The Great Zab or Upper Zab ( ("al-Zāb al-Kabīr"), or , , "(zāba ʻalya)") is an approximately long river flowing through Turkey and Iraq. It rises in Turkey near Lake Van and joins the Tigris in Iraq south of Mosul. The drainage basin of the Great Zab covers approximately , and during its course, the rivers collects the water from many tributaries. The river and its tributaries are primarily fed by rainfall and snowmelt – as a result of which discharge fluctuates highly throughout the year. At least six dams have been planned on the Great Zab and its tributaries, but construction of only one, the Bekhme Dam, has commenced but was halted after the Gulf War.