Groundwater and contaminant flow modelling in Olomoro area of Delta State

Abstract

Geophysical investigation and hydrogeological information have been used with a steady state groundwater flow simulation model to describe the aquifer system and the flow rate of contaminants in the Olomoro area of Delta State. The area was modelled with a grid of 100 row × 65 columns. A conceptual model was developed from the results of the Electrical resistivity survey. The aquifer zones delineated from the Electrical resistivity sounding and the well inventory of the area formed the basis for the flow modelling. The model was simplified into three layers; the top soil, the clayey sand/laterite/clay layer and the sand layer. The first two layers of thickness 2- 10m are assigned low hydraulic conductivity values while the third layer of thickness 10 - 100m is assigned high hydraulic conductivity value. The aquifer system is modelled as a single layer. The Groundwater Vistas software, version 4, from the Environmental Simulation International (ESI) containing the U.S. Geological Survey three dimensional finite difference code MODFLOW and MODPATH packages was used to simulate the conceptual understanding of the geology and hydrogeology of the area. The modelling results gave average groundwater flow velocity of the area to be about 388 m/year. This finding may provide baseline information during environmental impact assessment of the area.

Journal of the Nigerian Association of Mathematical Physics, Volume 15 (November, 2009), pp 205 - 212