LABORATORY OBSERVATIONS OF IMPACTS ON COARSE SEDIMENT BEACHES

In this paper we present laboratory observations of plunging wave breaker impact pressure responses on a steep coarse-grained beach, extending previous work conducted by Pedrozo-Acu�a et al. (2008). Scale laboratory measurements of plunging breaker impact events are reported and compared with the previous full-scale tests. These tests extend the previous relationships to a wider range of surf-similarity parameters and indicate a continued reduction in impact pressure as the transition from plunging impacts to surging impacts is approached. Additional results from scale tests conducted on a smooth impermeable slope also indicate the presence of a maximum impact pressure within the plunging breaker region; however also suggest it may be necessary to include roughness and permeability in the parameterization of the impact pressure.