The Little Zab or Lower Zab ( (al-Zāb al-Asfal), , (Zâb-e Kuchak), (Zāba taḥtāya)) originates in Iran and joins the Tigris in the Kurdistan region of Iraq. The river is approximately long and drains an area of c. . The river is fed by rainfall and snowmelt, resulting in a peak discharge in spring and low water in summer and early fall. Two dams have been built on the Little Zab, regulating the river flow, providing water for irrigation and generating hydroelectricity. The Zagros Mountains have been occupied since at least the Lower Palaeolithic, but the earliest archaeological site in the Little Zab basin, Barda Balka, dates to the Middle Palaeolithic. Human occupation of the Little Zab basin has been attested for every period since then.