Measurement of Sediment Concentration of the Oscillatory Flow in the Surf- and Swash-zone

Abstract

The sediment transports near the bed need to be accurately observed to validate the existing models that are based on the empirical formula for the sediment flux and to develop more realistic morphology prediction model. One of the essential tasks for the evaluating the existing models and developing new one is the precise measurement of the sediment transport at swash zone without disturbing flow. Different methods in estimating the sediment transport rates at the surf-zone and swash-zone such as measuring the time evolution of the bed profile, sand ripple volume and migration speed are investigated and evaluated. To develop more reliable estimation of the sediment flux by measuring the vertical profiles of sediment concentration and velocity without disturbing the flow conditions, method of estimation of the vertical sediment concentration profile by detecting the backscattered light intensity using high quality camera was tested and evaluated. The problems of different methods in estimating the sediment flux are identified and discussed.