In the early 2010s, the lower reaches of the river dried out completely after several years of seasonal dry-outs. The Zayandeh River basin has an area of 41,500 square kilometres (16,000 sq mi), altitude from 3,974 metres (13,038 ft) to 1,466 metres (4,810 ft), an average rain fall of 130 millimetres (5 in) and a monthly average temperature of 3 °C (37 °F) to 29 °C (84 °F).
