Field Measurements and Modelling of Longshore Sediment Transport

Measurements of suspended sediment concentration profiles, C-Profiles, and hydrodynamic conditions were obtained in the surf zone on a barred beach composed of fine sand using streamer traps. A simple model was used to estimate the total longshore sediment flux. C-Profiles predicted for wave-current conditions were found to compare favorably with the field data. In some cases the cross-shore distribution of LST exhibited two peaks associated with wave shoaling and breaking over the bars. Comparisons between present results and predictions from well-known longshore transport formula and a formulae for sediment transport in combined wave-current conditions generally show good agreement. The results indicates that sediment transport processes in the surf zone are not markedly different from those operating in unidirectional and combined wave-current flows under non-breaking wave conditions. The work contributes to the body of published field data by documenting the rates and cross-shore distribution of LST at a previously unstudied field site.