Evaluation and Comparison of frequency ratio, statistic index and entropy methods for groundwater potential mapping using GIS (Case study: jahrom Township)

Groundwater is considered one of the most valuable fresh water resources. The rapid increase in human population has increased the demand for groundwater supplies for drinking, agricultural, and industrial purposes. Produce groundwater spring potential maps an essential tool for implementing a successful groundwater determination, protection, and management program. The main objective of this study was to produce groundwater spring potential maps in the jahrom region, using frequency ratio, statistic index and entropy methods. Twelve hydrological-geological-physiographical (HGP) factors that influence locations of springs were considered in this research and processing in ArcGIS environment. These factors include slope degree, slope aspect, altitude, topographic wetness index (TWI), slope length (LS), distance to roads, distance to rivers, distance to faults, lithology, land use and fault density. The predicted results from the three models were validated using the receiver operating characteristics curve (ROC). From 103 springs identified, 70 (≈70 %) locations were used for the spring potential mapping, while the remaining 33 (≈30 %) springs were used for the model validation. The area under the curve (AUC) for the statistic index model was calculated as %91 and for frequency ratio and entropy the AUC were %92 and %92.7, respectively.