Coastal wetlands dramatically reduce property losses during hurricanes

September 1, 2017 by Tim Stephens, University of California - Santa Cruz
Coastal wetlands dramatically reduce property losses during hurricanes
Flooding in New Jersey caused by Hurricane Sandy, which made landfall in New Jersey and devastated the East Coast. A new study estimates that coastal wetlands reduced property damages from Sandy by an average of 22 percent in affected areas. Credit: Bridget Besaw

With the Atlantic hurricane season well under way and Tropical Storm Harvey causing devastation in Texas, a new scientific study reports that coastal wetlands significantly reduce annual flood losses and catastrophic damages from storms. Led by a team of scientists from the engineering, insurance, and conservation sectors, including researchers at UC Santa Cruz, the study found that coastal wetlands in the northeast United States prevented $625 million in direct flood damages during Hurricane Sandy, reducing damages by more than 22 percent in half of the affected areas and by as much as 30 percent in some states.

The study, published August 31 in Scientific Reports, quantified the flood reduction benefits provided by across the northeastern United States during Hurricane Sandy, as well as the benefits provided annually in Barnegat Bay in Ocean County, New Jersey. It used the risk industry's latest and most rigorous high-resolution flood and loss models and an extensive database of property exposure to show the correlations between property value and wetland presence, and between wetland extent and avoided flood damages.

The vast majority of public and private funding for coastal infrastructure goes toward built structures (e.g., concrete), with only about 3 percent going to restoration of natural infrastructure (e.g., wetlands), according to a recent analysis by UC Santa Cruz researchers. The authors of the new study said their findings make a clear case for reallocation of this coastal investment portfolio, particularly after disasters such as Hurricane Sandy.

"Wetlands can be incredibly effective at reducing property damages from catastrophic storms, and these effects can be clearly understood by combining state-of-art engineering models with coastal ecology and economic analysis," said lead author Siddharth Narayan, a coastal engineer at UC Santa Cruz. "Coastal habitats provide benefits that represent hundreds of millions of dollars in annual savings along the U.S. East Coast."

Coastal wetlands dramatically reduce property losses during hurricanes
The study shows that conserved wetlands provided risk reduction benefits during Hurricane Sandy even in highly urban environments like this urban salt-marsh in New York. Credit: Kevin Arnold
Clear correlation

The study showed a clear correlation between wetland cover and avoided property damages: the greater the extent of the wetland, the more protection it provides. Even relatively degraded wetlands in highly urban areas like New York City provided hundreds of millions of dollars in flood protection during Hurricane Sandy, preventing $140 million in flood damages in New York and $425 million in New Jersey.

In addition, the study demonstrated that coastal wetlands provide important coastal protection services year-round. Annual flood losses in Barnegat Bay, New Jersey, were 16 percent lower in places that had conserved their marshes than where the marshes were gone. In places that were 1.5 meters or less above sea level, the relative annual risk reduction benefits from wetlands were as high as 70 percent.

The study was led by UC Santa Cruz, The Nature Conservancy and the Wildlife Conservation Society in association with Risk Management Solutions and Guy Carpenter & Company, with funding from Lloyd's Tercentenary Research Foundation. This partnership between the conservation, engineering, insurance, and risk management sectors was born out of the realization that coastal development and climate change will continue to increase the risks to people and property from flooding and storm surge, and that protecting coastal habitats can mitigate some of these risks. Coastal habitats are natural defenses that can help reduce risk in a cost-effective way, adapting to changes in the environment and providing multiple benefits to society.

Coastal wetlands dramatically reduce property losses during hurricanes
Marsh wetland provides a first line of defense in coastal New Jersey. The study shows that properties fronted by salt-marshes experience 16 percent lower annual flood losses from storms than ones that have lost their fronting marshes. Credit: Jim Wright/LightHawk
Conservation and restoration

In a connected report from Lloyd's, the partners identified how the findings in the Scientific Reports paper can be used to fund wetland conservation and restoration. Before a disaster strikes, investments in habitat conservation that reduce coastal risk could reduce premiums on insurance and insurance-linked securities (such as resilience bonds). In this way, habitat restoration could pay for itself in savings. After a disaster strikes, private insurance and public recovery funds can support wetland conservation, with the benefits of further reducing insurance premiums and building coastal resilience against future disasters. The risk and insurance industry can play a critical role in wetland restoration for disaster prevention and recovery.

The magnitude of the benefits was surprising given how many coastal wetlands already have been lost throughout the region. For example, wetlands did not reduce as much damage in New York in part because of their extensive loss in past decades. At the same time, even relatively small, thin bands of wetlands serve as an effective first line of defense, and they can be restored to build coastal resilience.

