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Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover / THOMAS VEELEN

Swansea University Author: THOMAS VEELEN

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DOI (Published version): 10.23889/SUthesis.59834

Abstract

Salt marshes are intertidal coastal wetlands that are typically found in sheltered locations such as estuaries. They exhibit a diverse vegetation cover with flexible grasses and rigid shrubs. This vegetation provides coastal protection by attenuat-ing currents and waves. Unlike traditional hard defen...

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Published: Swansea 2020
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Karunarathna, Harshinie ; Reeve, Dominic E.
URI: https://cronfa.swan.ac.uk/Record/cronfa59834
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last_indexed 2022-04-15T03:31:25Z
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fullrecord <?xml version="1.0"?><rfc1807><datestamp>2022-04-14T16:12:40.3592998</datestamp><bib-version>v2</bib-version><id>59834</id><entry>2022-04-14</entry><title>Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover</title><swanseaauthors><author><sid>14da0c4d168034039b02d3daee536357</sid><firstname>THOMAS</firstname><surname>VEELEN</surname><name>THOMAS VEELEN</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2022-04-14</date><abstract>Salt marshes are intertidal coastal wetlands that are typically found in sheltered locations such as estuaries. They exhibit a diverse vegetation cover with &#xFB02;exible grasses and rigid shrubs. This vegetation provides coastal protection by attenuat-ing currents and waves. Unlike traditional hard defences, they o&#xFB00;er co-bene&#xFB01;ts by stabilising shorelines and enhancing natural habitats. However, it has remained unclear how salt marshes with a &#xFB02;exible vegetation cover contribute to coastal protection under storms with surge and wave components.In this thesis, I have developed a new coupled current-wave-vegetation model which includes the e&#xFB00;ect of vegetation &#xFB02;exibility on wave attenuation. The wave-vegetation model builds on novel laboratory experiments using arti&#xFB01;cial vegeta-tion in the Swansea University Wave Flume, where wave damping, water velocity &#xFB01;elds, and plant motion were measured simultaneously for the &#xFB01;rst time. A new work factor is introduced to explicitly account for vegetation &#xFB02;exibility in compu-tational models. Furthermore, a momentum sink term parameterisation is found to best resemble current-vegetation interactions. The advanced coupled model is successfully applied to simulate &#xFB02;ood risk in the Taf Estuary under six contrast-ing vegetation scenarios.My results highlight how the vegetation cover a&#xFB00;ects the coastal protection pro-vided by salt marshes. All modelled vegetation species constrain &#xFB02;ood currents to the main estuary channel and damp incoming waves. Although &#xFB02;exible grasses are 50% less e&#xFB00;ective in wave damping than rigid shrubs in the Taf Estuary. The wave conditions, wind conditions and local topography further a&#xFB00;ect the protec-tion provided. Additionally, rigid species can amplify orbital velocities above the canopy by inducing wave-averaged currents, but &#xFB02;exible species do not.It is recommended that the biomechanical properties of vegetation, including the &#xFB02;exibility, are included when modelling the coastal protection by salt marshes. My new computational modelling framework provides evidence to support the continuing uptake of salt marshes as sustainable coastal defences.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>Salt Marshes, Computational Modelling, Coastal Vegetation, Flood Risk, Laboratory Experiments</keywords><publishedDay>17</publishedDay><publishedMonth>6</publishedMonth><publishedYear>2020</publishedYear><publishedDate>2020-06-17</publishedDate><doi>10.23889/SUthesis.59834</doi><url/><notes>ORCiD identifier: https://orcid.org/0000-0002-7061-8012</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Karunarathna, Harshinie ; Reeve, Dominic E.</supervisor><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><degreesponsorsfunders>Swansea University</degreesponsorsfunders><apcterm/><lastEdited>2022-04-14T16:12:40.3592998</lastEdited><Created>2022-04-14T15:45:53.7196870</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Uncategorised</level></path><authors><author><firstname>THOMAS</firstname><surname>VEELEN</surname><order>1</order></author></authors><documents><document><filename>59834__23874__370f20badf5e4b5d9c160c5c0350e405.pdf</filename><originalFilename>van_Veelen_Thomas_PhD_Thesis_Final_Cronfa.pdf</originalFilename><uploaded>2022-04-14T16:10:40.9353729</uploaded><type>Output</type><contentLength>86688352</contentLength><contentType>application/pdf</contentType><version>E-Thesis &#x2013; open access</version><cronfaStatus>true</cronfaStatus><documentNotes>Copyright: The author, Thomas J. van Veelen, 2020.</documentNotes><copyrightCorrect>true</copyrightCorrect><language>eng</language></document></documents><OutputDurs/></rfc1807>
