Invertigation On The Responses Of Sediment Transport In The Jiaojiang Estuary Under Abnormal Weather Using The MIKE Model

The estuary area is among the most developed areas in many countries,as is our country.With the growing population and concentrated industrial development,the estuary is suffering more and more pressure.Among the many problems that occur in estuaries and nearshore areas,the migration and eventual fate of viscous sediments is critical.Moreover,due to the frequent abnormal weather in the coastal estuaries in recent years,the hydrodynamic sediment conditions in the estuary bay area have changed,which will inevitably lead to a new dynamic balance in the estuary area.However,the research work on the response process of sediment and bed under abnormal weather in the estuary area is limited.Therefore,the response process of the estuary to the typhoon by the estuary and the bottom bed in the Jiaojiang Estuary and the adjacent Taizhou Bay is selected.In the study area,the typhoon No.9711 was taken as an example to study the response of the estuary to abnormal weather.Based on the MIKE model,this paper collects the hydrological data of Taizhou Bay in Jiaojiang Estuary in detail,and establishes the hydrodynamic model of the Taizhou Bay area in Jiaojiang Estuary under normal conditions.Under normal conditions,the simulation results after the calibration are in good agreement with the actual measured values,and the applicability of the MIKE model to the study area is verified.Considering the factors such as tidal level,runoff and wind wave during the typhoon 9711,the hydrodynamic model under abnormal weather was established,and the response of the hydrodynamic field in the study area to abnormal weather was simulated.The peak value of the tidal level in abnormal weather is about 3.2m higher than the normal state.On this basis,using the proven hydrodynamic flow field,the sediment simulation model under normal state and abnormal state is constructed.Comparing the simulation results and the measured data under normal conditions,the change of sediment concentration and the measured value of the selected points are in good agreement with the measured values.Further analysis shows that the sediment content under normal conditions is significantly affected by the trend.The study on sediment transport in the Taizhou Bay area of Jiaojiang Estuary under abnormal weather shows that the area generally shows sediment transport to the sea;in the case of abnormal weather,the sediment concentration in the study area is about 3-7 times that of the normal state,and the mud is abnormal in the weather.The sand was transported to a farther area outside the Jiaojiang Estuary.Finally,the response of the bottom bed of the study area to abnormal weather is preliminarily explored.The study found that the change of bed bottom in the study area is not significant under normal conditions;while the bed responds to abnormal weather more severely,the maximum sedimentation volume in the estuary area can reach 0.41 m.