Climate change to hit American West water supply
Climate change could cut water flow in some of the American West's biggest river basins -- including the Rio Grande and the Colorado -- by up to 20 percent this century, the Interior Department reported on Monday.
This steep drop in stream flow is projected for parts of the West that have seen marked increases in population and droughts over recent decades, Interior Secretary Ken Salazar said in a telephone briefing.
"These changes will directly affect the West's water supplies, which are already stretched in meeting demands for drinking, irrigating crops, generating electricity and filling our lakes and aquifers for activities like fishing, boating and to power our economy," he said.
A new Interior Department report outlines increased risks to water resources in the U.S. West for the 21st century, including:
- a temperature increase of 5-7 degrees F (2.77 to 3.88 degrees C);
- more precipitation where it's already wet (northwestern and north-central parts of the American West) and less where it's already too dry (southwestern and south-central parts);
- a decrease in April 1st snowpack, a standard benchmark measurement used to project river basin runoff;
- an 8 to 20 percent decrease in average annual stream flow in several river basins, including the Colorado, the Rio Grande, and the San Joaquin.
"Climate change will add to the challenges we face, which will be felt first in the Western United States," said Anne Castle, the Interior Department's assistant secretary for science and water. She noted that some of the fastest population growth has occurred in the driest areas, including parts of Nevada, Arizona, Utah, Idaho and Texas.
"Water is on the leading edge of climate change, so many of these basins have already experienced significant ... decreases to water supply," Castle said.