Applications of a Physics Based Distributed Integrated Hydrological Model in Flood Risk Management

Abstract

A fully distributed, physics-based hydrologic modelling system, MIKE SHE, is used in several studies to simulate surface flow as runoff in case of flooding. The requirement for such model came from the necessity to simulate the hydrological processes and manage the flood risk for a stream network. The modelling tool is used to study new scenarios with modifications of structures, land use evolution and climate change. MIKE SHE, Système Hydrologique Européen, is a model within MIKE suite developed by DHI. It covers the major processes in the hydrologic cycle and includes process models for evapotranspiration, overland flow, unsaturated flow, groundwater flow, and channel flow and their interactions. MIKE SHE models are based on available spatial data such as land use, vegetation distribution and development, topography, pedology and hydraulic structures. The models are coupled with a fully dynamic one-dimensional river network modelling to ensure a good comprehension of the hydraulic dynamics inside the river. The models are calibrated based on remote sensing data and high-water marks from historical flooding events. For the Brivet river watershed, near to the Atlantic Ocean in France, the calibration of the model successfully reproduced the observed water levels at various gauging stations from rainfall measurements located inside the catchments. Once calibrated the model can be used to simulate scenarios to anticipate the evolution of the watershed such as urbanization or sea level rise in modifying the spatial data or structure regulation. In another case study located on a tributary of the Seine river, the model is applied to evaluate the benefits of stream renaturation and use of crop lands as flood expansion areas.