The whitewater river run from Headwaters to Inlet Alteras Lake in Idaho is a challenging and exciting adventure for experienced kayakers and rafters. The ideal streamflow range for this run is between 800 and 1,500 cfs, which provides a thrilling ride through Class III and IV rapids.

The river run covers a total of approximately 17 miles, with several notable rapids and obstacles along the way. One such obstacle is the "Slide Rapid," which features a steep drop and a narrow channel that requires precise navigation. Another challenging section is the "S-Turn Rapid," which features a series of tight turns and narrow chutes that must be navigated carefully.

Regulations for the area include requirements for personal flotation devices (PFDs) for all participants, as well as a minimum age requirement of 14 years old for kayakers and 6 years old for rafters. Additionally, all participants are required to have a permit from the Forest Service, and camping is only allowed in designated areas along the river.

Overall, the Headwaters to Inlet Alteras Lake river run in Idaho is a thrilling and challenging adventure for experienced kayakers and rafters, but should only be attempted by those with the necessary skills and equipment. It is important to follow all regulations and guidelines for safety and environmental protection.