Rain water harvesting potential locating in arid regions using TOPSIS; Case study Nain Plain

Rain water harvesting is one of the most significant water utilization management techniques to cope with water scarcity. Recognizing the potential of rain water is the first step in rain water management. The multi criteria decision analysis (MCDA) is known as an important tool in natural resources management decision particularly in water management. In this research¡ multi-criteria decision-making approach and geographic information system (GIS) were used to identify the areas with rainwater harvesting potential. The criteria including suitability for purpose¡ accuracy and ease of access¡ acceptance in the local communities¡ the cost and time were selected¡ and the weight of each criterion was calculated by using the Shannon entropy method. Totally¡ 31 indicators were selected for decision making and the weight each index was calculated and prioritized using TOPSIS. The results show that among the ranked indices¡ soil permeability has the highest weight (0.820) and the soil texture show the second order with the weight of 0.810¡ while the average annual rainfall and groundwater levels with the weights of 0.615 and 0.517 indicate the lower priority for rain water harvesting.