Identification of suitable sites for small rainwater harvesting structures using multi-criteria decision-making models (Case study: Isfahan province)

Identifying potential sites for small rainwater harvesting can help to improve crop water productivity especially rainfed cropping systems.In present study, suitable areas for creating small rainwater collection systems in Isfahan province were determined using multi-criteria decision making models including hierarchical analysis process and network analysis process. The selected variables were annual rainfall ( 111 synoptic, climatology , evaporation and rain gauging stations), land slope, soil permeability, vegetation cover, soil fertility, distance from city and village and distance from road. The results showed that in both AHP and ANP methods, Khomeni-Shahr region with about 63% and Mobarake with about 55% of area , have the largest suitable coverage (good and very good condition) for the small rainfall collection systems construction and Aran and Bidgol (4%) and Ardestan (6%) have the lowest percentage of suitable areas, respectively. For the entire province, according to the AHP and ANP methods, about 24.8 and 21.8% of the lands are categorized as good and very good class for the creating small rainwater harvesting systems, respectively. The results also indicated that for both AHP and ANP methods, about 76.3% of lands with good and very good conditions for the construction of these systems are located in dry and semi-arid areas and 23.7% in semi-humid areas. The statistical comparison between the two approaches showed a significant difference between the provided suitable zones for constructing these systems at 0.01 level. The defference may be attributed to assigned weight of input layers.