$1.7 million approved to develop new recharge site near Idaho Falls for the Eastern Snake Plain Aquifer

BOISE, Idaho (KIFI) – The Idaho Water Resource Board (Board) voted to approve $1.7 million in federal American Rescue Plan Act (ARPA) funds to develop a new aquifer-recharge site near Idaho Falls as part of efforts to increase Eastern Snake Plain Aquifer (ESPA) recharge capacity in the Upper Snake River area above Milner Dam.

Known as the “55th Road” recharge site, the project is located approximately seven miles northeast of Idaho Falls next to Highway 26. It would utilize an old, 8.6-acre gravel pit that has been purchased by the Enterprize Canal Co. The site is estimated to have a recharge capacity of 45 cubic feet per second. About half of the recharged water would remain in the ESPA for an estimated 1.5-2 years before returning to the Snake River as “reach gains” between Idaho Falls and Neeley, officials said.

Partners in ESPA recovery efforts were invited to comment at the Board meeting on aquifer recharge activities. Officials with the Twin Falls Canal Company, a key player in the Surface Water Coalition, urged the Board to do more aquifer-recharge in the Upper Snake region and in the Blackfoot-to-Neeley river reach to increase Snake River surface water flows and “reach gains.”

“That part of the river is critical to us – it’s a hot spot that needs to be addressed,” said John Simpson, an attorney for Twin Falls Canal Co. “Shorter aquifer-retention times are OK in that area because it will add to surface water flows.”

More surface water flows for Snake River irrigators could help reduce conflict with ground water irrigators, too, Simpson said.

Wesley Hipke, recharge program manager for the Board, noted he and IDWR staff have been actively looking for more reliable aquifer-recharge sites in the Upper Snake River Valley for the last eight years. Many of the potential sites are dependent on the availability of surplus reservoir storage in the Upper Snake system. During dry years, there is no surplus water for aquifer-recharge when the Bureau of Reclamation is working to store every drop of water to refill the reservoir system for irrigation needs, he noted.

Idaho Ground Water Appropriators (IGWA) officials also presented to the Board and expressed support for development of additional recharge sites to boost annual recharge amounts beyond the 250,000 acre-feet annual average target each year. Idaho Power Co. officials urged the Board to consider the importance of winter surplus flows for other river needs such as water quality, recreation and hydropower.

“We feel you need to focus on more than just the volume of recharge,” said Kresta Davis of Idaho Power.

In other action, the Board received an update from IDWR hydrogeologist Mike McVay about the status of numerous ground water flow models in the state. McVay reported a new Treasure Valley Ground Water Flow Model has been completed and is available for public use. The model uses an updated water budget for the Treasure Valley, which includes discharge data for agricultural drains – a major source of recharge for Treasure Valley aquifers – and it can be used as a tool to understand regional impacts posed by new water projects, housing developments, or large commercial and industrial projects, among other things, McVay said.

IDWR is working to build, maintain, enhance and use ground water flow models for the Spokane-Valley Rathdrum Prairie Aquifer, the ESPA (ESPAM 2.2), Wood River Basin, Big Lost River Basin, Raft River Basin, and the Mountain Home aquifer system, McVay said.

“I am in awe of what the Water Board and IDWR staff are doing to maintain all of those models,” IDWR Director Gary Spackman said. “It’s imperative we have that information because it provides scientific support for decisions about water rights and water management.”

In other action, the Board:

• Approved a $200,000 loan at 7.5 percent interest to the Boise City Canal Company. The loan is to replace the canal company’s main headgate and make other improvements. The total project cost is $422,000. The canal company also received a $122,000 aging infrastructure grant from the Water Board for the project. Boise City Canal Company serves about 750 urban homes in the Boise area.
• Received an update on the Mountain Home Air Force Base Water Resiliency Project. The project is a partnership between the U.S. Air Force and the Board to provide a new long-term water supply to the Mountain Home AFB. The Board will complete construction of a pumpstation at C.J. Strike Reservoir and 14.4-mile pipeline from the Snake River to the base. The Air Force will build a water-treatment plant at the base to treat water delivered by the pipeline. The current schedule includes issuance of a Request for Proposals for the design-build contract in August 2023, contractor selection in February 2024, and project completion in November 2025.