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Eastern Idaho Reservoirs Shrink Toward Record Low by Associated Press Lewiston Tribune, September 13, 2003

BOISE -- Water users in southern and eastern Idaho may be left with a record low level of water to carry over into the 2004 growing season, but the western side of the state is in much better shape, water managers said Friday.

In the Upper Snake River valley, from Jackson, Wyo., to Twin Falls, the eight-reservoir system contains about 8 percent of its capacity.

There is always less water in the fall than at the beginning of the growing season, but watermaster Ron Carlson predicted that this year's final drafting of Jackson Lake will leave the reservoir as low as it has ever been.

"In the worst case, if we had a winter like we did in 1977 winter and a summer like 2003, we would have a devastating situation with crop losses from Ashton to Twin Falls. But that's not what we're predicting," Carlson said. "If we have a normal snow year, we'll refill the system. We don't have to have a monster year to make everything right."

Eastern Idaho water managers predict that there will be 250,000 to 400,000 acre-feet of carry-over. An acre-foot of water is the volume that would one acre of ground one foot deep; it's equivalent to 325,851 gallons of water.

In the Boise and Payette systems, the carry-over situation is far better, officials said. Although Arrowrock Reservoir has been drained almost completely to allow for work on the dam, other impounds still have at least 50 percent or better storage.

Idaho Water Resources Department spokesman Dick Larsen said southwestern Idaho is looking at an essentially normal water year.

The key factor for agriculture, fish survival and water-based recreation next year will be the amount of snowfall in the mountains this winter.

Current long-range precipitation models by the National Weather Service Climate Prediction Center indicates Idaho should have about normal precipitation until springtime. After March, there's a chance the state could get more rainfall than normal through early summer, especially in the Panhandle.

Idaho also has a chance of warmer-than-normal temperatures this fall and in early winter. But spring and early summer in 2004 are expected to produce about normal temperatures.

Even if this winter brings above-normal snowpack, it takes a year or more to recharge groundwater stores. And because of the lower water table from recent drought years, Larsen said the department has been flooded with applications for new or deeper wells.

About 1,200 applications have been received so far this year, Larsen said, mostly for agricultural purposes. A normal year usually brings about 1,000.