High resolution rainfall-runoff simulation in urban area: assessment of Telemac 2D and FullSWOF 2D

Qiang Ma, Morgan Abily, Ngoc duong Vo, Philippe Gourbesville

Friday 3 july 2015

13:30 - 13:45h at Asia (level 0)

Themes: (T) Water resources and hydro informatics (WRHI), (ST) Catchment hydrology

Parallel session: 16C. Engineering - Industrial

Under extreme rainfall and runoff events, the complexity of urban environment makes difficult to estimate the flooding processes. To overcome this issue, practitioners are widely using high resolution data with numerical models solving the 2D-Shallow Water Equations (SWE). However, due to inherent limitations in the numerical simulations, the outcome of different mesh structures and numerical schemes may generate differences between the model results. This paper focuses on the possibilities, performance and limits of using standard numerical modelling approaches for high resolution rainfall-runoff process in the urban area. An extreme rainfall scenario in the city centre of NICE, France, is simulated with two different numerical models (Telemac-2D and FullSWOF-2D) using LiDAR dataset. These 2D SWE based codes rely on different meshing strategies (non-structured and structured) and different numerical schemes (Finite Element and Finite Volume). For high resolution modelling, the differences between the water depths simulated by these two models were compared and discussed to find the major courses and to evaluate the impact of modelling strategies on model quality. The emphasis is to optimize the balance including the strategy for LiDAR data inclusion, the computation time, the stability and the accuracy of the high resolution rainfall-runoff models in the urban flood simulation. Keywords: extreme rainfall, urban area, high resolution rainfall-runoff modelling, Telemac-2D, FullSWOF-2D, LiDAR data