Evaluating Groundwater Resources Potential in Herat-Marvast Plain Using a Combined Method of Analytic Hierarchy Process and Fuzzy Logic

Herat-Marvast plain is one of the most important agricultural regions in Yazd province and water exploitation from this aquifer is done for agricultural purposes. In recent years, declining groundwater level in the Herat-Marvast aquifer has led to increase in groundwater salinity and groundwater quality decrease. Therefore, the purpose of this study is to map groundwater potential in Herat-Marvast plain during 1996-2017 using effective factors in feeding groundwater aquifers, using Fuzzy-AHP method and GIS. To this end, layers including altitude, slope, geology, land use, average annual rainfall and temperature, drainage density and groundwater level were used to evaluate groundwater resources. These maps were weighted based on pairwise comparison using analytic hierarchy process. By applying the calculated weight of each criterion, the map of factors was prepared according to its importance on finding groundwater potential and then based on overlapping layers, the final map of groundwater potential was prepared by Fuzzy-AHP method. The results obtained from investigating the groundwater resources potential showed that 7.6, 17.74, 25.1, 18.85 and 30.61% of the area were located in very low, low, medium, high and very high potential zones, respectively. In general, according to the results, in the study area, alluvial plains and areas with low altitude and slope had the highest potential for groundwater formation and regions with hard rock formations and with high altitude and slope had the lowest potential for groundwater extraction.