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Sandy beaches are unique environments composed of unconsolidated sediments that are constantly reshaped by the action of waves, tides, currents, and winds. The most seaward region of the dry beach, referred to as the beach face, is the primary interface between land and ocean and is of fundamental importance to coastal processes, including the dissipation and reflection of wave energy at the coast and the exchange of sediment between the land and sea. The slope of the beach face is a critical parameter in coastal geomorphology and coastal engineering, as it is needed to calculate the total elevation and excursion of wave run-up at the shoreline. However, datasets of the beach-face slopes along most of the world's coastlines remain unavailable. This study presents a new dataset of beach-face slopes for the Australian coastline derived from a novel remote sensing technique. The dataset covers 13 200 km of sandy coast and provides an estimate of the beach-face slope every 100 m alongshore accompanied by an easy-to-apply measure of the confidence of each slope estimate. The dataset offers a unique view of large-scale spatial variability in the beach-face slope and addresses the growing need for this information to predict coastal hazards around Australia. The beach-face slope dataset and relevant metadata are available at https://doi.org/10.5281/zenodo.5606216 (Vos et al., 2021). [ABSTRACT FROM AUTHOR]

Laboratory wave flume experiments in coastal engineering and physical oceanography are widely used to provide an improved understanding of morphodynamic processes. Wave flume facilities around the world vary greatly in their physical dimensions and differences in the resulting distortion of the modelled processes are reconciled using scaling laws. However, it is known that perfect model-prototype scaling of all hydro and morphodynamic processes is rarely possible and there is a lack of understanding to what extent distorted models can be used for direct morphological comparison. To address this issue, distorted scale laboratory flume experiments were undertaken in three different facilities, with the aim to measure and compare beach profile evolution under erosive waves and increasing water levels. A novel approach was developed to transform and scale the different experimental geometries into dimensionless coordinates, which enabled a direct quantitative comparison of the beach profile evolution and sediment transport rates between the differing distorted experimental scales. Comparing results from the three experiments revealed that the dimensionless scaled morphological behaviour was similar after the same number of waves – despite very different degrees of model distortion. The distorted profiles appeared to be suitable for comparison as long as a modified version of the Dean number is maintained between them. The new method was then validated with two further published datasets, and showed good agreement for both dimensionless profile shape, dimensionless sediment transport and morphodynamics parameters. The new approach scales the sediment transport by the square of the runup, proportional to HL, rather than H 2, and yields good agreement between the datasets. It is further shown that the new scaling method is also applicable for comparing distorted profile evolution under water level increase, as long as the water level is raised in a similar way between the experiments and by the same total increment relative to the significant wave height (Δh/H s). • Three distorted laboratory wave flume experiments of different scales are compared. • Development of a new scaling methodology for comparing beach profiles of distorted experiments. • Analysis and validation of the method for a fixed and increasing water level. • Qualitative and quantitative comparison of distorted profiles possible by scaling with HL. • Two examples of application of the method, for a fixed and increasing water level. [ABSTRACT FROM AUTHOR]