Monitoring the Siltation Rate At Deurganckdok, Port of Antwerp, and Its Reduction By a Current Deflecting Wall
Type:
Presented during:
WODCON XX: "The Art of Dredging" - 2013, Brussels, Belgium
Authors:
Decrop B, Sas M, Zimmermann N, Roose F
Abstract: The tidal dock called Deurganckdok (Port of Antwerp) is situated in the macro tidal estuary of the Scheldt River and is directly connected to the river without the shielding properties of a lock. Due to its position in the estuary near the Estuarine Turbidity Maximum (ETM) of the estuary, large amounts of silt and clay are available for sedimentation. The dock effectively acts as a sediment trap, with a trapping efficiency as high as 0.43. During the first five years after its commissioning, the sedimentation of the dock has been closely followed by means of intensive monitoring of both long-term point measurements and through tide campaigns with high spatial resolution. The mass balance of the dock’s sediment bed has been monitored using density profiling. It was shown that the average rate of sedimentation of the dock is as high as 1 cm/day.
A semi-empirical model of the siltation of the dock has been developed to gain insights in the contribution of the different mechanisms of sediment exchange with the Scheldt River. Long term siltation calculations shown the model is capable of reproducing the sediment balance of the dock.
After numerical and physical modeling it was shown that a Current Deflecting Wall (CDW) has the potential to reduce the sedimentation in the dock (Roose et al, 2013). The construction of this structure has now been executed and the first monitoring results are available of the post-construction period. Due to the natural variability of the estuarine sediment concentration levels, the statistical trend change cannot be proven yet, but measurements of the flow pattern near the dock entrance reveal changes that can be incorporated in a semi-empirical model of the sedimentation, bringing forward first estimates of the sedimentation reduction in the dock.
Keywords: Sedimentation, tidal dock, Port of Antwerp, Current deflecting wall