Coastline connects the land and the sea, and serves as the essential residence for both natural and anthropogenic systems. Coastline has experienced fast changes in the past decades, especially under the quick development of socioeconomic development. These changes interact with the hydrodynamics and sediment dynamics in coastal waters, which attracts increasing attention worldwide. Researchers use various methods, including experiments, remote sensing, field data, and numerical models, to study the definition, the characteristics, and the temporal-spatial variations of coastline and its changes. Special attention has been paid to the interactions of coastline changes with coastal environments, such as tides, sediments. The case study indicates that the changed coastlines modulated the morphology of the inner Hangzhou Bay (HZB), China, thus increased/advanced the tidal amplitude/phase. The SSC and sediment fluxes were changed subsequently due to modulated tides and tidal asymmetry. The southward/northward sediment flux near Andong/Zhapu and bottom/surface level was enhanced/weakened from the 16th Century to 2013. Changed coastlines speeded up the deposition/erosion of sediment near the southern/northern bank. The section from Ganpu to Luchaogang was dominated by deposition over the years. Long-term coastline evolution of a macro-tidal estuary affects hydrodynamics and sediment transport dynamics.
 

Coastline changes,impacts,circulation,sediments,Hangzhou Bay