Grain Size Distribution Patterns ofthe Rizhao Coast and Their Bearing on Coastal Erosion

Field survey and grain size analysis have been carried out for two beaches of the Rizhao coast to reveal the current status of beach erosion. It is found that both the northern and southern parts of the National Seaside Forest Park are under erosion, except the middle part which remains under weak siltation. On the Wanpingkou beach, however, the northern and middle parts are under erosion, except the southern part which is slightly under siltation. The mean grain size of the National Seaside Forest Park is smaller than that of the Wanpingkou, owing to the difference in slope angles of the two beaches. The mean grain size decreases gradually from beach berm to low tide level. The sorting of particle in the National Seasside Forest Park beach is better than that of Wanpingkou. The sorting coefficient becomes smaller from land to sea or from north to south. The frequency distribution of the beach berm and shore face are dominated by double peak curves with flaty kurtosis, indicating a rather complicated sediment source. However, the frequency curve in low tide level is mainly dominated by single peak with sharp kurtosis, indicating a simple sediment source.