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

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Detailed Description

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 at: and

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Date Taken:

Length: 00:11:25

Location Taken: Sant 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”.


The letters USGS and the text “Science for a changing world” appear in white over a black screen and then fade out. A coral reef teeming with colorful fish appears and the title appears, reading “How our Reefs Protect Us, Valuing the benefits of U.S. Reefs”. 
Video clips continue to show healthy coral reefs and vibrant marine life. 

An aerial view of the world appears, showing the northern tip of Eastern Australia and the Great Barrier Reef appears in a sparkling blue. 

The eye of a hurricane with spiraling clouds appears above the Great Barrier Reef. 

Large waves crash against a reef and then a car is shown driving through saltwater as a large wave washes over the barrier of the Malecon in Cuba.  

Underwater footage of large waves crashing above a coral reef show the destructive power of wave energy.

A clip taken above water shows large waves crashing as they reach a reef while approaching the shore. 

An aerial view of Mexico’s coastline appears, with a computer-generated checkerbox grid over the coral reefs flickering into view. 

As the checkerbox grid fades, the camera zooms in as waves appear and slowly move toward shore over the coral reef. 

Scene changes to show USGS Research Geologist Dr. Curt Storlazzi speaking to the camera in front of waves crashing at Younger Lagoon on UCSC’s Coastal Science Campus. 

A graphic showing the 12 step program of USGS briefly fades into view, showing 12 graphic vignettes, organized in three columns of four rows of graphics, starting with first column labeled “Hazards” and “downscaling waves to shore”. 
1.    The first graphic, labeled “A: Offshore wave data” shows an island with North South East West directions to symbolize swell direction. 
2.    The second graphic, labeled “B: Representative sea states” shows a graph with deep-water wave energy varying greatly around a relatively stable average over time in years. 
3.    The next graphic, labeled “C: propagate to nearshore”, shows the wave shadow of an island as high energy waves move around it. 
4.    The next graphic, labeled “D: Reconstruct shallow water wave data” shows a graph with shallow-water wave energy varying by the conditions of 500-year storms. 

Then, the next column is Labeled “Ecosystem: Reef Flood Modeling” and shows the steps to evaluate the impact of ECOSYSTEMS on flooding. 
1.    The first graphic, labeled “E: 100-meter reef profiles” shows many transects around the coastline of the same island as previous graphics. 
2.    The next graphic, labeled “F: Storm intensity” shows a graph with wave energy increasing logistically as a function of return intervals in years. 
3.    The next graphic, “G: Effects of the reef” shows two reef profiles, without reefs in red and with reefs in blue. 
4.    The next graphic, labeled “H: Flood Frequency” shows a graph with two logistic growth curves representing higher flooding without reefs in red and lower flooding with reefs in blue. 

The third and final column is labeled “CONSEQUENCES: Assessing impact and benefits”.
1.    The first graphic, labeled “I: Map Flood Zones” shows an island with two shaded perimeters, one representing the flood line with reefs in red, which is closer to the ocean than the flood line without reefs in blue. 
2.    The next graphic, labeled “J: Assess Exposure” shows four equations, for “Cells, Area, People, and Built”, each showing that we are calculating the difference for each respective factor with and without reefs. The “people” equation relies on Census data and is labeled as such and the “Built” equation relies on HAZUS data and is labeled as such. 
3.    The next graphic, “K: Economic damage” shows a graph with four colorful logistic growth lines representing damage in percent by depth flooded in meters.  
4.    The next graphic, labeled “L: Assess risk reduction benefits” shows two graphs, each showing logistic growth curves in red for without reefs and in blue for with reefs. The first graph is labeled People Threatened and the second graph is labeled Money Threatened. The area between the curves is highlighted in green to represent the risk reduction benefits of reefs. 

A text box appears, reading “HAZARDS: Simulating nearshore wave hazards based on offshore wave energy measurements” and then an illustration of a large and powerful blue wave appears to its right. 

A text box appears, reading “ECOSYSTEM: Model flooding impacts with and without coral reefs” and then an illustration appears to its right of a coral reef ecosystem with reefs in blue and with degraded reefs in magenta. 

A text box appears, reading “CONSEQUENCES: Quantifying the protection benefits of coral reefs” and then an illustration appears to its right showing building profiles flooded with three different water levels, the lowest is labeled “BASELINE water level”. Above that, the next flood line is labeled “10-Year flood level with a Healthy Reef” and the highest flood line is labeled “10-year flood level with a degraded reef”.

After Curt Storlazzi says “10-year”, a small blue wave appears in the lower left corner. As he says 50, 100, and 500, the wave grows and becomes very large for the 500-year storm condition.

A map graphic fades in, showing all U.S. coral reefs, including the reefs in Puerto Rico, US Virgin Islands, American Samoa, Central Northern Mariana Islands, Hawaii, and Florida. The map shows “Annual Expected Benefits of reefs in dollars per kilometer” represented by a color gradient which shows high expected benefits in many areas, especially on the northern coast of Puerto Rico, around Oahu, and the eastern coast of Florida. 

The video of Curt Storlazzi fades away to show an illustration of a large wave over a coral reef on the left and the profiles of many buildings on the shore to the right. 

A degraded reef in magenta fades in over the illustration of the healthy coral reef and the profile of this degraded reef condition as it reaches the shore shows the degradation of the shallow shelf that existed under healthy reef conditions. 

A large wave in magenta fades in on top of the blue wave illustration to demonstrate that degraded reefs cause increased wave height and power. 

The camera zooms in as three flood lines are overlaid above the buildings on the right of the illustration. The building profiles are flooded with three different water levels, the lowest is labeled “BASELINE water level”. Above that, the next flood line is labeled “10-Year flood level with a Healthy Reef” and the highest flood line is labeled “10-year flood level with a degraded reef”.

A checkered transition, representing the high precision of this modeling, reveals an aerial image labeled as San Juan Puerto Rico, showing two flood profiles for conditions with reefs in blue, which is closer to the water, and conditions without reefs in red, which extends far past the beach and amidst the houses, showing that flooding without reefs would endanger a large area of infrastructure in this image.

The map graphic shown before, representing annual expected benefits of reefs in dollars per kilometer, fades in again with the text beneath that says “>1.8 billion”.

An infographic showing multiple human figures appears along with text that says “>18,000”.

Text appears that says “>$5 BILLION protected by reefs during the 100-year storm”.

The illustration with the coral reefs and building profiles reappears and an additional equation is overlaid, showing that one meter of reef height loss can result in a quadrupling of wave power and cause a doubling of flood damages. 

The illustration fades out and the scene changes to show UCSC Ocean Sciences Professor Dr. Mike Beck speaking to the camera on a beach in front of waves crashing at Younger Lagoon on UCSC’s Coastal Science Campus.

The letters “USGS” and the text “Science for a changing world” appear in white over a black screen and then fade out. The words “In Cooperation with” appear and fade out. 

Text appears, reading “These results can be found in the recent report by UCSC & USGS: Learn more at coastal and a link to the USGS report included in the detailed description for this video. 

Text appears, reading “Thanks to the Cal Academy of Sciences for Video and Images from Expedition Reef” along with the Cal Academy logo and a link to find the full Expedition Reef video which is included in the detailed description for this video.

A logo appears, reading “Jessie Kendall-Bar Art & Photography” with a kelp illustration and