Stevens Davidson Laboratory Researchers Evaluate Flood Wall Invention to Protect Coastal Cities from Tidal Surges
What if, within a few days of a severe storm being forecasted, Hoboken could be surrounded by a tremendously powerful retractable wall which would protect the entire city from tidal flooding from the Hudson River?
In the aftermath of Hurricane Sandy, coastal and ocean engineering researchers at the Davidson Laboratory/Center for Maritime Systems (DL/CMS) at Stevens are evaluating the durability of such a system in the university’s famed wave tank at the Davidson Laboratory. Using its state-of-the-art high speed towing wave tank, the researchers hope to uncover the effectiveness of the flood wall invention in mitigating the dangerous effects of extreme weather and safeguarding coastal communities.
The flood wall invention is a product from RSA Protective Technologies, which specializes in counterterrorist perimeter security protection for iconic buildings such as the United Nations, Citigroup’s and Prudential’s headquarters, and the Barclays Center. In partnership with consulting engineering firm Mueser Rutledge – which has led many high-profile waterfront construction projects including Hoboken Terminal, the World Trade Center and Battery Park – RSA hopes to market its flood wall system to Hoboken and other areas of New Jersey and New York as the region investigates effective ways to secure itself in a changing climate.
RSA’s flood wall invention consists of sturdy, half-ton bases which would be permanently built into a city’s infrastructure at low elevations near the water line. It also includes 20 ft. long, 4 ft. tall panels, which – as a storm approaches – could be quickly installed into the bases using trained crews, forklifts and other heavy equipment. Rubber gaskets seal the panels to restrain water, and other additions can be used to fit the panels around curves and deal with changes in grade and terrain.
According to RSA Operations Officer Bill Belinski, the beauty of the flood wall invention is that it is non-permanent, easily assembled, adaptable to an area’s natural topology, and unobtrusive.
“Our flood wall system gives the ability to re-grade a city very quickly within one or two days’ time,” Belinski said. “On an ordinary day, it doesn’t restrict people from seeing, accessing and enjoying the water and the views they love.”
Building off RSA’s patented “bollard” system technology, which can withstand the force of a 15,000 lb. truck ramming into it at 50 mph, the flood wall system is also built to resist tremendous lateral forces from waves and surge.
Stevens’ role in the partnership is to evaluate the robustness, strength and durability of the flood wall invention based on complex testing, data collection and analysis. Led by DL/CMS Director Alan Blumberg, the researchers will construct a flood wall model in its wave testing tank and then run a gauntlet of experiments to understand how the wall withstands various forces.
They will look at the impacts of waves at different amplitudes and frequencies, how high the wall will need to be to prevent waves from breaking overtop of it, whether the wall could resist a ship or vessel crashing into it, and the impacts of the wall on neighboring cities – i.e. where excess water stopped by the wall will ultimately end up.
“Our scale modeling analysis will ultimately ensure the flood wall is robust enough to withstand breaking waves and any powerful surge. The analysis will also investigate how to minimize unintended damage to surrounding areas from blocked water,” said Blumberg.
The genesis of RSA’s flood wall invention is the growing recognition by scientists, engineers and policymakers that climate change will likely bring destructive “100 year storms” and other extreme weather events ever more frequently while simultaneously causing rising sea levels, which will threaten to more regularly flood low-lying, heavily-populated urban areas. As the ensuing effects of Sandy proved – from destroyed homes to emergency evacuations to transportation system failures to a major economic slowdown – a second coastal disaster of that magnitude would be massively costly to life, limb and property, and the region cannot simply rebuild the existing infrastructure that was lost in the first storm.
RSA and Mueser Rutledge estimate that the engineering, fabrication and delivery of the flood wall invention would cost a city approximately $15 million per mile of coastline. More costs would incur for panel storage and maintenance, as well as training and deployment of installation crews. In addition, they recommend the flood wall as just one part of an overall system, including pumps that would protect against excessive rain and sewage system blockages which would prevent flooding from underground.
Although undoubtedly a costly undertaking for any municipality or region, Blumberg feels that after comprehensive testing and cost-benefit analysis, the flood wall may prove to be an excellent return on investment.
“Cities are going to have to answer a critical question: ‘What do we want to protect ourselves from – the 100 year storm or the 10,000 year storm?” Blumberg said. “In my opinion, storms of the future will be more frequent and more intense. So, when you compare the cost of the flood wall system to the costs of remediation after a storm or the costs of other storm protection alternatives, it no longer seems like such a large investment.”
Photo caption: Federal, state and local officials join representatives from RSA, Meuser Rutledge and Stevens for a presentation on the flood wall project. Pictured are Rick Ellman of Mueser Rutledge, Bill Belinski and Alex Kravecas of RSA, Carolyn Fefferman of Senator Menendez’ office, Matt Dikovics of Senator Lautenberg’s office, Rich Wolff and Fred Pocci of North Hudson Sewage Authority, Mitch Erickson of the U.S. Department of Homeland Security, Dave Hafner and Jesse Ottesen of Weeks Marine, and Alan Blumberg and Jon Miller of Stevens.
Flood wall photos property of RSA Protective Technologies, LLC.©