Grain-Size Distribution of Suspended Sediments

Field observations on the grain size distribution of suspended sediment in a surf zone has been carried out at Fukiage beach in 1990 and 1991. In these observations, a suction pump has been used to sample a sufficient amount of suspended sediment for grain size analysis. The instrument designed for the data collection worked well. Vertical distributions of sediment concentration for several grain sizes which compose suspended sediment are obtained. This enable us to do numerical simulations of beach evolution taking the composite character of suspended sediments into consideration. Results are compared with the ones obtained by conventional simulation method which assumes single grain size composition of beach materials, and discussed. The vertical distribution profiles of the concentration of suspended sediments are also compared with existing models and discussed.