At Point Pleasant Coast Guard Station, the rising ocean laps just below the quayside where cars are parked. At Avalon Dunes, it’s shown advancing along a bayside street lined with expensive homes. And at Double Creek Bridge south of Toms River, the waters of the Atlantic creep toward a beachfront house that’s already just yards from the regular high-tide line.
All three scenarios are depicted in photographs simulating the effects of a foot rise in sea-level on the Jersey Shore. These simulations — and others — can be seen thanks to a new online mapping tool published by Rutgers University to help local officials plan for coastal flooding in coming decades.
Some four months after Hurricane Sandy dramatically raised public concern about the power of the ocean, Rutgers officials are alerting government officials, businesses, and individuals to the likely effects of rising seas on their roads, bridges, beaches, docks, homes, and communities.
As ocean volume increase in response to rising global temperatures and melting polar ice caps, the average high-tide level around New Jersey’s coast is likely to be one foot higher than at present by 2050, according to a consensus of national and regional forecasts compiled by Rutgers.
That’s about twice as high as the global average because the mid-Atlantic coast is sinking at the same time that waters are rising, creating an especially urgent problem for low-lying areas of coastal Jersey and Delaware — where state officials have forecast up to 11 percent of the land mass could be inundated by three feet of water by 2100.
In an attempt to illustrate the practical effects of a phenomenon that may seem like a long-term abstraction, the mapping tool shows users how some locations would be affected at high tide by specific levels of sea-level rise.
The website invites users to simulate between one and six feet of sea-level rise by using a sliding scale and then to watch the impact of that manipulation on photographs of familiar locations and on local and statewide maps.
At Lake Como, a park bench some distance from the current level the water becomes a tiny island as a user adjusts the slider to three feet, a level that many climate scientists believe will be normal by the end of the century. At West Point Island Bridge near Tom’s River, a steel barrier beside a channel is submerged when the user simulates a four-foot rise in waters.
“While sea-level rise is a global phenomenon, adapting to its impacts is a local decision-making challenge that is going to require site-specific remedies,” said Richard Lathrop, a professor of environmental sciences at Rutgers. “Our goal is to spur long-range planning and adaptation measures. We see the tool as a first step for individual communities to be able to visualize potential vulnerabilities.”
The tool highlights the vulnerabilities of schools, hospitals, fire stations, and evacuation routes to different water levels.
In Cape May County, for example, the map shows schools at Avalon, Stone Harbor, and Wildwood would be submerged as the barrier islands flood beneath a three-foot rise in sea level. In Monmouth County, hospitals in Red Bank and Long Branch would be threatened by the same degree of sea-level rise, the tool indicates.
It also shows Federal Emergency Management Agency projections of what areas of New Jersey are vulnerable under so-called 100-year and 500-year flood projections, or floods so severe that they are deemed to be likely to occur only once in 100 or 500 years.
A swath of the coast from Tom’s River to Cape May and then up the Delaware Bay shore toward Philadelphia is susceptible to 100-year floods, while smaller areas on the Atlantic coast are subject to 500-year floods, according to FEMA’s projections on the mapping tool.
But the FEMA scenario is based on current sea levels and doesn’t take into account any future sea-level rise, Lathrop said. The agency, along with the National Oceanographic and Atmospheric Administration, is working on a revised model that may be published in coming months, he said.
FEMA’s flood elevations are used as baselines by the National Flood Insurance Program, which insures residents of flood-prone areas. They also govern the state’s ability to determine where development may occur in relation to those areas.
Local and county officials haven’t commented since the tool was published in early March, Lathrop said, but some were involved in its planning, which took about three years.
Lisa Auermuller, watershed coordinator for the Jacques Cousteau National Estuarine Research Reserve, which is managed by Rutgers, coordinated with local officials and sought their feedback.
“We didn’t assume that ‘if we build it, they will come,’” Auermuller said in a statement. “We listened to what they wanted, and included that in the project so we knew the finished product would be useful.”