Physical model study of beach profile evolution by sea level rise in the presence of seawalls

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

“…These experiments applied relatively large step changes in water levels because it was not practically possible to simulate sufficiently slow water level changes. Incremental changes in water level to the same amount as a single step resulted in the same profile, given sufficient time, although the intermediate evolution did differ (Beuzen et al, 2018). Bruun (1962Bruun ( , 1988 did not consider SLR or recession as rate changes because time is not a factor in an equilibrium response, which assumes sufficiently long enough has passed for equilibrium to have been reattained.…”

“…Until recently (Atkinson et al, 2018;Beuzen et al, 2018), few published laboratory-based experiments had detailed sufficiently long duration experiments to investigate beach profile responses toward equilibrium at varying water levels. The paper by Atkinson et al (2018) constitutes some of the research presented here (Chapter 4 in particular), although some additional experiments are included which could not fit into that paper or were incomplete at the time of submission.…”

“…In these cases, if abandonment of the area is not an option, the beach and dune system would probably need to be maintained through nourishment schemes, or substantial hard engineering approaches, such as the construction of dykes or seawalls. Regarding hard engineering approaches, Beuzen et al (2018) investigated the impacts of vertical and sloped sea walls on profile responses to SLR. They found that the erosion demand to raise the profile in the presence of seawall structures was the same as that without, however, due to the restricted access to landward sediment, this resulted in increased erosion of the beach adjacent to the seawall, which may result in the beach completely disappearing, leading to more wave energy arriving at the shoreline, increasing the risk of inundation.…”

“…The barred profile experiments consisted of eight experiments investigating erosive profile responses to water level change (IE1, SE1, E1C, and E1 -E5, Beuzen et al (2018). The profile development at the initial water level for E1 and E2…”

“…Two experiments were conducted at UNSW to investigate the difference in profile development under a single step water level rise and multiple, smaller, incremental steps, to the same level as the single step (see also Beuzen et al, 2018). .…”