Abstract
An equilibrium beach profile model is developed and coupled with a parametric hydrodynamic model to provide feedback between the evolving morphology and the hydrodynamics. The model is compared to laboratory beach profiles evolving toward equilibrium conditions under constant forcing. The equilibrium model follows the classical approach but uses the bulk sediment transport as the governing model parameter. This approach is coupled with empirically derived and normalised sediment transport functions and a parametric surf zone wave transformation model. The dissipation predicted by the surf zone model controls the cross-shore position of the maxima in the sediment transport functions and hence the cross-shore evolution of the beach profile. Realistic beach profile shapes are generated for both erosive (barred) and accretive (bermed) beach profiles, and predictions of bar and berm position are satisfactory. With more complex normalised sediment transport functions, the model can be applied to conditions with a cyclical wave climate. However, the model concept is better associated with erosive wave conditions and further work is required to improve the link between the modelled dissipation and local transport for accretive conditions.
Highlights
Shoreline change is a good proxy to quantify subaerial beach erosion or accretion rates but gives no information about profile shape or submerged sandbars. Such models are not coupled with the hydrodynamics and the beach profile evolution and bar morphology do not influence the shoreline evolution
The disequilibrium model is based on the conceptual approach for the bulk net sediment transport, (Q(t), [12,13], which provides a robust measure of overall beach erosion or accretion
To apply the model in the field, the key requirement is a set of beach profiles from different erosion and recovery conditions, from which representative cross-shore local sediment transport functions can be derived and normalised between the run-up limit and the depth of closure
Summary
Shoreline change is a good proxy to quantify subaerial beach erosion or accretion rates but gives no information about profile shape or submerged sandbars. Such models are not coupled with the hydrodynamics and the beach profile evolution and bar morphology do not influence the shoreline evolution. The evolution between the profile types was governed by the disequilibrium in the Gourlay number and shape functions for the beach profile between the depth of closure, runup limit, including a bar-trough function. This model produced realistic bar shapes, but was not compared to beach profile data, and did not include a hydrodynamic model
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
