The Idaho Water Resource Board approved construction of four test wells and two full-scale projects as part of ongoing efforts to increase Eastern Snake Plain Aquifer recharge capacity in the river’s upper section.

One full-scale project is slated adjacent to the existing 55th Road recharge site near Ririe, in partnership with Enterprize Canal Co., for $6.2 million.

The other, in the West Egin area, is to be built with Fremont-Madison Irrigation District and use excess water off Henry’s Fork of the Snake. The West Egin project, to cost just over $7.38 million, calls for adding 10 new recharge wells to the area.

The four test wells that the board approved are planned from Aberdeen-Springfield upstream to see if recharge wells are viable for developing larger projects.

IWRB since 2014 has conducted annual recharge following irrigation season. The board has increased recharge capacity, mostly in the south-central region’s Magic Valley downstream.

The two new aquifer-recharge sites will help to recover the aquifer, board member Brian Olmstead of Twin Falls said in a news release.

“We need to create 100,000 acre-feet of additional capacity in the Upper Snake River Valley to complement our recharge capacity in the Magic Valley,” he said. “This will help restore balance to the aquifer and work toward a sustainable future.”

Growth, and irrigation systems that return less water, are among reasons the aquifer has been in decline for decades. Volume is higher due to recharge, but most capacity projects and impacts have been in the river’s midsection below American Falls Reservoir.

Gov. Brad Little and the legislature in 2022 prioritized spending American Rescue Plan Act funds on additional recharge capacity in the Upper Snake River Valley. Goals included increasing volume across the aquifer and taking best advantage of a board water right in effect in years when flood-control releases occur.

Impacts of an annual water-rights call on the Eastern Snake Plain Aquifer vary based on factors including weather and anticipated demand for irrigation. A coalition of surface water users with senior rights reached a settlement with groundwater districts to stop curtailment this year. The parties are working on a long-term plan.

As for annual recharge, “we’ve seen where this program works,” IWRB recharge program manager Wesley Hipke told Capital Press. “It is making a difference with aquifer levels, and flows in the river. We are basically doubling down on that and adding more capacity.”

The Upper Snake has room for the capacity gain, and the projects “will have a more direct effect” in the immediate area, he said.

IWRB over the past decade added more than 2,100 cubic feet per second of aquifer recharge capacity below American Falls and 300 cfs in the upper valley, Hipke said. With the new projects, Upper Snake capacity will increase to 600 not including projects that other entities plan.

One cfs is just over 1.98 acre-feet per day.

“With our current capacity, this is the first year we’ve actually been able to reach our goal of 250,000 acre-feet per year on average” over the program’s 10 years, Hipke said.

Despite reaching the goal, a curtailment was ordered this spring, prompting settlement negotiations.

“For insurance, for prolonged dry periods, more recharge capacity is going to be beneficial,” Hipke said.