Author(s): D. Mcconnell; C. Druery
Linked Author(s):
Keywords: Flood surface; Modelling; Flood risk; Insurance
Abstract: Australian insurers have commenced offering flood insurance based on a mainstream flood risk database. However, the potential risks related to overland flooding in urban areas are not adequately identified. An empirical grid based model has been developed to provide a rapid assessment of potential overland flood extents from design rainfall intensities. The approach employs a flow accumulation analysis of digital elevation data identifying overland and mainstream flowpaths and their upstream catchment area. The rational method and AUSIFD are used to obtain design rainfall intensities and catchment concentration times, and thus allow design flows to be determined. The water surface, which is obtained by simply applying Manning's equation to a cross-section and bed slope along each flowpath, is intersected with the DEM to map the potential flood extents. A comparison with hydrodynamically modelled data and sensitivity checks of the empirical parameters has shown good agreement across a number of flood frequencies.
Year: 2011