Context • Groundwater major water resource throughout the world that is heterogeneously distributed and sustains diversified uses • The sustainability of groundwater usage highly dependent on the relative rates of groundwater abstraction e g via pumping) and groundwater renewal e g groundwater recharge) • Groundwater recharge ( the water infiltrating from the surface and reaching the saturated zone --> Robust long term GWR estimates at all scales strategic to implement sustainable and integrated water policies Problem • Spatially distributed GWR estimates from numerical modeling • Simulation of GWR challenge (input data, calibration data, and computational requirements) • Interest of the community for open source tools for GWR estimation in R Goals Contribute a new R package, rechaRge dedicated to the estimation of GWR --> for researchers, professionals, and stakeholders, both for hydrogeologists and non hydrogeologists --> Open to all GWR estimation methods --> Include state of the art functions for sensitivity analysis, calibration, and uncertainty analysis --> Collaborative project --> Invitation to integrate your model's code with the package