French coastal towns Sète and Marseillan demolished their roads to let nature reclaim the shore, reducing erosion and inspiring coastal management strategies.
Coastal erosion threatens French towns
Every autumn, dozens of coastal French communes face the challenge of the sea eroding their roads, sometimes by several meters during a single storm. This natural process has long been a concern for communities living along the coast, where the balance between land and sea is delicate and constantly shifting.A bold decision to retreat
In response to this threat, the towns of Sète and Marseillan chose a different approach: rather than reinforcing their coastal road with concrete, they decided to demolish it and rebuild it further inland. This decision was made to allow the dune line to naturally reform, offering a more sustainable solution to coastal erosion.Restoring the dune line
Between 2007 and 2012, 10 kilometers of the road were demolished and rebuilt 50 to 250 meters inland. This allowed the dunes to recover and the beach to expand. By 2014, the coastline’s retreat during storms had decreased from 20 to 10 meters, showing that the strategy was effective in reducing the impact of erosion.The cost and collaboration
The project, initiated by Thau Agglo in 2006, cost 55 million euros. Funding came from multiple sources, including the French State, European Union, the Region, the Department, and Sète Agglopôle. This financial arrangement reflected the scale of the project and the need for cooperation across different levels of government.The natural barrier between two worlds
The lido connecting Sète to Marseillan acts as a natural barrier between the Étang de Thau and the Mediterranean Sea. However, this barrier is vulnerable to erosion, especially when fixed in place by artificial structures. Between 1954 and 2000, the lido lost nearly 45 hectares of land to the sea, highlighting the urgency of finding a sustainable solution.A growing coastal erosion problem
Coastal erosion is not unique to the Hérault region. According to the Cerema, 27.6% of the French coastline is affected by erosion, with the figure rising to 50.1% for beach areas alone. Hérault is among five departments where at least half of the coastline is retreating, underscoring the widespread nature of the challenge.A preservation program in 2003
Faced with rapid erosion, the communes of Sète and Marseillan launched a preservation program in 2003. The core idea was to stop fighting the sea directly and instead give it space to move naturally. This approach was later implemented by Thau Agglo, aiming to restore the natural balance between the beach and the dune.Rebuilding the infrastructure inland
From 2007 to 2012, the old coastal road was demolished and rebuilt further inland, near the railway line. This allowed the dune to reform naturally and reduced the pressure on the coastline. The last section of the old road was destroyed in 2010, with materials being reused rather than discarded in landfills.A submerged wave attenuator
To further protect the coastline, a submerged wave attenuator was installed in 2013, 350 meters from the shore. This structure helps reduce the energy of waves before they reach the beach, effectively acting as an invisible breakwater. Monitoring by the BRGM confirmed its success in reducing coastal retreat.A model for future coastal planning
The results of this project have been measurable and significant. The beach now extends 70 to 100 meters wide, providing space for the sand to absorb wave energy. This approach has shown that giving the sea space can be an effective alternative to traditional coastal defenses, potentially inspiring other regions facing similar challenges.
