Zayanderud

Zayandeh River
Zayandeh River in Isfahan, Isfahan Province.
Native name	Zayanderud
Country	Iran
Basin features
Main source	Zagros Mountains 3,974 m (13,038 ft)
River mouth	Gavkhouni (endorheic) 1,466 m (4,810 ft)
Basin size	41,500 km2 (16,020 sq mi)
Physical characteristics
Length	400 km (249 mi)
Discharge	Average rate: 38 m3/s (1,300 cu ft/s)

Zāyandé-Rūd or Zāyanderūd (Persian: زاینده رود‎‎, from زاینده [zɑːjændɛ] “life giver” and رود [rʊːd] “river”), also spelled as Zayandeh-Rood or Zayanderood, is the largest river of the Iranian Plateau in central Iran.

The Zayandeh starts in the Zard-Kuh subrange of the Zagros Mountains in Chaharmahal and Bakhtiari Province. It flows 400 kilometres (249 mi) eastward before ending in the Gavkhouni swamp, a seasonal salt lake, southeast of Isfahan city.

The Zayandeh used to have significant flow all year long, unlike many of Iran's rivers which are seasonal, but today runs dry due to water extraction before reaching the city of Esfahan. 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). There are 2,700 square kilometres (1,000 sq mi) of irrigated land in the Zayandeh River basin, with water derived from the nine main hydraulic units of the Zayandeh River, wells, qanat and springs in lateral valleys. Zayandeh River water gave life to the people of central Iran mainly in Isfahan and Yazd provinces. Before the drying-out, water diverted per person was 240 litres (63 US gallons/53 imp gallons) per day in urban areas and 150 litres (40 US gallons/33 imp gallons) per day in villages. In the 1970s, the flow of the river was estimated at 1.2 cubic kilometres (0.29 cu mi) per annum, or 38 cubic metres (1,340 cu ft) per second.