ESTIMATION OF TRANSMISSIVITY VALUES FROM SURFACE GEOELECTRICAL METHOD IN PART OF MUBI, ADAMAWA STATE
Lazarus G. Ndatuwong
Adamawa State University, Mubi
Department of Pure & Applied Physics
Email: ndatuwong@gmail.com
ABSTRACT
An estimation of transmissivity distribution in part of Mubi metropolis of the basement rock terrain using surface geoelectrical method was carried out in this work. Thirteen (13) Vertical Electric Sounding (VES) were conducted in the area using SAS 1000 Terrameter with three (5) of the VES points located near five boreholes with an existing pumping test result. The resistivity data were modeled using IPI2Win and WinResist modelling software. The general shape of the resistivity curves model shows a highly resistive basement which considered the longitudinal conductance as the dominant Dar-Zarrouk parameter. Aquifer longitudinal conductance at each of the VES points were calculated using the well-known Dar-Zarrouk parameter equation outline in this work. Transmissivity values obtained from the pumping test resultare plotted against the aquifer longitudinal conductance values calculated from the VES data close to the boreholes. A linear regression relationship between transmissivity, T and the longitudinal conductance, Lc was established and used to compute the transmissivity values at each of the VES points where pumping test was not conducted. The result of the estimated transmissivity values and the transmissivity values obtained from the pumping test result were compared. The close agreement between the calculated transmissivity values from analysis of VES data and transmissivity values obtained from pumping test data attests to the validity of the method.
Key words: Aquifer, Transmissivity, Dar-Zarrouk, Vertical electrical Sounding (VES), Longitudinal Conductance.
