Climate change is leading to increasingly violent storms. Can seawalls hold back floods? In 2012, Superstorm Sandy pummeled the east coast of America. Winds blew in at 80 miles per hour and heavy rain pushed the ocean over 9 feet above average levels. In New York, storm surges brought 30-foot waves ashore, flooding streets, subways, and homes.
20 miles south of Manhattan – several neighborhoods on the small borough of Staten Island sat in ruins. Homes were completely leveled and 24 people were killed. As global temperatures rise, research has shown that increasingly violent storms will likely continue assaulting our coasts.
Paired with rising sea levels, that could mean higher risk of flooding and worsening catastrophic damage to areas like this – unless we learn to adapt. And for Staten Island, that means building a wall. Adaptation is this idea that we are physically remaking our cities to make sure that they are going to be resilient in the climate disasters of the future.
And that will also include retrofitting our cities for the everyday effects of climate change, which means things like extreme heat, heavy downpours, drought. A sea wall is one of these adaptations. It’s erected parallel to the coast to create a “hard shoreline”. It deflects daily tides to keep the shore from eroding away as it would under normal conditions.
If a natural disaster strikes, it’s meant to stop incoming storm surges or a tsunami. Now, if fortifying our cities with walls seems too simple and medieval, that’s because it kind of is. Climate change isn’t a single assault on a castle, it’s an ongoing, worsening crisis. And in order to evolve with that crisis, the adaptations we make need to include resilient infrastructure.
Resiliency is this idea that your city can respond to any type of threat – it might not just be a climate threat, but that you plan for disasters and emergencies in a way that will enrich everyday life for your residents anyway. In other words, building resilient infrastructure means we don’t have to choose between feeling safe and enjoying our cities.
For example, in 2008 New York Harbor School started the Billion Oyster Project, a resiliency plan that restores oyster reefs in New York Harbor. The reefs help filter the water and slow down powerful waves, preventing erosion and reducing flooding. The project is even doubling as an educational program for students around the city.
When natural solutions like that aren’t enough, cities may look for more intense options. Like sea walls. In hopes to prevent another Sandy-level disaster, Staten Island has recently received $615 million in funding for its own sea wall.
The structure will span about 5 miles and sit 20 feet above sea level. And it includes resilient design elements: The wall will double as a boardwalk, making it far less imposing and allowing residents to enjoy the coastal views. Plus, to keep Staten Island safe, the plan includes adaptations to the land surrounding the seawall.
Globally, rainfall during major storms is expected to increase 20% by 2100. Since much of Staten Island was initially built on wetlands, intense rainfall could easily flood neighborhoods — something a sea wall can’t prevent. So the resiliency plan includes returning several areas on the island to their natural marshy state.
And that helps to mitigate that storm surge when you have that coastal flooding, when you have heavy rain, and make sure that the water is not going to be trapped in where the buildings are. Several man-made ponds will also be excavated for drainage purposes.
These alterations required careful planning and analysis of the land they’re trying to defend. And altogether, they make a pretty well-rounded protection plan. But even with a multifaceted and resilient approach, these adaptations might not be enough. In 2018, New Orleans finished an upgrade on seawalls and levees designed to protect the city.
But 14 billion dollars later, engineers are saying the walls will be inadequate in 4 years due to sea level rise and sinking land. And in Kerala, India, sea walls have actually led to worsening coastal erosion. Climate change can be unpredictable, and we’re being put in a position to predict it anyway.
Resilient infrastructure is one way to tackle that uncertainty, but it’s not foolproof. Any type of infrastructure we are building to save ourselves from the adverse impacts of climate change is also going to introduce changes to our city that we are going to have to learn to live with. It’s moving beyond just building this one piece of infrastructure that would stay there for a century or two and really figuring out how you can innovate on the materials and the design over time, to address different challenges that will surface.
The reality is, that even with resiliency in mind, walling off the ocean is a band-aid solution on a growing wound. Building a wall to protect our cities is one thing – Building our cities to protect themselves is another.
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