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The island of Saint-Barthélemy has undergone massive development and “urbanization” in the space of just a few years. Residential buildings, hotels, houses and gigantic villas have all been built, as have roads and other infrastructure. This development has been accompanied by several devastating meteorological episodes, the most recent of which, Hurricane Irma in 2017, led to obvious changes in the landscape. In addition, the natural phenomenon of erosion also plays a role that cannot be ignored. Particularly in the regular changes to coastal shorelines.
While the Agence territoriale de l'environnement (ATE) is keeping a close eye on this issue, an in-depth, long-term study seems necessary. A scientist from Montpellier's Paul Valéry University has been assigned just such a task. Anaïs Coulon, a doctoral student in geography specializing in natural risk management, has been studying the evolution of the coastline on Saint-Barthélemy for several months. This is part of her thesis on the future of the island's coastlines. A vast undertaking.
From Thailand to Saint-Barth
Passionate about geophysics and the processes that shape landscapes, Anaïs Coulon holds a Master's degree in Natural Risk Management. A degree she obtained after studying the consequences and effects of the 2004 Tsunami in Thailand. Her work also took her to New Caledonia, where she studied the changes brought about by the construction of hotels, as well as the predicted changes to the environment linked to cyclonic risks and climate disruption. For her thesis, Anaïs Coulon had another idea in mind. “At first, I thought of comparing Saint-Barthélemy and the Philippines, but then I decided to focus solely on Saint-Barth,” she explains with a smile. A judicious choice dictated in part by collaborations already underway with Montpellier academics working with ATE, notably as part of the Safe Saint-Barth project. Judicious because, as Anaïs observes: “It's incredible because I already have a lot of data collected since 2021.”
“To understand the present, you have to look to the past”.
The question a novice in the field of research might legitimately ask is: what does a thesis on the coastline entail? I'm a beach doctor,” says an amused Anaïs Coulon. I observe, I question the indicators and I establish a diagnosis of the current state. But the most important thing is to study what happened ten years ago. To find out whether there have been any natural changes or human activities, such as sand nourishment on the beaches or the construction of low walls, which may have led to changes. To understand the present, we need to look at the past. And you can't imagine the future if you haven't done your homework beforehand. Nevertheless, it goes without saying that her work doesn't stop there.
Aware of the importance of integrating all the factors inherent in the general context into her study, Anaïs Coulon stresses the need to anchor her project in “local realities”. For her objective is also to “bring together and mobilize all the island's players to create synergy, understand expectations and determine what works and what doesn't”. With this in mind, since her arrival she has been meeting with local residents, tourism professionals and institutions. Not only to gather information, but also to present the initial results of her research.
Intertwined phenomena
There's a great deal of variability in the coastal systems of Saint-Barth,” notes the scientist. They are very sensitive to different effects, such as swell, for example. This can be seen on Saint-Jean with the phenomenon of erosion. Why is this so? That's what we're trying to understand. Because, as Anaïs likes to point out, “not everything is black and white”. Indeed, the coastline is “a complex object to study”, and she points out that this “interplay of nuances makes it difficult to come to any categorical conclusions”. All the more so as all the phenomena are happily intertwined: urbanization, swell, cyclones, erosion, tourist numbers - everything is linked and has consequences for the environment and its evolution. “The approach must therefore be considered on an island-wide scale,” insists the researcher. To find solutions adapted to the preservation of the coastline and its beaches that don't necessarily involve recharging with sand, never effective even in the short term, or installing breakwaters. “We also need to look at what's being done on a Caribbean scale,” slips in Anaïs Coulon, who is devoutly pursuing her work on the island before projecting herself beyond Saint-Barth.
