Charley River and Yukon River Professional Review and Guide
"For the advanced rafter, canoeist, or kayaker, the Charley offers many miles of whitewater challenges in a remote, seldom-visited wilderness. Known for its exceptional clarity, the Charley rises in the Tanana Hills, flowing from headwaters about 4,000 feet above sea level and descending at an average gradient of 31 feet per mile to meet the Yukon at 700 feet above sea level. With an average current of 4 to 6 miles per hour, the Charley is never dull over the course of its 88 miles and is considered to be Interior Alaska's premier whitewater river.
During high water, usually late May to July, the upper two-thirds of the river is lively and challenging. High water ocrurs at breakup and during rainstorms. Water levels rise dramatically within hours. At low water levels, exposed gravel bars and boulders require vigilant maneuvering and scouting as you thread through whitewater rapids."