EMPIRICAL FORMULATION OF SEDIMENT PICKUP RATE IN TERMS OF WAVE ENERGY FLUX DISSIPATION RATE

The rate of sediment pickup for suspension by breaking waves is shown to be proportional to the dissipation rate of wave energy flux within the surf zone. A database of mean concentration of suspended sediment has been compiled by collecting various data of field measurements and large-scale laboratory tests and by calculating the depth-averaged mean concentration. The wave energy flux dissipation rate is computed with the PEGBIS model for random wave breaking on beaches of arbitrary profile. By comparing the mean sediment concentration and the energy flux dissipation rate, a sediment pickup coefficient is assessed at a value of 0.0045 on the average. Use of this coefficient makes it possible to estimate the cross-shore variation of mean sediment concentration. Peak values of mean sediment concentration within measured cross-shore profiles agree well with the prediction based on the wave energy flux dissipation rate.