Reef balls to be installed to prevent erosion in front of resort on Desroches |04 July 2022

Mr Savy and Ms Simeon during the press conference (Photo: Salome Abel)

As part of a pilot study, the Islands Development Company (IDC) has started installing reef balls into the sea in front of the Four Seasons Resort on Desroches as a means to prevent further erosion on that part of the island.

The pilot project to mitigate beach erosion, caused by the impact of climate change, was announced by the chief executive of IDC, Glenny Savy, in a press conference held last week at the IDC headquarters, New Port.

Also present was the principal climate adaptation officer Annie Simeon from the Ministry of Agriculture, Climate Change and Environment.

A reef ball is a designed artificial reef that blocks the surge of current from hitting at beaches with full impact resulting in removal of sand. Its presence in the long run provides support to restore ailing coral reefs and to create new fishing and scuba diving sites.

They are made by pouring concrete into a fiberglass mold containing a central Polyform buoy surrounded by various sized inflatable balls to make holes for fishes to swim in and out. The molds are in different sizes and the one being used on the southern coast of Desroches is in the size of an oil barrel, placed 150m to 160m away from the beach.

Mr Savy stated that apart from Desroches, the project to restore beaches will also take place on the islands of Platte and Remire, among some of the outer islands being affected by beach erosion.

“I personally have witnessed the disappearance, in the early 1908s, of the southern island among the two islands on the African bank, an island which had infrastructure, accommodations and a coconut plantation etc.. which was gone in just a few years following rising sea level and now it doesn’t exist anymore,” Mr Savy said.

He stated that IDC learned of the effectiveness of the concrete reef balls being used in the Maldives and the company had sought for their expertise to counter beach erosion on the outer islands here.

He said that the project, with the involvement of a company in the Maldives, started three years ago where sea current and the hrights of waves were measured at different parameters in the waters of Desroches, Platte and Remire islands during the study.

He noted that IDC had been using groins armouring and wooden boundary walls at different angles as the source to mitigate beach erosion on the outer islands but most have not been effective.

For the time being only 80 such concrete reef balls have been aligned in the sea in front of the Four Seasons Resort on Desroches, among the 800 reef balls to be installed in the area.

The installment of the reef balls on Desroches started in April this year and the whole project is expected to finish before the end of December this year.

“We have witnessed a positive effect from the 80 reef balls installed so far and I hope that by the end of this project we would see an end to the loss of beaches on the island,” Mr Savy said.

He noted that IDC had been working in collaboration with the department of Environment on the project to which the latter is waiting for effective result of the reef balls to later use the same model to protect other coastal areas on Mahé, Praslin and La Digue, among other areas.

Mr Savy said the method is very expensive – at R15,000 per ball – and the various moulds for the project have been imported from the United States of America, one among various countries using this method to counter beach erosion.

All of the reef balls are made on site by IDC staff and they are being installed by the staff themselves.

He added that for the time being the tip of those reef balls can be seen at very low tide and that they will be working with the Maldivian company to see it they can be place a little bit further out on the sandy bottom.

He further added that demarcations have been placed to guide boats on the beach.

He stated that IDC will be making some balls on the island for the ministry.

Ms Simeon said that the World Bank has approved this beach erosion mitigation method as part of the blue barrier concept which is resilient against the impact of climate change while on the other hand helps to create an underwater ecosystem by humans, such as the growing of corals.

She said the ministry sees the project as a good initiative and will be looking forward to adopt it contrary to the usual rock armouring among other methods used to combat coastal erosion.    

Based on their structural design, reef balls are supposed to last over 500 years in seawater.

With the aid of some protection from the natural reef that grows around the concrete, they are expected to last indefinitely, turning into a natural reef over time.

Patrick Joubert