Koohrang also known as
Kouhrang and
Kurang is the name of a river, originating in the
Zagros mountains of western
Iran, which joins the
Dez River to form the
Karun, Iran's largest (by volume) river. A series of tunnels (Kuhrang Tunnels) have been built since the 1950s to redirect some of the Kuhrang's water toward the
Zayandeh River to meet the demands of increased population in
Esfahan and
Yazd provinces.