Rapid Inundation Modelling in Large Floodplains Using LiDAR DEM

Teng, Jin; Vaze, Jai; Dutta, Dushmanta; Marvanek, Steve

doi:10.1007/s11269-015-0960-8

Cited by 99 publications

(61 citation statements)

References 30 publications

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“…The SAR imagery was shown to be a valuable source for determining the observed flood extent, even though it appeared to be limited in areas of inundation depths smaller than 0.25 m and salt marsh/mangroves habitats. The limitation of remote-sensing-based flood detection due to dense vegetation cover has incidentally also been observed by Teng et al (2015). Nevertheless, the obtained model fit score of 0.53 demonstrates a high predictive skill of the present model and is similar to fit scores presented in Bates et al (2005).…”

Section: Model Performancesupporting

confidence: 81%

Investigating compound flooding in an estuary using hydrodynamic modelling: a case study from the Shoalhaven River, Australia

Kumbier

Carvalho

Vafeidis

et al. 2018

Nat. Hazards Earth Syst. Sci.

109

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Abstract. Many previous modelling studies have considered storm-tide and riverine flooding independently, even though joint-probability analysis highlighted significant dependence between extreme rainfall and extreme storm surges in estuarine environments. This study investigates compound flooding by quantifying horizontal and vertical differences in coastal flood risk estimates resulting from a separation of storm-tide and riverine flooding processes. We used an open-source version of the Delft3D model to simulate flood extent and inundation depth due to a storm event that occurred in June 2016 in the Shoalhaven Estuary, south-eastern Australia. Time series of observed water levels and discharge measurements are used to force model boundaries, whereas observational data such as satellite imagery, aerial photographs, tidal gauges and water level logger measurements are used to validate modelling results. The comparison of simulation results including and excluding riverine discharge demonstrated large differences in modelled flood extents and inundation depths. A flood risk assessment accounting only for storm-tide flooding would have underestimated the flood extent of the June 2016 storm event by 30 % (20.5 km 2 ). Furthermore, inundation depths would have been underestimated on average by 0.34 m and by up to 1.5 m locally. We recommend considering storm-tide and riverine flooding processes jointly in estuaries with large catchment areas, which are known to have a quick response time to extreme rainfall. In addition, comparison of different boundary set-ups at the intermittent entrance in Shoalhaven Heads indicated that a permanent opening, in order to reduce exposure to riverine flooding, would increase tidal range and exposure to both storm-tide flooding and wave action.

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Section: Model Performancesupporting

confidence: 81%

Investigating compound flooding in an estuary using hydrodynamic modelling: a case study from the Shoalhaven River, Australia

Kumbier

Carvalho

Vafeidis

et al. 2018

Nat. Hazards Earth Syst. Sci.

109

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“…The most common approaches followed for the river and riverine areas topography estimation and the DEM generation are ground surveying topographic approaches and photogrammetric techniques. However, the use of such techniques in flood inundation modelling, especially in complex river topographies involve some limitations such as the small spatial extent and the possibility to produce several errors and affect the accuracy of the produced DEM [57,58]. These limiting factors can be minimized with the use of high accuracy aerial photographs or orthophotos.…”

Section: Hydraulic-hydrodynamic Modellingmentioning

confidence: 99%

An Operational Method for Flood Directive Implementation in Ungauged Urban Areas

et al. 2018

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An operational framework for flood risk assessment in ungauged urban areas is developed within the implementation of the EU Floods Directive in Greece, and demonstrated for Volos metropolitan area, central Greece, which is frequently affected by intense storms causing fluvial flash floods. A scenario-based approach is applied, accounting for uncertainties of key modeling aspects. This comprises extreme rainfall analysis, resulting in spatially-distributed Intensity-Duration-Frequency (IDF) relationships and their confidence intervals, and flood simulations, through the SCS-CN method and the unit hydrograph theory, producing design hydrographs at the sub-watershed scale, for several soil moisture conditions. The propagation of flood hydrographs and the mapping of inundated areas are employed by the HEC-RAS 2D model, with flexible mesh size, by representing the resistance caused by buildings through the local elevation rise method. For all hydrographs, upper and lower estimates on water depths, flow velocities and inundation areas are estimated, for varying roughness coefficient values. The methodology is validated against the flood event of the 9th October 2006, using observed flood inundation data. Our analyses indicate that although typical engineering practices for ungauged basins are subject to major uncertainties, the hydrological experience may counterbalance the missing information, thus ensuring quite realistic outcomes.

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“…Analyses on regional to global scales are essential to identify hotspots, provide consistent information for international financing of mitigation projects, and implement adaptation measures in a concerted and consistent manner (Döll et al, 2003;Adhikari et al, 2010;Pappenberger et al, 2012;Schumann et al, 2014). The simulations on regional to global scale are also necessary to determine specific locations for more in-depth analysis using detailed hydraulic and hydrodynamic models (e.g., MIKE FLOOD by DHI, 2005; TVD by Teng et al, 2015) which cannot be applied across very large areas.…”

Section: Introductionmentioning

confidence: 99%

Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods

Mateo

Yamazaki

Kim

et al. 2017

Hydrol. Earth Syst. Sci.

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Abstract. Global-scale river models (GRMs) are core tools for providing consistent estimates of global flood hazard, especially in data-scarce regions. Due to former limitations in computational power and input datasets, most GRMs have been developed to use simplified representations of flow physics and run at coarse spatial resolutions. With increasing computational power and improved datasets, the application of GRMs to finer resolutions is becoming a reality. To support development in this direction, the suitability of GRMs for application to finer resolutions needs to be assessed. This study investigates the impacts of spatial resolution and flow connectivity representation on the predictive capability of a GRM, CaMa-Flood, in simulating the 2011 extreme flood in Thailand. Analyses show that when single downstream connectivity (SDC) is assumed, simulation results deteriorate with finer spatial resolution; Nash-Sutcliffe efficiency coefficients decreased by more than 50 % between simulation results at 10 km resolution and 1 km resolution. When multiple downstream connectivity (MDC) is represented, simulation results slightly improve with finer spatial resolution. The SDC simulations result in excessive backflows on very flat floodplains due to the restrictive flow directions at finer resolutions. MDC channels attenuated these effects by maintaining flow connectivity and flow capacity between floodplains in varying spatial resolutions. While a regional-scale flood was chosen as a test case, these findings should be universal and may have significant impacts on large-to globalscale simulations, especially in regions where mega deltas exist.These results demonstrate that a GRM can be used for higher resolution simulations of large-scale floods, provided that MDC in rivers and floodplains is adequately represented in the model structure.

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Rapid Inundation Modelling in Large Floodplains Using LiDAR DEM

Cited by 99 publications

References 30 publications

Investigating compound flooding in an estuary using hydrodynamic modelling: a case study from the Shoalhaven River, Australia

Investigating compound flooding in an estuary using hydrodynamic modelling: a case study from the Shoalhaven River, Australia

An Operational Method for Flood Directive Implementation in Ungauged Urban Areas

Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods

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