A highly efficient 2D flood model with sub-element topography

Abstract. Channel maintenance activities, understood as vegetation and sediment management, have a potential to change the conveyance capacity of a watercourse and thus, to provide a benefit from a flood risk perspective. Vegetation and its overgrowth is one of the main factors influencing flow capacity and hence river conveyance. Despite the undesirable consequences associated with flooding, it is rare that sufficient funds are available to undertake all necessary maintenance activities. In the face of limited budgets, flood risk managers must take difficult decisions in order to decide how and where limited resources should be invested. This paper presents a national scale approach to identify the strategically important watercourses where conveyance related works produce the greatest benefit. This is done by identifying watercourses where maintenance works may have a potential to positively maintain or increase conveyance capacity and watercourses where the attribution of area or receptors benefiting is important. Assembling together this information produces a picture of the strategic lengths of watercourse to be maintained.

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“…It could be possible to use more sophisticated methods such as the one used in the National Assessment of Flood Risk in England [8].…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Supporting decision-making for channel conveyance maintenance

2016

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“…The new toolkit is therefore based upon new inundation model software RFSM-EDA (Rapid Flood Spreading Model: Explicit Diffusion waves with Acceleration) that uses a unique sub-grid meshing system. RFSM-EDA is orders of magnitude faster than a traditional 2D hydraulic model [31,32], and has adopted the Rapid Flood Spreading Model with Explicit Diffusion wave with Acceleration terms (RFSM-EDA). The RFSM-EDA model has previously been adopted for strategic flood risk planning proposes and has the capability to be used to run tens of thousands of different scenarios.…”

Section: Two Dimensional Flood Spreading Simulationmentioning

confidence: 99%

Methods and tools to support real time risk-based flood forecasting - a UK pilot application

et al. 2016

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Abstract. Flood managers have traditionally used probabilistic models to assess potential flood risk for strategic planning and non-operational applications. Computational restrictions on data volumes and simulation times have meant that information on the risk of flooding has not been available for operational flood forecasting purposes. In practice, however, the operational flood manager has probabilistic questions to answer, which are not completely supported by the outputs of traditional, deterministic flood forecasting systems. In a collaborative approach, HR Wallingford and Deltares have developed methods, tools and techniques to extend existing flood forecasting systems with elements of strategic flood risk analysis, including probabilistic failure analysis, two dimensional flood spreading simulation and the analysis of flood impacts and consequences. This paper presents the results of the application of these new operational flood risk management tools to a pilot catchment in the UK. It discusses the problems of performing probabilistic flood risk assessment in real time and how these have been addressed in this study. It also describes the challenges of the communication of risk to operational flood managers and to the general public, and how these new methods and tools can provide risk-based supporting evidence to assist with this process.

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“…To address these issues a time-based version has been developed and applied (Falter et al, 2013). This has recently been further developed by Jamieson et al (2012a). The primary objective of the new model is to improve the physical representation of the flood inundation aspects but retain the computational efficiencies afforded by the original model.…”

Section: Model Backgroundmentioning

confidence: 99%

“…The coarse mesh of impact zones forms the computational mesh of the inundation model as this offers significant increases in computational efficiency when compared with traditional, flat cell, models (i.e. models with each grid cell defined by a single elevation (Jamieson et al, 2012a)). This meshing system requires the analysis of the floodplain topography using a preprocessing algorithm.…”

Section: Model Backgroundmentioning

confidence: 99%

A flood risk analysis model with topographical inundation and life-loss

Gouldby¹,

Lhomme²,

Jamieson³

et al. 2015

Proceedings of the Institution of Civil Engineers - Water Manag

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Quantified models of flood risk that incorporate an explicit representation of the performance of flood defence infrastructure are becoming an increasingly important component of efforts to manage flood risk. The models have been applied to support a wide range of decisions, including long-term strategic planning, assessment of investment needs and shorter-term asset management. The model currently applied in practice by the Environment Agency in England and Wales makes a number of simplifying assumptions to achieve computationally practical run-times. One of these simplifications relates to the volume-based flood-spreading algorithm that is applied. This paper describes the implementation of a new time-based inundation model within the existing risk analysis modelling approach. The new inundation model offers a significant increase in the representation of the physical processes within the flood simulation component of the risk analysis model. It also offers new outputs in terms of estimates of maximum depths and flood velocities. Velocities are known to be an important factor in flood-related fatalities. A simplified method to estimate life-loss has been combined with new output from the improved inundation model to illustrate how estimates of risk to life could be provided.

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A highly efficient 2D flood model with sub-element topography

Cited by 31 publications

References 26 publications

Supporting decision-making for channel conveyance maintenance

Supporting decision-making for channel conveyance maintenance

Methods and tools to support real time risk-based flood forecasting - a UK pilot application

A flood risk analysis model with topographical inundation and life-loss

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