糖心视频

(糖心视频) -- The American West has a drinking problem. On farms and in cities, we are guzzling water at an alarming rate.

Scientists say that to live sustainably, we should use no more than 40 percent of the water from the Colorado River Basin. As it is now, we use 76 percent, nearly double the sustainable benchmark.

The water supports the populations of California, Arizona, Nevada, Utah, New Mexico, Colorado and Wyoming, providing for agriculture and cities. With a changing climate and continued population growth, increasing demand for water may make this vital resource increasingly scarce.

There are some safeguards in place against water scarcity. The reservoir Lakes Mead and Powell can provide approximately five years of average annual stream flow at full capacity for insurance against low rainfall years.

But John Sabo, an associate professor in Arizona State University鈥檚 School of Life Sciences, believes that 50 years in the future 鈥� rather than five 鈥� should be the planning mark for water usage.

鈥淢y take on that is we鈥檙e already beyond the point where we have enough insurance against the bad years, which is why a year and a half ago we started talking about water rationing before it started raining in December,鈥� says Sabo, who is also director of research development in ASU鈥檚 Global Institute of Sustainability.

After dipping to a record low in 2011, Lake Mead presently sits at below half capacity, and that鈥檚 with favorable rainfall and snowpack accumulating in the Rocky Mountains, which feed the Colorado.

Also, to our detriment, there is a culture dedicated to creating an oasis in the Southwest鈥檚 arid environment. Most of the West鈥檚 water falls in the mountains, where it slowly melts, We collect it and then spread it thin across the deserts. Moving water from wet areas to dry areas makes people feel safe, according to Sabo.

鈥淲e have lawns, palm trees and lush green parks because we store water from far away to offset the arid reality of the desert,鈥� he says.

Regardless of how much our lawns guzzle, the largest use of water isn鈥檛 in urban areas but in agriculture. Farming uses 77 percent of the water allocated for human use in Arizona, according to the Morrison Institute for Public Policy鈥檚 publication 鈥淲atering the Sun Corridor.鈥�

For example, Southwestern farms produce approximately 75,000 acres of lettuce annually. As much as 55,000 acres of that is grown in Arizona, according to University of Arizona publications. Of Arizona鈥檚 lettuce, 95 percent is grown in the southwestern corner, in Yuma county, which receives an average rainfall of about 3.6 inches.

鈥淧eople might ask, why are we growing lettuce in Arizona?鈥� questions Sabo. 鈥淲ell, it鈥檚 because it鈥檚 warm here in the winter and people want salads in the winter. And if you want a salad in the winter and you don鈥檛 want to wait for natural salad season to come around, you鈥檝e got a tradeoff, and that tradeoff is the water footprint.鈥�

The water footprint of produce isn鈥檛 often taken into consideration, however.

鈥淭here鈥檚 this 鈥榚at local鈥� movement that has done a great job to educate people about how your decisions at the supermarket relate to your carbon footprint and climate change,鈥� says Sabo. 鈥淏ut there鈥檚 nothing like that for water, and I think there needs to be.鈥�

Since most water isn鈥檛 used for cities, urban lifestyle changes aren鈥檛 going to do much to solve the problem. Shorter showers and eco-friendly appliances aren鈥檛 enough to make a significant impact on our massive water use.

Sabo proposes that the Southwest cuts its water use to 60 percent. To get there, it comes down to policy and investment in infrastructure for the future.

鈥淵ou would never know we had a water shortage here,鈥� says Sabo. 鈥淲e don鈥檛 pay a lot for it, we don鈥檛 expect pay a lot for it and we don鈥檛 expect to have to conserve it.鈥�

David White, co-director of ASU鈥檚 Decision Center for a Desert City (DCDC), says that Arizona water policy has done a good job of providing adequate supplies for the growth of the region up to this point. But environmental and demographic factors will likely require changes in that system. The DCDC uses research to inform environmental policy in times of uncertainty.

鈥淲e鈥檝e been able to deliver a consistent and reliable amount of water to residents even though the amount of water that comes into our system fluctuates wildly,鈥� says White. 鈥淭hat system has been effective over the past 100 years under a set of conditions and assumptions that may be changing due to climate change, extended and prolonged droughts, and increased demand as a result of population growth. It faces new challenges,鈥� adds White.

Home to more than half of Arizona鈥檚 population, Maricopa County grew by 24 percent from 2000 to 2010, according to U.S. Census Bureau data. Additionally, 鈥淲atering the Sun Corridor,鈥� projects the 2030 population of Phoenix and Tucson to exceed 7.8 million.

One way to reduce water use is through the addition of more sustainable infrastructure. According to Sabo, this would be most effective in areas of growth and expansion, such as Ahwatukee, Anthem and Sunrise.

鈥淩etrofitting historical Phoenix would be a pain in the neck,鈥� says Sabo. 鈥淭he idea is to build sustainable infrastructure as we build out. Reclaimed water is cheaper to add in to unbuilt suburbs than to retrofit in older cities. When the time comes for refurbishing the old potable infrastructure in the central city, then we can consider retrofitting for dual distribution of potable water for drinking and reclaimed water for landscape irrigation at home.鈥�

Such changes would help us follow White鈥檚 recommendation to stop siphoning our limited groundwater sources and live off of renewable surface water instead. Groundwater is water that is stored in underground aquifers. Although it is replenished by rainfall, we use it much faster than it can be replaced.

鈥淕roundwater supplies a bank or a backup of water,鈥� says White. 鈥淏ut by and large it鈥檚 a nonrenewable source and we should try to live within our means.鈥�

It鈥檚 unlikely that the Southwest would run out of water. But as temperatures rise and population swells, how we value our water supply is going to change.

鈥淵ou鈥檙e either going to have to pay more for it or you鈥檙e going to have to pay more for your winter salad,鈥� says Sabo. 鈥淓ither the farms or the luxury to use water the way we do in cities is going to go.鈥