If a northeast storm of similar magnitude as the March Storm of 1962 were to hit today, the high-water mark likely would top nine feet, about a half-foot higher than 50 years ago, due to sea level rise.
Six inches may not be much, but it can mean hours lost to an already tight window for evacuations. It also can mean critical evacuation routes, low-lying bridges and neighborhoods that never used to flood, now will.
“With changing sea levels, it actually takes a storm of lesser strength now to create the same impact,” said Thomas Herrington, a coastal engineering professor at Stevens Institute of Technology.
Engineers charged with making needed upgrades to infrastructure, including roads, bridges, utility lines and flood-control devices, are keeping sea-level rise as a critical variable in plans.
As road-improvement projects are completed in coastal areas, one of the problems traffic engineers have tried to fix along state roads are those spots vulnerable to tidal flooding. In some cases, they’ve been successful, in others, problems still exist.
When the state finished rebuilding the Ocean City-Egg Harbor Township bridge (sometimes mistakenly called the Ocean City-Longport bridge) in 2002, the road leading to the bridge from the Egg Harbor Township side was raised several feet to stop the frequent tidal flooding, said David Lambert, state director of bridge engineering and New Jersey Department of Transportation engineer.
Raising roads to deal with tidal flooding, especially as flooding seemingly has increased in some areas due to sea-level rise, has been a priority for projects along coastal areas, but the state can raise roads only so high.
“The 100-year storm is generally the guide we use when we raise a road or bridge,” Lambert said. “It can’t always be done because of the cost and socioeconomic impacts.”
Atlantic County Emergency Director Vince Jones said the county pays attention to every road that floods and has been noting changes in flooding patterns. For example, Jones said, the bridge on Mays Landing-Somers Point Road that was damaged during Hurricane Irene never used to flood, but in the past few years more water has come into that tidal creek than before.
“You can see a deviation in the wetlands, where some of these small channels and creeks have actually widened a bit, the contour has changed, so the water is going in a different direction,” Jones said.
In Dennis Township, Cape May County decided to raise Sea Isle Boulevard by five feet in a $9 million project as part of a response to tidal flooding, especially keeping sea-level rise in mind.
There still are problem areas that are especially dangerous because they can affect major evacuation routes. One of those, the Black Horse Pike in the West Atlantic City section of Egg Harbor Township, floods almost about once a month due to high lunar tides. The state is working on a new project in another attempt to fix that problem, but construction is still some time off, Lambert said.
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