Assessment of groundwater potential in the Khenifra-Azrou basin, Central Massif, Morocco using frequency ratio and Shannon's entropy approaches

Abstract

The objective of this research is to identify groundwater potential zones in the fractured terrain of the Khenifra-Azrou Basin using the Frequency Ratio (FR) and Shannon's Entropy (SE) models. A total of thirteen factors influencing groundwater were included, including distance to faults, fault density, distance to rivers, drainage density, Normalized Vegetation Index (NDVI), Land Surface Temperature (LST) and several topographical factors such as elevation, slope, slope aspect, profile curvature, plan curvature, Topographic Position Index (TPI) and Topographic Wetness Index (TWI). Groundwater potential maps were generated from the two models and were classified into four classes: low, moderate, high and very high. These maps were then validated based on the distribution of water points across the potential zones and by calculating the accuracy (ACC) and kappa coefficient. The results for the Frequency Ratio model show that the high and very high potential zones cover 37.72 % and 19.71 % of the area, while for the Shannon's Entropy model these zones cover 35.33 % and 20.22 % respectively. Validation with water points showed that for the FR model 41.03 % and 43.68 % were in the high and very high zones, whereas for the SE model 37.29 % and 45.09 % were in these classes. The accuracy and kappa coefficients for the FR model were 85.77 % and 57.64 %, and for the SE model were 85.77 % and 58.87 %. These results provide important insights for groundwater management and planning in the Khenifra-Azrou Basin.