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Gravel Barrier Beach Morphodynamic Response to Storm Events / KRISTIAN IONS

Swansea University Author: KRISTIAN IONS

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Abstract

Gravel beaches and barriers form a valuable natural protection for many shorelines. Gravel beach response to waves has been studied extensively, for regular and irregular waves, but there is little reported investigation of beach response to bimodal wave conditions, quite commonly experienced at mid...

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Published: Swansea 2021
Institution: Swansea University
Degree level: Master of Research
Degree name: MSc by Research
Supervisor: Karunarathna, Harshinie
URI: https://cronfa.swan.ac.uk/Record/cronfa58789
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Abstract: Gravel beaches and barriers form a valuable natural protection for many shorelines. Gravel beach response to waves has been studied extensively, for regular and irregular waves, but there is little reported investigation of beach response to bimodal wave conditions, quite commonly experienced at midlatitudes. The paper presents a numerical modelling study of gravel barrier beach response to storm wave conditions. The XBeach non-hydrostatic model was set up in 1D mode to investigate barrier volume change and overwash under a wide range of unimodal and bimodal storm conditions and barrier cross sections. The numerical model was validated against conditions at Hurst Castle Spit, UK. The validated model is used to simulate the response of a range of gravel barrier cross sections under a wide selection of statistically significant storm wave and water level scenarios thus simulating an ensemble of realisations of barrier volume change and overwash. This ensemble of results was used to develop a simple parametric model for estimating barrier volume change during a given storm and water level condition. Attempts were also made to model overwash and crest changes of barriers, however further study Is required. Numerical simulations of barrier response to bimodal storm conditions, which are a common occurrence in many parts of the UK, reveals that barrier volume change and overwash from bimodal storms will be higher than that from unimodal storms if the swell percentage is greater than 40%. The limitations of the modelling approach and the model results are noted. The model is demonstrated as providing a useful tool for estimating barrier volume change, a commonly used measure used in gravel barrier beach management.
Item Description: A selection of third party content is redacted or is partially redacted from this thesis due to copyright restrictions.ORCiD identifier: https://orcid.org/0000-0001-7659-0586
Keywords: Coastal Engineering, XBeach, Computational Modelling, Morphodynamics
College: Faculty of Science and Engineering