This summer, a short-lived curtailment order brought a dispute to a head between farmers irrigating from the Snake River and those dependent on groundwater. Without a long-term plan to share water, the cuts could come back next year. TWIN FALLS, Idaho—Along the banks of the Snake River, below the Magic Valley’s fields of barley, wheat, and corn, groundwater from a massive aquifer springs from steep, dark rock and crashes down the cliff to the river.