Seychelles: post-tsunami environmental assessment


Executive Summary

The Seychelles island group was struck by a series of powerful tidal surges, resulting from the tsunami, generated by the earthquake off Indonesia on 26 December 2004. As a direct consequence of these tidal surges two people lost their lives, and hundreds of families suffered damage to their homes and livelihoods. The effects of the tsunami were compounded by exceptionally heavy rainfall on 29 December, causing flooding, landslides, and tree/rock falls.

The Seychelles are globally recognized for the richness of their marine and terrestrial ecosystems, which in turn support the islands’ main economic activities; tourism and fishing. There was concern that in addition to its direct impacts on human communities, the tsunami may have caused damage to the islands’ environmental values, thereby indirectly affecting livelihoods.

In response to a request from the Government of the Republic of Seychelles, the UNEP Asian Tsunami Disaster Task Force organized a Rapid Assessment Mission to Seychelles at the beginning of February 2005. The mission team conducted site visits and held meetings with key stakeholders, both governmental and non-governmental, with an interest in management of the islands’ environment and natural resources.

The team concluded that the principal environmental impacts had largely been confined to the granitic inner islands, which include the main centres of population on Mahé, Praslin and La Digue, with the outer islands apparently escaping relatively lightly due to the physical shelter provided by the Seychelles bank.

The main categories of environmental impacts recorded were:

❍ severe damage to beaches, including west-facing coasts in some areas;

❍ severe damage – approaching 100% in places – to granitic island coral reefs on carbonate substrates exposed to the north and east, with less damage to reefs on a granitic substrate;

❍ serious damage to coastal vegetation, including many fallen and severely destabilized trees;

❍ some damage to sea-grass beds (due to smothering by sediment) and other marine and coastal ecosystems, including those such as wetlands that protect the coastline from erosion and flooding;

❍ discharge of sewage from a fractured pipeline into coastal wetlands on Mahé; and

❍ significant quantities of debris washed up along the shore.

Significantly, shoreline damage was focused where deep channels lead through or up to the fringing coral reefs, focusing and amplifying the wave energy at these points. Thus, two of the primary assets of the fringing reefs - shelter and access to the open ocean – have encouraged coastal development just above the high tide line, but the access channels also increased vulnerability to the tsunami (and therefore to other wave, tide and storm-related threats). This risk will only intensify with climate change, due to rising sea level and increasing extremes of weather. The pattern of tsunami damage serves as an indicator of future vulnerability, unless appropriate measures are taken.

A rapid cost assessment of repairing the damage caused by the tsunami was conducted by the Government of Seychelles in January 2005. This resulted in a total estimate of USD30 million, but only USD1.3 million were budgeted for responding to the environmental impacts.

The UNEP rapid environmental assessment drew the following general conclusions based on site visits and discussions with Seychelles organizations:

❍ the tsunami damage in the Seychelles is extensive, the response of authorities has been speedy and thorough, in this way limiting secondary impacts. It is especially relevant to mention the inherent limitations of the islands’ human, technical and financial resources. Government disaster management programmes have shown resilience during the tsunami but were stretched to the limit of local operational capabilities. Sound waste management limited the load of waste and pollution reaching the sea;

❍ it is clear that beach-crest and coastal vegetation were very important in reducing the impact of the tsunami wave, due to their role in sediment stabilization, sand trapping and wave attenuation. The maintenance and expansion of mangroves and coastal vegetation is important for reducing the vulnerability of the coastal zone to erosion and impacts of severe storms and tidal surges;

❍ the damage caused by the tsunami and the severe rainfall of December 2004 must be seen in the context of increasing frequency over recent decades of the impacts from other natural hazards, including fires, landslides, storms, drought, rising sea level, and rising ocean temperatures. These threaten the functioning of the marine and terrestrial ecosystems which are the lifeblood of the Seychelles economy and of worldwide importance.

UNEP recommends that action in response to the tsunami should involve wider activities to secure long-term sustainable management of the Seychelles natural environment. In addition to direct repair and mitigation measures, action is needed to:

❍ design and implement an extensive capacity-building programme for the key stakeholders involved in managing the Seychelles environment;

❍ identify and implement an ecologically sustainable means of ensuring that the coastline is as resilient as possible to the impacts of increased storminess and rising sea levels, both predicted as consequences of global climate change; and

❍ design and implement robust environmental monitoring and early-warning systems.

Given the richness of the marine and terrestrial ecosystems, as well as the commitment of Seychelles to Integrated Coastal Zone Management and the just management of their nature, Seychelles has an opportunity to present itself as an example of a Small Island Developing State in preserving its beauty, reducing disaster and laying out a credible way forward to sustainable development.