"Our models traditionally focus on man-made coastal defense structures, or on other gray architecture solutions, like elevating properties above sea level," said coauthor Paul Wilson, vice president of model development at RMS and an expert in hurricane and storm surge. "This study is pioneering because it applies cutting-edge modeling science to natural defenses, and it allows us to put a financial value on the role wetlands play in protecting our coastal communities against storm surges."

Quantifying the economic value of natural defenses will increase their relevance and inclusion in coastal management priorities. Although the risk-reduction role of coastal wetlands is often included in risk models, it is not clearly recognized by risk modelers, insurers, brokers, and clients. The risk-reduction role of wetlands can be straightforwardly included in the products of the risk and engineering sectors, and thus more readily considered in and habitat restoration decisions.

"Although these might be strange bedfellows, engineers, insurers, and conservationists can come together to save people, property, and nature," said coauthor and project lead Michael Beck, lead marine scientist for the Nature Conservancy and a research associate at UC Santa Cruz. "Our work together shows where we can find innovative solutions for reducing flood risk and conserving ."

"Lloyd's Tercentenary Research Foundation aims to fund cutting-edge scientific research that contributes positively to society; this principle is embodied in the ongoing project led by the University of California at Santa Cruz," said Jean-Bernard Crozet, trustee of Lloyd's Tercentenary Research Foundation and head of underwriting modeling at MS Amlin. "Coastal ecosystems such as coral reefs, mangroves, and salt marshes play a fundamental role in reducing the risk of storm surge. The LTRF believes that improved quantification of these benefits will, in turn, lead to better management and conservation of these natural ecosystems, contributing not only to risk reduction along our coasts but to our planet's sustainability in the long run."

Explore further: Coastal wetlands save hundreds of millions of dollars in flood damages during hurricanes

More information: Siddharth Narayan et al. The Value of Coastal Wetlands for Flood Damage Reduction in the Northeastern USA, Scientific Reports (2017). DOI: 10.1038/s41598-017-09269-z

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4.2 / 5 (5) Sep 01, 2017
Pity that this research goes against Human's natural nature to infest and destroy nature.

Civic Virtue is bankrupt now in the Age of the Global Fascist Axis. Mammon is God and patriotism is peddled to the highest bidder.

The present disaster in the Great State of Taxless, is only to expected in a social order based upon accumulating personal wealth. While denying the Civil Society the funds necessary to protect people from their own base instincts and other natural disasters.
1 / 5 (5) Sep 01, 2017
Fortunately, elevated CO2 level is very helpful for coastal wetlands. It helps salt marshes resist encroachment by the sea, thanks to "CO2 fertilization," which helps C3-photosynthesis wetland vegetation grow better.

But the benefits for wetlands are dwarfed by the benefits for arid areas. Extra CO2 not only helps C3 & CAM plants grow faster and healthier, it also makes C3 & C4 plants more water-efficient and drought-resistant. As a result, arid region are "greening."

Even National Geographic, which heavily promotes the climate scare, admits anthropogenic climate change is greening deserts, though they didn't mention that it's the CO2 that's responsible:


The best evidence is that anthropogenic climate is real, but modest & benign, and CO2 emissions are very beneficial for both agriculture and natural ecosystems.
Sep 01, 2017
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1 / 5 (4) Sep 02, 2017
Why not save the stupid theorizing and just go ask the Dutch what they do? They have the experience.
Sep 02, 2017
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1 / 5 (4) Sep 02, 2017
Billy Meier clearly stated, in 1951:

21.Through the guilt of the people, all storms will assume increasing and more violent forms, such as hail storms, blizzards and flooding rains, as however also the ozone-layer will become very dangerously damaged.

22.Monstrous deluges will belong ever more to the order of the day, because through the overpopulation, the forest wetlands and swampy plains will become altered in function to become residential areas, whereby the wild waters of the flooding rain will find their way into the houses of the people because they can no longer escape into uninhabited wetland areas.

Along with more than 200 proven corroborations and counting, and many yet to come...
Da Schneib
3.7 / 5 (6) Sep 02, 2017
Insurance actuaries are extremely pragmatic. When they talk about risk, they're not guessing. They're not interested in politics, environmentalism, saving industries or jobs, science, or anything else except reducing the amount of losses their companies have to pay for.

To them, protecting property from casualty losses is the entire point; if they say wetlands protect what's behind them from losses, they have the numbers to prove it.

Get over it.
not rated yet Sep 07, 2017
"In a 2003 publication, the National Research Council of the National Academy of Sciences reported that roughly 343,200,000 gallons of oil were released into the sea annually, worldwide.

Of this amount, the report estimates the origin of that oil as follows:

Use or consumption of oil (which includes operational discharges from ships and discharges from land-based sources): 37%
Transportation (accidental spills from ships): 12%
Extraction: 3%
Natural seeps: 46%"
That's almost a million gallons/day, and our resident crank Bubba is trying to suggest 100 gallons will have some affect.

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