Temps de lecture :2 minutes
Most people in industrialized countries take water for granted: they simply have to turn a faucet. But this attitude now lies at the root of some increasingly irresponsible behavior, of which there is no better illustration than the growth of desert cities in the very heart of arid regions.
The population of Las Vegas, for example, grows by more than 50,000 people annually, despite its very low rainfall of less than five inches (around 100 mm) a year. This situation is problematic because the people of the US are insatiable consumers of water, at an average rate of 600,000 cubic feet (17,000 cubic meters) per person, per year—30 times more than the people of Tanzania, for example. In tourist towns, water is also needed for visitors (40 million a year in Las Vegas), who are attracted by infrastructure such as swimming pools, parks, and golf courses. The watering of a golf course requires more than 175,000 cubic feet (5,000 cubic meters) of water per day, the average consumption of a town of 12,000 people.
To feed the demands of these parched cities, huge quantities of water generally need to be imported, requiring costly infra? structure (dams, canals, pumping stations), often at the expense of taxpayers, and taking a heavy toll on the environment. The flow of the Colorado river, which feeds the southwest of the USA, has now been severely reduced, causing serious damage to the ecosystems of the river and its delta. For coastal cities, the construction of seawater desalination plants may seem to offer an alternative, but such plants require a huge amount of energy to run.
Part of the solution must involve reducing consumption: adapting agriculture for a dry climate, replacing lawns with “desert gardens” that do not require watering, and increasing the range of water-saving measures within homes. Water tariffs have proved an efficient strategy: when water prices rise more quickly than water demand, tariffs create an incentive to use water more sparingly, and therefore more responsibly.