Visitors to Shoshone Falls will see the season’s highest flows starting Wednesday, June 1, through around mid-June.
The amount of water cascading over the 212-foot falls will top out at nearly 1,500 cubic feet per second (cfs), which is well below the volume seen in years with higher runoff, but it’s still a spectacular display.
The two weeks of higher flows are the result of federal water managers releasing water stored in the Upper Snake River reservoirs to help young salmon and steelhead migrate downstream to the Pacific Ocean.
This flow augmentation will total about 54,000 acre feet before the falls return to their summer minimum flows by mid-June. Most of the water in the Snake River upstream of Shoshone Falls is diverted for agricultural irrigation. Some of what remains is funneled through Idaho Power’s Shoshone Falls Power Plant, with the rest going over the falls. Idaho Power maintains scenic flows of at least 300 cfs over the falls from April 1 through Labor Day.