Maritime sounding campaign and ESIA for underwater connection in new Caledonia

Maritime sounding campaign and ESIA for underwater connection in new Caledonia

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Carrying out a maritime sounding campaign and studies on the environmental and social impact of an underwater connection between New Caledonia and the Baie des citrons/Anse Vata

Project date: 2013-in progress
Location: New Caledonia
Reference: 130579

Project Description

The New Caledonia Post and Telecommunications Office (OPT-NC) wishes to reinforce and secure its network and particularly secure the Nouville central office network, joined by a single land connection to the Gallieni central office in the centre of Nouméa.

The project for this consultation is to establish a new optical fibre cable connection between the Nouville and the Baie des Citrons central offices directly or via Anse Vata. This connection will include an underwater part around 5 km long and land extensions between the landing points.

Two paths are envisaged in the provisional route of the optical fibre cable connection:

1) Basic route, from Nouville (Anse Lallemand) to the Baie des Citrons.

2) An alternative route from Nouville (with two landing stations in Anse Lallemand) to Anse Vata.

Services provided

Phase 1: Carrying out a geophysical campaign and maritime sounding for reconnaissance and selection of the optical fibre cable connection and provision of the campaign report.

The mapping reconnaissance assignment met 4 specific aims:

Bathymetric reconnaissance by deploying a multi-beam probe with resolution adapted to the objectives. A nature section on sea-beds, characterising possible singularities on the sea-beds by implementing side-scan sonar and taking samples with a bucket or using divers. An underground characterisation section implementing a sediment probe device. A section searching for ducts or metal objects / obstacles (cables, channelling, pumps, etc.) that must be located before any work can begin.

As a result of the geophysical campaign, a geotechnical campaign was carried out to officially confirm the cable route.

Phase 2: Carrying out an environmental and social impact assessment study to install an optical fibre connection between Nouville and the Baie des Citrons or Anse Vata and provision of the complete impact study file.

Phase 2 aims to be able to launch all requests for authorisation and permits required to install cable on the route chosen as a result of the sounding campaign and the impact assessment study.

All incidents are assessed, along with how they potentially affect the state of conservation for species and habitats. This synthetic analysis will lead to determining whether the project is likely to cause a significant incident. When appropriate, measures to reduce incidents, adapted to the supposed impact level and the local context will be proposed.

En continuité des formations et de la cartographie des herbiers réalisée à Anjouan, le même travail a été réalisé p…