Thread: With Sea Level Rising, Will Your Town be Underwater?

With Sea Level Rising, Will Your Town be Underwater?

Environment | Mon, 03/18/2013 - 6:23 am | Updated 6 days 15 hours ago
By Deborah McGuire

RIO GRANDE – With hurricanes, Nor’easters, droughts and other naturally occurring events, it seems like the people of Cape May County are in a constant state of flux when it comes to the water that surrounds us.

Now a new component has been added to the mix – rising sea levels to the tune of four millimeteres, or slightly more than one-eighth of an inch, per year. Factor that rise into the amalgam of other meteorological and geological issues that face both shore and mainland residents alike, and those four millimeters suddenly seem huge.

Scientists predict rising sea levels due to climate change and subsindence will affect the Jersey Coast over the next century, causing current low lying areas to become submerged.

As part of a project to assist municipalities and counties to prepare for rising sea levels, researchers at Rutgers University, in conjunction with the National Oceanic and Atmospheric Administration (NOAA) have developed an online mapping tool that shows a look at which parts of the state are in danger of severe flooding if the ocean and bays continue to rise as expected.

Lisa Auemueller, watershed coordinator for the Rutgers-managed Jacques Cousteau National Estuarine Research Reserve, said the impetus for creating the NJFloodMapper came from conversations between the university and municipal and county officials about the subject of climate change. “What we kept hearing was their flooding problems just keep getting worse. More and more coastal flooding kept occurring more and more frequently.” The project was started in 2009.

Auemueller said municipal officials on barrier islands noticed during super high tides, nor’easters and flooding events, more and more storm drain inlets were backing up onto roadways from the bay.

“Streets were impassable even during flooding events that didn’t rank high enough to think the roads would be flooded,” said Auemueller. “They kept seeing these consistent problems.”

According to Ken Branson, spokesman for Rutgers University, the goal of the project was to give assistance to towns and counties to prepare for rising sea level.

“That map shows where schools, hospitals, fire and police stations are in the flood zones and illustrates the vulnerabilities posed by future severe storms,” Branson stated.

“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, professor of environmental sciences and director of the Grant F. Walton Center for Remote Sensing and Spatial Analysis. “Hurricane Sandy showed us that local land-use planners and managers need access to detailed, information about what and who may lie in the path of rising sea levels – and the path of high tides and storm surges built on top of those new, higher sea levels.”

“Cape May County has some significant challenges with flooding and storms,” said Auemueller. She noted anyone using the interactive map on the website can “bump up” the sea level up to three or four feet to see the models show there will be significant challenges.”

The interactive map is based on sea level rise, not storm predictions, thereby giving the user an opportunity to define the sea level rise, ranging from the current high water mark of zero feet or a rise in one foot increments.

Auemueller said scientists project an additional foot of sea level rise to 2050 and three feet by the year 2100.

“Those are conservative numbers,” she said, “our scientists at Rutgers say there is a great likilhood that we can be above those one-foot and three-feet increments at those time frames. A lot of it has to do with melting ice sheets and the whole connectedness of our water system.”

Another significant factor affecting sea level rise in New Jersey, as well as several other areas along the Mid-Atlantic coast is subsidence, where the land sinks.

“The land is going down, but it’s going down through two different processes,” said Norbert Psuty, Professor Emeritus Institute of Marine and Coastal Sciences at Rutgers University.
Psuty said virtually all of the barrier islands are sand. “Sand is loose and it’s self-compacting. Just the weight of the sand is driving water out of the pores below it, and in the process of compacting the surface is going down.”

Another process adding to subsidence involves plate tectonics and the origin of the North American continent.

“The oceans and the continents form and reform and go through a process of evolution,” explained Psuty. “The North American plate that we’re on is being driven by convection cell that is in the earth. The convection cell is rising on the west coast of North America and going down on the east coast of North America. As it’s going down, it’s pulling the continent down with it, so we are undergoing in our area a kind of depression-type of subsidence as the East Coast is slowly moving down.”

The professor said the combination of the loose material in the barrier islands and the general downward movement of the continent, especially on the East Coast, is approximately two millimeters (one-sixteenth of an inch) per year – the same amount of sea level rise.

“The net effect is a general change in the water level of about four millimeters per year,” said Psuty. “If you look at the tide gauge at Cape May and the tide gauge at Atlantic City, they say the tide gauges are being drowned at the rate of about four millimeters per year. That four millimeters is a combination of the world’s oceans coming up and the land surface going down.”
Psuty said another factor that may be involved in subsidence is the drawdown of aquifers as communities over pump water and drawdown water so fast pore spaces are created that cannot survive, causing additional collapse and bringing the surface down more quickly.

While four millimeters per year doesn’t seem like a huge number, Psuty said looking historically at sea level over the past century, in our area sea level has risen 16 to 18 inches.

“That’s historical. We’re not predicting that. This is what happened.”

With the foot-and-a-half rise over the past 100 years, Psuty added some things have been obliterated by drowning and other things, such as roads, parcels of land and buildings are now closer to sea level.

“Obviously storms are now operating on a sea level that is 16 – 18 inches higher than it was a century ago, so the opportunity for flooding is increased.”

By using NJFloodMapper, anyone can simulate sea level rises of one foot (the rise many scientists expect in the next 50 years) to six feet. The user can see the advisory based flood elevation information recently released by the Federal Emergency Management Agency that shows what areas are vulnerable to coastal flooding and 100-year and 500-yearflood information. Maps depicting areas affected by Hurricane Sandy’s storm surge are also included. In addition, the tool allows a user to display the location of key buildings like hospitals, firehouses and schools and allows the user to enter specific addresses. The website also shows which communities are most vulnerable to the effects of sea level and flooding – not just because of their location, but because of the age and relative poverty of their people. Poverty can affect a community’s ability to prepare for storms and rebuild afterward.

The NJFloodMapper website can be found at: www.njfloodmapper.org .

With Sea Level Rising, Will Your Town be Underwater? - Cape May County Herald

It's amazing that people believe that crap.