Comparison of FAHP and FANP Decision-Making Methods in Determining the Appropriate Locations for Constructing an Underground Dam for Water Harvesting

The recent droughts in Iran made a decline in groundwater table and the migration of villagers to cities was hindered supplying drinking water for the current population. Therefore it should be considered as an important issue. In this regard, it is possible to achieve this goal by constructing underground dams that recently have been suggested to replace by medium and small overland dams. The aim of this study was to compare and investigate the efficiency of multi-index decision-making methods, that is identified as  Fuzzy Analytical Hierarchy Process (FAHP) and Fuzzy Analytical Network Process (FANP), to find an initial suitable location for constructing an underground dam in Birjand watershed catchment. The GIS information layers consist of distance to waterways, the geology of the area, the slope of the area, distance to the floodplain, distance to villages, distance to wells, springs and qanats, land use, distance to faults and distance to roads. By using the FAHP and FANP algorithms, weights of information layers were obtained. The results of both methods showed that suitable locations for constructing underground dams are located in the vicinity of low slope waterways. The results of both methods were compared by Chi-Square Test. The result of this test showed that the FAHP and FANP models are significantly different and the FANP method is more accurate.