There is still plenty of snow in the mountains, but with ample space to catch it in Jackson Lake, runoff on the Snake River is unlikely to reach historic levels.
That’s the assessment Mike Beus, operations manager for the Bureau of Reclamation, delivered at the agency’s water meeting in Jackson last night. The bureau controls releases at Jackson Lake and Palisades dams to supply water for irrigation in Idaho and prevent floods.
Runoff in the upper Snake basin is projected to be about 130 percent of normal, Beus said. But because of last year’s drought, the uppermost reservoirs are filling slowly. The Jackson Lake reservoir was drawn down to 18 percent of capacity last fall, and Palisades was nearly empty.
The bureau is releasing only 300 cubic feet per second from Jackson Lake Dam; it will double the flow shortly before Memorial Day weekend and increase the release to 2,500 cfs by June 1.
The agency plans to gradually increase the dam release as tributaries drop off, thereby reducing the risk of flooding. The bureau projects a maximum release of just over 5,000 cfs beginning in late June. Once the runoff subsides, the release will be held steady at 2,500 cfs through the end of September.