spelling 2022-04-14T16:12:40.3592998 v2 59834 2022-04-14 Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover 14da0c4d168034039b02d3daee536357 THOMAS VEELEN THOMAS VEELEN true false 2022-04-14 Salt marshes are intertidal coastal wetlands that are typically found in sheltered locations such as estuaries. They exhibit a diverse vegetation cover with flexible grasses and rigid shrubs. This vegetation provides coastal protection by attenuat-ing currents and waves. Unlike traditional hard defences, they offer co-benefits by stabilising shorelines and enhancing natural habitats. However, it has remained unclear how salt marshes with a flexible vegetation cover contribute to coastal protection under storms with surge and wave components.In this thesis, I have developed a new coupled current-wave-vegetation model which includes the effect of vegetation flexibility on wave attenuation. The wave-vegetation model builds on novel laboratory experiments using artificial vegeta-tion in the Swansea University Wave Flume, where wave damping, water velocity fields, and plant motion were measured simultaneously for the first time. A new work factor is introduced to explicitly account for vegetation flexibility in compu-tational models. Furthermore, a momentum sink term parameterisation is found to best resemble current-vegetation interactions. The advanced coupled model is successfully applied to simulate flood risk in the Taf Estuary under six contrast-ing vegetation scenarios.My results highlight how the vegetation cover affects the coastal protection pro-vided by salt marshes. All modelled vegetation species constrain flood currents to the main estuary channel and damp incoming waves. Although flexible grasses are 50% less effective in wave damping than rigid shrubs in the Taf Estuary. The wave conditions, wind conditions and local topography further affect the protec-tion provided. Additionally, rigid species can amplify orbital velocities above the canopy by inducing wave-averaged currents, but flexible species do not.It is recommended that the biomechanical properties of vegetation, including the flexibility, are included when modelling the coastal protection by salt marshes. My new computational modelling framework provides evidence to support the continuing uptake of salt marshes as sustainable coastal defences. E-Thesis Swansea Salt Marshes, Computational Modelling, Coastal Vegetation, Flood Risk, Laboratory Experiments 17 6 2020 2020-06-17 10.23889/SUthesis.59834 ORCiD identifier: https://orcid.org/0000-0002-7061-8012 COLLEGE NANME COLLEGE CODE Swansea University Karunarathna, Harshinie ; Reeve, Dominic E. Doctoral Ph.D Swansea University 2022-04-14T16:12:40.3592998 2022-04-14T15:45:53.7196870 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised THOMAS VEELEN 1 59834__23874__370f20badf5e4b5d9c160c5c0350e405.pdf van_Veelen_Thomas_PhD_Thesis_Final_Cronfa.pdf 2022-04-14T16:10:40.9353729 Output 86688352 application/pdf E-Thesis – open access true Copyright: The author, Thomas J. van Veelen, 2020. true eng
title Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
spellingShingle Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
THOMAS VEELEN
title_short Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
title_full Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
title_fullStr Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
title_full_unstemmed Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
title_sort Computational Modelling of the Coastal Protection Function of Salt Marshes with Flexible Vegetation Cover
author_id_str_mv 14da0c4d168034039b02d3daee536357
author_id_fullname_str_mv 14da0c4d168034039b02d3daee536357_***_THOMAS VEELEN
author THOMAS VEELEN
author2 THOMAS VEELEN
format E-Thesis
publishDate 2020
institution Swansea University
doi_str_mv 10.23889/SUthesis.59834
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
active_str 0
description Salt marshes are intertidal coastal wetlands that are typically found in sheltered locations such as estuaries. They exhibit a diverse vegetation cover with flexible grasses and rigid shrubs. This vegetation provides coastal protection by attenuat-ing currents and waves. Unlike traditional hard defences, they offer co-benefits by stabilising shorelines and enhancing natural habitats. However, it has remained unclear how salt marshes with a flexible vegetation cover contribute to coastal protection under storms with surge and wave components.In this thesis, I have developed a new coupled current-wave-vegetation model which includes the effect of vegetation flexibility on wave attenuation. The wave-vegetation model builds on novel laboratory experiments using artificial vegeta-tion in the Swansea University Wave Flume, where wave damping, water velocity fields, and plant motion were measured simultaneously for the first time. A new work factor is introduced to explicitly account for vegetation flexibility in compu-tational models. Furthermore, a momentum sink term parameterisation is found to best resemble current-vegetation interactions. The advanced coupled model is successfully applied to simulate flood risk in the Taf Estuary under six contrast-ing vegetation scenarios.My results highlight how the vegetation cover affects the coastal protection pro-vided by salt marshes. All modelled vegetation species constrain flood currents to the main estuary channel and damp incoming waves. Although flexible grasses are 50% less effective in wave damping than rigid shrubs in the Taf Estuary. The wave conditions, wind conditions and local topography further affect the protec-tion provided. Additionally, rigid species can amplify orbital velocities above the canopy by inducing wave-averaged currents, but flexible species do not.It is recommended that the biomechanical properties of vegetation, including the flexibility, are included when modelling the coastal protection by salt marshes. My new computational modelling framework provides evidence to support the continuing uptake of salt marshes as sustainable coastal defences.
published_date 2020-06-17T04:17:26Z
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score 11.036815

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