Integrated Numerical Simulation of Water Resources in Crystalline Aquifers at Koué Watershed Scale (Western Côte d’Ivoire)

Abstract

The present work applied the HydroGeoSphere (HGS) model in humid tropical area to Koué watershed scale to simulate flows in porous and fractured area of crystalline aquifers. It integrates rainfall, physiographic, fractures, hydraulic drilling and hydrodynamic data. The simulation of flows in porous area concerned 5 test zones. The input database of the model is implemented on a triangular grid in porous area using Gridbuilder software and interactive block grid in fractured area. In order to use the model in these two environments, boundary condition was set. The infiltrations rate of the earth layers is estimated in the order to 10 −5 ms −1 . The model simulates the pumping with a good reproductivity of the drawdown profiles of groundwater at the drillings. The storage coefficients vary between 9.9 × 10 −4 and 2 × 10 −3 . The hydraulic conductivities vary from 8.5 × 10 −6 to 2 × 10 −5 . 73.9% of the drillings studied has a high hydraulic conductivity and shows a strong drawdown of the groundwater table. The study of the static levels of the ground water allowed indicating the distribution of the water resources in the drillings: 57% are deep in the first 10 meters, 36% between 10 and 20 m, and 7% in the higher level to 20 m deep in the earth.