Seawalls sound like a good idea — and on the surface, they are. Build a big, tough wall between the ocean and the land, and you stop the waves, right?
Not exactly.
As coastal towns face rising seas and stronger storms, seawalls have become the go-to defense strategy. They’re easy to understand, politically appealing, and they send a clear message: “We’re doing something to fight back.”
But here’s the catch.
Seawalls don’t just hold back water. They also disturb the natural flow, shift erosion, and in many cases, make things worse over time. They’re not useless — but they’re far from the silver bullet we pretend they are.
Let’s break it down.
Seawalls Reflect Wave Energy — They Don’t Absorb It
Water doesn’t just hit a seawall and give up. It bounces back.
When a wave crashes into a concrete wall, its energy is reflected outward and downward. That bounce-back intensifies the force at the base of the wall, scouring the sand or sediment that supports it. This process, known as scour, eats away at the shoreline directly in front of the wall.
Over time, the beach disappears — not because of rising seas alone, but because of how the wall disrupts the wave dynamics.
So while the structure might protect the property behind it for a while, it often destroys the beach in front of it. And let’s be honest: if your solution to sea-level rise is to erase the coast… it’s not a solution at all.
They Create a False Sense of Security
Here’s the emotional trap: when there’s a seawall, people feel safe. Developers keep building, buyers keep buying, and communities assume they’re protected.
Until they’re not.
The presence of a seawall often encourages high-risk coastal development under the assumption that the wall will always hold. But seawalls don’t eliminate risk — they delay it. And when they fail, they fail hard.
This illusion of safety can lead to greater losses down the line — financially, environmentally, and sometimes even in lives.
Seawalls Fail Dramatically When Overwhelmed
Nature always plays the long game.
When seawalls are overtopped or breached by storm surge, the water tends to rush behind the wall, eroding the land it was meant to protect. Unlike dunes, wetlands, or mangroves — which absorb water gradually — a failed seawall turns into a channel for destruction.
Think of it like building a dam without a spillway. Eventually, pressure wins. And when it does, the damage is far worse than if the water had been allowed to flow naturally.
In many coastal areas, once a seawall goes, rebuilding it becomes harder and more expensive — especially if erosion has already eaten away at the ground underneath. Which brings us to the next problem.
They Can Block Beach Access and Harm Local Ecosystems
Seawalls don’t just hold back waves — they hold back nature.
In many cases, seawalls cut off the beach from inland areas, making it harder for people (and wildlife) to access the shore. This can lead to a cascade of effects:
- Public beach access disappears
- Tidal habitats get squeezed or lost entirely
- Sea turtles can’t nest
- Shorebirds lose habitat
- Sand movement is disrupted, which changes the dynamics of nearby beaches too
In short, seawalls don’t just change the coastline — they break the relationship between land and sea.
And unlike living shorelines (like dunes or mangroves), seawalls do nothing to regenerate or adapt over time. They’re static structures in a dynamic world — which is why they often fail when the ocean decides to rewrite the rules.
So… Should We Stop Building Seawalls?
Not entirely. In some places — especially densely built urban coastlines with nowhere to retreat — seawalls may still be part of the short-term strategy.
But they should never be the only strategy.
Relying on seawalls alone is like trying to hold back the tide with a dinner plate. It might work for a moment, but you’re going to get soaked eventually.
Instead, we need to:
- Combine gray infrastructure (like seawalls) with green infrastructure (like marshes, reefs, dunes)
- Stop building in erosion-prone, high-risk coastal areas
- Embrace managed retreat where appropriate
- Restore natural barriers that actually absorb and dissipate wave energy
- Design flexible, living coastlines that adapt, rather than resist
Final Thoughts: When Defense Becomes a Distraction
Seawalls feel like action. They look like protection. But in many cases, they simply buy time while making the underlying problems worse.
Real coastal resilience means working with nature — not trying to out-engineer it with concrete and hope.
If we want to protect the coast, we need to stop fighting the ocean and start listening to what it’s telling us. And it’s been saying the same thing for a long time:
You can’t wall your way out of rising seas.
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