Colorado River Expected To Experience Shrinkage
December 24, 2012

Shrinking Colorado River Could Lead To Water Shortages

redOrbit Staff & Wire Reports - Your Universe Online

Researchers anticipate the Colorado River will shrink by 10-percent over the next few decades, and that could spell trouble for the approximately 40 million people who rely on it for water.

Richard Seager, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory, and colleagues report the river will fall victim to warmer weather caused by increasing amounts of greenhouse gases in the Earth's atmosphere.

Those changes could not only disrupt long-standing water-sharing agreements in the southwestern US, but could also ultimately lead to a shortage of H2O, the researchers warn.

Ten percent "may not sound like a phenomenally large amount except the water and the river is already over-allocated," Seager, lead author of a study that appears in the journal Nature Climate Change, said in a statement on Sunday.

His team's findings "expands on findings published in 2007 in the journal Science," which claimed the southwest was "becoming more arid as temperatures rise and rainfall patterns shift from human-caused climate change," the university explained.

Likewise, a recent US Department of the Interior report predicted a 9-percent decrease in the flow of the Colorado River, as well as "longer and more severe droughts" within the next 50 years.

The newest research focuses on three primary regions -- the Colorado's headwaters, the greater California-Nevada region, and the state of Texas. Utilizing the same climate models used in the Intergovernmental Panel on Climate Change's (IPCC) forthcoming Fifth Assessment Report, the researchers discovered all three regions will experience warmer temperatures, leading to increasing evaporation and drier conditions.

Those conclusions are based on estimated seasonal changes in precipitation, evaporation, water runoff and soil moisture between the years 2021 and 2040, the researchers explained. The climate models also predict temperature increases of 1 to 2 degrees Celsius in all three areas.

"The Colorado headwaters are expected to see more precipitation on average, but annual stream flow is expected to decline by 10 percent, and as much as 25 percent during springtime, as warmer temperatures boost evaporation," the Columbia University team concluded.

That 10-percent decrease is approximately five times the amount of water used by the entire city of Las Vegas during a full calendar year, they point out.

As for the other regions, the researchers say California and Nevada "will also see big changes in spring, with a projected 20 percent drop in spring runoff," while Texas will "overall become drier with a 10 percent decline in annual runoff."