Evaluation of Aquifer Characteristics in Southern part of Imo State, Southeastern Nigeria

Abstract

The hydrogeological characteristics and groundwater potential of parts of Imo State, Southeastern Nigeria were evaluated via bacteriological analysis, chemical analysis, pumping test data, borehole logs, geophysical survey and sieve analysis. Transmissivity value ranges from 88.0m2/day to 135.0m2/day. The hydraulic conductivity varies from 0.05cm/sec to 0.50cm/sec. The geophysical survey and borehole logs confirmed that the area is sand dominated. The sieve analysis results indicate: coarse grained sand > medium grained sand > fine grained sand > gravel > (silt and clay). The borehole logs give a good lithostratigraphic profile of the subsurface rocks in the area. The aquifer system in the study area is mainly unconfined. The study revealed low concentrations of cations and anions which are attributed to the paucity of soluble materials in the bed-rock of the formation and the overlying soil. The microbial analysis of the water samples indicate high value of total coliform when compared with the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO) maximum permissible limits for drinking water. The pH value varies from 4.5 to 6.8 with a mean value of 5.5. These findings indicate that the area has good groundwater potentials and high aquifer recharge.