a river in northern Turkey. The length of the Yeşil is about 450 km, and its basin covers an area of 36,100 sq km. In its upper and middle course, the Yeşil flows northwest through a midmountain valley, parallel to the ranges of the Pontic Mountains. The river then turns north, intersects the Canik Mountains, and discharges into the Black Sea east of the city of Samsun, forming a delta. The Yeşil’s main tributaries are the Cekerek (left-bank) and the Kelkit (right-bank). The river is fed primarily by meltwater and rainwater; high water is in the spring and early summer. The average flow rate at the mouth is about 150 cu m per sec, with a maximum of 2,000 cu m per sec. The waters of the Yeşil are used for irrigation. Near Almus, there is an important hydroelectric power plant. The cities of Turhal, Amasya, and Çarşamba are located on the Yeşil.