The Gowd-i zerrah, i.e., Zerrah Depression (Persian for "lake depression") is the lowest part of an inland drainage basin covering large parts of southern Afghanistan and Iran known as the Sistan Basin. The Sistan Basin is an endorheic basin and encompasses a complex system of rivers, shallow lakes, marshes and wetlands as its watershed, draining into the Hamun Lakes in southeastern Iran. Occasional outflows from these lakes are carried back into Afghanistan by the seasonal Shile river to the basin's terminus, the Godzareh depression in Afghanistan. The depression is flat and very shallow with fine textured sediment at its lowest portions. The lowest section of the Godzareh depression is 467 m above sea level. The depression only receives runoff water when the main tributaries are overflow