Detailed technical studies have looked both above and below the surface to assess the potential options and feasibility of a new marina in St Peter Port Harbour.
They include a subsea survey, for which a large 'jack-up barge' spent a month in the harbour earlier this year. Boreholes were drilled from this platform to collect samples of material from both on and below the seabed for laboratory analysis, so that engineers could build a detailed picture of what is lying beneath the water.
The data was used to establish where any new structures can be installed, such as the breakwater and pontoons, and to identify what depths of water can be achieved in the different locations by dredging sediment and rock from the seabed.
As well as looking at the rock strengths and dredging possibilities, samples were checked for contamination.
A separate survey of the existing piers and berths was also carried out, to consider how close to these structures Guernsey Ports can dredge without risking damage to the foundations. Combined with the results of the underwater study, this has helped to identify the total area available for development, and where different facilities can be positioned.
Modelling studies were conducted to establish the need for a breakwater, to provide sufficient shelter for a new marina. Its impact on the wave environment within the harbour was also assessed using an extension of the computer-based wave model. This looked at various wind conditions, as well as different designs and position for the new structure, to identify the optimum location, length and configuration.
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It also modelled the effect of waves reflecting off a breakwater, to ensure there were no negative impacts to other parts of the harbour.
A separate computer simulator was used to assess how Condor vessels and other large commercial traffic would be able to manoeuvre within the harbour, to ensure they would not be restricted by any new breakwater.
A further, detailed environmental impact assessment will also be carried. This will assess what potential effects, positive or negative, a new marina may have, and how best to manage these. This will help to ensure that any development results in a net gain in biodiversity.
The current consultation period closes on Monday 12 December 2022. To find out more about the project, and to have your say, browse the latest information using the buttons below.
