Securing Manoeuverability Of A Deep Draft Ship In A Sediment LoadedTidal River Berth

Abstract

Sedimentation near a deep draft ship berth at a tidal river cannot be avoided due to tidal currents and turbulent processes. But reductions in sedimentation can significantly decrease maintenance dredging costs. Transport and deposition of sediments in a tidal environment depend on factors like sediment size, settling velocity, tides and is controlled by unsteady current velocities and stochastic turbulent processes. A technical solution, minimizing sedimentation near the berth of a deep drafted ship to secure manoeuverability, is presented. The hydrodynamic situation at the tidal part of a river was simulated, using MIKE3 HD and RMA2 hydrodynamic models. Exchange of sediment-loaded waters entering the berth could be significantly reduced with a flow-guiding sheet pile wall. Relevant physical processes (sediment transport, erosion and deposition) were modelled using RMA2/SED2D. Thus, reduction of sedimentation was verified using MIKE3 HD to get a look to hydrodynamics around the sheet pile wall. To understand the process of sedimentation near the ship it is important to know the dynamic behaviour of the tidal environment and resulting hydrodynamics, also influenced by varying discharges from the upstream non-tidal part of the river system. It is shown that near bed sand transport could be guided. However, the structure described above act as a sediment trap for suspended material. Applicability and sensitivity of the different models is compared. Besides technical aspects of the construction to be modeled it is pointed out which modeling capabilities are necessary to find critical flux conditions in the model domain and how they influence the overall design of the structure. Reprint: „Securing Manoeuverability of a Deep Draft Ship in a Sediment loaded Tidal River Berth“. 5th International Conference on Computer Modelling of Seas and Coastal Regions, Coastal Engineering 01, 19 21 September 2001, Rhodes, Greece.