Caption: SPC-SOPAC Senior Technical Officer Salesh Kumar deploys a wave and current meter on the reef slope at Avatoru, Rangiro,a French Polynesia where it observed swell and storm waves for five months, gathering important baseline information for coastal hazard maps. Photo: SUPPLIED.
The biggest atoll chain in the world, the Tuamotu Archipelago comprises 78 islands, of which 41 are home to nearly 20,000 people. They cover an ocean area the size of western Europe, but have a land area of only 885 square kilometres. The atolls are just a few metres above sea level. They are picture-perfect paradise islands, but they are highly vulnerable to waves, storm surges and strong winds associated with tropical cyclones.
‘In order to make an accurate assessment of potential impacts of natural disasters on people, property and the environment, it is necessary to gather good baseline information on the interaction between the ocean and the land. This allows us to better model and therefore understand hazards, and then develop plans to mitigate the effects of disasters,’ said Mr Jens Kruger, Physical Oceanographer for the Oceans and Islands Programme run by SPC’s Applied Geoscience and Technology (SOPAC) Division.
Mr Kruger was commenting on the work that has taken place since July 2011. He said that it included obtaining sufficient data — bathymetric (lagoon and ocean depth), topographic (land elevation), oceanographic (waves, water flow and water level) and geomorphologic (landform characteristics) — to model the wave-breaking patterns and associated inundation from cyclone-induced waves.
‘Using the baseline data to model coastal inundation will help the Tuamotu Archipelago’s inhabitants to plan ahead so as to reduce the worst impacts of these natural disasters,’ said Mr Kruger. ‘It will help the people of the Tuamotus to protect themselves and their property. It will also produce benefits for the environment, tourism and pearl cultivation, as the Tuamotu group is a strategic area for French Polynesia’s tourism and pearl farming sectors.’
Emilie Nowak, Engineer in the Urban Planning Department (Government of French Polynesia) reports that outputs such as the production of risk maps and the economic analysis of housing options in inundation zones will be very useful to French Polynesia.
‘This work will result in refining the current risk plans for the Tuamotu archipelago, developed under the national risk assessment and planning program but for which limited bathymetric and topographic data was available at the time.’
Ms Nowak also noted that the data collection campaign undertaken by the SOPAC team in French Polynesia resulted in training a French Polynesia government agent in using the multi-beam sounder to collect bathymetric data.
Mr Kruger said that the survey work and subsequent modeling was at the request of the Government of French Polynesia, and made possible through the Disaster Risk Reduction in Pacific Overseas Countries and Territories Project financed by European Development funds.