GIS-Based Groundwater Potential Mapping in Khorramabad in Lorestan, Iran, using Frequency Ratio (FR) and Weights of Evidence (WoE) Models

In this study groundwater potential map of Khorramabad in Lorestan Province, Iran was produced using two different methods; Frequency Ratio (FR) and Weights of Evidence (WoE) within a geographic information system (GIS) environment. In the first step, wells location inventory map consisting of 212 wells with yield more than 10 m3/s was prepared, then 140 (70%) were randomly selected for training, while the remaining 72 (30%) were used for the model validation. Likewise, twelve influencing groundwater factors, namely altitude, slope angle, slope aspect, plan curvature, topographic wetness index, land use, drainage distance, drainage density, fault distance, fault density, geology and soil maps were prepared and integrated into spatial database. In order to analyze groundwater productivity, FR and WoE models were applied. The resulting maps were then classified into four categories namely low, moderate, high, and very high. In the last step, the produced maps were validated using receiver operating characteristic (ROC) technique. The areas under the ROC curve (AUC) was obtained 0.891 and 0.882 for the generated FR and WoE maps respectively, indicated the very good capability of both models for modeling groundwater potentiality in the study area.