Modelling the capacity of the LLN lake to retain run-off water

Details

Supervisors

Soares Frazao, Sandra

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil des constructions, à finalité spécialisée
Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

enThis thesis presents the development, calibration, and application of a high resolution hydraulic and hydrological model for the Louvain-la-Neuve urban catchment and retention lake system using the Storm Water Management Model (SWMM). The modelling approach integrates detailed GIS-based catchment delineation, observed and synthetic rainfall time series, calibrated storage–outflow relationships, and a stepwise refinement of the sewer network to achieve a physically consistent and validated digital twin of the system. The simulation results demonstrate that careful parametrization, particularly of impervious surfaces and hydraulic rating curves, allows the SWMM model to closely reproduce observed water levels and outflows, providing robust validation against field sensor data. Systematic scenario analysis, including the incorporation of planned urban developments and extreme rainfall events derived from IDF curves, reveals that while lake storage capacity is generally sufficient for rare high-volume storms, the sewer network frequently reaches critical thresholds in much more common short-duration high-intensity rainfall. Vulnerabilities are particularly pronounced in slope transitions and diameter reductions within the pipe system. The study underscores the importance of high resolution integrated modelling for effective urban flood risk assessment and infrastructure planning. By bridging the gap between physical realism and practical decision support, the presented modelling framework offers a transferable tool to diagnose system weaknesses, guide targeted upgrades, and ensure sustainable urban water management in the face of growing hydrometeorological pressures.