How Our Reefs Protect Us: Valuing the Benefits of U.S. Reefs

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The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards during storms. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision-making. Here we combine engineering, ecologic, geospatial, social, and economic tools to provide a rigorous valuation of the coastal protection benefits of all U.S. coral reefs in the States of Hawaiʻi and Florida, the territories of Guam, American Samoa, Puerto Rico, and Virgin Islands, and the Commonwealth of the Northern Mariana Islands. We follow risk-based valuation approaches to map flood zones at 10-square-meter resolution along all 3,100+ kilometers of U.S. reef-lined shorelines for different storm probabilities to account for the effect of coral reefs in reducing coastal flooding. We quantify the coastal flood risk reduction benefits provided by coral reefs across storm return intervals using the latest information from the U.S. Census Bureau, Federal Emergency Management Agency, and Bureau of Economic Analysis to identify their annual expected benefits, a measure of the annual protection provided by coral reefs. The annual value of flood risk reduction provided by U.S. coral reefs is more than 18,000 lives and $1.805 billion in 2010 U.S. dollars. These data provide stakeholders and decision makers with spatially explicit, rigorous valuation of how, where, and when U.S. coral reefs provide critical coastal storm flood reduction benefits, and open up new opportunities to fund their protection and restoration. The overall goal is to ultimately reduce the risk to, and increase the resiliency of, U.S. coastal communities.

Learn more:

The Value of U.S. Coral Reefs for Risk Reduction” and
Rigorously Valuing the Role of U.S. Coral Reefs in Coastal Hazard Risk Reduction

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Date Taken:

Length: 00:03:21

Location Taken: Santa Cruz, CA, US

Video Credits

USGS Contact: Curt Storlazzi (

We thank Jessica Kendall-Bar of Jessie KB Art & Photography for contributing all underwater, above-water, and interview video footage as well as infographics and animations to accompany this narrative ( We also thank the Cal Academy of Sciences for video and images featured from 0:11 – 0:29 and 0:45 – 0:53 from their educational series “Expedition Reef”.



Reefs provide more than food, they also provide protection. Hurricanes, typhoons, and cyclones form over the tropical ocean, sometimes doing serious damage when they make landfall. Reefs dissipate waves' energy, reducing wave height, and slowing the water before it crashes into the shore. Scientists created a computer simulation to understand how this works. 
Curt: So how do we do this? It's a 12-step program in three parts... First, identifying the hazard, understanding the role of coral reef ecosystems in reducing that hazard, and then quantifying the consequences. We compute different storm return interval conditions: the 10-year, the 50-, 100-, and the 500-year storm conditions. We do that along all 3100 kilometers of coastline and then what we do, is we model the flooding and we do that under two sets of conditions: we do it with the current reefs and then we model if reef degradation occurs. So we run our flood models with the current reefs and then with these future, theoretical degraded reefs. So then we can quantify that area protected by the reefs for different storm intervals and we can quantify that at very high precision, specifically, at 10 square meter intervals along all 3100 kilometers of U.S. shoreline. 
So what have we found? U.S. coral reefs provide over 1.8 billion dollars of protection annually. They protect over 18,000 people from flooding annually. And over 5 billion dollars are protected for the 100-year storm. Basically, those losses would double if those coral reefs were degraded. 
Mike: Across the U.S., coral reefs are struggling, but the good news is that they can recover, particularly if we find the resources to help manage them better. This new study, by helping to quantify the benefits of coral reefs can help us find the opportunities to fund the needed conservation and restoration. We can use these results to help inform the recovery spending after the hurricanes from 2017. That represents 100 billion dollars in funds that could be used to help restore and recover our national natural defenses.