A 2D Shallow water model with depth-dependant porosity applied to the Severn River

Vita Ayoub (1, 2, 3) , Carole Delenne (2, 3) , Patrick Matgen (1) , Pascal Finaud-Guyot (3, 2) , Renaud Hostache (1)

1 LIST - Luxembourg Institute of Science and Technology
2 LEMON - Littoral, Environment: MOdels and Numerics
3 HSM - Hydrosciences Montpellier

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 that 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-dependent 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. The model is evaluated using both gauge and spatial data.

Mots clés: large scale flood model; shallow water equations; depth-dependent porosity; high-resolution data; fast simulations

Domaines: Sciences de l'environnement; Sciences de l'ingénieur [physics]

Vita Ayoub, Carole Delenne, Patrick Matgen, Pascal Finaud-Guyot, Renaud Hostache. A 2D Shallow water model with depth-dependant porosity applied to the Severn River. River Flow 2020 - 10th Conference on Fluvial Hydraulics, Jul 2020, Delft / Virtual, Netherlands. ⟨hal-02945686⟩