【環境科学】沿岸部の水防における湿地帯の経済効果

Protection provided by coastal wetlands helped avoid $625 million of flood damages in the United States during Hurricane Sandy according to an evaluation in Scientific Reports this week.

As the frequency and costs of flood damage from storms continue to increase, strategies are needed to reduce the risk that are both physically sound and cost-effective. These solutions could include natural ecosystems such as wetlands and reefs. However, there has been a lack of large-scale evaluations of the value of coastal wetlands for reducing property damage caused by flooding.

Using high-resolution risk models from the insurance sector, Siddharth Narayan, Michael Beck and colleagues estimated that wetlands across 12 states on the east coast of the United States helped to avert approximately $625 million in direct flood damages during Hurricane Sandy in 2012. The authors then assessed the risk reduction benefits of salt marshes in Ocean County, New Jersey using a database of synthetic storms. Here, the authors found that the presence of salt marshes led to a 16% average reduction in annual flood losses and that marshes reduced the maximum annual risk to properties behind marshes at all elevations. The authors suggest that their findings could provide incentives for wetland restoration based on their risk reduction benefits.