ASSESSMENT VULNERABILITY OF AQUIFER VIA DRASTIC MODEL AND COMPARISON WITH G-O-D MODEL USING GEOPHYSICAL PARAMETERS, IMO RIVER BASIN, SOUTHEASTERN NIGERIA

Abstract

Assessment vulnerability of aquifer via DRASTIC and G-O-D modelsfor comparative analysis and for result affirmation and confirmation using geophysical parameters was carried out to ascertain the vulnerability status of the aquifers in Nsuka Formation, Imo River Basin in Southeastern Nigeria.The aquifers are investigated by both DRASTIC and G-O-D indices. The DRASTIC and G-O-D models are both developedto determinethevulnerabilityof the aquifers.Having comparedtheresultsofbothDRASTICand G-O-Dmodelsby geophysicalparameters,both proved appropriatein identifying the vulnerability of aquifers. The areas of low and high vulnerability within the study area as interpreted from the DRASTIC Model tie with those as interpreted from the G-O-D Model. Correlation of the indices got from the two models gave a correlation coefficient of 0.885628 calculated from the Pearson’s correlation coefficient model and correlation coefficient of 0.885607 obtained from the regression line of data points obtained in the plotof DRASTIC against G-O-D indices, signifying high relationship. The study revealed that 76% of the studied area is characterized with low/negligible vulnerability which could signify areas of moderate groundwater quality.The G-O-D Model in this study is used as a confirmation tool to the DRASTIC Model.