EGU2020-11562, updated on 12 Dec 2021
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Towards fast large-scale flood simulations using 2D Shallow water modelling with depth-dependant porosity

Vita Ayoub1,2,3, Carole Delenne2,3, Patrick Matgen1, Pascal Finaud-Guyot2,3, and Renaud Hostache1
Vita Ayoub et al.
  • 1Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, Esch-sur-Alzette, Luxembourg
  • 2HydroSciences Montpellier, Université de Montpellier, CNRS, IRD, Montpellier, France
  • 3Institut national de recherche en sciences et technologies du numérique, Lemon, Montpellier, France

In hydrodynamic modelling, the mesh resolution has a strong impact on run time and result accuracy. Coarser meshes allow faster simulations but often at the cost of accuracy. Conversely, finer meshes offer a better description of complex geometries but require much longer computational time, which makes their use at a large scale challenging. In this context, we aim to assess the potential of a two-dimensional shallow water model with depth-dependant porosity (SW2D-DDP) for flood simulations at a large scale. This modelling approach relies on nesting a sub-grid mesh containing high-resolution topographic and bathymetric data within each computational cell via a so-called depth-dependant storage porosity. It enables therefore faster simulations on rather coarse grids while preserving small-scale topography information. The July 2007 flood event in the Severn River basin (UK) is used as a test case, for which hydrometric measurements and spatial data are available for evaluation. A sensitivity analysis is carried out to investigate the porosity influence on the model performance in comparison with other classical parameters such as boundary conditions.

How to cite: Ayoub, V., Delenne, C., Matgen, P., Finaud-Guyot, P., and Hostache, R.: Towards fast large-scale flood simulations using 2D Shallow water modelling with depth-dependant porosity, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11562,, 2020.


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