Water levels to stay high all summer

The Natural Resources Conservation Service (NRCS) predicts eastern Idaho streamflows are projected to be at 150 to 250 percent of average in June and July. In the Clearwater and Panhandle regions, streams are expected to run at 100 to 125 percent of average. The predictions are subject to variables, including future weather conditions, uncertainty in forecasting, and potential errors in data. May precipitation was below normal across the state and may have kept many streams from flowing even higher. Precipitation ranged from 45 to 90 percent of average across the state and was highest in the Big Wood and Upper Snake basins. With the exception of the Mud Lake area, Idaho, as a whole, has already received its annual average precipitation for the water year, which runs from October to September. Mackay Reservoir is 58 percent full and has been releasing water since mid-February. In the Upper Snake basin, the Henry’s Lake, Island Park, Grassy Lake, Ririe, Blackfoot and American Falls reservoirs are nearly full. Jackson Lake and Palisades Reservoir are being managed for flood control. Jackson Lake is 80 percent full at 1111 percent of average. Palisades Reservoir is 59 percent full. Snake River inflow near Alpine, above Palisades, is forecast at 183 percent of average. The NRCS said there will be plenty of water to top off the reservoirs when operators determine the time is right. At other reservoirs around the region, Salmon Falls Reservoir is at 89 percent of capacity and at the highest May 31 storage since 1984. Releases from Oakley Reservoir have ceased as inflows decreased and irrigation demand increased. The reservoir is 80 percent full and at its highest since 1999. Bear Lake is 83 percent full and Montpelier Reservoir is 78 percent full. Reservoir carryover into next year is expected to be good but depends on irrigation demand, which, in turn, depends on how hot and wet the summer is. Throughout the region, rivers and tributaries will be running high well into the summer.