索曲流域位于南羌塘陆块东部，由发源于唐古拉山南坡的本曲、索曲、连曲和益曲等四条贯通性河流组成，是怒江上游面积最大的汇水区域。
Made up of Benqu , Suoqu , Lianqu , and Yiqu , which originate from the south of Tanggula mountain , Suoqu drainage area is the largest catchments section in Nujiang .
益曲