Water crisis in Iran

Water crisis in Iran refers to the problems which due to the water scarcity occur in Iran. Water scarcity can be a result of two mechanisms: physical (absolute) water scarcity and economic water scarcity, where physical water scarcity is a result of inadequate natural water resources to supply a region's demand, and economic water scarcity is a result of poor management of the sufficient available water resources. Iran is encountered to both problems.

Rainfall in Iran is highly seasonal, with a rainy season between October and March, leaving the land parched for the remainder of the year. Immense seasonal variations in flow characterize Iran's rivers. For example, the Karun River in Khuzestan carries water during periods of maximum flow that is ten times the amount borne in dry periods. In numerous localities, there may be no precipitation until sudden storms, accompanied by heavy rains, dump almost the entire year's rainfall in a few days. Water shortages are compounded by the unequal distribution of water. Near the Caspian Sea, rainfall averages about 1,280 mm per year, but in the Central Plateau and in the lowlands to the south it seldom exceeds 100 mm.

Internal renewable water resources are estimated at 128.5 billion cubic meters (BCM)/year (average for 1977–2001). Surface runoff represents a total of 97.3 BCM/year, of which 5.4 BCM/year comes from drainage of the aquifers and thus needs to be subtracted from the total. Groundwater recharge is estimated at about 49.3 BCM/year, of which 12.7 BCM/year is obtained from infiltration in the river bed and also needs to be subtracted. Iran receives 6.7 BCM/year of surface water from Pakistan and some water from Afghanistan through the Helmand River. The flow of the Arax river, at the border with Azerbaijan, is estimated at 4.6 BCM/year. The surface runoff to the sea and to other countries is estimated at 55.9 BCM/year. Per capita water availability in the pre-Islamic Revolution era was about 4,500 cubic meters. In 2009, this figure was less than 2,000 cubic meters.

There are 42 large dams under operation in Iran with a combined storage capacity of 33 BCM/year. These dams lose about 200 million cubic meters of storage capacity every year due to sedimentation (0.5–0.75% of their storage capacity). Most dams are multi-purpose dams for hydropower, irrigation, flood control and—in some cases—drinking water supply.

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