir fear for our water future—in both scientist and citizen alike. Yet such conditions need not be predictors of our water fate.
Exactly how the water demands of the 21st century's growing population will be met is, indeed, a formidable challenge. Half of the world's 6 billion people now live in urban environments—projected to increase to 60% by 2030—and the majority of the globe's 16 mega-cities (10 million or more residents) reside in regions confronting mild to severe water stress, according to the United Nations (2003). Between 1950 and 2000, the world's population more than doubled (United Nations, 2002), and its water demands roughly tripled (Postel and Vickers, 2004). From 2000 to 2050, global population is projected to grow 45%, reaching nearly 9 billion people (United Nations, 2002). Clearly, the world's water demands are increasing, but nature's present—and future—water budget remains largely fixed at the limits of its primordial creation.
From where and at what cost future water supplies will be derived remains an unanswered and troubling question for many public officials and water managers. With falling groundwater tables and approximately 800,000 dams now altering natural river flows worldwide—more than 75% of the river systems in the United States, Canada, Europe, and the former Soviet Union are already diverted by dams—much of the developed world's freshwater sources have already been tapped (Postel and Richter, 2003). Signs of water stress are apparent in the receding levels of some of the world's largest and most prized bodies of fresh water: Lake Mead in Nevada, the largest human-made reservoir in the United States (Ritter, 2003); Lake Chapala, the largest freshwater body in Mexico (Carlton, 2003); and the Aral Sea in Central Asia, once the world's fourth largest lake and now a mere third of its original volume (Postel and Richter, 2003). The levels of Lake Chapala are dropping because of development and outmoded irrigation techniques used by the arid region's farmers. Cyclical droughts in the region have been aggravated by rapid population growth. That, along with declining home values for U.S. and Canadian retirees, is putting in peril the $200 million in annual revenues provided to that poor region by expatriates. The lake also is becoming a dead zone for marine life, with several fish species practically wiped out. "Time is awfully close to running out," says Dr. Woen Lind, a Baylor University biology professor who has studied Lake Chapala (Carlton, 2003).
After more than a century of water supply development and accompanying exploitation of the natural ecosystems on which water systems depend, the goal of quenching humanity's thirst for more water seems as elusive as ever. The severity and cost of the world's droughts and chronic water supply problems are worsening, arguably leading to a global water crisis. Yet, on every continent and in nearly every water system facing drought or long-term water shortage, there exists a glaring if not nagging antidote: the elimination of water waste:
[I]t is evident that there must be a great amount of water wasted in many cities. Millions of dollars are being spent by many of our larger cities to so increase their supply that two thirds of it may be wasted. This waste is either intentional, careless, or through ignorance. (Folwell, 1900, p. 41)
We need ... to reduce leakage, especially in the many cities where water losses are an astonishing 40 per cent or more of total water supply. (Annan, 2002)
Water waste—from leaking, neglected underground pipes to green lawns in deserts, and the application of archaic flooding methods to grow food crops—is so prevalent that it is typically considered normal if not inevitable. But is this a reasonable assumption, one that should continue to guide drought response and water management today? To be sure, all water systems will have some leaks, the human experience relies on water for its functional value as well as its aesthetic and inspirational qualities, and beneficial reuse is a component of some irrigation losses. But to what extent have we defined our true water needs in contrast to our water wants, demands, and follies? If Singapore, Copenhagen, Denmark, and Fukuoka, Japan, are able to minimize their total unaccounted-for water (UFW) losses to 5% or less, how efficiently is water used in Jordan and in Taipei, Taiwan, and Johannesburg, South Africa, that more than 40% is lost to leakage and unexplained uses? (Postel and Vickers, 2004) Does a resident
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■ Indoor Single Family Residential, GPCD*
□ Outdoor Single Family Residential, GPCD*
□ Unaccounted-for Water, GPCD
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