Preferred Options
DHI’s modelling and testing programme (carried out in October and November 2007) saw the number of possible groyne structures narrowed down to two preferred options for a final modelling study and cost analysis. These were:
- Parallel structures cutting through the existing eastern sandspit to provide a 120 metre-wide channel directly to deeper water;
- Symmetrical structures incorporating an outer basin between the existing shoreline and outer breakwater to provide more manoeuvring space and allow vessels to better align themselves to the prevailing wave direction.
The location of the groynes on the eastern sandspit would reduce potential environmental impacts during construction, because all of the work required could be undertaken from one side.
Selected Option
DHI’s final report on the project’s modelling and preliminary design identified the parallel groyne structure as the most effective option. Further study resulted in the release of the groyne structure Preliminary Design Report, which suggests three potential construction methods – Geotextile Core, Rubble Mound and Concrete Sheet Piles.
Illustrations and details of the three design concepts currently under consideration are contained in the Update newsletter – June 2008.
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