Dangqu

The Dangqu (Chinese: 当曲, p Dāngqū) or Dam Chu (Tibetan: འདམ་ཆུ, w 'Dam Chu, lit. "Marshy River") is a 234 km (145 mi) river in the Qinghai province of the People's Republic of China. It runs from its source in an eastern offshoot of the Tanggula Mountains (唐古拉山), receives its main tributary the Buqu (布曲), and has a confluence with the Ulan Moron, where the Tongtian River is formed. The Dangqu has been discovered to be the actual headwater of the Yangtze River under modern criteria, although the nearby Ulan Moron or Tuotuo was traditionally regarded as the primary river of the two.^[1]