Exponentially cascaded cross-sectional volume estimates from elevation data

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Bastian Van den Bout, Vera Glas


The relationship between discharges and flow heights is a critical component of hydraulic modelling, often carried out involving data on the elevation profiles of the river bed. However, obtaining and using cross-sectional profile data can be resource intensive. Methods for profile estimation from rasterized elevation and bathymetry can help overcome this. In this paper, an efficient algorithm for cross-sectional estimates of discharge-volume relationships is presented as part of the FastFlood method. The method uses exponentially cascading to estimate profiles efficiently with lower resolution further away from the channel center-lines. Two study cased are presented, the Sunkoshi River in North Nepal, and the Rhine river at the border between Germany and the Netherlands. For these areas the discharge-volume relationship is compared for a full 2D hydrodynamic model, the Fastflood method and an estimate through Mannings equation using cross-sectional area and wetted perimeter. We observe a similar match between the model setups, with deviations within a 5% percent range. There is an excellent estimation of general flow depths with the improved FastFlood methodology. Moreover, the application of a localized estimate of Manning’s flow law can provide flow velocities, but limitations remain due to the absence of inertia in the Fastflood model.




Civil and Environmental Engineering, Engineering


flood, Simulation, hydraulic, FastFlood


Published: 2024-02-13 07:46

Last Updated: 2024-02-13 15:46


CC-BY Attribution-NonCommercial 4.0 International