"THE BRANDO" hotel - Biological monitoring of SWAC
Project ownership for the Seawater Air Conditioning (SWAC) system: biological monitoring
Project date: 2010-2013
Customer: TAHITI BEACHCOMBER SA
Location: French Polynesia
Within the framework of planning "The Brando" hotel on the Tetiaroa atoll, it was envisaged to set up a SWAC to provide air conditioning for the different buildings. This device required a pipeline to be laid from Motu Onetahi towards the open sea (depth of around 1000 m). Despite the different precautions taken, the laying work made an impact on the lagoon environment and the external reef of the atoll.
Within the framework of our contract to carry out the project's overall impact study, we looked at the initial condition of the site directly concerned by the SWAC laying work. Environmental monitoring (during and after the work) was envisaged within the framework of this impact study and the French State Environment Directorate services wish it to be included in the impact document.
CREOCEAN therefore ran monitoring on the different compartments of the environment appraised during the initial inventory, namely the marine biocenosis, ciguatera and hydrological parameters. Furthermore, we moved coral masses in the lagoon to limit the project impact.
MONITORING THE "OCEAN" PART
- Monitoring marine biocenosis: external reef monitored by quadrant photos made in triplicate at 2 depths either side of the laying axis (5m-10/15m), namely 8 stations each comprising 4 quadrants plus a control station positioned to the south. This monitoring technique is particularly appropriate for monitoring jobs. It is actually easy to implement and means that the evolution of coral communities is simple to follow.
- Monitoring water quality: by continuous immersion of a multi-parameter probe over periods of 1 to 2 weeks.
- Measurements and tests: the parameters measured in situ (multi-parameter probe) are as follows: temperature, pH, salinity, dissolved oxygen and turbidity.
- Ciguatera monitoring (food poisoning caused by consuming fish from coastal and oceanic coral environments): monitoring protocol set up with the Louis Malarde Institute in Papeete, specialised in ciguatera research and surveillance.
- Managing the file with the authorities
MONITORING THE "LAGOON" PART
- Monitoring water quality: carried out by CREOCEAN personnel free diving using photographic material
- Monitoring water quality: similar protocol and resources implemented to any offered for monitoring water quality outside the lagoon, namely continuous measuring periods over 1 to 2 weeks.
- Monitoring the ciguatera
MOVING CORAL COLONIES
- Control of mechanical operations to move the largest colonies
- Manual displacement of small, dispersed colonies and storage for subsequent use in a coral garden for example.