How Collier’s Mangroves Saved $62 Million in Hurricane Damage

With hurricane season on the rise and evidence showing that they are only getting more catastrophic, it’s imperative to ask the experts how to avoid irreparable damage. Dr. Siddharth Narayan, a coastal engineer and global expert in nature-based solutions, based at East Carolina University, North Carolina, is helping quantify just how powerful mangroves can be at combating hurricanes. “Mangroves definitely help protect from storm surges,” Narayan told Coastal Breeze News. “But we should be aware of exactly where and how that protection is offered.” 

When Hurricane Ian charged across the southwest coast of Florida in 2022, leaving behind disastrous flooding and billions in damages, something fascinating occurred just behind the eye of the storm: a quiet line of defense helped hold the water at bay. That defense wasn’t concrete - it was the tangle of roots and canopies of Florida’s mangrove forests. 

“It’s like throwing a wall of water at a wall of roots,” he said. “Dense mangrove vegetation resists flow, reduces water speed, and limits how far floodwaters travel inland.” 

In the first comprehensive, state-wide assessment of the value of mangroves in protecting people and property from coastal flooding in Florida, Narayan called the results “surprising, but logical given how much development lay just behind dense mangrove stands.” 

In Collier County alone, mangroves prevented $62 million in damages, protecting over 8,000 people. His study also emphasized that there was a 25% average reduction in flood damages across the state due to mangrove presence, and 626,000 people were less exposed to flooding thanks to mangroves during Irma.  

Across South Florida, mangroves reduced flood damages from storm surge by 30% during Hurricane Ian. His work also found similar average reductions in flood damages across the state due to mangrove presence during Irma. The benefits were most significant in southwest Florida, where large areas of mangrove forest lie between the Gulf and densely developed communities. 

Narayan’s research combines high-resolution computer models with real-world hurricane data to simulate what flooding would look like with - and without - mangroves, and as his work has shown in Texas and the US Northeast, salt marsh wetlands, too. Using detailed vegetation maps and a friction-based modeling approach, his team can estimate how much floodwater is slowed or deflected by these coastal forests. Narayan and his colleagues demonstrate that these ecosystems are not just ecologically valuable - they function as critical infrastructure, delivering measurable flood protection and savings.  

But there’s a catch: these benefits aren’t static. Mangrove forests themselves are changing—shifting northward with warming temperatures, and becoming increasingly vulnerable to repeated hurricanes, sea-level rise, and development. 

“We’re not dealing with a fixed seawall,” Narayan explained. “We’re dealing with dynamic, evolving ecosystems. That makes modeling harder.” 

He highlighted that while mangroves provide vital protection, their benefits are not evenly distributed. In rare cases, the presence of mangroves can actually increase flooding to nearby areas if the water is redirected. “Just like with a levee, you want to be behind it, not in front of it,” he said. 

So what does this mean for Collier and Lee counties? According to Narayan, it means taking a closer look at where mangroves are located and how development patterns interact with them. His findings suggest that FEMA, state flood agencies, and insurers incorporate mangroves into their official flood risk maps and resilience planning, as well as prioritizing mangroves that provide the highest flood protection value for preservation, particularly where they protect high-value properties or dense populations. 

“If we want to call mangroves natural defenses, then we have to think about where we build in relation to them,” Narayan said. “People who choose to build close to the coast should be making fully informed decisions.” 

His work has informed flood risk policies for the U.S. Army Corps of Engineers and the Intergovernmental Panel on Climate Change. He’s also contributed to World Bank reports - like one in Jamaica showing that mangroves reduced cyclone damages by 25% to 30% in vulnerable coastal regions. 

Narayan, who grew up on the coast of Chennai, India, has studied shorelines in Europe, Asia, the Caribbean, and the U.S.—bringing a unique global perspective to coastal resilience. “Every coastline presents its own challenges,” he said. “But one thing is consistent everywhere: people want to keep their ecosystems intact and still feel safe. I work on how to do both.” 

Links to Dr. Siddharth Narayan’s full peer-reviewed article: 

Valuing the Flood Risk Reduction Benefits of Florida’s Mangroves: 

https://www.nature.org/content/dam/tnc/nature/en/documents/Mangrove_Report_digital_FINAL.pdf