Swash - Research

Research

It is said that conduct of morphology research and field measurements in the swash zone is challenging since it is a shallow and aerated environment with rapid and unsteady swash flows. Despite the accessibility to the swash zone and the capability to take measurements with high resolution compared to the other parts of the nearshore zone, irregularity of the data has been an impediment for analysis as well as critical comparisons between theory and observation. Various and unique methods have been used for field measurements in the swash zone. For wave run-up measurements, for example, Guza and Thornton (1981, 1982) used an 80m long dual-resistance wire stretched across the beach profile and held about 3 cm above the sand by non-conducting supports. Holman and Sallenger (1985) conducted run-up investigation by taking videos of the swash to digitise the positions of the waterline over time. Many of the studies involved engineering structures, including seawalls, jetties and breakwaters, to establish design criteria that protect the structures from overtopping by extreme run-ups. Since the 1990s, swash hydrodynamics have been more actively investigated by coastal researchers, such as Hughes M.G., Masselink J. and Puleo J.A., contributing to the better understanding of the morphodynamics in the swash zone including turbulence, flow velocities, interaction with the beach groundwater table, and sediment transport. However, the gaps in understanding still remain in swash research including turbulence, sheet flow, bedload sediment transport and hydrodynamics on ultra-dissipative beaches.