Idaho Surface Water Coalition, Groundwater Districts File Joint Motion to Expand Statewide Mitigation Plan
BOISE — The Surface Water Coalition (SWC) and nine groundwater districts took a significant step Friday to shore up Idaho’s strained water management system, filing a joint motion with the Idaho Department of Water Resources (IDWR) seeking approval of the First Addendum to the 2024 Stipulated Mitigation Plan. The filing formally initiates the process to bring three additional water districts — the Little Lost River Basin, Big Lost River Basin, and Upper Big Lost River Basin Ground Water Districts — into the existing agreement.
The joint motion follows weeks of technical review and negotiations among SWC members and all participating groundwater districts, according to officials involved in the process. The agreement reflects a shared commitment to protect Idaho water users, support the health of the Eastern Snake Plain Aquifer (ESPA), and ensure compliance with state water law — including Idaho’s prior appropriation doctrine, which governs the order in which water rights are honored.
Uniform Standards Across All Participating Districts
Under the terms of the First Addendum, the newly joining groundwater districts will be held to the same core requirements already binding existing participants. Those obligations include groundwater conservation targets, storage water commitments, and participation in mitigation measures such as managed aquifer recharge. The uniform standards are designed to ensure that all parties contribute fairly and consistently to addressing impacts on the ESPA and to protecting senior water rights under Idaho law.
SWC Chairman Alan Hansen emphasized the urgency of strengthening the plan given current conditions across the state. “With declining reach gains and ongoing drought conditions, strengthening this Mitigation Plan is essential,” Hansen said in a statement. “The agreed-upon terms for the First Addendum make sure that everyone is operating under the same standards at a time when Idaho’s water system is under severe pressure.”
Hansen also underscored the agricultural stakes involved. “Every person at the negotiating table represents Idaho farmers and irrigators who depend on this resource. Our goal has always been to build a plan that works not just today but for the long-term stability of Idaho agriculture and the aquifer we all rely on,” he said.
The agreement arrives at a critical moment. Irrigation season is now underway, and southern Idaho is grappling with severe declines in the Snake River’s reach gains on top of a statewide drought emergency declared by IDWR Director Mat Weaver on April 13. Water managers and agricultural stakeholders say the timing of the addendum underscores just how important a unified, science-based approach to water management has become. Idaho’s agricultural economy — dependent on reliable irrigation water — stands to benefit from a more comprehensive and coordinated mitigation framework. Increasing demand for water has already strained the Upper Snake River system, making cooperative management agreements like this one increasingly vital to the region’s long-term water security.
Next Steps Before IDWR and Future Negotiations
With the joint motion now filed, the SWC, the Idaho Groundwater Appropriators (IGWA), existing participants, and the newly joining groundwater districts will move forward with implementing the First Addendum. Simultaneously, parties will advance informal negotiations regarding the extension of the broader 2024 Mitigation Plan.
Officials said the process required careful deliberation. “This process required careful review and hard conversations, but we remained focused on getting it right,” Hansen noted. “By holding to consistent standards and working through the data together, we have reached a solution that supports all Idaho water users and protects the integrity of the Mitigation Plan.”
The SWC reaffirmed its commitment to collaborative, data-driven water management that upholds Idaho law, protects senior water rights, and ensures the long-term viability of the Eastern Snake Plain Aquifer — one of the most critical natural resources for agriculture across southern and southeast Idaho.
Water management challenges are not limited to the Snake River corridor. Communities across the region, including in Bannock County, are navigating their own infrastructure demands. The City of Pocatello recently began seasonal water flushing operations as part of ongoing efforts to maintain water system quality for residents.
What Comes Next
The Idaho Department of Water Resources will now review the joint motion seeking approval of the First Addendum to the 2024 Stipulated Mitigation Plan. If approved, the three newly joining groundwater districts will become bound by the same mitigation requirements as existing participants. Informal negotiations over the extension of the 2024 Mitigation Plan are expected to continue in parallel. Water users, agricultural operators, and policymakers across Idaho will be watching IDWR’s decision closely as drought conditions persist and the 2026 irrigation season intensifies.