Once-in-a-lifetime floods to become regular occurrences by end of century

Superstorm Sandy brought flood levels to the New York region that had not been seen in generations. Causing an estimated $74.1 billion in damages, Sandy was the fourth costliest U.S. storm behind Hurricane Katrina in 2005 and hurricanes Harvey and Maria in 2017.

Now, researchers at the Stevens Institute of Technology have found that 100-year and 500-year flood levels could become regular occurrences for the thousands of homes surrounding Jamaica Bay, New York, by the end of the century.

The U.S. National Science Foundation-funded study, led by Reza Marsooli, can help policymakers and the coastal municipality of Jamaica Bay make decisions on whether to apply coastal flood defenses or other planning strategies or policies for reducing future risk. It also provides an example of how coastal flooding will increase in the future across the New York region and other areas because of the impacts of climate change.

"While this study was specific to Jamaica Bay, it shows how drastic and costly an impact climate change will make," said Marsooli, whose research appears in the journal Climatic Change. "The framework we used for this study can be replicated to demonstrate how flooding in other regions will look by the end of the century to help them mitigate risk and best protect communities and assets in impacted areas."

Marsooli and colleagues found that the historical 100-year flood level would become a nine-year flood level by mid-century (2030-2050) and a one-year flood level by late 21st century (2080-2100).

Most recently reached by Superstorm Sandy, 500-year flood levels would become 143-year flood levels by mid-century and 4-year flood levels by the end of the century. Sea level rise would result in larger waves, which could lead to more flood hazards such as erosion and damage to coastal infrastructure.