Kara Su

(Western Euphrates) a river in eastern Turkey, the northern extension of the Euphrates River. Length, 470 km; basin area, about 22, 000 sq km. It flows mainly through deep gorges, its valley widening only at the cities of Erzurum and Erzincan. The water is in flood in the spring and very low in thesummer. The river is used to float logs.