Some irrigation districts face shortfalls

By DAVE WILKINS

Capital Press

South-central Idaho ground water users have been ordered to provide up to 84,300 acre-feet of replacement water for surface water users this year or face curtailment.

Pumpers were given until May 13 to secure the required replacement water, Idaho Department of Water Resources Interim Director Gary Spackman ordered April 29. Failure to comply with the order will result in curtailment of ground water rights junior to April 5, 1982, potentially drying up 73,782 acres in Southern and Eastern Idaho.

The replacement water will go to the Twin Falls Canal Co. and American Falls Reservoir District No. 2 to make up for predicted shortfalls in water supplies this irrigation season.

Spackman predicted that the Twin Falls Canal Co., will face a shortfall of up to 56,900 acre-feet this year, and the American Falls Reservoir District a deficit of up to 27,400 acre-feet.

Five other members of the Surface Water Coalition are expected to make it through the irrigation season without any shortfall, Spackman said.

Ground water districts are expected to appeal the order. They disagree with the methodology used by the department to calculate how much replacement water is required.

"We have some major issues," Lynn Tominaga, executive director of Idaho Ground Water Appropriators, said in an interview May 7. "We have some concerns and have asked for reconsideration, but we haven't seen a final decision."

Pumpers want to make certain that the required mitigation is based on their ground water diversions and not on drought or other factors that can reduce surface water supplies, Tominaga said.

They also question whether the department has fully taken into consideration the effects of aquifer recharge projects, conversion of some irrigation wells to surface water deliveries and other activities that have improved the health of the aquifer.

The 84,300 acre-feet is the maximum amount that ground water users will have to provide this year. It could be less if the state's water supply continues to improve.

The department will reassess the situation in early to mid-July. The outlook is more promising now than it was just a month or two ago, according to the department.

According to the May 1 Idaho Water Supply Outlook Report, most irrigators in the state should be able to make it through the season, thanks to good reservoir storage.

Cool, wet weather in April and early May helped to boost snowpack levels and should delay runoff.

State water officials have determined that ground water diversions contribute to reduced water availability for canal companies and irrigation districts because the aquifer is interconnected with surface water sources.

Each spring the state water director assesses water supplies and determines whether and how much replacement water will be required.

Link

Idaho Department of Water Resources: www.idwr.idaho.gov

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