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A new report found sea level rise will make flooding more frequent and severe in coastal communities. Here, street flood in Atlantic City during a late-winter storm in 2013.

(Erin O'Neill/NJ Advance Media)

The high tides fueling minor flooding along parts of the Jersey Shore today will be able to push water further inland and put property at risk in a few decades, according to a new study, as rising sea levels makes waterfront communities more vulnerable.

The report released today by the Union of Concerned Scientists found that flooding is already occurring more often in places like Atlantic City. The city now averages nearly 30 days per year with tidal flooding, according to the report, up from five days per year in the 1970s. But as sea levels increase, the report says the city — and other coastal towns — can expect more frequent and disruptive flooding from high tides.

"Within the timeframe of a 30-year mortgage, East Coast communities will see dramatic changes in the number and severity of tidal floods each year, unless, of course, serious steps are taken to try to manage those floodwaters, and those steps are successful," Erika Spanger-Siegfried, a senior analyst with the Union of Concerned Scientists and a co-author of the report, said in a statement.



"We expect the number of tidal floods to triple in the Atlantic City area to 90 a year in just 15 years," said Spanger-Siegfried. "Without adaptation efforts, roads that link west Atlantic City to the mainland, could end up closed on a regular basis."

The study — called “Encroaching Tides: How Sea Level Rise and Tidal Flooding Threaten U.S. East and Gulf Coast Communities over the Next 30 Years” — relied on 52 tide gauges from the National Oceanic and Atmospheric Administration along the East and Gulf coasts. The analysis uses coastal flood advisories issued by the National Weather Service as an indicator of present-day flooding and relies on projections that sea level will rise four feet by the end of the century.

The report found that today there are 32 flooding events per year in Atlantic City, 41 in Cape May and 33 in Sandy Hook. By 2030, the number of events per year with sea level rise would jump to 92 in Atlantic City, 128 in Cape May and 88 in Sandy Hook. Fifteen years later, by 2045, the number of annual events would spike to 244 in Atlantic City, 302 in Cape May and 211 in Sandy Hook.

Most floods that now occur at high tide are classified as nuisance flooding, meaning the water may block roadways or back up sewers and storms drains but doesn’t pose a direct threat to life or property. While strong winds or a storm are usually needed for extensive coastal flooding, the report says that “higher seas will mean that high tides can reach farther inland, creating flood conditions that last longer and disrupt daily life for growing numbers of people.”

The report found that the high tides creating nuisance flooding in Atlantic City and Cape May will be capable of causing extensive flooding by around 2042.

The report makes a series of recommendations for how towns should address the threat of tidal flooding in the future, including upgrading infrastructure and developing a long-term vision. The report also calls for a coordinated national response that will incentivize, regulate and mandate action.

Cape May Mayor Ed Mahaney said major hazard mitigation projects — including a sea wall, pumping stations and beach replenishment — have been put in place in the city over the last 50 years. He said those projects have already reduced flooding to the minimum that occurs with major storms off the coast but the city continues to look for ways to reduce risk.

Mahaney said controlling flooding has been a priority there “because our sustainability and our survivability both depend heavily on having this island intact and maintaining the environmental assets that we’re blessed to have.”

Erin O'Neill may be reached at eoneill@njadvancemedia.com. Follow her on Twitter @LedgerErin. Find NJ.com on Facebook.