Benchmarking of flood inundation extent using various dynamically linked 1D-2D approaches

An accurate representation of linking processes between one-dimensional (1-D) and two-dimensional (2-D) models is of particular importance for many flood-modelling projects. This paper provides a comparison of 1-D/2-D linking methods used to simulate a hypothetical embankment failure. Comparisons were made by implementing 1-D/2-D linked models using two different 1-D/2-D linking methods, namely water levels and discharges, using both the alternating direction implicit (ADI) and total variation diminishing (TVD) 2-D numerical schemes widely used in flood models such as Flood Modeller Pro (http://www.floodmodeller.com). The flood inundation levels and extent predicted by each numerical scheme were similar when the discharge method was used to link the models, whereas they were dependent on the numerical scheme when the water-level method was used. Consequently, where decisions affecting public safety are informed by the modelling, such as evacuation following a breach, it is recommended that the discharge-linking method should be used for linking models.