BOISE, Idaho — The Idaho Department of Water Resources mailed letters to about 1,700 entities warning widespread groundwater curtailments may occur throughout the Eastern Snake Plain Aquifer, unless the water outlook improves.
IDWR Director Gary Spackman sent the warning, dated Jan. 28, to agricultural irrigators, cities, cemetery districts, power companies, industrial plants such as Jerome Cheese and Glanbia Foods, and others who rely on well water.
Spackman explained IDWR completed curtailment predictions based on years with similar Upper Snake River runoff forecasts. Surface Water Coalition irrigators made a call against junior groundwater users in 2005, requiring them to provide mitigation water or be curtailed for decreases in spring flows caused by their pumping.
According to IDWR’s calculations, there’s a roughly 5 percent chance runoff will be the same as in 2001 — the worst water year since 1981. That would result in a 227,000-acre-foot water obligation from groundwater irrigators with a priority date after Sept. 23, 1974, and the potential curtailment of 76,000 irrigated acres.
There’s a 30 percent chance that groundwater users with a priority date after 1989 will owe about 38,000 acre-feet, with the potential for 13,000 acres of irrigated ground to be curtailed. There’s also a 50 percent chance of no obligation.
IDWR Deputy Director Mat Weaver said the calculations were made during the first week of January, and the moisture outlook has further eroded since, increasing the odds of curtailments. Weaver emphasized certain groundwater users are also facing a recent IDWR ruling that they owe additional water to satisfy a call by Rangen, Inc., a research fish farm in Hagerman.
“I think between the two delivery calls, unfortunately, it’s looking very likely we will be taking curtailment action this year,” Weaver said, acknowledging there’s some acreage overlap.
Internally, Weaver said IDWR has considered the need to hire additional staff and coordinate with law enforcement if curtailment orders must be delivered because they would be “of a size and magnitude we’ve not had to deal with in the past.”
Lyle Swank, watermaster for Water District 1, said snowpack in the Upper Snake system is just slightly below normal. However, more than 60 percent through the water year, two key reservoirs are less than a quarter full.
Lynn Tominaga, executive director of Idaho Ground Water Appropriators, believes he could mitigate calls under a 1989 priority date. But he doubts he could purchase enough water to avoid locked wells under a 1974 priority date.
“If it stays like it has been during the last two months, there won’t be any water available,” Tominaga said.
Spackman must make his water supply forecasts by April 15.
Chubbuck Public Works Director Steve Smart plans to share the IDWR letter with his City Council and warn them of the “specter of curtailment.”
“If it does actually happen, we’ll have no choice but to eliminate landscape irrigation,” Smart said.
John Simpson, an attorney with the Surface Water Coalition, believes Spackman was wise to send notice of the declining water conditions to help users make appropriate planting decisions.
“I was in a meeting yesterday where the Bureau of Reclamation stated reach gains in the area from Blackfoot down to Milner were at all-time lows,” Simpson said.