Some Idaho Water Users Could See Curtailment This Summer TWIN FALLS, Idaho (KLIX)-Idaho water officials are warning some that there may be water curtailments this summer as spring runoff is expected to be less than normal. The Idaho Department of Water Resources (IDWR) is warning junior water rights holders of possible curtailment as the projected runoff into the Snake River will only be about 80 percent of normal, or about 2.6 million acre-feet between April and July. IDWR predicts a 40,500 acre-foot shortfall to senior water rights holders in the Eastern Snake River Plain (ESPA) region. Junior ground water pumpers could see cutbacks if they are not part of one of four approved mitigation plans. IDWR said after May 1, it will identify junior ground water users that may see water curtailment this summer.