Author(s): Michael Butts, Birgitte Von Christierson, Craig Mackay, Terry Van Kalken, Sílvia Leirião
Linked Author(s): Terry van Kalken
Keywords: Integrated hydrological-hydraulic modeling, satellite imagery, uncertainty, floodplain inundation, riparian wetlands
Abstract: Floodplain risk management at catchment scale must address flood risk within an integrated water resources management strategy. Flood inundation modelling is important not only for assessing the flood risk to life and property but also for the potential impacts of flood mitigation on riparian wetlands. In this paper, we present an integrated flow modeling tool capable of representing a comprehensive range of flood and catchment processes, including the hydraulic processes in the river, river-floodplain exchanges across the banks, the dynamic surface water-ground water interactions, and the infiltration and evaporation effects. The capabilities of this tool are demonstrated on flood inundation modeling in the Lower Murrumbidgee River, Australia. One of the most important challenges in simulating flood behaviour for catchment management is the need to verify the reliability of model predictions. Traditional observation data are limited to flows or water levels within the river channels. Using satellite imagery and aerial photographs, we investigate the impact of different processes and uncertainties on the flood dynamics and flood extent. The results show that floodwater retention and spilling upstream are very sensitive to local topography and may significantly affect flooding behaviour downstream. This is confirmed when we compare the performance of the integrated hydrological model with high resolution hydraulic modeling. For the longer time scales of wetland flooding, where the hydro period is important for the health and functioning of the riparian wetlands, infiltration and evaporation processes become important
Year: 2017