The Whitewater River Run originates in Section 9 of Township 5 South, Range 1 East, at an elevation of 4,400 feet in Shelter Cove, California. It flows through the Trinity National Forest and the Six Rivers National Forest before emptying into the Pacific Ocean. The ideal streamflow range for the river is between 300 and 1,200 cubic feet per second (cfs), depending on the time of year and weather conditions.

The class rating of the Whitewater River Run varies depending on the segment. The upper segment is rated Class III-IV, while the lower segment is rated Class II-III. The total length of the river is approximately 30 miles.

Specific river rapids and obstacles include the Class IV Hell Hole Rapid, which is located in the upper segment of the river, and the Class III Goat Rock Rapid, which is located in the lower segment. The river also has several waterfalls and cascades, as well as narrow channels and boulder gardens.

There are specific regulations that apply to the Whitewater River Run. The river is managed by the Bureau of Land Management (BLM) and the National Park Service (NPS). All boaters are required to obtain a permit from the BLM or NPS before entering the river. Additionally, there are regulations regarding camping, trash disposal, and fire restrictions.

In conclusion, the Whitewater River Run offers a diverse range of rapids and obstacles for experienced boaters. Its ideal streamflow range, class rating, segment mileage, specific river rapids/obstacles, and regulations make it a popular destination for whitewater enthusiasts.