Aquifer recharge

Part of Milepost 29 aquifer-recharge infrastructure north of Eden, Idaho.

The Idaho Water Resource Board recharged roughly 447,950 acre-feet of water into the Eastern Snake Plain Aquifer last winter, according to a staff report.

It was the fourth straight year the board has been able to exceed its annual average goal of recharging 250,000 acre-feet. Gary Spackman, Director of the Idaho Department of Water Resources, praised the board for meeting and exceeding recharge targets.

“It’s just a remarkable accomplishment,” Spackman said in a press release.

Two new recharge sites in the Magic Valley region, Milepost 29 on the Milner-Gooding Canal and Wilson Canyon on the North Side Canal, added to the board’s recharge capacity this season.

The board recharged 364,000 acre-feet of water in the Magic Valley over 202 days. In the Upper Snake Valley, the board recharged 83,984 acre-feet over 74 days, said Wesley Hipke, the board’s recharge project manager.

With substantial funding and direction from the Idaho Legislature, the board has been working to restore the ESPA to sustainable levels since 2014 by diverting Snake River water to multiple aquifer-recharge sites in the ESPA region.

Up to that point, the ESPA was being over-drafted by about 200,000 acre-feet of water per year. Aquifer levels have been declining since the 1950s.

A 2015 historic settlement between the Surface Water Coalition and the Idaho Ground Water Appropriators in the ESPA region has led to an annual reduction in ground water pumping by 240,000 acre-feet by ground water users.

The board’s recharge program, combined with that settlement, have played a major part in causing ESPA water levels to increase in recent years.

The key is to continue to work toward those gains over the long term, Hipke said.

“We know that drought years will be coming in the future, so we have to exceed our recharge goal in wet years to stay on track with our long-term goals,” he said.

The board paid canal companies and irrigation districts $3.46 million this winter to use their water-conveyance systems to move water to ESPA recharge sites, he said.

Looking ahead to next year, Hipke said staff has been making investments in the Upper Snake Valley for the development of off-canal recharge sites in the Egin Lakes and Butte-Market Lake areas, among others.

All of those sites are intended to increase recharge capacity and provide flexibility in operations, he said.

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