DELINEATING FLOOD EXTENTS WITHOUT HYDRODYNAMICS – YES OR NO?
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| Year of publication | 2018 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Traditional approach to delineating flood extents is through the hydrodynamic modelling procedures or geographic information systems (GIS). The former follow the the laws of physics describing the flow of water in channels and inundated areas (Murty et al., 2014). The latter is primarily based on the comparison of flood water surface elevations and the digital elevation model (DEM). Despite the absence of hydraulic connectivity and the omission of friction, such approaches have been successfully applied in multiple works for the identification of areas prone to being flooded (Wang et al., 2002, Zheng and Wang, 2006, Tonisson et al., 2008, Chau et al., 2013, McInnes et al., 2015, Seenath et al., 2016). The AIZM model (Koli, 2013) is a GIS-based non-hydradynamic tool for delineating flooded areas based on known water surface elevations and DEM. Since the computation neglects hydrology and hydrodynamical aspects of flowing water, one could expect bad performance of the model. In order to evaluate the tool’s ability to produce relevant outputs, it was tested using in 30 river reaches. The analysis was based on comparison of the modelled flood extents with those acquired from airborne imaging during real flood events that occurred in the Czech Republic in summer 1997, 2002 and spring 2006, and post-event field surveys. The input water depths were derived from flood marks‘ elevations. The AIZM’s performace was assessed taking into consideration the contribution of various river reaches‘ and the adjacent floodplains‘ characteristics to the flood extents‘ accuracy. The analysis allowed the identification of both the key limitations and the generally favourable conditions under which the AIZM model is able to deliver accurate outputs. Based on the results, on of the main conclusions of this research is that the AIZM model can be a useful tool for the delineation os flooded areas in cases where only flood water surface elevations are available, for instance for reconstructions of inundations during past flood events, as well as for promt displaying in an operational use. |
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