浅水湖泊生态清淤设计底高程的分区回淤余量确定方法OA

To address the disconnection between the design bottom elevation at the construction drawing stage and the effective water depth during the maintenance period in ecological dredging of shallow lakes,a method for determining baseline bottom elevation,zonal re-siltation allowance and constraint-based adjustment was developed.Taking a 13.75 km2 dredging unit in the Taihu Lake Basin as an example,and combining dual-frequency sounding,sediment cores,hard bottom interface,and 12-month resurvey data,the allowances for nearshore,inlet-affected,open-water and wind-wave resuspension-sensitive zones were determined as 0.06,0.10,0.04 and 0.08 m,respectively.Zonal correction increased dredging volume from 3.367 to 4.061 million m3,which is 0.956 million m3 less than the 5.017 million m3 required under a uniform 0.12 m allowance across the entire lake.In the resurvey,46 points remained within the baseline bottom elevation,with a retention rate of 95.8%.The method balances pollutant-layer removal,hard-bottom protection,construction acceptance and disposal of dredged sediment,and provides a basis for the refined design of bottom elevation in ecological dredging of shallow lakes.