The Whitewater River Run from Periodic Spring to Upper Dam in Wyoming is a class III-IV river with an ideal streamflow range of 200-700 cfs. This 6.5-mile segment offers exciting rapids and obstacles such as "Little Niagara," "Pinball," and "Boulder Garden." The run ends at Upper Dam, which marks the beginning of a calmer stretch of the river.

It is important to note that the river is only suitable for experienced kayakers and rafters. Novices are strongly advised to seek professional guidance or opt for calmer stretches of the river. Additionally, the area is subject to specific regulations, including the requirement for a permit to float the river. The permit can be obtained from the Bridger-Teton National Forest Service.

In conclusion, the Whitewater River Run from Periodic Spring to Upper Dam is an exciting and challenging stretch of river suitable for experienced kayakers and rafters. With its class III-IV rating and specific regulations, it is an area that requires careful planning and preparation to ensure a safe and enjoyable experience.