Calibrating a High-Performance Hydrodynamic Model for Broad-Scale Flood Simulation: Application to Thames Estuary, London, UK

Abstract

The Thames Estuary, Greater London represents a particularly challenging application for broad-scale strategic analysis of flood risk. It needs a robust flood model and comprehensive risk analysis framework to support the design of London's long-term flood risk management strategy. Traditionally, flood inundation modelling and risk analysis have to be performed by dividing the entire region into smaller disconnected flood plains due to the restriction of model capability and limitation of computational power. This approach essentially neglects the interaction of flood waves between different sub-floodplains and overlooks the broad-scale effects on flood risk. This work aims to test the High-Performance Integrated hydrodynamic Modelling System (HiPIMS) developed at Newcastle University for high-resolution flood simulations over a very large domain, covering 1250km2 of the flood-prone zones in the Thames Estuary, London, UK. This unified modelling strategy directly takes into account the broad-scale effects caused by localised interventions and disturbances, and hence support more comprehensive flood risk analysis and management. As part of the integrated simulation work, model calibration has been done to choose an appropriate value of Manning's roughness coefficient (n) through systematic numerical experiments at resolutions from 40m to 5m. Results are compared with the observed tidal water levels at eight gauging stations along the estuary. In the ongoing work, the calibrated model is being used to conduct further simulations to investigate the flood risk in the estuary as a result of climate change and sea level rise.