Safe disposal of dredged material in a sensitive environment - operational planning of dredging activities based on innovative plume predictions
Type:
Presented during:
CEDA Dredging Days 2009 - Dredging Tools for the Future, Rotterdam
Authors:
Aarninkhof S - Royal Boskalis Westminster; Luijendijk A - Deltares The Netherlands
Abstract: Ras Laffan Port Expansion Program foresees in a major extension of Ras Laffan Port (Qatar) to accommodate ongoing growth of the country s LNG production. Marine works related to dredging, reclamation and construction of breakwaters were inherently associated with the release and accumulation of fine material within the new port area. This fine material had to be removed. As it was not suitable for filling purposes, it had to be disposed in an offshore disposal area.
To demonstrate that such disposal operations could be carried out without violating strict environmental criteria around the disposal areas, a state-of-the-art 3D plume model was used to simulate a variety of disposal scenarios. The results provided valuable insight in the dynamics of sediment plumes over a spring-neap cycle. To enable operational use on-board, a novel interpretation method was developed to transform the model predictions into socalled Safe Disposal Maps. These maps showed green areas where disposal operations could safely be carried out as a function of the tide conditions at hand.
This paper adopts the Ras Laffan case to demonstrate the capability of present-day numerical models to provide realistic simulations of sediment plumes and at least equally important the applicability of such complex techniques in dredging practice through innovative interpretation of model results. In the context of increasing environmental awareness on dredging projects worldwide, the availability of such tools is of crucial importance to enable reliable impact assessments and environmentally-safe planning of dredging operations.
Key words: Environment, disposal operations, turbidity, plume prediction