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Idaho water year off to a good start

Published on January 9, 2013 3:01AM

Last changed on February 6, 2013 8:09AM


Capital Press

Mother Nature has been good to Idaho irrigators thus far this water year, which began Oct. 1.

"Overall we're off to a great start," said Ron Abramovich, water supply specialist with the Natural Resources Conservation Service in Boise.

There's a lot of snow in the central mountains above 7,000 feet. But it's been unique because there's very little snow below 6,500 feet, he said.

With higher temperatures in November, moisture came as rain in the lower elevations. Lower temperatures above 7,000 feet allowed the moisture to fall as snow several feet deep. As a result there were five or six sites with near-record snowpack in the upper elevations and near record lows in the lower elevations in mid-December, he said.

Lumping those elevations together, Jan 1 snowpack percentages range from 130 percent to 160 percent of normal in the central mountains to 68 percent of normal in the Weiser basin. Elsewhere, the snowpack is near normal at 80 to 120 percent of the 1981 to 2010 medians.

Northern Idaho has already received all of its annual precipitation in the first three months of the water year, and snowpack in the Upper Snake basin is at near normal or better, he said.

Adding to the good news is there's still more than half of the winter season to come and Idaho is back in the storm track, he said.

A long, dry summer -- dominated by a high-pressure ridge that stopped storms from tracking into the state -- resulted in minimal valley and mountain precipitation. But October precipitation ranged from 65 percent to 85 percent of normal across southern and central Idaho and 165 percent to 180 percent in west-central and northern Idaho, NRCS reported in its water supply outlook report released Jan. 7.

The wet trend continued in November, bringing 200 percent of normal precipitation to the Big Lost and Little Wood basins, 65 percent to 75 percent south of the Snake River and 89 percent in the Bear River basin, the report said.

Carryover is also positive, with reservoirs 80 percent to 115 percent of average with the exception of a few in central and southern Idaho. Hydro plant maintenance at Magic Reservoirs necessitated a drawdown, which resulted in water stores at only 23 percent of average, Abramovich said.

Salmon Falls and Owyhee are also low at 55 percent and 66 percent of average, respectively. Those areas need good snowfall, which they are presently getting, he said.

"It's looking like a full water supply across most of the state," he said.

But "we don't need any flaming hot fireballs from nature. We don't want to lose snowpack too early," he said.


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