Interior Dept. Study Projects 9% Drop In Colorado System Runoff By 2050 - SL Trib

[hatrack]

The Colorado River Basin likely will lose about 9 percent of its annual runoff by mid-century because of a warming climate, further squeezing Utah and its neighbors in a region that already expects to struggle getting water to its growing population, according to a U.S. Interior Department report released Monday.

Bureau of Reclamation scientists calculated likely regional temperature and precipitation models based on a range of possible carbon dioxide emissions, then used the mean of the results to predict an 8.5 percent reduction in water supply. The report actually predicts a 2.1 percent increase in precipitation for the Upper Colorado Basin — of which Utah is a part — but temperatures 5 to 7 degrees warmer than today’s are expected bring more rain than snow, and enough more evaporation to sap the supply.

In the Lower Colorado Basin, precipitation is expected to decline 1.6 percent. "Water is the lifeblood of our communities, rural and urban economies and our environment," Interior Secretary Ken Salazar said in a statement, "and small changes in water supplies or the timing of precipitation can have a big impact on all of us."

The report, a requirement of the Secure Water Act of 2009, projects wetter conditions in the Northwest and north-central United States, and further drying out in the Southwest. Even where moisture increases, winter rains — in place of snows — may decrease springtime and summer runoff for irrigation.

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http://www.sltrib.com/sltrib/politics/51690000-90/utah-percent-report-river.html.csp