Laboratory beach profile dynamics and responses to changing water levels with and without nourishment

Abstract

This thesis presents the results of reduced-scale, laboratory wave flume physical model experiments. Following Bruun's (1954 and 1962) original proposal, Sea Level Rise (SLR) is expected to lead to cross-shore losses of sand volume from beaches. While some field studies have documented some of the characteristics anticipated with profile response to SLR (i.e. loss of beach volume and shoreline erosion), until this research commenced, there had been no Firstly, thanks must go to each of my research advisors. Professor Tom Baldock for his advice, support and guidance throughout this process. Professor Peter Nielsen for his support and encouragement to investigate various aspects of beach dynamics that interested me. Dr David Callaghan for his guidance and support in helping me appreciate many aspects of numerical analyses. I have learnt so much in my time at UQ, and I feel very privileged to have had the opportunity to work closely with each of you. Thank you also to Dean Patterson, for your encouragement and regular feedback at the coastal research group meetings. Thank you to all other members of the UQ coastal research group, it has been a pleasure to know you all and learn about your respective areas of research. Thanks to Mr Jason van der Gevel and Mr Stewart Matthews for all their assistance in the hydraulics laboratory and maintaining the wave makers, ensuring smooth operation over the thousands of hours I logged on them. Thanks to Dr Van Thuan Nguyen for his assistance in developing and debugging the electronics and software for the laser profiling system. Thank you to Ms Sheng Wu, Ms Chase Bawden, Ms Laura Beckingham, Dr Tomoko Shimamoto and Dr Florent Birrien for their assistance in operating the wave flumes and collecting profile data. Special thanks must be afforded to my wife, Lizzy, for her love, understanding and unwavering support, without whom, I would not have undertaken this project. Elise, you arrived halfway through my candidature and have brightened every day since, providing an endless source of inspiration and most welcome play-breaks.

Sandbar dynamics in microtidal environments: Migration patterns in unprotected and bounded beaches

“…As a result of generalized o shore trends, all the studied sites show the establishment of at least one well-de ned NOM cycle [14] with a more or less gradual migration of bars outside of the bar zone, their decay, and subsequent generation of new inner bars triggered by energetic storm events or clusters. The recurrence of such cycle, consistent with observations of NOM patterns along other microtidal Mediterranean coasts [31,50] as well as along multi-barred beaches in mesotidal environments [14,15,29], further reinforces the idea that, although single bars may indeed tend towards an equilibrium point dependent on local wave climate, the overall bar system may never reach a stable equilibrium in the long term [51][52][53].…”

“…Di Leonardo and Ruggiero [58], discussing an extensive bathymetric data set for the mesotidal US Paci c Northwest, observed a similar result, with steeper parts of the coast presenting bars closer to the shoreline than mildly sloping parts. The strong reduction of the hydrodynamic forcing over bars, due to the sandy features gradually moving towards higher depths and decreasing their interaction with waves, is indeed suggested as one of the most important bar-depleting conditions [24]; this nding is further reinforced by experimental evidence (see, e.g., [53]).…”

A Process-Based Numerical Model of Shoreface Profile Evolution

“…The model has been assessed by correlation with various laboratory profile evolution experiments as well as field data conditions, as an assessment of overall performance and, particularly, the distortion factors D and D 1 in equations ( 2) and ( 4) respectively. Figure 7 shows profiles and q x modelled over 5 hours correlated with the measured 5 hour profile for Experiment SE1 of Atkinson (2018). The initial…”

A new approach for scaling beach profile evolution and sediment transport rates in distorted laboratory models

“…The sandy beach tested was not protected. The results used here correspond to test E5 from Atkinson (2018) [26].…”