GIS – based groundwater potentiality mapping using AHP and FR models in central Antalya, Turkey

Groundwater is considered as one of the essential natural resources stored beneath the earth surface by infiltration through various rock layers. Groundwater potential supplies almost 30% of fresh water in the world, and in general, 65% of groundwater is used for agricultural irrigation, 25% as drinking water, and the remaining 10% is utilized as industrial water. The main aim of this study is to delineate groundwater potential zones in the central Antalya province, Turkey using the analytical hierarchy process (AHP) and frequency ratio (FR). Seven thematic layers including lithology, slope, drainage density, landcover/landuse, lineament density, rainfall, and soil depth were considered as influencing parameters to run these models. The preparation of all geospatial datasets was carried out in GIS environment and Google Earth Engine. Besides, some authorized relevant web portals were also tried for obtaining the required spatial data. The findings of analysis by AHP and FR models show that Muratpasa, Kepez, and eastern Dosemealti in the eastern part of study area are characterized by high potentiality of groundwater, while the regions in southern, western parts covered by igneous rocks and other less permeable sediments, also featured by high and steep slopes are followed by low or very low groundwater potential. Consequently, the results from both models were assessed using receiver operating curve (ROC) and area under curve (AUC) for validation. The validation in this study confirms the higher effectivity of results achieved by FR than the AHP model.