A New Rapid Flood Inundation Model

In this study, we propose a new Rapid Flood Inundation Model (RFIM). The purpose of the RFIM is to generate predictions of water depth and flood extent using less computer resource than required by two-dimensional shallow water equation models (SWEMs). To be useful the RFIM must produce predictions that are comparable with those obtained from SWEMs. The model described here is an improvement on previous RFIMs as it dynamically adjusts the head driving the flood flow to account for the rate of flood inflow and the frictional resistance of the floodplain. This allows the RFIM to adapt predictions of inundation extent to surface characteristics to the area over which the water is spreading. Improvements in the technique are demonstrated by application has been applied to an area of urban floodplain in Thamesmead, London, UK. This demonstrates that the method significantly improves the level of agreement between the proposed RFIM and a SWEM when compared with the performance of a previous spreading algorithm.