Above Average Reservoir Levels Offset Below Normal Idaho Snowpack01/24/2018
Snowpack levels in many basins in Idaho and Eastern Oregon are well below normal but reservoir levels are significantly above average.
That means irrigators have a significant amount of water in the “bank” — reservoirs — to fall back on this year in case snowpack levels continue to remain below normal.
“The snowpack is lagging behind but the good thing is that … we still have some pretty good reservoir levels,” said Tim Page, who manages the Boise Project Board of Control, which provides water to 167,000 acres of farms and five irrigation districts in southwestern Idaho.
As of Jan. 22, total snowpack in the Boise River basin was 65 percent of normal, according to the Natural Resources Conservation Service.
But the amount of water stored in the Boise River system’s reservoirs is above average.
“It looks like we’re in pretty good shape as of right now,” Page said.
The same scenario is repeated in many basins throughout Idaho, according to the NRCS January water supply outlook report for the state.
“Reservoir storage is in good shape across the state with nearly all reporting normal to well above normal storage for this time of the year,” the report states. “Idaho’s reservoirs are the bright spot now for next year’s water supply outlook.”
Only a few basins have near or above normal snowpack levels right now.
“If snowpacks and projected stream flow volumes remain below normal, above normal reservoir storage will be critical to make up the difference and should help to provide adequate irrigation supplies in most areas,” the NRCS report states.
Snowpack is well below normal in southwestern Idaho basins. For example, it’s 55 percent of normal in the Weiser River basin, 76 percent of normal in the Payette River basin and 65 percent in the Boise River basin.
In the Owyhee River basin in Eastern Oregon, snowpack is 39 percent of normal. The Owyhee Basin feeds water into the Owyhee Reservoir, which provides water to 118,000 acres of irrigated farmland in Eastern Oregon and part of Idaho.
But the reservoir is 67 percent full with 482,000 acre-feet of water. That’s about 150 percent of normal for this time of year.
The reservoir is already close to having enough water to provide growers with a normal irrigation supply this year, said OID board member and farmer Bruce Corn.
“Certainly, it looks good for this year,” he said.
But, he added, “Snowpack is pretty grim. That doesn’t bode well for stream flows.” Unless snowpack levels pick up, “we could be looking at an empty reservoir at the end of the year.”
In Eastern Idaho, it’s a different story.
Reservoirs are at record levels in the Snake River basin and snowpack is slightly above normal, said Tony Olenichak, program manager for Water District 1, which is the state’s largest and provides water for about 1.2 million acres of irrigated farmland.
“It looks pretty good right now,” he said. “We’re in a lot better position than the southwestern part of the state.”
Source: Sean Ellis, Capital Press