(Tunca), a river that flows through Bulgaria and, in its lower course, through Turkey; a left tributary of the Maritsa River. The Tundzha measures 405 km in length, 345 km of which is in Bulgaria, and drains an area of approximately 7,900 sq km. It originates on the southern slopes of the Stara Planina and flows through the Kazanluk Basin and the Thracian Plain. It is fed by snow and rain. High water occurs in winter and spring. The mean flow rate in the lower course is approximately 40 cm m per sec. Waters of the Tundzha from the G. Dimitrov and Zhrebchevo reservoirs in Bulgaria are used for irrigation. The city of Iambol, Bulgaria, is on the Tundzha, and the city of Edirne, Turkey, is at the river’s mouth.