Atlantic City and Cape May among coastal communities most exposed
JON HURDLE reports for NJ Spotlight
Towns up and down the Jersey Shore are being exposed to increased flooding as a result of sea-level rise rather than storms, according to a new federal report.
What’s now known as high-tide flooding (HTF) is a growing threat for coastal communities around the country, especially along the Northeast Atlantic coast from Maine to Virginia, which is expected to see more of that type of flooding than other regions over the next year, according to the report from the National Oceanographic and Atmospheric Administration (NOAA).
New Data Shows an ‘Extraordinary’ Rise in U.S. Coastal Flooding (NY Times)
Coastal Flood Exposure Mapper (NOAA)
High-tide flooding worsens, more pollution carried to sea (EnviroPolitics)
The report cited data from tide gauges at Sandy Hook, Atlantic City and Cape May as showing an increasing number of days over the last 20 years when tides were more than half a meter above the average high-tide level. And it forecast the numbers will rise further as ocean levels increase, causing more flooding.
The report predicts six to 11 days of high-tide flooding in the Northeast from May 2020 to April 2021, more than any other region.
“Evidence of a rapid increase in sea level rise-related flooding started to emerge about two decades ago, and it is now very clear,” it said. “This type of coastal flooding will continue to grow in extent, frequency, and depth as sea levels continue to rise over the coming years and decades.”
Effects of high-tide flooding
The effects will include flooding of, and restriction of access to, homes; damage to roads and wastewater systems, and downward pressure on real estate values, the report said.
HTF is also known as “nuisance” or “sunny-day” flooding because it is typically not driven by storms but by a full moon or tidal currents that swell the existing effect of higher sea levels.
Atlantic City saw nine HTF days last year, up from five in 2000, and the number is expected to increase to between eight and 14 days this year. By 2030, HTF days are projected to rise to 20 to 35, and accelerate to as many as 155 by the end of the century.
At Sandy Hook, one of three New Jersey tide gauges NOAA used, the number of HTF days more than doubled to 11 between 2000 and 2019, and the number of such floods is expected to rise to between 10 and 15 this year. The forecast is similar for Cape May, which experienced seven HTF days last year and is expected to see between six and 11 this year. The peak season for high-tide flooding at all three New Jersey sites is the fall, NOAA said.
It follows a report by the Science and Technical Advisory Panel, a Rutgers University-led group, which said last year that seas rose 1.5 feet at the Shore over the last century, almost three times as much as the global mean sea level, as land subsidence amplified the effect of rising ocean waters along the mid-Atlantic coast.
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