Posted on October 5, 2026
Hold the line. For decades, this was the standard approach when it comes to coastal protection. “But the challenges coastal communities face today have outgrown that approach”, says Vicky Stratigaki, Lead Engineer Project Development and Conceptual Design at Jan De Nul. “The real challenge is not to defend today’s shoreline, but to make sure our coasts remain safe in a system that will continue to change for decades.”
Vicky, what is putting our coastlines to the test today? What is coming our way?
“The obvious answer is sea-level rise, but it is broader than that. We are facing increasingly severe storm surges, waves, flooding and erosion, often all at once. On the other hand, natural coastal buffers are under pressure. Ecosystems like dunes, wetlands and mangroves absorb wave energy, trap sediment and provide room for a coastline to respond dynamically. When these systems disappear, or get squeezed between the sea and fixed infrastructure, we lose part of the coast’s natural capacity to adapt.“
How can we take our changing world into account when we design coastal protection?
“The key concept is adaptability. We cannot predict with absolute certainty what the sea level, storm climate or coastal landscape will look like at one particular location several decades from now. Future-proofing therefore does not mean selecting one future scenario. It is about making sure the solution performs safely today, while leaving room to adapt it later. Monitoring is an important part of that. Design, observe, adapt. That principle is key.”
Any recent examples?
“Take the Prince Hendrik Sand Dike on the Dutch island of Texel. Instead of simply making the existing concrete dike higher and stronger, we placed 5.5 million cubic metres of sand in front of it, creating a new dune landscape and salt marsh. The result is a coastal defence system with two hundred hectares of new nature that works with natural processes: sand, wind and water can continue to shape the landscape, while the dune system protects the island against storms and flooding.”
This is very different from common hard structures in coastal protection.
“It is. But we do not turn this into a discussion of grey versus green. It is a spectrum of solutions, with at one end conventional engineering: dikes, seawalls, breakwaters and storm-surge barriers. They can provide very high and predictable levels of protection and remain indispensable in many locations. Then there are softer measures such as beaches, nourishments and dunes. Further towards the nature-based end of the spectrum are ecosystems like wetlands, salt marshes and mangroves. Increasingly we are working in between, with hybrid solutions that deliberately combine both hard and soft measures. They are different tools in the same toolbox.”
How do we decide when to choose grey, nature-based or hybrid?
“The most important thing is that we do not start from a technology. We start from the coastal system and the problem that needs to be solved. What level of protection is required? What are the dominant waves, water levels and erosion processes? How much space is available? Is sediment available and can it move through the system? These are some of the questions we need to answer before working towards a solution.”
Can it sometimes make more sense to intervene offshore rather than directly at the coastline?
“Absolutely. Coastal protection does not have to start at the exact line between land and sea. A coastline is influenced by waves, currents and sediment transport across a much larger coastal profile. Intervening offshore or in the nearshore zone can therefore sometimes reduce the wave energy reaching the shoreline or influence the way sediment is transported towards and along the coast. That is one of the reasons why we often incorporate submerged breakwaters or different types of reefs, such as oyster, mussel or coral reefs, into our solutions.”
