Protecting Our Coastline With Autonomous Marine Vehicles

This article was originally published in Thinkers & Makers, a magazine from Akkodis featuring the smartest minds and innovative projects that are driving the future of technology and engineering.

Global warming is leading to higher sea levels. A rise in average sea levels means that extreme sea levels, storm surges, and coastal flooding are more likely when storms hit. That puts people living by the sea in danger and threatens their homes and livelihoods, not to mention precious natural habitats.

As the world scrambles to decarbonize, governments are also looking for ways to mitigate the damage already being done by climate change. One important area of focus is improving flood defenses.

Increasing Flood Risk

It’s getting urgent: The Intergovernmental Panel on Climate Change’s (IPCC) latest estimates warn that in the best-case scenario, average sea levels could increase by 30-60cm (or 60-110cm in the most pessimistic scenario) by 2100.

The European Environment Agency has warned that storms that used to devastate the coast once a century are now expected to increase by a factor of ten before 2050 in many Atlantic and Mediterranean coastal locations in Europe. Images of violent waves crashing over seawalls, flooded homes, and displaced people may dominate the headlines when storms hit. 

Still, their impact goes far beyond the apparent effects – coastal flooding can destroy precious biodiversity along the shoreline by flooding wetlands or dunes. Agricultural land that becomes salinated after submersion in seawater for long periods is less productive for farmers.

The US Environmental Protection Agency has also noted that flooding is becoming more frequent along the country’s coastline. Nearly every site measured has experienced an increase in coastal flooding since the 1950s. This rate is accelerating in many parts of the East and Gulf Coasts. 

The storm surge and flood barriers in many coastal locations allow water to pass in normal conditions and close to lessen the impact on the coast when storms hit. However, these barriers are simply no longer up to the job. Akkodis experts set out to develop a cost-effective and flexible solution that would better protect coastal communities and natural environments.

Zoran Adam-Gaxotte, a marine engineer by training and R&D project leader and specialist in innovation and coastal preservation within the Applied R&D department at Akkodis, is leading the SABRES project. 

“I’m passionate about innovations that can help preserve the coastline," he said. “I started the SABRES project in 2019 because I could see that the risk of coastal flooding would become a big concern for coastal communities in the coming years”. 

Submersibles Step up 

The aim of the SABRES project was to develop an environmentally friendly way of creating a barrier against the waves in areas at risk of coastal flooding. At the same time, the project sought to minimize the impact on the local marine ecosystem and sediment dynamics.

Adam-Gaxotte and his team came up with an innovative solution: Submersible and Autonomous Breakwater based on a Removable and Ecofriendly System. 

The fleet of autonomous submersible vehicles is designed to have a breakwater effect and combat coastal flooding in an intelligent and adaptable way.

The vehicles can be deployed when there is a high storm risk and removed once the risk has passed, reducing the local environmental footprint compared to permanent flood defenses. The SABRES system's flexibility means it can adapt to different storm scenarios, making it more effective at protecting the coastline.

When the storm alert comes, each craft navigates autonomously, avoiding any obstacles, to a strategic position at sea before diving down, anchoring itself to the seabed, and finally deploying its breakwater device. Once the storm has passed, the SABRES submersibles retract their breakwater solution, rise to the surface, and return to the port base.

“Traditional ways of combatting coastal flooding have big drawbacks – they are cumbersome and permanent. They have a significant long-term impact on marine ecosystems, driving away populations of some species or encouraging invasive ones that harm local biodiversity,” Adam-Gaxotte said. “But we just had to put up with them as there were no alternatives.”

These fixed, old-style solutions also cannot adapt to individual storms or to the natural evolution of the coastline itself. They are expensive, too—often needing to be rebuilt after a big storm. Worst of all, they don’t completely rule out the risk of coastal flooding, as recent storms have demonstrated.

For all those reasons, combined with intensifying warnings about rising global temperatures and sea levels, authorities have been calling for a more intelligent and sustainable solution to protect the coast. They are seeking a made-to-measure and budget-friendly approach.

“I’m passionate about innovations that can help preserve the coastline. I started the SABRES project in 2019 because I could see that the risk of coastal flooding would become a big concern for coastal communities in the coming years”.

Zoran Adam-Gaxotte, SABRES R&D Project Leader, Akkodis

Multi-skilled Project

The project uses a broad skill set, building on the knowledge of marine biology, coastal hydrodynamics, meteorology, economics, and social sciences. Specialists in mechanics and naval design, robotics, geotechnics, and eco-design work alongside IT experts. They contribute their skills in embedded systems, artificial intelligence, automation, and cybersecurity.

The team has also been working with other researchers seeking answers in the same field, including the Gladys laboratory at the University of Montpellier. They tested its innovative coastal hydro-morphodynamic modeling algorithm, Opti-Morph, using the case study of a storm swell hitting the coast of Palavas-les-Flots on the Mediterranean coast of France. This area is protected by SABRES craft.

The project has drawn on expertise beyond the project team itself. The SABRES solution is based on a particularly innovative fleet management algorithm. It is enabled thanks to an artificial intelligence study* focused on the potential of “SWARM” (decentralized) approaches in optimizing fleet navigation tasks in space environments. 

The SABRES work has been taking place in France. With its approximately 1,200km of Atlantic coastline, it is particularly at risk from coastal flooding. Still, the innovative technology could help protect other coastlines worldwide, keeping local inhabitants safe and protecting their homes. This solution could safeguard essential fishing, tourism, and cargo transportation industries and preserve valuable natural environments such as wetlands and dunes. 

Breakwater Demonstrator

The solution will also save governments money. A recent study published in Nature Climate Change found that coastal flooding could result in economic damage of nearly €1 trillion per year by 2100 without investment in adaptation measures. 

The team is now developing two small-scale prototypes to demonstrate the technology's capabilities and attract investment. The first model will use artificially generated swell to demonstrate the submersibles' breakwater capabilities. Depending on the predicted storm and the local coastal configuration, it will also help estimate the number needed in a fleet. 

The second demonstrator uses made-to-measure remote-control boats to test the innovative Akkodis algorithm, which will control the automatic piloting of the SABRES fleet, allow the craft to dodge obstacles, and optimize their routings.

*M. Mounsif, K. Zehnder, Y. Motie and Z. Adam-Gaxotte, "SwarMind: Harnessing Large Language Models for Flock Dynamics," 2023 10th International Conference on Soft Computing & Machine Intelligence (ISCMI), Mexico City, Mexico, 2023, pp. 171-177, doi: 10.1109/ISCMI59957.2023.10458573.