Simulation of Groundwater Flow in the Voltaian (Around Tamale) Using Carbon-14

Abstract

Studying the process of groundwater flow in subsurface systems using numerical simulation has been widely practiced. The purpose of this study was to establish a 2D groundwater flow model for evaluating groundwater resources of the Voltaian Basin (around Tamale) in the Northern Region of Ghana. To understand the rate of abstraction of groundwater in the study area, a finite-element, steady-state groundwater flow model was used to simulate groundwater flow in the aquifer. COMSOL Multiphysics’ (FEMLAB) Earth Science Module (ESM) package which is finite element analysis and solver software was used. The radioisotope used in the study was Carbon-14. Three wells were sampled for Carbon-14 concentration and used for the model verification, based on elevation. From the results, groundwater in the study area moves generally from higher to lower hydraulic head along paths perpendicular to the equipotential lines. The groundwater flow paths in the aquifer in the study area indicated that flow is predominantly regional. There was a regional groundwater flow from Kanshegu to Nawuni. Kanshegu appears to be recharge area and Nawuni as discharge area. The flow rate obtained using Carbon-14 date was 2.86×10-7 m/s. The overall flow rate obtained from the model simulations was 2.66×10-7 m/s with an error margin of 6%.