Hydrogeophysical investigation of aquifer properties and lithological strata in Abraka, Nigeria

Abstract

The purpose of this study is to investigate the aquifer properties and lithological strata of Abraka, Nigeria. This was carried out by employing the geoelectric, geophysical well logging and pumping test methods. Ten vertical electrical soundings using the Schlumberger configuration were occupied to investigate the geoelectric properties of the subsurface, while two wells were drilled to evaluate the lithology and aquifer parameters of the study area. The result of the lithological study showed that the subsurface formations consist of lateritic sand, fine and medium grain sand mixed with clay, coarse sand, medium coarse sand and very coarse sand. The interpretation of the geoelectric data using a combination of curve matching and Win Resist computer iteration showed close correlation with the well record. The geoelectric result revealed that the fifth layer with a resistivity range of between 509 and 1033Ωm and a depth range of between 31.5 and 45.9m is the preferred layer to source for good quality water in the area. The result of well logs also showed that the electrical conductivity and the total dissolve solid which were obtained as 0.0105mS/m and 67.43mg/m3 respectively falls within the World Health Organisation benchmark for potable water. The result of pumping test further revealed that the transmissivity, storativity and specific capacity of the aquifer are 0.0713m2/min, 1.3×10−5 and 0.39m2/min respectively. It is inferred from this survey that the aquifer is confined and capable of yielding adequate and good quality water for the people.