Colorado River runoff picture stays good

2011-03-07T18:10:00Z 2011-03-07T18:14:53Z Colorado River runoff picture stays goodTony Davis Arizona Daily Star
March 07, 2011 6:10 pm  • 

While Southern Arizona's severe drought continues, the Northern Rockies that generate most of our water supply continue to produce above-normal snowpack. That keeps the signs positive for now for the crucial spring-summer runoff season that feeds Lake Mead -- the source of Tucson's Central Arizona Project water.

In a forecast released Monday, the federal government predicted that April-June runoff would be 116 percent of normal. That's up from 113 percent in the February 2011 forecast. Snowpack is currently 118 percent of normal, down slightly from 120 percent in early February.

March is often a crucial month in runoff seasons, because an early heat wave can melt snowpack prematurely and reduce the final runoff total--a phenomenon that occurred as recently as 2009. But if the current numbers hold up, the feds will have enough water to release some extra from Lake Powell to Lake Mead, thereby forestalling shortages on the Central Arizona Project for a few years. Without good runoff, the first shortage could occur as soon as 2012 or 2013.

Locally, however, Tucson's drought seems worse than ever. We've reaped only 1.17 inch of rain since Oct. 1 -- the start of the unofficial "water year" used by forecasters -- compared to a norm of 4.78 inches.

Looking ahead, the National Weather Service predicts that the drought will ease up a bit in the coming months, with slightly enhanced chances of above normal precipitation and temperatures. Temperatures are expected to be above normal. 

 

 

 

 

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Star reporter Tony Davis covers topics in this blog that you have read under his byline for more than 30 years in the Southwest: water, growth, sprawl, pollution, climate change, endangered species, mining, grazing and traffic.

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