Surviving a warmer world: Global forecast is 'mostly dry'

Climate change is already being blamed for altered rainfall patterns and shrinking glaciers that provide water for drinking and agriculture. Part 1 of an occasional series.

from the April 5, 2007 edition

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A city slakes its thirst

How will humans cope with a drier climate? The city of Albuquerque has shown how much water can be saved through a concerted effort – if resources are available. But its experience also highlights the complex demands made on water resources.

The state's major river, the Rio Grande, cuts through Albuquerque. But it's only a dry riverbed part of the year. The city draws virtually all of its water from an underground aquifer, says John Stomp III, water resources manager for the city. By some accounts, Albuquerque once was thought to be sitting atop an aquifer with enough fresh water to fill Lake Michigan.

But in 1993, a closer look reversed that verdict: The city's underground lake was far smaller than previously estimated – and it was disappearing fast.

In 1994, the city set a goal to cut water consumption by 30 percent over 10 years. By 2004, it had cut consumption by 33 percent. By 2014, it aims to reduce that to 40 percent below 1994 levels.

To meet its goals, the city tightened its building code to improve efficient use of water. It gave tax rebates to residents and businesses for each low-flow toilet or shower head installed in existing buildings. It offered a $100 credit for installing water-efficient washing machines. It gave rebates for xeriscaping – replacing water-hungry lawns and plants with drought-tolerant species – and it changed landscaping codes to require this approach in new developments. The city also irrigates its parks and other public lands with treated municipal wastewater and has been hunting down and repairing leaky water mains.

Sending water back underground

Albuquerque also has built a diversion dam across the Rio Grande and is completing an enormous water-distribution facility nearby. Both open for business next year.

When they do, the city will rely on river water for 70 percent of its needs and use the underground aquifer to make up for shortfalls during dry years. During wet years, it plans to use some of the Rio Grande water to recharge the aquifer.

While the new IPCC reports may begin to add new urgency to water planning, up until now it's been difficult to factor global warming into water-resource plans, Mr. Stomp says.

The earlier models he's relied upon have given conflicting answers to questions surrounding local precipitation.

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