Coupled Simulation Of Wave And Tide On Beach To Nourish

In the coastal waters of Zhejiang Province,suspended sediment concentration is high and there is little supply of sand so that mud coexist on most sandy beaches.Meanwhile,the modification of beach and shoreline backward affect coastal landscape.The simulation of coupled tide-wave process in the sea area adjacent to Hetou Beach is carried out in this paper and the nourishment measures on the beach and their effects are analyzed.It is of great significance for enriching the theory of coastal dynamics and of value for improving the beach landscape.Tidal level,velocity and suspended sediments were observed on the Hetou beach nearby seas for one week in this study.Simultaneously,concentration and grain size of suspended sediment were analyzed and topographic measurement were also conducted.The formation mechanism of mudification phenomenon of Hetou Beach was revealed through the combination of field survey data and coupled tide-wave simulation.It has been shown that the weak wave action,strong tidal current and high sediment concentration are the main reasons for the coexistence of sand and silt.Two kinds of nourishment measures(6 options),such as beach sand compensation and corner extension,were designed.Through coupled tide-wave simulations,the significant wave heights and tidal current distributions for two measures of beach sand compensation and corner extension were analyzed.It has been found that the waves were enhanced and the tides were weakened in the sea at the outer side of the beach by both measures,helping improve the sand modification phenomenon.Further analysis of synchronous beach sand compensation and corner extension on the wave field and tidal current field was conducted.It has been found that the beach improvement is the best when the sand compensation is of 40m and meanwhile the corner extension is of 80m,i.e.the ratio of the corner length to the beach width is 2.5.