Salt River Project outlines Verde reservoir recovery, SRP–CAP interconnect and pumped storage plans

Salt River Project officials told the Arizona House Natural Resources, Energy and Water Committee that SRP is pursuing three projects intended to strengthen regional water and energy resiliency: a Verde River sediment‑mitigation and potential reservoir‑raise feasibility study, an SRP–CAP interconnection facility funded in part by a federal grant, and a large pumped‑storage energy project paired with existing SRP reservoirs.

SRP Director of Water Strategy Kyle Tillman and project manager Joseph Gardner said the projects aim to recover lost storage, make better use of surface supplies and create energy storage to balance the grid.

Tillman told the committee that SRP has lost substantial storage at Horseshoe Reservoir since it was built: “We have lost about 40% of our storage capacity at Horseshoe Dam due to sediment,” he said, citing sedimentation measured in a 2012 survey as the most recent full survey. SRP and the Bureau of Reclamation completed a 30% design package and feasibility study options and will seek congressional approval and federal project authorization if the bureau’s environmental review supports construction.

Two of the Verde alternatives studied would raise Bartlett Dam by roughly 61 feet or 102 feet to recover storage capacity, SRP said. The agency described a multi‑partner feasibility effort: 23 nonfederal partners contributed funding or technical support to the Verde study. SRP said the bureau’s NEPA environmental review is expected to take about two years once it begins, and that final congressional and construction timelines could extend the project a decade or longer.

On the SRP–CAP interconnection, Tillman said the project would create a bidirectional exchange that lets entities use stored credits and move SRP‑stored water into or through the CAP system where currently physical access is limited. SRP said it applied for and received federal funding under a Lower Colorado River Basin conservation grant program enacted in the Inflation Reduction Act; Tillman said the project is slated to receive about $154,000,000 in federal funds to help build the interconnection. He told members the project is at roughly 30% design, SRP is coordinating operational and water‑quality modeling with CAP, and SRP expects the NEPA process to start in 2025 and to begin construction in 2027 with target operation in 2029 if approvals proceed on schedule.

Joseph Gardner described a Salt River pumped‑storage concept that would pair Apache Lake as a lower reservoir with a new upper reservoir to provide up to roughly 2,000 megawatts of energy storage. Gardner said the facility would use reversible pump‑turbine technology and exchange water between two reservoirs on a non‑consumptive basis; SRP estimates the new upper reservoir could hold about 20,000 acre‑feet and said operation would be targeted for the mid‑to‑late 2030s. He said pumped storage can respond in seconds and pairs well with carbon‑free generators.

Committee members asked whether raising a dam or enlarging storage could reduce downstream deliveries; Tillman said existing water‑rights and contractual obligations to downstream users would continue to be honored under the project alternatives and that SRP’s designs and accounting would preserve contracted deliveries.

Members also raised cost questions and timing. SRP said the Verde alternatives’ construction costs are not finalized; the agency will provide cost estimates as part of the NEPA and subsequent design documents. SRP said the Verde feasibility work and NEPA review could take 10–15 years from the current stage if congressional authorization and funding are required.

SRP officials said they would make design information available during the NEPA public process and encouraged stakeholder engagement through that federal review.