Sistan Basin

The Sistan Basin is an inland endorheic basin  encompassing large parts of southwestern Afghanistan and minor parts of southeastern Iran, one of the driest regions in the world and an area subjected to prolonged droughts. Its watershed is a system of rivers flowing from the highlands of Afghanistan into freshwater lakes and marshes and then to its ultimate destination: Afghanistan's saline Godzareh depression, part of the extensive Sistan  terminal basin. The Helmand River drains the basin's largest watershed, fed mainly by snowmelt from the mountains of Hindu Kush, but other rivers contribute also.