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Using the DRASTIC and GOD Techniques, a thorough evaluation of the aquifer vulnerability in the Imo River Basin, Southeast Nigeria, was conducted. The goal of the current study is to evaluate the two methods' capability for evaluating aquifer vulnerability in the study area by contrasting them. In contrast to the DRASTIC model, which assesses aquifer vulnerability using seven hydro-geological parameters, the GOD model estimates groundwater vulnerability across large regions based on just three parameters, including groundwater confinement, overlying strata, and depth to groundwater (depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity). These index approaches used a variety of meteorological, geological, and hydro-geological observations to gather their data. The GOD and DRASTIC Indices were computed using sieve analysis to assess the hydraulic conductivity of the various strata covering the aquifers. The study's findings showed that the DRASTIC Index (DI) has a range of 76 to 192 with a mean value of 140.8. The Benin Formation has a mean DI of 162, which indicates high susceptibility, whereas the Ajali and Ameki Formations were determined to have average moderate vulnerabilities with DI values of 101 and 139, respectively. The Imo Shale, Ogwashi, and Nsukka Formations were calculated to have mean DI values of 76, 77, and 85, respectively, indicating modest aquifer vulnerability. The GOD Index across the study area ranged from 0.1 to 0.504 with a mean value of 0.328, it was also discovered. The mean GOD Index for the Benin Formation is 0.504, indicating high susceptibility, while the GOD Index values for the Ajali and Ameki Formations were assessed to be 0.105 and 0.112, respectively, indicating low vulnerability. Low vulnerability was identified for the Imo Shale, Nsukka, and Ogwasi Formations, with GOD Index values of 0.15,0125 and 0.1, respectively Due to its shallow aquifer depth and loose, uncompacted character, our data suggest that the Benin Formation has the highest vulnerability levels. Therefore, serious efforts should be made to keep an eye out for any potential anthropogenic pollution of the research area's aquifers. |
