Swamp Stomp
Volume 17, Issue 40
As the devastation wrought by this year’s hurricanes continues to be felt in the Caribbean and the Gulf states, a recent study finds that coastal wetlands have the capacity to substantially mitigate property damage due to flooding and storms, saving taxpayers millions of dollars annually in averted losses.
The study, jointly conducted by researchers from the University of California Santa Cruz and scientists from private insurance, conservation and engineering groups, assessed the value of the ecosystem services provided by wetlands to mitigate flood damage in the northeastern United States caused by hurricane Sandy in 2012. Through the use of advanced computer modeling of storm surge flooding and a vast database of properties damaged, the researchers estimated that $625 million worth of property damage was averted due to the presence of coastal wetlands from Maine to North Carolina, with a 22% average reduction of damages for each of the 707 zip-code areas assessed in the study.
Their findings established a clear positive correlation between the presence of wetlands and the value of nearby properties, as well as between wetland area and averted losses due to flooding. This was true even in heavily urbanized coastal areas that had lost most of its wetlands, such as New York, where wetlands cover only 2% of the land yet still saved the state $140 million.
Wetlands are able to provide this service by acting like a buffer between the ocean and inland properties. As the storm surge produced by a hurricane moves onto the land, wetland vegetation significantly reduces the wave energy and height, with some wetlands attenuating surge action by up to 70 centimeters per kilometer.
Despite the profound ecosystem service value provided by coastal wetlands, only about 3% of private and public monies spent on coastal infrastructure are invested in wetland restoration while the rest is spent on “grey” infrastructure, such as concrete seawalls that can be expensive to maintain and often only redirect flood water to other areas, potentially exacerbating the damages to life and property.
Aside from damages caused exclusively by hurricanes, the researchers also measured the annual flood mitigating benefits derived from salt marshes in Barnegat Bay in Ocean County, New Jersey. They found that properties buffered by wetlands experienced an average of 16% fewer losses than those not buffered from the ocean by wetlands, suggesting that wetland restoration is a good investment even if few hurricanes make landfall in the region.
In an affiliated report by Lloyd’s Tercentenary Research Foundation, who provided funding for the wetlands ecosystem service study, strategies for funding wetlands restoration based off of the latter study’s findings were assessed.
Such strategies included investing in flood mitigating wetland restoration and conservation before a catastrophic weather event, which would reduce the price of insurance premiums and securities, allowing the resulting savings to pay for the initial costs of restoration. Then, after a natural disaster does occur, a portion of the public and private recovery and rebuilding funds would be allocated towards further wetland restoration efforts, making the coasts even more resilient and reducing flood insurance premiums further.
By quantifying the monetary value of the ecosystem services provided by wetlands, wetland conservation is made legible to politicians, investors and laypeople, increasing the likelihood that these areas will be managed responsibly both for the benefit of humans and for the benefit of the ecosystems themselves.
Sources: Narayan, Siddarth et al. “The Value of Coastal Wetland for Flood Reduction in the Northeastern USA.” Scientific Reports. 31 August 2017. Web. 26 September 2017.
Stephens, Tim. “Coastal wetlands dramatically reduce property losses during hurricanes.” University of California Santa Cruz Newscenter. 31 August 2017. Web. 25 September 2017.