Influence of Dumping Soils on Pumping Stations
For Yangtze Estuary，a massive amount dredge spoil will cause back-siltation in navigation channel，and the maintenance will cost higher than it should be.
In fact，some measurements of loss ratio of disposal zone had been done for 3 times in 2011.The multi-beam sonar is used to go on fine measurement after dumping sediment completed.The volume change of disposal zone can be obtained by means of the depth change of disposal zone and the throwing sediment amount can be obtained through measuring instrument installed in dredgers.The results were shown in the table 1.
Table 1 loss ratio of dumped sediment on storage pool
Total amount of dumped sediment is 1.55 million m3，the residual in the disposal zone is only 0.35 million m3 and total loss of dumped sediment is 1.19 million m3，so the average loss ratio is 77%.
The field survey showed that lots of sediments were transported by runoff and tidal current.