Cost benefit study confirms coral reef restoration could be a cost effective way to save lives and money

Researchers developed a modeling system to quantify the value coral reef restoration could provide to 1,000 kilometers, or 621 miles, of coastline in Florida and Puerto Rico. The research compared how much flooding storms could cause with and without coral reef restoration at a 10 square meter, or 108 square feet, resolution. Researchers then determined how many people and how much property and economic activity reef restoration could protect by preventing coastal flooding.

"Coral reefs are natural coastal barriers that can substantially reduce coastal flooding and erosion," said Curt Storlazzi, lead author and research geologist from the U.S. Geological Survey. "Over the past few decades, we've lost a lot of reefs to global and local stressors and restoring them can re-establish the protection they once provided."

Reefs can absorb and weaken damaging waves. As a result, waves that hit shores are smaller and cause less flooding and erosion, saving lives and money. Restoring degraded or destroyed coral reefs could protect nearly 3,000 people each year in Florida and Puerto Rico alone. Reefs could also prevent more than $391 million in damage to property and lost economic activity annually.

Using a budget of $3 million per kilometer, the study calculates a benefit-to-cost analysis of reef restoration and maintenance. About half of the budget is allocated to establishing reefs and the other half to maintenance. In about 20 percent of the study area, the value of property and economic activity protected from storm damage would be greater than the cost of reef restoration.

"This approach represents a massive advance in characterizing the effectiveness of nature-based infrastructure for coastal protection. Modeling benefit-to-cost of protection and/or restoration can also be applied to other ecosystems, such as beaches, marshes, oyster reefs, and mangrove forests," said Borja Reguero, professor at the University of California, Santa Cruz. "In addition, this modeling system can be used to assess the impacts of future changes in storms or sea level, helping us to measure when and how cost effective it is to adapt."

Vulnerable populations are disproportionately exposed to risks from natural hazards. Restoration could provide monumental benefits to the people who most need help. This study shows that vulnerable populations could receive two- to three times more protection from flooding relative to the general population.

"Our goal in this study was to provide sound science to identify who benefits from restoration and where those benefits are felt most," said Storlazzi. "We want people to understand that restoring coral reefs isn't just about protecting beautiful and diverse habitats. It's about protecting people, their cities, and the places they call home."

This study also provides a framework to calculate benefit-to-cost analyses for coral reef restoration in hazard risk reduction. This establishes an avenue for coral restoration projects to be considered for post-disaster mitigation funding from agencies like the Federal Emergency Management Agency or the U.S. Army Corps of Engineers, alongside traditional risk-reduction methods such as bulkheads or breakwaters.

Coral reef restoration can be longer lasting than manmade structures alone. If sea levels change, manmade structures like levees or seawalls would need to be made taller. However, coral reefs are living animals and can grow with changing sea levels.

"Most hazard mitigation and disaster recovery funding supports artificial infrastructure, such as seawalls, that degrade nature," said Michael W. Beck, Director of the UCSC Center for Coastal Climate Resilience and a co-lead on the project. "By valuing the benefits of natural infrastructure, we level the playing field and open major new funding opportunities for reef restoration."

What about the value coral reefs provide industries such as tourism, recreation, and fisheries? This study only considers the economic benefits of avoided damage. As a result, the true economic value of coral reef restoration is likely much higher.

The new study by the U.S. Geological Survey, University of California, Santa Cruz, and the National Oceanic and Atmospheric Administration titled "Hybrid coral reef restoration can be a cost-effective nature-based solution to provide protection to vulnerable coastal populations" was published today in the journal Science Advances.