The Middle Santiam River in Oregon is a popular destination for whitewater rafting enthusiasts. The ideal streamflow range for this river run is between 800-2000 cfs, which typically occurs during the spring and early summer months. The class rating for this river is Class III-IV, making it suitable for intermediate to advanced paddlers. The segment mileage for this river run is approximately 13.5 miles, starting at the Middle Santiam Wilderness Boundary and ending at the Willamette National Forest Boundary.

There are several notable rapids and obstacles on this river, including Green Wall, Gut Buster, and Boxcar. Green Wall is a challenging rapid that requires precise navigation through a tight channel with a steep drop and strong currents. Gut Buster is another difficult rapid that requires paddlers to navigate through a narrow chute with large waves and technical maneuvers. Boxcar is a technical rapid that requires precise navigation through a series of boulder fields and drops.

In terms of regulations, all boaters are required to obtain a permit from the Willamette National Forest before embarking on this river run. Additionally, there are restrictions on camping and campfires along the river, and all boaters are required to follow Leave No Trace principles to minimize their impact on the environment. Overall, the Middle Santiam River offers a thrilling whitewater experience for experienced paddlers seeking a challenge.