Vulnerability assessment of Seychelles’ coastal assets to oil spills

Details

Supervisors

Hanert, Emmanuel

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences et technologies de l'environnement, à finalité spécialisée

Abstract

Small island developing states (SIDS) are particularly vulnerable to oil pollution incidents, with little to no infrastructure available to detect, monitor or combat those spills. Seychelles archipelago is no exception to this rule as oil pollution could heavily impact its tourism industry, which accounts for about a 25% of its GDP. However, with a steady increase in maritime transport through the region as well as an increase in shipping incidents, its coastal assets vulnerability to oil spills remains largely unexplored. To tackle this deficiency, we developed a high resolution ocean circulation model of Seychelles plateau (SP) simulating ocean currents during three consecutive years (2018-2020). Those currents were used to simulate oil spill dispersal backward-in-time from six coastal areas of significant ecological and/or economical importance. That allowed us to identify which offshore areas pose the greatest threat to those sites. Our results show a clear seasonality of the offshore risk distribution that is driven by the seasonal changes in the atmospheric and oceanic circulations. We also show that the risk distribution can extend over most of the plateau during the year, which means that an oil spill coming from anywhere on the plateau could potentially impact a sensitive coastal location in less than five days. By overlaying the simulated risk distributions with areas with a high maritime traffic density, prone to shipping incidents (i.e. shallower than 10m) and under oil exploration licences, we identified the major north-south shipping route as an area of particularly high risk to most sensitive coastal locations. We therefore advise that this particular route should be closely monitored by the local authorities.