The San Juan River is a popular whitewater rafting destination located in the southwestern portion of Colorado. The ideal streamflow range for the San Juan River is between 500 and 2,500 cubic feet per second (cfs). This range provides the best conditions for intermediate level rafters, with Class II and Class III rapids.

The San Juan River can be broken down into two main segments. The upper segment spans from Pagosa Springs to the town of Arboles, covering a distance of approximately 30 miles. This segment is known for its scenic beauty, with towering cliffs and beautiful rock formations. The lower segment spans from Arboles to the town of Navajo Dam, covering a distance of approximately 26 miles. This segment features more challenging rapids, including several Class III rapids.

One of the most notable rapids on the San Juan River is the "Razor Blade" rapid, located in the lower segment. This Class III rapid features a narrow channel with sharp rocks and challenging maneuvering. Other notable rapids on the San Juan River include "Rock Garden," "Hippie Hole," and "Pine Tree."

There are specific regulations in place for the San Juan River. All rafters must obtain a permit from the Bureau of Land Management (BLM) before embarking on their trip. Additionally, all rafters must follow Leave No Trace principles and pack out all trash and waste. Camping is only allowed in designated campsites along the river.

Overall, the San Juan River offers a thrilling whitewater experience for intermediate level rafters. With its beautiful scenery and challenging rapids, it is a must-visit destination for any whitewater enthusiast visiting Colorado.