BOISE — Southwestern Idaho’s water supply situation for 2015 looks adequate at this point but it’s still uncertain and could change if mountain snow melts too quickly.
“The bright spot is that the reservoirs are sitting pretty good. What’s unknown right now is how the river flow does when we get closer to April,” said Greg Curtis, superintendent of Nampa & Meridian Irrigation District, the valley’s largest.
Curtis said the district, which delivers water to 69,000 acres, usually banks on getting by on natural river flows until about July before switching to water stored in reservoirs.
But an unusually warm February caused snow in the Boise River basin to melt much quicker than normal this year, and the river is experiencing April-like flows in March, he said.
How the river flows hold up later in the season is a big question mark that could change things for better or worse, Curtis said.
“I think it will be an OK season,” he said, but added that “it’s hard for me to predict” at this point.
Snowpack in the basin was at 73 percent of the 30-year average on March 12 but because of decent reservoir carryover supplies from last year, “I’m suspecting we’ll have an adequate amount of water this year,” said Boise Project Board of Control Manager Tim Page.
BPBC delivers water to five irrigation districts and 165,000 acres in the valley.
But Page said he’s concerned about how fast the snow will melt. If it melts rapidly, the river flows will be reduced too quickly, he said.
The best scenario would be for the snow to melt off gradually “so we can run off river flow for as long as possible and put water into the reservoir at the same time,” Page said.
Pioneer Irrigation District Manager Mark Zirschky said water supply managers are watching the weather forecast very closely.
“The snowpack’s coming off earlier than we want it to,” he said. “Right now I’d say it has a chance to be a decent year but we don’t know that for sure quite yet.”
The Payette River system, which supplies water for 155,000 acres, also tentatively anticipates an adequate supply of water this year, said watermaster Ron Shurtleff.
“We’re probably sufficient,” he said. “We’re not plush by any means.”