The Whitewater River, located in southern California, offers a popular whitewater rafting experience. The ideal streamflow range for the Mainstream - Headwaters to Confluence with Cooper Canyon segment is between 200 and 400 cubic feet per second (cfs), which typically occurs during the spring months.

The class rating for this segment is considered to be Class III, with some Class IV rapids. The segment mileage is approximately 8.5 miles, and the river features several notable rapids and obstacles, including "The Chute," "S-turn," and "Rock Garden."

It is important to note that the Whitewater River is located on public land managed by the Bureau of Land Management, and therefore visitors must follow regulations and obtain the necessary permits. Additionally, the river is subject to seasonal closures due to fire danger and other safety concerns.