Modeling of Coastal Morphological Processes

Roelvink, J.A.; Walstra, D.J.R.; Wegen, Mick van der; Ranasinghe, Roshanka

doi:10.1007/978-3-319-16649-0_28

Cited by 5 publications

(5 citation statements)

References 70 publications

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“…Morphodynamic modelling is used to understand and predict the evolution of coastal features such as beaches, dunes and sandbars. This is important for a range of coastal engineering applications, including assessment of damage during extreme events, mitigation of coastal erosion, the design of coastal structures, assessment of different protection strategies, and the generation of possible future scenarios to use in coastal zone management (see, e.g., [1][2][3][4][5]). In addition, beach morphology is influenced by rivers and streams beyond the coastal area, forming what has been referred to as the Watershed-Coast System [6], the integrated modelling of which is becoming increasingly important in the context of climate change [7].…”

Section: Introductionmentioning

confidence: 99%

Acceleration of Morphodynamic Simulations Based on Local Trends in the Bed Evolution

Newell,

Maldonado

2023

JMSE

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Due to the significant mismatch in timescales associated with morphological and hydrodynamic processes in coastal environments, modellers typically resort to various techniques for speeding up the bed evolution in morphodynamic simulations. In this paper, we propose a novel method that differs from existing ones in several aspects. For example, unlike previous approaches that apply a global measure (such as a constant acceleration factor that uniformly amplifies the bed evolution everywhere), we track and extrapolate local trends in morphological changes. The present algorithm requires the setting of four different parameters, values for which we set through an extensive calibration process. The proposed method is compared against the simple acceleration technique built into the popular software XBeach (wherein it is called morfac) for eight different beach profiles (including linear, Dean, and measured profiles). While the accuracy of both methods is generally similar, the proposed algorithm consistently shows a greater reduction in computational time relative to morfac, with our algorithm-accelerated simulations being on average 2.6 times faster than morfac. In light of these results, and considering the algorithm’s potential for easy generalisation to address arbitrary coastal morphodynamic problems, we believe that this method represents an important addition to the toolbox available to the community interested in coastal modelling.

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Section: Introductionmentioning

confidence: 99%

Acceleration of Morphodynamic Simulations Based on Local Trends in the Bed Evolution

Newell,

Maldonado

2023

JMSE

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“…Reducing the computational costs of numerical simulations of the morphological evolution in rivers, estuaries and coastal areas is a critical issue for engineers and geomorphologists [e.g. 4,25,26]. Even though simulation tools of physical systems have greatly benefited from the increasing computational power over the last decades thanks to progress in CPU performances and parallelization technologies, the use of morphodynamic upscaling techniques is still widely popular and becomes essential when long-term evolutions must be predicted [e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Even though simulation tools of physical systems have greatly benefited from the increasing computational power over the last decades thanks to progress in CPU performances and parallelization technologies, the use of morphodynamic upscaling techniques is still widely popular and becomes essential when long-term evolutions must be predicted [e.g. 4,25,26]. Classical approaches for morphodynamic acceleration have been developed primarily for costal and estautuarine applications [6,13,24].…”

Section: Introductionmentioning

confidence: 99%

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Mathematical study of linear morphodynamic acceleration and derivation of the MASSPEED approach

Carraro

Vanzo

Caleffi

et al. 2018

Advances in Water Resources

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Morphological accelerators, such as the MORFAC (MORphological acceleration FACtor) approach [24], are widely adopted techniques for the acceleration of the bed evolution, which reduces the computational cost of morphodynamic numerical simulations. In this work we apply a non-uniform acceleration to the onedimensional morphodynamic problem described by the de Saint Venant-Exner model by multiplying all the spatial derivatives by an individual constant (≥ 1) acceleration factor. The final goal is to identify the best combination of the three accelerating factors for which i) the bed responds linearly to hydrodynamic changes; ii) a consistent decrease of the computational cost is obtained. The sought combination is obtained by studying the behaviour of an approximate solution of the three eigenvalues associated with the flux matrix of the accelerated system. This approach allows to derive a new linear morphodynamic acceleration technique, the MASSPEED (MASs equations SPEEDup) approach, and the a priori determination of the highest acceleration allowed for a given simulation. In this new approach both mass conservation equations (water and sediment) are accelerated by the same factor, differently from the MORFAC approach where only the sediment mass equation is modified. The analysis shows that the MASSPEED gives a larger validity range for linear acceleration and requires smaller computational costs than that of the classical MORFAC approach. The MASSPEED approach is implemented within an example code, using an adaptive approach that applies the maximum linear acceleration similarly to the Courant-Friedrichs-Lewy stability condition.Finally, numerical simulations have been performed in order to assess accuracy and efficiency of the new approach. Results obtained in the long-term propagation of a sediment hump demonstrate the advantages of the new approach. Keywords:SWE -Exner model, Morphological accelerators, MASSPEED approach, MORFAC approach, long term morphodynamic evolution IntroductionReducing the computational costs of numerical simulations of the morphological evolution in rivers, estuaries and coastal areas is a critical issue for engineers and geomorphologists [e.g. 4, 25, 26]. Even

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“…Supplementary Materials:The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/geohazards3040024/s1, References[69][70][71][72][73][74][75][76][77][78][79][80][81] are cited in the Supplementary Materials.…”

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confidence: 99%

Assessment of Flood Hazard in Climatic Extreme Considering Fluvio-Morphic Responses of the Contributing River: Indications from the Brahmaputra-Jamuna’s Braided-Plain

et al. 2022

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Climate change is expected to raise river discharge and sea level in the future, and these near-term changes could alter the river flow regime and sedimentation pattern of future floods. Present hazard assessment studies have limitations in considering such morpho-dynamic responses in evaluating flood hazards or risks. Here, we present a multi-model-based approach to quantify such potential hazard parameters influenced by climate change for the most vulnerable communities living on river bars and islands of the Brahmaputra–Jamuna River. River flood-flow and flood wave propagation characteristics are predicted to be affected by changing temporal distribution patterns of precipitation as a result of enhanced global warming. Increased incidences of large multi-peak floods or uncommon floods resulting in long-duration floods driven by sea-level rise may happen as a result of this. To assess it, we have set up a hydromorphic model, Delft3D, for the Brahmaputra–Jamuna River forced by upstream flow, generated from a hydrological model SWAT, over the Brahmaputra basin. The simulations cover moderate, wettest, and driest conditions of the RCP8.5 scenario, and the results reflect the flooding consequences of the near-future, mid-century, and end-century. Floods in the Brahmaputra–Jamuna River are becoming more severe, frequent, and long-lasting, as a result of climate change, and are expected to last until the end of November rather than the current September timeline. While assessing the hazard, we found that the pattern and timing of the flood are as equally important as the peak of the flood, as the river continuously adjusts its cross-sectional area with the flow. The study also demonstrates that, depending on their location/position, climate-induced hazards can affect sand bars/islands disproportionally. The high flood depth, duration, and sedimentation have a significant impact on the sand bars downstream of the river, making them more vulnerable.

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Modeling of Coastal Morphological Processes

Cited by 5 publications

References 70 publications

Acceleration of Morphodynamic Simulations Based on Local Trends in the Bed Evolution

Acceleration of Morphodynamic Simulations Based on Local Trends in the Bed Evolution

Mathematical study of linear morphodynamic acceleration and derivation of the MASSPEED approach

Assessment of Flood Hazard in Climatic Extreme Considering Fluvio-Morphic Responses of the Contributing River: Indications from the Brahmaputra-Jamuna’s Braided-Plain

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