An Appraisal of Subsurface Geology and Groundwater Resources of Owerri and Environs Based on Electrical Resistivity Survey and Borehole Data Evaluation
Source: Environmental Monitoring and Assessment, Volume 70, Number 3, September 2001 , pp. 303-321(19)
The research was aimed at determining the depth to the water table, aquifer thickness and subsurface geology of the study area thus revealing its groundwater distribution as well as its potential as a substitute to the surface water resources. Vertical electrical soundings were carried out in the study area with maximum electrode spread. The Schlumberger electrode configuration technique was adopted. VES data were processed using Schlumberger analysis package. Lithologic logs of already existing boreholes in the study area were collected, evaluated and comparison were carried out. The results reveal alternating layers of sands, sandstones, gravel and clay. The lithologic logs revealed that the study area is underlain by coastal sands (Benin formation). The water table varies from 1064 m and thickness of the aquifer ranges from 2080 m. Results show that the study area is underlain by a thick extensive aquifer that has a transmissivity of 2.8 × 10^-2m^2 s^-1 to 3.3 × 10^-1m^2 s^-1 and storativity 1.44 × 10^-4 to 1.68 × 10^-3m s^-1 values. The specific yield is about 0.31. The sandy component of the study area forms more than 90% of the sequence, therefore the permeability, the transmissivity and the storage coefficient are high with an excellent source of groundwater resources.
Document Type: Regular paper
Affiliations: 1: Department of Geology, Federal University of Technology, P.M.B. 1526, Owerri, Nigeria (author for correspondence, e-mail: email@example.com) 2: Department of Geology, Federal University of Technology, P.M.B. 1526, Owerri, Nigeria
Publication date: 2001-09-01