On the use of the diffusive wave for modelling extreme flood events with overbank flow in the floodplain

Moussa, Roger; Bocquillon, Claude

doi:10.1016/j.jhydrol.2009.06.006

Cited by 81 publications

(58 citation statements)

References 57 publications

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“…The hypothesis of the diffusive wave, less restrictive, is a priori more satisfactory. Moussa and Bocquillon (2009) apply a model based on this approximation to the Lez River catchment, neighbouring the Gardon River basin, and obtain good results. A hydraulic model based on the full Saint-Venant equations requires fine topographic data, and its calculation times are more important.…”

Section: The Choice Of the Modelsmentioning

confidence: 99%

A coupling of hydrologic and hydraulic models appropriate for the fast floods of the Gardon River basin (France)

Laganier¹,

Ayral²,

Salze³

et al. 2014

Nat. Hazards Earth Syst. Sci.

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Abstract. Mediterranean catchments are regularly affected by fast and flash floods. Numerous hydrologic models have been developed, and allow modelling of these floods. However, these approaches often concern average-size basins of a few hundred km 2 . At larger scales (> 1000 km 2 ), coupling of hydrologic and hydraulic models appears to be an adapted solution. This study has as its first objective the evaluation of the performances of a coupling of models for flood hydrograph modelling. Secondly, the coupling results are compared with those of other modelling options. The aim of these comparisons is to clear up the following points. (1) Is a simplified routing model (lag and route) as efficient as a full hydraulic model for the modelling of hydrographs, in the intermediary downstream part of the stream? (2) Is adding lateral inflows necessary for all studied events? (3) What is the impact of the qualities of upstream hydrologic modelling feeding the coupling? The coupling combines the SCS-LR (Soil Conservation Service-lag-and-route) hydrologic model of the ATHYS platform and the MASCARET 1-D hydraulic model based on full Saint-Venant equations. It is applied to the Gardon River basin (2040 km 2 ) in the south of France. For the seven studied events, the results of the coupling are satisfactory, the calculated Nash indexes varying between 0.61 and 0.97. The comparisons with the other modelling options show the important role of the spatial distribution of rains during events: when rains are centered on the intermediary downstream part of the catchment, adding lateral inflows is necessary; when rains are more important in the upstream part, the quality of the hydrologic modelling upstream of the coupling has a strong impact. Furthermore, the used coupling of models seems well adapted for water rising and flooded area forecasting. The future developments of the tool will concentrate on this point.

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Section: The Choice Of the Modelsmentioning

confidence: 99%

A coupling of hydrologic and hydraulic models appropriate for the fast floods of the Gardon River basin (France)

Laganier¹,

Ayral²,

Salze³

et al. 2014

Nat. Hazards Earth Syst. Sci.

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“…This being the case, an extreme flood event can be simply characterized as a flood event with a small probability of occurrence, but with a significant impact on human society in terms of general damage, human casualties and overall social disruption. Taking into account all of these considerations, four types of flood events can be generally characterized as extreme flood events, including: (1) dam-break floods (Duffaut 2013;Bergman et al 2014;Raška and Emmer 2014), (2) storm surges (Chau et al 2013;Breilh et al 2014;Androulidakis et al 2015), (3) flash floods (Moussa and Bocquillon 2009;Martínez Ibarra 2012;Foulds et al 2014;Amengual et al 2015;Kvočka et al 2015), and (4) extreme/large river floods (Zhi-Yong et al 2013;Bruwier et al 2015;Herget et al 2015;Schröter et al 2015;Antico et al 2016). Among these types of extreme flood events, flash floods and large river floods are the most common and generally the most serious extreme events (Ashley and Ashley 2008;Di Baldassarre et al 2010), which pose the greatest flood risk to the general population.…”

Section: Introductionmentioning

confidence: 99%

Flood hazard assessment for extreme flood events

2016

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Climate change is expected to result in an increase in the frequency and intensity of extreme weather events. In turn, this will result in more frequent occurrences of extreme flood events, such as flash flooding and large-scale river flooding. This being the case, there is a need for more accurate flood risk assessment schemes, particularly in areas prone to extreme flooding. This study investigates what type of flood hazard assessment methods should be used for assessing the flood hazard to people caused by extreme flooding. Two flood hazard assessment criteria were tested, namely: a widely used, empirically derived method, and recently introduced, physically based and experimentally calibrated method. The two selected flood hazard assessment methods were: (1) validated against experimental data, and (2) used to assess flood hazard indices for two different extreme flood events, namely: the 2010 Kostanjevica na Krki extreme river flood and the 2007 Ž elezniki flash flood. The results obtained in this study suggest that in the areas prone to extreme flooding, the flood hazard indices should be based on using the formulae derived for a mechanics-based analysis, as these formulations consider all of the physical forces acting on a human body in floodwaters, take into account the rapid changes in the flow regime, which often occur for extreme flood events, and enable a rapid assessment of the degree of flood hazard risk in a short time period, a feature particularly important when assessing flood hazard indices for high Froude numbers flows.

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“…Equation (1) is the mass conservation equation, and Equation (2) is the momentum conservation equation where terms not proportional to acceleration due to gravity have been neglected according to the diffusive hypothesis. Equations (2) and (3) can be merged in Equation (1) …”

Section: D Model Equationsmentioning

confidence: 99%

“…The physical process becomes very complex to simulate and is no longer satisfactorily represented by a 1D scheme. Quasi two-dimensional (2D) models discretize the floodplain into a network of virtual river branches and spills linked with the main river channels [2]. When the influence of backwater effects cannot be neglected, the coupling of the 1D and the quasi-2D schemes is needed [3].…”

Section: Introductionmentioning

confidence: 99%

The FLO Diffusive 1D-2D Model for Simulation of River Flooding

Aricò

Filianoti

Sinagra

et al. 2016

Water

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An integrated 1D-2D model for the solution of the diffusive approximation of the shallow water equations, named FLO, is proposed in the present paper. Governing equations are solved using the MArching in Space and Time (MAST) approach. The 2D floodplain domain is discretized using a triangular mesh, and standard river sections are used for modeling 1D flow inside the section width occurring with low or standard discharges. 1D elements, inside the 1D domain, are quadrilaterals bounded by the trace of two consecutive sections and by the sides connecting their extreme points. The water level is assumed to vary linearly inside each quadrilateral along the flow direction, but to remain constant along the direction normal to the flow. The computational cell can share zero, one or two nodes with triangles of the 2D domain when lateral coupling occurs and more than two nodes in the case of frontal coupling, if the corresponding section is at one end of the 1D channel. No boundary condition at the transition between the 1D-2D domain has to be solved, and no additional variable has to be introduced. Discontinuities arising between 1D and 2D domains at 1D sections with a top width smaller than the trace of the section are properly solved without any special restriction on the time step.

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On the use of the diffusive wave for modelling extreme flood events with overbank flow in the floodplain

Cited by 81 publications

References 57 publications

A coupling of hydrologic and hydraulic models appropriate for the fast floods of the Gardon River basin (France)

A coupling of hydrologic and hydraulic models appropriate for the fast floods of the Gardon River basin (France)

Flood hazard assessment for extreme flood events

The FLO Diffusive 1D-2D Model for Simulation of River Flooding

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