Special Reports

Water solvable

With a city water plan that looks ahead 50 years and a state groundwater budget that accounts for the next century, we're looking to a wet future. Tucson is widely recognized for its conservation efforts - we're using less water than we have in the past. But all of the planning and saving is designed for one thing: to keep Arizona growing. Pima County's population is expected to nearly double by the middle of the century. By then, Tucson Water predicts its demand will double as well, by an extra 111 million gallons a day. To get all that water, in the short run, we'll likely drink treated waste water. A bit longer term, we'll buy or lease water from farmers and tribes. But what happens after that? After the last person learns to turn off the water while brushing his teeth, after we all master the art of the quick shower, after we've squeezed all the moisture we can from the state's farms, tribes and water treatment plants, what then? Some of the most futuristic ideas out there are perfectly sensible. Some can only be described as downright wacky. Logical or loopy, they're all potential solutions to a need for water that can only grow - along with the thirst of our cities. Towing icebergs

Oceans account for 97 percent of the Earth's water, and most of the remaining 3 percent is fresh water frozen in glaciers, icebergs and polar ice caps. So why not lug the giant blocks of ice down here to the desert, where water is scarce? It's an idea that's been bandied about for decades, though more proposals have been floated than icebergs themselves. Even Tucson Water's 50-year plan suggests icebergs as a possible solution to the West's natural scarcity of water. "Where the practical end of the spectrum grades into the improbable is not clear," the plan says, "and cost may not be a limiting factor if there is a great enough need." The big challenge with towing an iceberg is getting it to Los Angeles or some other port before the thing melts. Engineers have proposed fitting icebergs with propellers, attaching sails and using tugboats. Even then, it could take months to complete the trip, and most of the iceberg would melt. To prevent that, some suggest wrapping icebergs in plastic to trap melted water and stem evaporation. Even if icebergs were carved like ship's bows for a streamlined journey, as some suggest, tugboats would burn enormous amounts of fuel pulling their cargo thousands of miles. There is precedent: a Canadian company makes vodka and bottled water from icebergs harvested off the Newfoundland coast. "This is the water destined for us, for millenniums, which we rightfully deserve," proclaims the Canadian Iceberg Water Co. Web site. Desalination

Local water planners have long joked that their fallback option is running a pipe through Sonora, Mexico, and desalinating the Sea of Cortez. The slightly more likely scenario, experts say, is the construction of massive desalters along the Southern California coast. Inland states like Arizona might help pay for such plants and, in turn, take some of the Colorado River water Californians have been using. Industrial-size desalters have become far more efficient in recent years thanks to advances in filtration technology. But their main drawback continues to be their energy consumption: it requires an enormous amount of pressure to force millions of gallons of water through membranes able to trap salts. That's why desalination is most common today in the oil-rich Middle East - Saudi Arabia gets about 70 percent of its drinking water from the ocean - and why desalination won't come cheap. Cloud seeding

Cloud seeding - encouraging rain by dropping tiny particles into clouds - is a promising way to increase the water in the Colorado River, the state's water experts say. Cloud seeding is done on small scales in Colorado and Utah. But the idea of enhancing the snowpack in central Colorado's highlands - at a scale that could increase the Colorado's flow by 10 percent to 15 percent - hasn't been seriously discussed for decades. Back then, the costs of cloud seeding were estimated at up to $15 million, with returns of about 10 times that much through power generation and new water uses. Downstream drying from cloud seeding, a concern of critics for decades, is unlikely, experts say. But ski towns would spend more time digging out cars and driveways even as they enjoy the extra powder on the runs. Draconian rules

Before local governments start limiting subdivisions and building permits because of water shortages, they might first enforce mandatory conservation. Cities and counties could ban fountains, golf courses, swimming pools and other nonessential uses of water. New homes here already must include water-saving fixtures, such as low-flow toilets. But more could be done to reduce how much water each of us consumes at home, conservation experts say. Among the ideas: ● Double-plumbing houses with a separate network of pipes to capture "graywater" from drains, showers and washing machines, then using that supply for outdoor watering. ● Installing instant hot-water heaters that make it unnecessary to run faucets until the water warms up. ● Adopting stricter landscaping codes that require drought-tolerant plants, or paying people to rip out their lawns, as is done in Las Vegas today. ● Harvesting rainwater from rooftops with cisterns attached to gutter spouts. Tapping rivers and lakes

Imagine the Central Arizona Project, but bigger: a giant pipe heading from the Mississippi River, the Great Lakes, or - most likely - the Columbia River of the Northwest. Comical, you say? Unwieldy? Maybe. But it's not entirely out of the question, Western water experts say. There are precedents. The Colorado-Big Thompson Project carries lake water under the Continental Divide to the east face of the Rockies, to supply many Front Range towns. Aurora, a suburb of Denver, has proposed tapping the Gunnison River, the one Western Slope river not yet diverted. And then there's our own Central Arizona Project, a 336-mile canal with the capacity to deliver 1.5 million acre-feet of Colorado River water - each acre enough to supply a family of five for a year - to Arizona's cities. The Colorado River, the nation's seventh largest, has an average flow of about 15 million acre-feet a year. By contrast, the Columbia carries 192 million acre-feet a year and the Mississippi more than 400 million. So they have more. And we want it. Tapping into it hasn't progressed from the brainstorming to the planning stages. But experts aren't ruling it out.