Robust reefs, fewer floods

  • Courtesy The Nature Conservancy

    How a coral reef dissipates wave energy is demonstrated at Palmyra Atoll.

LIHUE — Kauai’s coral reefs protect the island from about $11 million worth of damages every year, according to a new study released by the U.S. Geological Survey, The Nature Conservancy and the University of California Santa Cruz.

And that $11 million is part of a nationwide total of more than $1.8 billion in flood protection that reefs offer every year in the United States.

The study estimates annual flood protection benefits for Hawaii Island to be at $51 million, $376 million on Maui, and $394 million on Oahu.

That’s because reefs take the power out of waves before they reach land, acting as breakwaters and keeping the ocean from delivering a full-fledged hit to the coastline, and whatever building or street happens to be in the way.

In fact, in the study, researchers state coral reefs can dissipate as much as 97 percent of incident wave energy before it reaches shore.

And people from Hawaii say that the report could be a game-changer for Hawaii.

“We know that Hawaii benefits in many ways from healthy coral reefs, and now we can quantify those benefits and identify specifically who receives them —whether they be coastal businesses, resorts, homeowners or critical government infrastructure like military bases, roads and sewage treatment plants,” said Kim Hum, The Nature Conservancy’s Hawaii Marine Program director.

The study points out the areas with the greatest flooding and where it could potentially be slowed or stopped by reef restoration.

“By rigorously valuing these benefits, we can help mobilize the public and private investments needed for reef management,” Hum said.

USGS research geologist and study lead author Curt Storlazzi said the report can be used by coastal managers, emergency response agencies and local and national governments to identify where to invest in reef management as a natural defense against coastal flooding related to hurricanes, storms, sea-level rise and other coastal threats.

Researchers also reminded the public of the bad news: globally, coral reefs are dwindling. They highlight the 2015 Hawaii mass-bleaching event as an example, when coral loss reached an average of 50 percent on Maui and up to 90 percent on some of West Hawaii’s reefs.

“The good news is that reefs can recover, and may even adapt to changing ocean conditions, particularly if we identify the threats to them and sufficient financial resources to manage those threats,” researchers stated in a press release about the report.

The report’s co-author, Michael Beck of UC Santa Cruz, says the U.S. has already appropriated more than $100 billion for recovery from hurricanes Harvey, Maria and Irma, and that coral reefs could reduce damage caused by future storms.

Invest in reef management and that cost would drop, researchers say.

“We need to identify new and innovative funding opportunities to proactively build our reefs and coastal resilience,” Beck said. “For example, disaster recovery funding from FEMA (Federal Emergency Management Agency) is now being used to identify where reefs can provide natural coastal defenses.”


Jessica Else, environment reporter, can be reached at 245-0452 or

  1. Charlie Chimknee May 3, 2019 2:45 am Reply

    Aloha Kakou, Aloha Jessica,

    The article leaves me wondering what damages reefs, like then news that skin lotions for tanning or sun protection, is that right, can damage the reefs. Did our legislature wisely ban the sale of those products here in Hawaii…?

    Education is needed for those bringing those chemicals here from out of state.

    Is it true that the skin protection lotions only stop reddening of the skin but do not protect the skin from damage thwt could become cancer…? There’s that pesky reliance we have gotten ourselves into again from more man made chemicals.

    There was no mention of how many years it takes reefs to naturally grow. It’s not like we can just grow then anywhere in tropical waters.

    Like you said it seems we better protect what reefs we got already.


  2. HaenaHui May 3, 2019 3:10 pm Reply

    !!!!!!!!!!!Save the Reefs Keep the Road Closed Permanantly!!!!!!!!!!

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