A local time stepping algorithm for GPU-accelerated 2D shallow water models

Nat. Hazards Earth Syst. Sci.

et al. 2020

Self Cite

Abstract. With the aim of improving resilience to flooding and increasing preparedness to face levee-breach-induced inundations, this paper presents a methodology for creating a wide database of numerically simulated flooding scenarios due to embankment failures, applicable to any lowland area protected by river levees. The analysis of the detailed spatial and temporal flood data obtained from these hypothetical scenarios is expected to contribute both to the development of civil protection planning and to immediate actions during a possible future flood event (comparable to one of the available simulations in the database) for which real-time modelling may not be feasible. The most relevant criteria concerning the choice of mathematical model, grid resolution, hydrological conditions, breach parameters and locations are discussed in detail. The proposed methodology, named RESILIENCE, is applied to a 1100 km2 pilot area in northern Italy. The creation of a wide database for the study area is made possible thanks to the adoption of a GPU-accelerated shallow-water numerical model which guarantees remarkable computational efficiency (ratios of physical to computational time up to 80) even for high-resolution meshes (2.5–5 m) and very large domains (>1000 km2).

Section: The Parflood Modelmentioning

confidence: 99%

Enhancing the resilience to flooding induced by levee breaches in lowland areas: a methodology based on numerical modelling

Ferrari

Dazzi

Nat. Hazards Earth Syst. Sci.

et al. 2020

Self Cite

“…Morales-Hernandez et al (2014) show that a 2D GPU model may even outperform a 1D-2D coupled model in terms of execution time. Moreover, the implementation of optimization techniques, such as the local time stepping strategy (Dazzi et al, 2018), and the development 30 of codes able to exploit the multi-GPU architecture typical of High Performance Computing (HPC) clusters (Turchetto et al, 2018;Ferrari et al, 2018) can further enhance the efficiency.…”

Section: Serial Vs Parallel Modelsmentioning

confidence: 99%

“…CC BY 4.0 License. performance of this code for field applications was assessed in previous works (Vacondio et al, 2016;Dazzi et al, 2018Dazzi et al, , 2019Ferrari et al, 2018Ferrari et al, , 2019.…”

Section: The Parflood Modelmentioning

confidence: 99%

A methodology based on numerical models for enhancing the resilience to flooding induced by levee breaches in lowland areas

Ferrari

Dazzi

et al. 2019

Preprint

Self Cite

Abstract. With the aim of improving resilience to flooding and increasing preparedness to face levee breach-induced inundations, this paper presents a methodology to create a wide database of numerically simulated flooding scenarios due to embankment failures, applicable to any lowland area protected by river levees. The analysis of the detailed spatial and temporal flood data obtained from these hypothetical scenarios is expected to contribute both to the development of civil protection planning, and to immediate action during a possible future flood event (comparable to one of the available simulations in the database), for which a real-time simulation may not be feasible. The most relevant criteria concerning the choice of the mathematical model, the grid resolution, the hydrological conditions, the breach parameters and locations are discussed in detail. Results of the application of the proposed methodology to a 1,100 km2-pilot area in Northern Italy are presented. The creation of a wide database for the study area is made possible thanks to the adoption of a GPU-accelerated shallow water numerical model, which guarantees a great computational efficiency (ratios of physical to computational time up to 80) even for high-resolution meshes (2.5–5 m) and large domains.

“…However, most of the GPU-accelerated models are based on uniform Cartesian grids, characterized by two main limitations: (i) a unique resolution must be adopted in the whole domain, and (ii) the domain must be rectangular. The adoption of non-uniform grids in GPU-accelerated models has recently gained attention in the literature [43,[49][50][51][52][53][54][55][56], since it allows the use of high resolution only in the portions of the domain where it is needed.…”

Section: Introductionmentioning

confidence: 99%

A GPU-Accelerated Shallow-Water Scheme for Surface Runoff Simulations

Aureli

Prost

et al. 2020

Water

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The capability of a GPU-parallelized numerical scheme to perform accurate and fast simulations of surface runoff in watersheds, exploiting high-resolution digital elevation models (DEMs), was investigated. The numerical computations were carried out by using an explicit finite volume numerical scheme and adopting a recent type of grid called Block-Uniform Quadtree (BUQ), capable of exploiting the computational power of GPUs with negligible overhead. Moreover, stability and zero mass error were ensured, even in the presence of very shallow water depth, by introducing a proper reconstruction of conserved variables at cell interfaces, a specific formulation of the slope source term and an explicit discretization of the friction source term. The 2D shallow water model was tested against two different literature tests and a real event that recently occurred in Italy for which field data is available. The influence of the spatial resolution adopted in different portions of the domain was also investigated for the last test. The achieved low ratio of simulation to physical times, in some cases less than 1:20, opens new perspectives for flood management strategies. Based on the result of such models, emergency plans can be designed in order to achieve a significant reduction in the economic losses generated by flood events.