Idaho water director tells Jefferson County: delivery-call orders and expanded boundary require mitigation plans by late 2025

Matt Weaver, director of the Idaho Department of Water Resources, told Jefferson County commissioners that actions the department issued this spring and summer on the Eastern Snake Plain Aquifer were aimed at fulfilling statutory duties and court rulings, not to punish irrigators. “Nothing in the actions that I took this spring or this summer were done out of maliciousness or to be punitive in any way to the groundwater users,” Weaver said.

Weaver outlined two decades of litigation and management rules tied to delivery-call proceedings and summarized recent hydrology and management activity. He said the state and groundwater districts have averaged about 250,000 acre-feet per year of recharge and roughly 350,000 acre-feet per year of conservation measures from 2016 through 2023 — “in combination, that’s about 600,000 acre feet of management activities,” he said — and credited those efforts with helping stabilize aquifer levels this decade.

Weaver reviewed the effects of last year’s expansion of the administrative boundary under Senate Bill 1341 (the Eastern Snake Plain Aquifer Area of Common Groundwater Supply Expansion Act), which he said brought roughly 1,400 additional groundwater rights into delivery-call proceedings. He told the board that, because newly included rights will need mitigation plans and because approval of new mitigation plans can take 18–24 months in contested cases, he issued an order giving those newly included groundwater users until Nov. 1, 2025 to participate and to have mitigation plans in place. That timeline, Weaver said, effectively gives roughly an 18-month window to join existing mitigation plans or develop new ones.

On forecasting and “in-season” injury calculations, Weaver said the department bases determinations on an April forecast that protects senior surface-water rights, and that courts have required in-season recalculation when injury occurs later. That process, he said, can create a “roller-coaster” effect for users because April forecasts can differ materially from conditions measured in July or at season’s end.

Weaver also discussed resources and next steps. He said the department has increased staff in its water-distribution unit but still lacks capacity to establish and measure the many water districts needed for administration; he intends to seek a budget enhancement for roughly five additional FTEs. He noted the Idaho Water Resource Board recently launched a groundwater-to-surface-water conversion grant program seeded at $20 million, with awards up to $5 million (board materials referenced a 75% cost-share for hard conversion projects and 50% for soft conversions) to encourage permanent conversions from groundwater to surface water where feasible.

Commissioners pressed Weaver on incidental recharge, whether flood-irrigation practices should be credited and how accounting changes would redistribute benefits and burdens. Weaver cautioned that changing accounting rules could create winners and losers because the system is net-sum accounting of debits and credits; he said those are policy questions for the legislature.

Weaver concluded that, if parties can reach a new mitigation plan that addresses averaging across years and protects individual farmers who have met obligations, the legal and practical disputes might ease. He offered to meet with local groundwater districts and follow up with commissioners on technical and administrative questions.