Determining suitable locations for rainwater harvesting using GIS and FAHP

Rapid population growth, economic and social development, urbanization, and increased food demand have put pressure on freshwater resources in different regions of the world. Increasing demand for water leads to overexploitation of water resources and water shortage. Therefore, there is a need for effective alternative solutions to deal with this problem. Collecting and harvesting rainwater is one of the practical solutions to deal with water shortage. However, the selection of potential areas for the location of rainwater harvesting structures in a watershed requires the examination of several factors, including topography, land slope, soil type, rainfall intensity, land use cover, drainage, river flow, and socio-economic criteria. This shows that the planning and implementation of rainwater harvesting projects is a multi-objective and multi-criteria problem that depends on several criteria. Therefore, the integration of geographic information system (GIS) and multi-criteria decision analysis (MCDA) approaches is essential. In this research, a GIS-based model with a combination of fuzzy logic and AHP was used to determine suitable areas for the construction of rainwater harvesting structures in the Golidagh watershed for 2018. The results showed that 9.92% of the studied area has very high potential, 25.7% high, 21.58% moderate, and 42.8% poor rainwater harvesting potential. According to the findings, it is suggested to create suitable rainwater collection structures in designated places to reduce water shortage.