IWRA Proceedings

AbstractStudy on the water availability in Iran, using the international water indicators Hossein Malekinezhad Assistant Prof. Yazd University, Yazd, Iran hmalekinezhad@yazduni.ac.ir Abstract The climate of Iran is one of great extremes due to its geographic location and varied topography. The summer is extremely hot with temperatures in the interior rising possibly higher than anywhere else in the world; certainly over 55°C has been recorded. Annual rainfall ranges from less than 50 mm in the deserts to more than 1600 mm on the Caspian Plain. The average annual rainfall is 252 mm and approximately 90% of the country is arid or semiarid. Overall, about two-thirds of the country receives less than 250 mm of rainfall per year. In the last century (since, 1900) the population of Iran has increased about six-fold. The population growth rate, which was less than 0.6 percent in the beginning of this period, reached the rate of 3.19 percent in the decade from 1976 – 1986. Fortunately; it has considerably decreased once again in the last decade. The major changes in population growth rate, resulting from reduction of mortality and increase of natural growth rate, occurred in the 1960s and afterward. In the period from 1961-2000, the urban population increased by about 31.7 million and the rural population increased by 11 million. In 1956, there were only three cities with a population over 250,000 in Iran, while in 2000 the number of cities with a population of over one million reached seven. The direct impact of population growth on the water resources management of the country was an increased need for potable water in population centers. Indirect impacts were increased demand for agricultural products, development of irrigated lands, and the need for job opportunities and more income, especially in the agricultural sector. The main source of water resources throughout the country is annual precipitation. According to studies carried out for formulation of the Water Comprehensive Plan, the main characteristics of annual precipitation and its conversion to water resources are as follows: • Average annual precipitation 417 bcm • Average annual evaporation & transpiration 299 bcm • Surface currents 92 bcm • Direct seepage to alluvial aquifers 25 bcm This paper reviews and assesses water scarcity indicators in Iran based on the international indicators. The most widely used indicator, the Falkenmark indicator, is popular because it is easy to apply and understand but it does not help to explain the true nature of water scarcity. The International Water Management Institute model (IWMI model), The Water Resources Vulnerability Index and the Water Poverty Index are the other international indicators that are evaluated for the water resources situation and availability of water in Iran.