YARLUNG TSANGPO, LHATZE TO LHASA
According to Arlene and her story in "Many Rivers to Run" by Dave Manby, in 1986, she and a friend (Dan Dixon or "Greystoke") attempted to kayak the Yarlung beginning at the source but were stymied by weather beaten roads. Instead, after kayaking in a snowstorm on Lake Manasarova (Mampan Yumco, 30.687384°, 81.477978°) and then weeks of hitchhiking (this was only two years after the Chinese opened Tibet to foreign travellers), they put-in at Lhatze (29.121037°, 87.577060°). Arlene had to leave at Shigatze (29.315250°, 88.904705°), but Dan continued to the confluence with the Lhasa River (Kyi Qu, 29.340828°, 90.761943°). His kayak was stolen here, and may be hanging from the rafters of a trekking shop on the square across from the Potala (not for sale). Most of the section they ran is Class II but halfway between Shigatze and Lhasa the river flows through a 20 mile stretch of Class 3 ending with two short class 5 drops which Dan ran solo because the portages were more dangerous than the rapids (see pic above). Today there is a road through this canyon, though the main road between Lhasa and Shigatze is now further south. The Chinese team portaged this canyon on their 1998 trip from the source to the Great Bend.
The put-in elevation was about 13,000', takeout near the confluence with the Kyi Chu (Lhasa River) was about 11,000, total distance about 300 miles, average gradient about 7' per mile. Much of the river is now roadside. Flow ranged from about 10,000 cfs to 25,000 cfs. The Class 3 section is occassionally run by Windhorse Adventures of Lhasa (http://www.windhorsetibet.com/tour_type/river-journeys/).