A concrete colossus flanked by two yellow cranes stands facing the ocean. No doubt, the view will be breathtaking in the future offices of the Caisse des dépôts du Sénégal. Too bad if this building placed on the cornice of Dakar, of which only the gray carcass is visible for the moment, is close to the maritime public domain, “inalienable”.
Another building on the seafront, built with the authorization of the government, by ministerial decree of March 1, 2019. How much sand will it take to raise this cement giant of about twenty floors? And will this building hold out for a long time against the onslaught of the waves? This tower alone symbolizes all the paradoxes of the tragedy that strikes the coasts of the African Atlantic coast, where the sea advances by 1 to 5 meters per year on average, and where the sand disappears visibly, double victim of the erosion and large-scale extraction for the construction industry.
It illustrates the challenge facing coastal States to rethink their development model in the face of the effects of climate change, a theme at the heart of COP 27, which is being held in Egypt until November 18. “Africa will see its population double by 2050, recalls Arnaud Vander Velpen, expert at the United Nations Environment Program / GRID (Geneva). Inevitably, this will accelerate the rural exodus towards cities and areas coastal areas, and therefore unbridled urbanization. The demand for sand – one of the main components of concrete – will therefore explode.” However, this concreting accentuates the natural erosion. An infernal cycle with catastrophic consequences.
“We Senegalese, who have such a strong link with the sea, are witnessing the gradual disappearance of our beaches”, laments, facing the shore of the Dakar peninsula, the president of the Platform for the Environment and reappropriation of the coastline, Moctar Ba. The damage is already there, along the 700 kilometers of coast of the “country of teranga“(“hospitality” in Wolof, the main language). To the south of the capital, on the Petite Côte, a tourist destination once popular for its large stretches of sand lined with coconut palms, hoteliers have seen their beaches shrink to a trickle, until you put the key under the door.
A life on hold
In Saint-Louis, in the north, the concern has become existential about the Langue de Barbarie, this narrow strip of sand which separates the sea from the river and the island of Saint-Louis. “With the rise in sea level and the intensification of swell episodes, this cordon has weakened, because it is composed of sand, a loose sediment and therefore very sensitive to erosion, explains Professor Boubou Aldiouma Sy, geomorphologist at Gaston-Berger University in Saint-Louis. The coastline has retreated at full speed.”
Thousands of inhabitants live here, on borrowed time. More than once, they saw the swell raging at their gates. “Do you see the three walls over there? It was our house. It collapsed one day of heavy weather, a few years ago”, shows Pa Wade, a fisherman from the district of Guet Ndar, like his father and his grandfather. The nightmare began one evening around 7 p.m., after prayers. “We saw waves of 3-4 meters, the floor was hit first, after the water infiltrated, remembers this 37-year-old father. The canoes that were on the beach came knocking on the facades. We took a few things before everything collapsed.”
In the district of Guet Ndar, in Saint-Louis (Senegal), fishing nets rub shoulders with the ruins of houses destroyed by the swell, on a coast where the sea is advancing rapidly.
Charlotte Lalanne
In 2017 and 2018, two years of strong storms, a hundred houses suffered the same fate. Two schools fell, gutted by the tidal wave. At Guet Ndar, fishing nets rub shoulders with these ruins of cinder blocks, between which kids and goats weave their way. Nearly 3,000 residents have already been relocated to makeshift camps, 8 kilometers away, while waiting for something better. In the next few years, families living on the front line facing the sea will be asked to clear off to leave a strip of 20 meters behind the highest tide point. “A team from the town hall visited the houses and put these red marks on the walls. This means that we will have to move one day”, says Baye Diop, another fisherman.
Fishermen repair their equipment in the district of Guet Ndar, in Saint-Louis (Senegal)
Charlotte Lalanne
The authorities are careful not to specify when the ax will fall for these 10,000 or so people, but a new work could delay the deadline. A dyke of huge basalt rocks has just been completed over a length of 2 kilometers in front of these houses. At the initiative of this project, the State of Senegal, financed by the French Development Agency to the tune of 16 million euros. “This is an emergency solution, says Pape Aldiouma Cissé, coordinator of the coastal erosion control project at the Saint-Louis municipal development agency. In the meantime, we are working on a sustainable project with the World Bank.”
Sandmen
It remains to be seen which one. In Saly, on the Petite Côte, the hope of hoteliers has been reborn since the installation, in 2019, of permanent installations: a dozen breakwaters parallel to the beach, offshore, to break the force of the swell, and several “groins”, perpendicular to the shore, which act as a barrier retaining part of the sediments in transit. In addition to these works, the beach has been refilled with sand extracted at sea. The operation has, it is true, made it possible to recover several meters of the seashore, but it cannot be replicated everywhere. “Such a device would not work in Saint-Louis, which is more exposed to currents: nearly 1 million cubic meters of sand drift there each year, slices Rafael Almar, researcher at the (French) Research Institute for Development. Saint-Louis, breakwaters would quickly be buried.” On the other hand, the replenishment of the beach is envisaged. But how many times will you have to use it? And where are we going to find this sand that everyone is tearing up?
The question is all the more pressing as the return of sand to certain beaches could well lure the looters who are rampant everywhere on the African Atlantic coast, from Morocco to Benin via Senegal. In most of these countries, the extraction of sea sand has been prohibited for several years, but mafias have got their hands on this lucrative black market. Some would even benefit from the complicity of senior local officials. In 2021, a study by the organization Enact, which investigates transnational crime in Africa, revealed that in Morocco “trucks mobilized to transport sand to construction sites are suspected of belonging to parliamentarians and politicians “. According to estimates, up to 50% of the sand used there is illegally mined, the report says.
“The problem will only get worse”
Traffic seems less industrialized in Senegal, but the ballet of carters, who fill their trailers with sand, is well known there. And the precious granules also end up with construction suppliers. There too, the demand is not about to weaken, a gigantic new city, Diamniadio, supposed to relieve the land pressure on the capital, being in full construction at the gates of Dakar.
“The problem will only get worse, warns Arnaud Vander Velpen, of the United Nations Environment Programme. Most of the infrastructure that developing countries need has not yet been built. This is why we have hired a dialogue with players in the mining industry to encourage them to produce differently in order to reduce waste production by co-producing construction sand, which should of course be decontaminated. This discussion will take time, but it is a serious avenue .”
In Dakar, Moctar Ba, who fights to preserve the Senegalese coast, offers another: “Let’s stop concrete the coast and return to our traditional materials, like earth, more adapted to our climate.” To set an example, he builds his own mud house, an ocher palace across the road from the Corniche, which taunts its neighbors of glass and steel.