| Beach nourishment has been regarded as the main measures to combat coastal erosion. It has been widely developed in Europe, America, Japan and other countries riching in experience and theory. In recent years, several beach nourishment projects were carried out in our country, but it's still at the initial stage. And most of them focused on the design and simulation for the nourishment lacking of the study on the evolution of the nourished beach which need to analyse the beach sediment, geomorphology, hydrodynamics, ecology and so on after the project. In this paper, sediment and geomorphology of the west was studied in order to provide some reference data for the others.Samples collected from the west beach before, immediately,3 months and 1 year after the beach nourishment were analysed by dry sieving. Changes of sediment characteristics and its influence on the nourished beach was studied by grain-size parameters combining with Gao-Collins grain-size trend analysis. Data of beach profile monitored by Electronic Total Station and bathymeter were analysed and mapped by Regional Morphology Analysis Package (RMAP) associatied with the longshore transport rate to analysis the variation between before and after the nourishment.It was found that, (1) sediment from the new beach after nourishment became coarser, better sorting. The mean grain size decreased from 1.87Φto 1.4Φand the coefficient of the sorting decreased from 0.97 to 0.81 one year after the nourishment, which showed that the nourished beach kept well suggesting that the grain size of the filling materials were suitable. Sediment mostly consisted of bed load and saltation load; net sediment transport tendency changed from moving offshore to alongshore dominated. Characteristics of the filling material made an influence on the filling area and its up-down stream obviously, but this influence decreased over time for that they fixed well with the natural beach sediment and fitted well with the local hydrodynamic conditions more and more. (2) Immediately after the nourishment, the shoreline went seaward significantly as well as the widened berm, and retreated back in the filling area one year later especially during the earlier period. In contrast, it accumulated seaward outside the filling area. As a whole, the unit erosion rate (about 0.9--5.4m3) decreased gradually after six months so that the beach performed to be a stable one which was eroded about 9925.5 m3. The impact of the long-shore transport (annual net long-shore transport rate is about 1.2×104m3-1.6×104m3) on the beach geomorphology is greater than the cross-shore transport. Dominated orientation of the long-shore transport was from NE to WS resulting in various erosion in the filling area and deposition in the down-stream. The A great deal of sand was filling onto the eroded beach made a huge alteration on the nearshore landform, especially on the offshore bar which also presented a seasonal variation. Comparing to the natural beach, the whole beach was widened seaward showing a good nourishing. (3) Hard structures eg. offshore submerged breakwater, breakwater, groins made a positive contribution on dissipating the wave energy, preventing sand flowing away and stabilizing the nourished beach.
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