NUMERICAL MODELING OF GROUNDWATER FLOW IN AN URBAN ENVIRONMENT: INSIGHTS FROM N’DJAMENA, CHAD

Groundwater flow modeling in urban areas is of great importance in the context of water level depletion due to the high population, unplanned urbanization and industrial growth. In N’Djamena, groundwater is the main source of drinking water. Under these conditions, groundwater flow modeling is essential to better understand the dynamics and behavior of the urban groundwater system of the city. The goal of this work is to analyze groundwater flow dynamics in the urban environment of N’Djamena using the well-known MODFLOW model. In this study, we combine field studies and modeling in order to reach this goal.  Results of piezometric monitoring conducted across 200 boreholes and wells showed that the groundwater head ranging from 269.55 m to 304.01 m, with a general flow direction from southeast to northwest, confirming the direct influence of the Chari River on groundwater dynamics. The MODFLOW-based numerical model accurately reproduced the observed hydrodynamic response of the aquifer, as demonstrated by a coefficient of determination (R²) of 0.95 obtained during model calibration.  The results of the model developed could be used an operational decision-making tool for the sustainable management of groundwater resources of N'djamena.