Irrigators in eastern and south-central Idaho are facing curtailment if they don’t secure enough water to make up for a predicted 74,100 acre-foot shortfall to senior water right holder Twin Falls Canal Co.

Idaho Department of Water Resources Director Mathew Weaver issued an order on May 10, finding the mitigation plans of nine groundwater irrigation districts are deficient in securing enough water.

Idaho Ground Water Appropriators, which represents the common interests of its district members, disagrees.

Its attorney, Thomas J. Budge of the Racine Olson law firm, filed notice with IDWR on Tuesday that eight groundwater districts have secured storage water to fully mitigate the injury caused by their members. The notice said IGWA has copies of storage water leases covering the districts’ mitigation obligations.

Other users

The problem is while the districts have secured water to cover their portion of the shortfall, Weaver is requiring them to cover the injury from all groundwater users — including those who aren’t members of the districts — to avoid curtailment, Budge said.

Those other groundwater users include other irrigation districts and many cities. State code authorizes groundwater districts to mitigate for their members only. The director’s demand they mitigate for all groundwater users violates state law, he said.

IGWA is requesting the director to either amend or vacate and replace his order to allow groundwater districts to provide storage water specifically to mitigate for injury caused by groundwater use within the district.

“The ground water districts have offered to supply storage water as mitigation in order to avoid curtailment, but Director Weaver rejected their offer. He has said he will allow them to mitigate with storage water only if they provide enough storage to cover all groundwater users, including those who are not members of the districts,” he said.

“I assume he is doing this so that IDWR does not have to proceed with curtailment against anyone,” he said.

IDWR declined to comment.

Affected acres

IDWR hasn’t published the number of acres of farmland that would be dried up, but Budge’s understanding is it would be about 600,000 acres.

“This has been a very frustrating experience for groundwater users. Since 2016, IGWA’s members have conserved 2.6 million acre-feet of groundwater by reducing how much they pump from the aquifer, converting farmland from groundwater to surface water irrigation and conducting managed aquifer recharge,” he said.

On average, they have conserved about 325,000 acre-feet per year — much more than the 240,000 acre-feet called for by the 2015 settlement agreement between IGWA and the Surface Water Coalition, he said.

“Idaho is really at a crossroads for water management. Curtailment of groundwater use is not the solution. Idaho has the ability to keep all of Twin Falls Canal Company’s land irrigated without resorting to mass curtailment, but it will require a commitment to invest in modern technology to use our existing water supplies more strategically and efficiently,” he said.

“The question for state leaders is whether they want to solve our water conflicts by drying up tens or hundreds of thousands of acres of farmland, or by pursuing reasonable alternatives to meet current water demands with available supplies,” he said.