Measures to mitigate coastal erosion in Seychelles |18 April 2016

A Small Island Developing State, Seychelles has not been sparred like the majority of other island states around the world from the harmful effects of coastal erosion.

The coastal zones remain one of the most vulnerable areas with regards to the ever-changing climatic conditions and shocks. With about 85% of the current population living within the vicinity of the coastal areas, there is increasing pressure on the coastlines to cater for economical and recreational needs of humans, but also for the coast to adapt and become resilient to the ever-increasing frequency and intensity of natural hazards.

The 2004 tsunami that struck certain coastal areas around Seychelles brought to the forefront the need to manage, protect, and minimise the vulnerability of our coastlines from these natural hazards like extreme storm-surges originating from abnormal spring tides, and tsunamis which accelerate the recession of coastlines through erosion. With fishing and tourism the pillars of our economy, it is vital therefore that measures are put in place to protect the beaches not only from erosion but also to secure the livelihoods of the fisherman and tourism establishments that depend on the coasts for their survival.

Acknowledging that climate change is one of the main reasons why our coastlines are becoming more and more vulnerable to unexpected anthropogenic and natural shocks, the climate adaptation & management section of the Ministry of Environment, Energy & Climate Change (MEECC) has found it mandatory to implement on the ground approaches to deal with coastal erosion through the use of soft and hard engineering methods that not only slow down erosion effects contributing to coastal recession, but also secure the coastlines from further environmental degradation. Charged with the management, protection and conservation of all coastal zones in Seychelles, the coastal zone unit is therefore mandated to implement measures that will not only safeguard our beaches, but also enhance their adaptation and resilience to factors that undermine their longevity and aesthetic values.

With rock armoring and timber pilings the weapons of choice to combat coastal erosion, it is however important to assess which methods are suitable for each individual affected beach as some methods may do more harm than good in the long term. Assessments of coastal protection and rehabilitation works depend largely on the severity of the coastal erosion as well as cost implications.

Rock armoring

Rock armoring as a hard engineering method is very costly compared to timber pilings which are a softer and less costly method, but in terms of long-term protection rock armoring is very viable. The objectives of both methods however, is not only to reduce the impacts of wave energy on the exposed beaches, but to re-create beaches in the future. These two methods mentioned work well with several other soft components that aim to create healthy coastal fronts teeming with healthy beach fringe vegetation. If such healthy coastal fronts are to survive, it is therefore important to prevent human impacts such as trampling from both humans and vehicles from damaging the already fragile beach fringes.

Trampling is currently being controlled by the use of large rocks or concrete bollards that are placed on the back dune to prevent vehicular access on the dunes. When it comes to coastal protection works or rehabilitation, cost is always a factor and as such, there are several locations where these structures have been placed to block vehicular access on vulnerable beaches. More locations have been identified in the inner islands where these structures have to be put in place to reduce vegetation loss.

There is also the need to re-vegetate such locations in an effort to enhance the beach fringe ecosystem which plays an important part in erosion control. Coastal plants have been largely overlooked in the past as effective coastal barriers, but the emphasis now is on integrated coastal management practices that not only look at the human intervention factor to mitigate coastal erosion, but also the importance of coastal plants in trapping sands which help to stabilise the back dunes and help in re-forming affected beaches.

Coastal plants

The intensity of erosion caused by both natural and human induced factors, constantly pose a threat to the survival of many coastal flora and fauna that help to stabilise the beachfront. Beach fringe plant species consisting of mostly bushes and small trees such as vouloutye, with its many low branches and extensive root systems, are vital component in beach stabilisation as they decompose and become part of the soil. The decomposing matter increase cohesiveness, as well as supplying essential nutrients to the soil necessary for plant growth of emerging seedlings. The creeping Patatran, on the other hand, spreads over the soil surface, securing more space for other species to grow and thus helping to form new land. Aesthetically, they are also beneficial by covering the rock armoring network when they spread, thus helping to give a more natural look to re-habilitated beaches that have undergone beach protection works.

Coastal plants should also be credited with absorbing excess salt during the South-East monsoon, thus protecting the inland native plants from salt spray, while their branches withstand strong winds which would otherwise have affected the inland plants.

One critical observation of coastal erosion is their ability to undermine and affect beaches that are important commercial and recreational hubs. With erosion becoming more active and destructive over time, many local beaches are losing their pristine character and social appeal. Many beaches which are well frequented by both locals and tourists such as Anse à la Mouche, Anse Gaulette, Anse Royale and Anse Kerlan on Praslin are examples where the beach front have undergone major transformations due to coastal erosion. In many instances, beaches have receded to distances of up to 40 metres such as Anse Kerlan on Praslin, whereby property owners are losing much-valued land before their eyes. The continued threat of erosion is undermining the tourism industry due to the continued menace of extreme weather events such as storm surges which are increasing in intensity and frequency. With that in mind, many private properties such as hotels are approaching the coastal unit to seek proper advice on how to deal with erosion issues near their property. They are seeking the best methods and practices that will not only counter the erosion issues, but also protect their properties in the long term. Many establishments take part in beach monitoring programmes which is important as beach profile data collected can help in making informed decisions on appropriate coastal measures to implement.

Supervision of government projects relating to coastal protection works are also vital as is the supervision of private projects that seeks to protect vulnerable coastlines. Examples where successful rock armoring and protection schemes implemented by the then environmental engineering and wetlands section has occurred include Petite Anse Marie Louise at Takamaka whereby a stretch of 111m of coastline was being scoured by strong waves. This stretch also served as the sole access road for a number of families residing the upper part of Petite Anse Marie Louise. The erosion was making it impossible for vehicles to arrive at these homes, which during the water shortage period in 2008; PUC (Public Utilities Corporation) bowser trucks could not deliver water to the residents. The environmental engineering and wetlands section responded to concerns brought out by the district administration and the residents themselves by implementing the rock beaching project which was polished up by re-vegetation by Takamaka students, the Seychelles National Youth Council, Lions Club of Paradise Seychelles and the environment department. The project has been highly successful and effective in restoring and enlarging the road through backfilling and the beach has been re-formed due to the deposition of sand over the rock beaching.

Projects undertaken

Another key project undertaken in 2013 was the rehabilitation of the Anse à La Mouche beach that was severely eroded. The project consisted of rehabilitating 178 meters of severely eroded coastline by the use of backfilling with coral fill to re-create the dune-land, installation of timber pilings to protect inland from incoming waves and trapping onshore sand transport, as well as re-vegetation to stabilise the newly created dune-land. 

Upon completion of the backfilling and timber pilings installation, a landscaping plan was initiated with various stakeholders to provide a recreational and buffer area for the Anse à La Mouche coastal front. Beach protection schemes involving rock armor have also been implemented at La Passe, La Digue. More recently in March 2016, a beach protection scheme involving the temporary dumping of rocks to protect the road infrastructure at Anse Gaulette, Baie Lazare has been implemented. This was an emergency response to the continued threat of erosion that was undermining the road network in that area.

It is Important to note that many beach protection schemes have also been implemented by private individuals and hotels to protect their establishments from the harmful effects of erosion. Notable examples include the Bel Ombre Hotel coastal rehabilitation scheme involving timber pilings to counter the threat of coastal erosion and at Paradise Sun Hotel on Praslin.

The joint collaboration between the Ministry of Environment, Energy and Climate Change is very important to ensure that the projects are done in a professional manner that meets coastal engineering standards and regulations. Major coastal protection projects are planned for the future to tackle coastal erosion around Seychelles. However, the cooperation and support from the general public are very important if these projects are to succeed and reach the required results we all seek to achieve.