Swash on steep and gently-sloping beaches

In the last twenty years, the importance of sediment transport in the swash zone has been established. The disproportionately high sediment transport rates in this region make its inclusion in general nearshore models vital. As part of this U.K. Natural Environmental Research Council project (grant number: NERlA/S/1999/00144), high frequency (8 Hz) measurements were made of the water depth and vertical variations in suspended sediment concentration and water velocity, using state-of-the-art instrumentation. Further measurements included nearshore and offshore wave conditions, tidal elevations, wave run-up limits, groundwater variations, sediment grain size distributions, beach slopes and changes in morphology at time-scales from minutes to weeks. Fieldwork was carried out on a gently-sloping (tan p - 0.03; d50 ~ 0.27 mm) and steep beach (tan p - 0.09; d50 ~ 0.55 mm). Both experience similar wave climates which allows a direct comparison between hydrodynamics and sediment transport in the swash zone...