Mekong in NE Tibet
After unknowingly competing to complete first descent of the Mekong headwaters in Qinghai 1999, Pete Winn and Masauki Kitamatura agreed to a joint first descent of the Mekong in Tibet, with the assistance of Lui Li of Sichuan Scientific Exploration Association of Chengdu. They put-in at Qamdo (31.144582°, 97.181302°) in April and ran about 80 miles of the 180 stretch to the Yunnan border near Yangjing before deciding to abort the expedition near 30.355957°, 97.766967° because the trail left the river at the third difficult portage for their three 16' catarafts. It took four days to hike to the nearest town with a truck and two days driving over snow covered 15,000' passes to reach the main highway. At Qamdo the average gradient was 15' per mile at a flow of 2500 cfs, which increased to about 25' per mile at 10,000 cfs by the time the team aborted the expedition at Tibetan Terminator Rapid.
The first descent of the section from Tibetan Terminator to the Yunnan border was probably completed by a self supported kayaker in June 2004 - see the link for Mekong in SE Tibet. This is too difficult to be a good repeat run.
First Descent of the Mekong in Tibet by Pete Winn.
Excerpt from "Dancing on the Edge" by John Mattson, who was a kayaker on this expedition (click "contact" to purchase a book with the full story and stories about many other adventures of his).