Short-term Evolution of Jianshan Tidal Flat in Qiantang River Estuary and Its Influencing Factors
The evolution of flats and channels resulting from erosion and sedimentation is one of the key issues in the study of tidal estuaries.Jianshan Reach is located in the transition section of the Qiantang River estuary.Due to the com-bined effect of runoff and tidal current,the erosion and sedimentation of tidal flats vary greatly,and the main channel swings frequently.Previous studies were mostly limited to physical models or numerical simulations,lacking comparative analysis with on-site measured data.Based on the measured terrain data of Jianshan tidal flat from 2020 to 2021,com-bined with recent hydrodynamic processes,this paper analyzed the changes in flat slope,terrain erosion and sedimenta-tion,and typical section elevation,and studied the impact of runoff and tidal dynamics on the recent evolution of the flat.The results show that the tidal flats exhibit periodic alternation of erosion and sedimentation,and are distributed in a stepped shape before the flood season,with multi-level steep ridges in the horizontal direction.During the flood season,there was significant erosion of the nearshore flats and slight sedimentation of the offshore channel bars.After the flood season,the floodplain generally silts up,and the nearshore water flow concentrates to form a scouring tidal channel.The main controlling factors for the evolution of the Jianshan tidal flat are the discharging runoff and upwelling tidal current.The interaction between the runoff and tidal dynamics and the tidal flat forms a morphological pattern of"flood erosion as well as tidal deposition,and large deposition after large erosion".
tidal flat evolutionQiantang River estuarytiderunoffmacro-tidal estuary
万方数据
维普
