Flooding in New Suffolk during Superstorm Sandy in October 2012.

Flooding in New Suffolk during Superstorm Sandy in October 2012. Credit: Randee Daddona

Flooding should be a big concern for many Long Island property owners now, and even more so in the decades to come. That conclusion is based on the region's experience with major storms like Superstorm Sandy, the reality of rising seas, and a recent study that paints an alarming picture.

Risk Factor, an online tool by the nonprofit First Street Foundation, estimates that more than 130,000 properties on Long Island could be affected by a severe flooding event. That’s a little more than 11% of Long Island’s total properties.

And the risk will get higher in the future as the effect of climate change on precipitation, sea levels, sea surface temperatures, and other factors is expected to increase the number of properties at risk of severe flooding over the coming decades. In 30 years, it’s anticipated that as many as 140,000 properties on Long Island would be affected; that equates to as many as 17.6% of residential properties. 

The model produced by First Street — a Brooklyn-based research and technology group that produces data on flood, wildfire, and extreme heat risks — does not take into account any increased development on the coastline or new efforts to discourage further building on our shores.

And it pegs the likelihood of a severe flooding event, also known as a 1-in-100-year flood event, occurring by 2052 at a worrisome 26%. Long Island has seen that kind of flooding before. A Columbia University study estimated Sandy to be a 1-in-103-year flooding event.

To add perspective to its findings, the Risk Factor tool attempted a re-creation of Superstorm Sandy’s flood. This recreated model calculated that approximately 84,000 properties on Long Island were affected by Sandy. In reality, however, Sandy was estimated to have severely flooded, damaged or destroyed roughly 100,000 Long Island residences. So the model actually could be an underestimation.

Naturally, risk varies by community on Long Island, and nextLI, a project of Newsday Opinion, has built a map below for our readers to get a more detailed look. 

The good news is that the future does not have to be as grim as depicted by First Street. Long Islanders do not have to accept this risk as inevitable.

Risk Factor goes into detail on steps Long Islanders can take as individuals and as a community to increase resiliency against flooding. They vary from such extremes as relocating or elevating a home onto posts, to short-term mitigation efforts such as building permeable pavements to absorb water and reduce runoff, to longer-term solutions like making a sustained and concerted effort to preserve and expand our living shorelines, so they serve as effective buffers against storms.

The data is alarming, but it is only a documentation of the past. If Long Island can use this information as a spur to action, we can lessen the chance that the region will suffer from the worst predicted flooding and reduce the number of places threatened by our changing climate.

Opinions expressed by Jun-Kai Teoh, a data journalist for nextLI and member of the editorial board, are his own.