Integrated flood-drought climate change impact analysis and adaptation planning – case of Herk-Mombeek catchment, Belgium

The increasing risks of flood and drought events, driven by climate change and urbanization, are particularly pronounced in Flanders, Belgium, where vulnerability to hydrological extremes is high. This study focuses on a significant land-based agricultural and fruit production area in Flanders, which is highly vulnerable to droughts and floods. We use a data-driven, distributed hydrological model, coupling AquaCrop with a simplified groundwater model, to simulate interactions between surface and groundwater, and to simulate the land use and management impact on catchment runoff and groundwater recharge. We conducted a detailed sensitivity analysis on the model parameters and calibrated the model with focus on the validity of actual local physical processes. Furthermore, we project future water allocation under multiple climate scenarios to quantify the spatial and seasonal distribution of flood and drought impacts in both current and future climates. The outcomes provide a research basis for subsequent evaluations of possible land-based climate adaptation actions and propose a comprehensive action plan in close consultation of the local stakeholders.