isla

 

product

2018

 

Diploma project

Under the guidance of Guillaume Foissac

In partnership with Biorock Technology

 

Coral islets and atolls that gravitate one or two meters above the sea are the first to be threatened by sea level rising, erosion and flooding being more and more frequent and disastrous.

 

In the 1970s, Thomas Goreau and Wolf Hilbertz developed an electrolytic mineral accretion process. It consists of immersing a metal structure in the sea and connecting it to a low current. By electrolysis, calcium carbonate is formed around the metal structure. The main advantage of this process is that despite the acidification of the ocean, corals develop up to five times faster on such devices because

the accretion produced solidifies their skeletons. The two researchers have initiated a certain number of pilot projects that have demonstrated the effectiveness of their technology in restoring eroded beaches. These projects are carried out with salvage materials and a limited budget. They work mainly on a voluntary basis and must travel to each site to install their artificial reefs themselves.

 

Wanting to democratize their technology, I imagined Isla, a wave breaker that self-welds thanks to electrolytic mineral accretion. It allows the waves to arrive on the beach with less intensity, and the sand to remain there more permanently. Designed with the support of Thomas Goreau, it is a solar powered product which can be sent to and installed directly by the locals which are concerned.

 

Photo credits : Véronique Huygue

Guillemette de Brabant

The emerged part of the device has orange markings that are a tidal scale. More than a precise indicator, their intent is to give an idea of sea level fluctuations.

The wave breaker is delivered flat, folded and disassembled.

The structure is energy self-sufficient. The electrical cables are hidden in a main pole.

The module is placed on the sand, about one meter underwater, quite close to the shore. As soon as accretion begins, the structure welds itself to the seabed, which consists of limestone.

Studies allow me to understand why dikes often fail in the end. When perpendicular to the waves, the waves are refracted and not dissipated. The force exerted on them is therefore increased tenfold. In doing so, the sand at the bottom of the dike is gradually pushed offshore and the foundations eventually give way. For the wave to be dissipated, the obstacle must therefore be porous and its main face must be inclined. The porosity of coral reefs is precisely what makes them so effective.

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