University of Bath DOCTOR OF ENGINEERING (ENGD) Coastal protection and nearshore evolution under sea level rise Bayle, Paul Award date: 2020 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? 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Oct. 2021 Coastal protection and near-shore evolution under sea level rise Paul Bayle A thesis presented to the Faculty of Engineering & Design of the University of Bath in partial fulfillment of the requirements for the degree of Doctor of Philosophy Bath, September 2020 Water Informatics Science & Engineering (WISE) Water Innovation and Research Centre (WIRC) Centre for Infrastructure, Geotechnical and Water Engineering (IGWE) Faculty of Engineering & Design University of Bath, UK Coastal protection and nearshore evolution under sea level rise Supervisors: Dr. Chris Blenkinsopp Senior Lecturer at University of Bath, UK Dr. Alan Hunter Senior Lecturer at University of Bath, UK Examination committee: Dr. Kevin Briggs Lecturer at University of Bath, UK Dr. José Alsina Senior Researcher at Universitat Politècnica de Catalunya, Spain Author declarations: This thesis is composed of my original work and contains no material previously published or written by another person except where due reference has been made in the text. The contributions by others to the Journal articles used in this thesis is clearly stated in my thesis. The work published in the thesis was carried out since the commencement of my Research degree at the University of Bath and do not include any other work submitted to qualify for another degree or diploma at any other institution. This work was financially supported by the Water Informatics: Science and Engineering Centre for Doctoral training. Copyright: Attention is drawn to the fact that copyright of this thesis/portfolio rests with the author and copyright of any previously published materials included may rest with third parties. A copy of this thesis/portfolio has been supplied on condition that anyone who consults it understands that they must not copy it or use material from it except as permitted by law or with the consent of the author or other copyright owners, as applicable. iv Acknowledgements I am writing these lines after my successful viva and after addressing all my corrections. I am in a relieved and exited state, as working on this PhD over the last 4 years was a hard work and a very rich experience. I am also writing this just before leaving the UK after spending 5 years living in this beautiful country, so I am also a bit nostalgic and sad. I am going to try to translate this combination of feelings in the best way, and thank all the persons involved in this journey, without forgetting anybody I hope! Nothing could have been possible without you Chris! From our first exchange before even applying to WISE, you have always been very enthusiastic about working with me, and this was very motivating for me. I have told you this many times, but you are the best version of a supervisor that a PhD student could dream of. You were available, responsive, supportive and you knew how to structure and shape my work while leaving me enough freedom in my research which surely contributed to the person and scientist I am today. Besides the valuable time we had together at work, you also became a friend, who with I enjoyed sharing a beer (s), a nice meal and obviously, surfing (both in the field and the new lab in Bristol...). There is not enough space here to describe all your amazing work and support, but I hope you know how grateful I am, and I hope you will remain the same all along your career, with all your future students. I know we will keep collaborating, and try to organise research visits in each other’s universities as much as we can (depending on the forecast...), so I know this is just the beginning of a long and nice collaboration. Thanks! I want to thank all the person in charge of WISE, especially Tom Arnot for recruiting me and trusting a french guy over a skype from a hut in Malaysia. This program is particularly complete, inclusive and inspiring, and my PhD outside of this scheme would definitely not have been the same. Thank you for giving me the chance to be part of this journey. I also want to thank all my cohort (cohort 2, the best one): it was very nice to spend the first year in Exeter with you all, I think we were a nice mix of personalities, and a few of you are now friends for life (they will recognise themselves). I want to thank the Aussie team with Tom Baldock, Ian Turner and Tom Beuzen, who were present all along my PhD (mainly because I am slow at writing papers), especially Tom Baldock who spent a lot of time with me during his sabbatical in Bath. I want to thank the Plymouth team, with Daniel Conley and Gerd Masselink for their help during DynaRev1. The french team, represented by Rafael Almar only: merci pour le temps passé v au téléphone à m’expliquer les bases du fonctionnement d’une caméra. And obviously the Bath team with Chris, but also Alan Hunter and Oscar Bryan. The North Cove field experiment was one of the richer experiences of my PhD, and this would have not been possible without you George. Thank you for trusting a french lad met at a conference, and inviting him for a two-week field trip with your team. More generally, thanks for being such a passionate and interesting person, I learnt a lot with you. I also thank all the persons involved in this experiment, which made me aware of the impact and application of my work: David Cottrell (a real genius), Heather Weiner, Connie Allen, Richard Harris and all the local community who welcomed me. Kevin, tu es la personne parfaite pour faire la liaison entre mes remerciements liés au travail, et les remerciements pour les proches. Tu m’as énormement apporté niveau recherche et tu as toujours pris le temps de m’expliquer les choses, j’ai beaucoup appris, merci! J’espère que cela restera pareil dans nos collaborations futures. Mais bien entendu, tu es plus un ami qu’un collègue, et j’espère qu’on arrivera à profiter du temps sur Bordeaux, surtout pour se remettre au squash. I want to thanks all the amazing people who I shared my office and corridor space with: Ioanna, Olivia, Naomie, Russell, John, Keveh, Badr, Astrid, Valentina, Zaharatu, Gwyn, Emily, James, Erwin, Aurelie, Mahan... William Bazeley, for being such a good mate in the lab, and outside. Mehrnaz, it was great to do my PhD at the same time as you, we will stay friend. Marianno and Marios, thanks for being such great volleyball and basketball mates. My PhD in Bath would have not been the same without the best rugby club in the country, Avonvale RFC, and all its members. I enjoyed every single moment in this club, until the last memorable send off party. You will all stay forever in my heart, but I am sure I will see you on many tours in the future. Special thanks to Wedgie, Archie, Marcus, Jonny, Donald, Josh, Moggy and Steve for your great welcome at the club and generally as part of your life for the last 4 years. Merci à mes parents pour leur éternel soutien et confiance. L’amour et l’éducation que vous m’avez donné sont les principaux facteurs de cet accomplissement. Merci Justine d’être la meilleure soeur du monde. Je vous aime tout les trois très fort. Merci à tous mes amis francais. Peu d’entre vous savent ce que je foutais vraiment en Angleterre pendant 5 ans, mais peu importe. Votre amitié est et sera toujours le pilier principal de ma vie. Julia, mon petit calin, merci de m’avoir supporté pendant le lockdown, et plus géneralement dans la vie. Tu as une place speciale dans mon coeur! vi Summary Coastlines are extremely valuable assets for many countries as they play a major role in the national and local economy. In this context, sandy coastlines are particularly challenging as they are one of the most developed types of coast but also one of the most vulnerable in terms of erosion risk. The threat of erosion is mainly driven by storms, including storm surge and waves, and long term sea level rise which is expected to increase in rate with the on-going climate change. In response to this forcing, sandy beaches have been and will be protected in many areas. However, most of the coastal defences, whether hard or soft, are not designed to face the combination of these threats, with storms acting on a higher water level.