Colorado River — Westwater Canyon

About

Westwater Canyon carves seven miles of Class III–IV whitewater through black Precambrian granite — some of the oldest exposed rock in the American Southwest. The Colorado River builds power through two miles of flatwater approach from Westwater Ranch before entering the canyon proper, where granite walls compress flows averaging 8,500 CFS into technical rapids and hydraulics. At optimal flows between 3,000–15,000 CFS, the canyon delivers continuous whitewater punctuated by several major drops that have claimed rafts and kayaks for decades. The BLM manages this section as the Westwater Canyon Wilderness Study Area, requiring advance permits that limit daily launches. Most parties run it as an overnight trip, camping on beaches between the granite walls before exiting to two more miles of desert flatwater toward Cisco. USGS gauge 09163500 tracks the flows that make or break a Westwater trip — below 2,000 CFS means scraping rocks, above 20,000 CFS means enormous hydraulics that flip even large rafts.