Estimating of changes in the volume of sandy beach during a storm

An approach is proposed for predicting storm-induced changes in subaerial volume of a sandy beach based on the author’s model of sediment transport in the swash zone. Input parameters in the model are the mean sand size, the slope of the beach and a chronogram of heights and periods of waves in deep water. To calibrate the model, published data from experiments in wave channels were used. Verification of the model was based on the published data from field observations. It is shown that on profiles with a developed system of nearshore bars, beach changes are small even during strong, prolonged storms, while on shores without bars or with one bar, storm erosion is measured in tens of cubic meters per meter of shore. From the calculations it follows that in the intensifying phase of the storm, the slope and volume of the beach decrease, and in the attenuation phase, on the contrary, they increase. Adaptation to external influences occurs with a certain time lag. Changes to the beach under the influence of two successive storms of approximately equal strength are largely determined by the first of them. The root mean square error of the calculations ranges from 11 to 24% relative to the average value of recorded changes in beach volume.