BOISE — Irrigation water will flow until the middle of October in many parts of the Treasure Valley of Idaho and Oregon and many irrigation districts will finish the year with a lot more carryover water than normal.
Mountain snowpack reached near-record levels in many basins in southwestern Idaho and Eastern Oregon last winter and the result was a plentiful water supply this year and ample supplies heading into next season.
“It’s been a pretty good water year,” said Tim Page, manager of the Boise Project Board of Control, which provides water to 167,000 acres and five irrigation districts in southwestern Idaho.
Page said the project plans to cease deliveries on Oct. 16, which is about a week later than in recent years.
The project will also finish the year with about 220,000 acre-feet of carryover water, depending on how much demand there is on the system between now and Oct. 16. That’s about 75,000 acre-feet more than last year.
The Owyhee Project, which supplies water to 1,800 farms and 118,000 irrigated acres in Eastern Oregon and part of Idaho, will shut off about the middle of October, depending on demand, said Bruce Corn, a farmer and member of the Owyhee Irrigation District’s board of directors.
The Owyhee Reservoir will end the season with more than 400,000 acre-feet of carryover water for next year, Corn said. The reservoir hasn’t had that much carryover water since 2011.
“That pretty much assures us of a normal water supply for next year,” Corn said. “If we have a dry winter, we’ll still have an adequate amount of irrigation water for next year.”
Pioneer Irrigation District tentatively plans to cease water deliveries to its 5,800 patrons on Oct. 6, although the actual date will be confirmed during a board meeting next week, said PID Manager Mark Zirschky.
As of now, it looks like the district will carry over about 50 percent of its total reservoir storage water into next season, well above the normal 20-25 percent total, Zirschky said.
He said the district was able to get by on natural flow in the Boise River much longer than normal this year and therefore didn’t have to use as much of its reservoir storage as usual.
The Payette River system, which provides irrigation water to about 160,000 acres, will end this year with its reservoirs about 70 percent full, as opposed to about 50 percent in a typical year, said watermaster Ron Shurtleff.
“We’re going to go into this winter very healthy,” he said. “We could weather a real short water year and still come out fine on the Payette.”
The Weiser Irrigation District plans to cease water deliveries on Oct. 15, it’s normal cutoff date, said chairman Vernon Lolley.
The district will finish the year with about 30,000 acre-feet of carryover water, which is “way ahead of where we normally are,” Lolley said.