The Whitewater River Run Immediately Below Boulder Top to Upstream Side of King's Pasture is a popular rafting route in Utah. The ideal streamflow range for this segment is between 400 and 1,200 cubic feet per second (cfs), which provides thrilling rapids without being too dangerous. The segment runs for approximately 7 miles and is rated as a class III to IV, making it suitable for intermediate to advanced rafters.

The river rapids and obstacles to watch out for include the Boulder Top Rapid, which is a class IV rapid with a steep drop and strong currents. The Widowmaker Rapid is another challenging obstacle, with a sharp turn and large waves. The river also features smaller rapids and obstacles throughout the segment, making it an exciting and dynamic run.

There are specific regulations to this area that should be followed to ensure safety and conservation. Rafters must obtain a permit to raft on the river, which is managed by the Bureau of Land Management. Additionally, rafters must follow Leave No Trace principles by packing out all trash and minimizing any impact on the surrounding environment.

Overall, the Whitewater River Run Immediately Below Boulder Top to Upstream Side of King's Pasture is a thrilling rafting experience for intermediate to advanced rafters. With its ideal streamflow range, class rating, and specific rapids and obstacles, it offers adventure and excitement in a beautiful natural setting.