a river in the Uzbek SSR, a right tributary of the Amu Darya. The Surkhandar’ia originates at the confluence of the Tupalangdar’ia and Karatag rivers, which flow down the southern slope of the Gissar Range. It measures 175 km in length (287 km from the source of the Karatag) and drains an area of 13,500 sq km. High water is from June through August. The mean flow rate 6 km from the mouth, at the hydrometrical site of Manguzar, is 65.8 cu m per sec. The Southern Surkhan Reservoir is situated on the river.