Delineation of groundwater potential zones using multi- criteria analysis (AHP), Frequency Ratios (RF), remote sensing and GIS: a case study of the Batcham municipality (West Cameroon)

Abstract This study uses the methods of multi-criteria analysis (AHP) and Frequency Ratios (FR) to identify areas of high groundwater potential in order to facilitate the implementation of boreholes and help decision-makers improve access to drinking water in the Batcham municipality. The database used is made up of geological data, hydroclimatic data, well data, and satellite images. Each of the methods used is based on the study of the relationships between the factors controlling the groundwater potential. Among these factors, ten (10) were retained on the basis of previous work; these are: slope, elevation, land use, land cover, lineament density, drainage density, topographic wetness index, curvature, geology, rainfall, and the static water level. The AHP allowed, according to the user's expertise, to assign weights to each factor controlling the water potential. The FR made it possible to study the relationships linking each variable with high flow rates. The thematic layers obtained were integrated into a GIS environment to generate the groundwater potential map. Four classes of groundwater potential have been identified: bad, moderate, good, and excellent. The bad classes represent 8.32% and 11.21%; moderate 36.57% and 28.70%; good 43.55% and 38.93%; and excellent 11.56% and 21.16%, for the AHP and FR models, respectively. The overlying of wells with high flow rates on areas of excellent groundwater potential shows perfect concordance, which validated the final map. The result map was also validated by sensitivity curve analysis, and the receiver operating characteristic (ROC) curve from which result accuracy was obtained is 70.63% and 80.28% for the AHP method and FR method, respectively. The maps obtained can help decision-makers choose appropriate sites for groundwater research and for drilling boreholes.