American Samoa included in new study on value of coral reefs

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American Samoa is included in a new indepth study released today by the  U.S. Geological Survey titled “Rigorously Valuing the Role of U.S. Coral Reefs in Coastal Hazard Risk Reduction,”

The study –funded in part by the *U.S. Department of the Interior’s (DOI) Office of Insular Affairs demonstrates annual benefits of coral reefs including a flood-protection barrier for more than 18,000 coastal citizens and $1.8 billion worth of coastal infrastructure in the United States and its trust territories.

The study will help managers take effective actions to reduce the risk to, and increase the resiliency of, U.S. mainland and U.S. insular area coastal communities to flooding and other hazards..

The research, led by USGS research geologist Curt Storlazzi, analyzed flood risk and assessed reef benefits of populated U.S. reef-lined coasts of Hawaii, Florida, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, Puerto Rico and the U.S. Virgin Islands.

It is the first time that scientists have combined real-world computer models of storms and waves with engineering, ecological, mapping and social and economic tools to create detailed, rigorous estimates of the value of coral reef defenses along U.S. mainland and U.S. insular area coastlines both in the long-term (annualized) and for more infrequent events such as 50- or 100-year storms.

The study models can forecast localized threats to people and economic damage in areas with and without coral reefs at a 10-square meter (108 square feet) resolution along more than 3,100 kilometers (1,920 miles) of populated U.S. coral reef-lined shoreline.

“Our Office was glad to collaborate with the USGS and leverage funds available through the Coral Reef and Natural Resources Initiative,” said DOI Insular and International Affairs Assistant Secretary Doug Domenech. “This highlights the important role that coral reefs play not only for coastal communities in the U.S. mainland, but also in the U.S. insular areas.

“These research results will be of great interest to the U.S. Coral Reef Task Force, a body tasked to lead U.S. efforts on coral reef ecosystems and that the Interior and the Department of Commerce chair jointly.”

Coral reefs, noted Storlazzi, are coastal barriers that can substantially reduce coastal flooding and erosion by reducing the energy of waves as they wash ashore.

“Our goal in this study was to provide sound science to identify where, when and how U.S. coral reefs provide significant coastal flood reduction benefits to ultimately save dollars and protect lives.” noted Storlazzi.

The value of coastal flood risk reduction provided by coral reefs varies from location to location, primarily because of population density and the elevation of coastal areas. For example, coral reefs shield more than 3,300 people on Maui each year but just over 100 on Guam, where most housing and infrastructure is located at higher elevations because of the nearly constant threat of typhoons. Coral reefs annually protect $183 million worth of buildings and economic activity in Puerto Rico, $675 million in Florida and $836 million in Hawaii.

According to Storlazzi, these data indicate that in the event of a 50-year storm (which has a 2 percent chance of occurring in any given year), the economic and protective benefits of coral reefs are even greater. In such a storm, for example, coral reefs off the heavily urbanized coast of Miami-Ft. Lauderdale, Florida, would provide more than $1.6 billion in protection, and off the coast of Honolulu, Hawaii, they would provide more than $435 million in protection.

The study also calculates the extent to which critical infrastructure, such as hospitals, fire stations, roads and power plants, are protected from coastal flooding by coral reefs.

Photo: Amy West, USGS Science Communications Contractor