Publication Date:
2011-10-08
Description:
Two-dimensional flood inundation models are widely used tools for flood hazard mapping and an essential component of statutory flood risk management guidelines in many countries. Yet we still don't know how much physically complexity a flood inundation model needs for a given problem. Here, three two-dimensional explicit hydraulic models, that can be broadly defined as simulating diffusive, inertial or shallow water waves, have been benchmarked using test cases from a recent Environment Agency for England and Wales (EA) study, where results from industry models are also available. To ensure consistency the three models were written in the same code and share subroutines for all but the momentum (flow) and time stepping calculations. The diffusive type model required much longer simulation times that the other models, whilst the inertia model was the quickest. For flows that vary gradually in time, differences in simulated velocities and depths due to physical complexity were within 10% of the simulations from a range of industry models. Therefore, for flows that vary gradually in time it appears unnecessary to solve the full two-dimensional shallow water equations. As expected however, the simpler models were unable to simulate supercritical flows accurately. Finally, implications of the results for future model benchmarking studies are discussed in light of a number of subtle factors that were found to cause significant differences in simulations relative to the choice of model. Copyright © 2011 John Wiley & Sons, Ltd.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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