Saturday, March 13, 2010

Water shortages may hit northern Rockies

John S. Adams in USA TODAY: Much of the nation may be snow-weary, but farmers and ranchers who rely on winter snowpack in the northern Rockies for irrigation during the dry months of the growing season could face water shortages this summer unless more snow arrives soon. Wet spring and summer conditions in 2008 and 2009 helped pull the region out of a decade-long drought, but now hydrologists are once again reporting below-average mountain snowpack throughout much of the northern Rockies.

As of early March, according to the U.S. Drought Monitor, snowpack was at or near record-low levels in many locations from northeastern Utah northward along and near the Idaho border with Montana and Wyoming.

…"There's not much time to make it up," said hydrologist Phil Morrisey of the Natural Resource Conservation Service in Idaho. "Even an abundant snowfall in March would be unlikely to make much of a difference this late in the season." Some river basins in eastern Washington, Idaho, Wyoming and Montana are below 50% of their average seasonal snowpack for this time of year, according to Conservation Service snow monitoring data.

In the lower Yakima River basin in south-central Washington, snowpack is at about 80% of normal. Conservation Service hydrologist Scott Pattee said four of five reservoirs there will not fill to capacity this spring, which could mean trouble for farmers.

"It's going to mean water rationing for junior water-rights holders," Pattee said. Junior water rights are those issued most recently, he explained. Senior water-rights holders have first rights to irrigation waters. According to hydrologists across the region, most Rocky Mountain river basins typically accumulate 80% to 85% of their seasonal snow by March 1. They said April 1 is when most states in the region reach the peak snowpack….

Idaho Springs in 2006, shot by Dasneviano, Wikimedia Commons

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