Longshore Transport at a Detached Breakwater, Phase II

Abstract

The second phase of a field experiment conducted by the Coastal Engineering Research Center (CERC) to develop correlations between wave characteristics and longshore sediment transport is reported herein. Wave heights, periods, directions, and longshore currents were measured by visual observation and the average longshore sediment transport rates were determined from sequential volumetric surveys behind an offshore breakwater which was regarded as a total trap. The data analyzed covers a period of seventeen months from 20 April 1976 through 30 August 1977. During this period there were twelve surveys of the sediment volume trapped behind the offshore breakwater. The correlation constant, K, in the relationship I = K P_lb (Shore Protection Manual, 1984) is tested and compared with earlier longshore sediment transport results of others as well as the Phase I data at Channel Islands reported on by BRUNO et al. (1980).