GROUNDWATER POTENTIAL MODELLING OF SOME SELECTED PARTS OF ONDO METROPOLIS SOUTHWESTERN NIGERIA.

Abstract

Groundwater potentiality assessment is an effective tool for groundwater management. This study explored the potential of a GIS-based FAHP technique in the field of groundwater hydrology. The approach was applied to model aquifer potential conditioning factors derived from interpreted geoelectrical parameters and remote sensing data. 106 depth sounding (VES) data locations were identified in the Study area. The acquired VES data were quantitatively interpreted to determine the subsurface lithologic parameters in the form of resistivity and thickness. The interpreted results were used to derive the groundwater potential conditioning factors (GPCFs), namely: longitudinal conductance (Lc), transverse resistance (TR), transmissivity (T), aquifer thickness (AQT), Aquifer resistivity (AQR) coefficient of anisotropy (COA) and Slope. Using the derived geoelectrical-based GPCFs values, the GPCFs themes were produced in the GIS platform. The produced GPCFs themes were multi-critically analyzed using the mechanism FAHP data mining model algorithm to produce groundwater potentiality indexing (GPI) map. Furthermore, to compare the performance of the FAHP data mining model result, multi-criteria decision analysis-analytic hierarchy process (MCDA-AHP) model was applied. The efficiency of the FAHP and MCDA- AHP-based GPI maps were evaluated using well data records. The results of the well data correlation with the predictive model maps show linear correlation of 0.87 and 0.76 for FAHP and MCDA-AHP data mining models, respectively. These results show that both models have good performance in prediction of groundwater potential zones, with the FAHP as a better alternative. These maps and models could be used as future planning tool and part of vital supports for decision making for locating appropriate positions of new productive wells in the study area.