A two-dimensional laboratory investigation of sediment transport, induced by shallow-water waves, showed that the sediment motion over suspension-dominant asymmetric ripples is closely related to the development of eroding beaches. High-speed motion picture analysis revealed that vortices, formed over this type of ripple, play a crucial role in transporting the sediment to the offshore region. A relation for net offshore sediment flux was formulated for sand 0.02 cm in diameter. A simple model

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... or eroding beaches was proposed and its validity was checked by using two existing data sets for 0.02-cm sand beaches; the model could predict fairly well profile and shoreline changes in the early stages.