The Whitewater River Run from Headwaters to Rio San Antonio in Colorado is a popular stretch of river for whitewater rafting and kayaking enthusiasts. The ideal streamflow range for this run is between 500 and 3000 cubic feet per second (cfs), which typically occurs during the months of May through August.

This segment of the river is classified as a Class III-IV, meaning it is considered to be moderately difficult with some challenging rapids. The total distance of this run is approximately 10 miles, with various rapids and obstacles to navigate throughout. Some notable rapids include Zoom Flume, Guide Ejector, and Pinball.

In terms of regulations, all boaters are required to have a personal flotation device (PFD) and a helmet. Additionally, all commercial rafting companies must be licensed and adhere to safety guidelines set forth by the state.

Overall, the Whitewater River Run from Headwaters to Rio San Antonio is a thrilling adventure for experienced whitewater enthusiasts looking for a challenging and exhilarating ride. It is important to always check streamflow levels and follow all safety regulations when navigating this stretch of the river.