The Whitewater River Run from Sawtooth Wilderness Boundary to Confluence with Salmon River in Idaho is an exciting and challenging adventure for experienced kayakers and rafters. The ideal streamflow range for this run is 500-2,000 cfs, with the peak season being from May to June. The class rating ranges from Class III to IV, with some sections reaching Class V during high water.

The segment mileage for this run is 20 miles, with various rapids and obstacles to navigate. The most notable rapids include Velvet Falls, a Class IV rapid that requires precise maneuvering through a narrow chute, and Kipper Creek Rapid, a Class III rapid that features a series of waves and holes.

As for specific regulations, the Whitewater River Run is located within the Sawtooth National Recreation Area and is managed by the U.S. Forest Service. Permits are required for commercial and private trips, and the group size cannot exceed 25 people. All participants must wear personal flotation devices and follow Leave No Trace principles.

Overall, the Whitewater River Run from Sawtooth Wilderness Boundary to Confluence With Salmon River offers a thrilling and scenic experience for experienced paddlers, but caution and careful preparation are necessary to ensure a safe trip.