Zhaqu River in Qinghai and Tibet

扎曲
Originated in the Yushu Tibetan Autonomous Prefecture in Qinghai Province, Zhaqu River has been viewed as the true source of Lancang River. In summer, the green grassland and quite valley forms a magnificent landscape. 

扎曲:青海玉树州杂多县东部的水系(其西部水系是当曲),是澜沧江上源,澜沧江干流源头为扎曲河的扎阿曲,发源于唐古拉山北麓的采莫赛东部,行政隶属于玉树州杂多县扎青乡。

扎阿曲和扎那曲汇合后,始称扎曲,流经囊谦县,在娘拉乡入西藏昌都市。澜沧江在青海还有解曲(吉曲)、子曲和巴曲3条支流,出境后均流入西藏昌都市。[1] 曲:康巴区域称江河的语音的汉译,如当曲等等(而卫藏区域语音是藏布)。