Hydrological budget of Mayotte: groundwater flow and water resources of Petite Terre Island

Based on an analysis of available data combined with new observations, we propose a steady-state model of the freshwater lens of Petite Terre island in Mayotte. The hydrological balance of the airport's meteorological station allows us to estimate the annual recharge using Turc formula. This recharge is on the order of two million cubic meters per year, a portion of which could be extracted for the drinking water supply. Simple modeling under the Dupuit Boussinesq approximation enables to characterise the form of the lens and estimate its volume. We show that the model accords with available data. These results suggest the existence of a significant resource and call for the implementation of further monitoring and analysis, coupled with a review of the groundwater extraction strategy by public authorities in a socially and politically tense island context.