For a desert community, where summertime temperatures routinely exceed 115 degrees, Phoenix uses water with a profligacy that has long astonished newcomers.
Flying into the city, the grays and browns of the desert landscape are transformed into blues and greens. As if it were a finely wrought brooch of turquoise and lapis lazuli, the city seems to be defined by the deep, startling green of golf courses bordered by the shimmering blue of thousands of swimming pools.
First impressions aren’t always accurate, but this one is.
The Phoenix metropolitan area contains 80 golf courses and 300,000 swimming pools. Each year, more than 20,000 pools are constructed.
An average swimming pool holds about 20,000 gallons of water. And because of evaporation losses, pools in the desert climate of Phoenix need frequent topping off, amounting to a complete refill every year. Those losses amount to enough potable water to supply 30,000 households annually.
As the drought in the Colorado River and in the Valley of the Sun has deepened, Phoenix has begun to pay some attention to conservation, but the swimming pool culture appears to be untouchable.
“Truthfully, people say they can’t live in Arizona without a pool,” said Paul Charman, senior conservation planner with the Arizona Department of Water Resources.
The Phoenix Water Department’s Web site, while stressing obvious (and relatively petty) conservation measures such as using low-flow toilets, running your dishwasher only when it’s full and not watering your lawn when it rains, has only one recommendation for pool owners.
“Invest in a swimming pool cover to help prevent evaporation.”
As Susanna Eden and Sharon Megdal wrote in “Water and Growth” in 2006: “Water planning in Arizona has served to accommodate growth, not restrict it. It has been recognized by growth proponents and opponents alike that the more efficiently water resources are managed, the more growth water supplies will support. With current technology, Arizona has enough water to support a (much larger) population, assuming that essentially all the water would go to municipal and industrial users. However, as more than one observer has commented, environmental stresses and economic dislocations will be felt long before growth reaches the theoretical limits of Arizona’s water supply.”
But if, as many experts suggest, the current drought is the new “normal,” Arizona’s water resources might be far more constrained than policymakers and analysts are willing to admit.
Using multiple variants on predictive models which correctly modeled the Colorado’s flow between 1990 and 2005, Martin Hoerling of NOAA and John Eischeid of the University of Colorado found during a 2007 study that “… the 42-run average predicts a 25 percent decline (from 13 million acre feet) in streamflow during 2006-2030, and a 45 percent decline during 2035-2060.”
The average “natural flow” of the river would then, in three decades, decline to less than 7 million acre-feet, an amount that would meet less than 50 percent of today’s demands. As Hoerling and Eischeid conclude, “These projections further expose the risky (belief) by Colorado River users that streamflows will always materialize to match legislated requirements.”