Identification of potential groundwater locations using geophysical data and fuzzy gamma operator model in Imo, Southeastern Nigeria

Groundwater is among the most important resources of water supply of the worldwide population. The objective of this research is to select the most suitable drilling location of new groundwater wells, with a decision-making tool using geographic information system (GIS). The optimum location was evaluated based on the hydro-geoelectrical parameter derived from vertical electrical sounding (VES) including longitudinal conductance, aquifer thickness, aquifer resistivity, transmissivity, formation factor, and porosity. The analysis of the VES data revealed that the porosity values range from 1.8 to 21%, the formation factor values vary between 0.0355 and 0.14, the transmissivity values range from 3.4 to 6 m 2 /day, the longitudinal conductance values vary from 3 to 4.6 Ω −1 , the aquifer thickness values range from 4.1 to 8.5 m, the aquifer resistivity varies between 0.7 and 40 Ω m. Hydro-geoelectrical data were integrated into GIS to precisely determine the best location for groundwater wells. Fuzzy liner membership was used to standardize the criteria layers; then, these layers were combined using fuzzy gamma overlay to produce the suitability map. The study area was classified into four classes: excluded, low suitability, moderate suitability, and high suitability. It is recommended that this method should be adopted by different governmental agencies involved in water resources management in Nigeria.