By FERNANDA SANTOS
16 June 2013
PHOENIX (The New York Times) – The hiss of sprinklers serenades improbably green neighborhoods early in the morning and late at night, the moisture guarding against the oppressive heat. This is the time of year when temperatures soar, water consumption spikes and water bills skyrocket in this city, particularly for those whose idea of desert living includes cultivating a healthy expanse of grass.
Half of the water consumed in homes here is used to irrigate lawns, but there is a certain curiosity about the way water is used in Phoenix, which gets barely eight inches of rain a year but is not necessarily parched.
The per capita consumption here, 108 gallons a day, is less than in Los Angeles, where residents average 123 gallons a day. And though humid Southeastern cities like Atlanta have grappled with recurrent water shortages, there is no limit here to how many times someone can wash a car or water flowers in a yard.
“We’re often maligned as being an unsustainable place simply for existing in an arid climate,” said Colin Tetreault, senior policy adviser for sustainability for Mayor Greg Stanton. “But that’s just myopic.”
Phoenix gathers its water from several places. It relies on melting snow in the north to feed the rivers that supply its water system: the Salt and the Verde, which begin and end in Arizona, and the overstretched Colorado, which slices the Southwest. It pumps from aquifers, strained by development over time, and then works to replenish them whenever water is in surplus, which happens occasionally.
To irrigate its many golf courses, it reuses most of the water drained from bathroom faucets and washing machines. It uses treated wastewater to cool a nuclear power generating station and to feed a man-made wetland complex known as Tres Rios, home to more than 150 species of birds.
A system of canals crisscrosses the city and stretches beyond its boundaries, a legacy of the prehistoric Hohokam Indians that allowed fertile farms to flourish in the desert. To this day, half of all the water used in the Sun Corridor, the area from Phoenix to Tucson, goes to agriculture, according to a 2011 report by the Morrison Institute for Public Policy at Arizona State University. Steadily, though, much of the farmland has given way to development.
Figuring out how water will be used here is like solving a puzzle speckled with blank pieces, in which the unknowns are the housing market and climate change.
Water managers weigh wet and dry cycles over the past 100 years against climate change models designed in the previous year and demographic projections. They also analyze the way parcels of land are zoned to make assumptions about how water will be used.
Overall, demand for water has declined steadily in this and in many other metropolitan areas, because of water-efficient technologies like low-flow toilets, and stricter building codes. Still, the draining of rivers and other water sources — from overdevelopment, poor management, climate change or a little bit of all of these — has forced communities to rethink their strategies. Some have used money as the main incentive to get people to give up their addiction to turf. […]
“There’s a need to use water to make our community livable, but in an intelligent way that thinks about long-term sustainability,” said Dave D. White, a director of the National Science Foundation’s Decision Center for a Desert City. “Because there’s no new supply out there.” [more]