TWIN FALLS, Idaho — Eastern Snake Plain Aquifer groundwater entities representing nearly 1 million well-irrigated acres have unanimously endorsed an agreement aiming to reverse declining aquifer levels.
The affected groundwater groups — including nine groundwater districts and an irrigation district with wells — had until Aug. 1 to opt into the agreement, approved July 1 to resolve the decade-old Surface Water Coalition call. The seven Coalition members, who have also ratified the agreement, claimed injury due to Snake River spring flow declines below Blackfoot, attributed to junior well irrigation.
The groundwater entities, represented by Idaho Ground Water Appropriators, Inc., will be asked to reduce groundwater use within ESPA boundaries by 11 percent, in exchange for protection from future curtailment.
Models estimate the reduction should average 240,000 acre feet in annual groundwater savings — roughly equal to the aquifer’s rate of decline.
“I think the agreement is the only way we’re going to get there, and the aquifer has got to be fixed,” said Brian Olmstead, general manager of Twin Falls Canal Co., a Coalition member.
Olmstead said future discussions will focus on well irrigators who aren’t represented by groundwater districts or who draw from feeder aquifers outside of ESPA boundaries, hydrologically connected but not part of the current agreement.
The state has pledged to average another 250,000 acre feet of annual recharge — purposefully injecting surface water into the aquifer.
IGWA will also give the Coalition a flat 50,000 acre feet of mitigation water annually and invest $1.1 million each season in “soft conversions,” switching certain groundwater users to surface water.
Individual groundwater districts will be tasked with setting terms for achieving the reduction, addressing lingering questions such as how to factor in well priority dates and how to credit farmers for past improvements aimed at irrigation efficiency.
IGWA Executive Director Lynn Tominaga has spent the past two months educating members about the terms of the agreement. Tominaga said a 17-member steering committee comprising a leader from each participating entity has been formed to help resolve outstanding issues.
IGWA attorney T.J. Budge explained the “game changer” that drove the discussions was a recent change in Idaho Department of Water Resources policy, adding groundwater levels to the factors used to predict mitigation obligations in the Coalition’s call. Budge said the change, mandated by an Idaho district judge, would have made curtailment much more difficult to avoid.
Budge said to help farmers cut their water use, groundwater districts may provide supplemental funding to improve the attractiveness of USDA’s Conservation Reserve Enhancement Program, which pays groundwater users to stop irrigating farm land.
Lynn Carlquist, a Hazelton farmer who chairs the North Snake Groundwater District, said cropping patterns will have to change in his region, where water-intensive corn has become more common in rotations. He views stabilizing the aquifer as imperative for the sustainability of Idaho farming, not just for resolving a water call.
“Trying to make this so everybody thinks it’s fair and equitable is going to be a real problem,” he said.