November 15, 2013
CLEMSON — Clemson University and Georgia Tech may compete on the football field, but researchers from the two institutions are working together and have developed a new approach for protecting coastal areas from flooding, which could be used to safeguard major metropolitan areas.
“Elevation is the key to reliable flood protection. High ground is safe, while low-lying ground will always be vulnerable,” said Lawrence Murdoch, professor in Clemson’s environmental engineering and earth sciences department. “Barriers are currently the only method in routine use for flood protection, but lessons from hurricane Katrina and Superstorm Sandy showed that low-lying regions are devastated when levees fail.”
The researchers reference Galveston, Texas, which was raised by several meters after being nearly destroyed by a hurricane in 1900. The extra meters of elevation have protected Galveston from severe damage during a dozen hurricanes over the last century.
The method of raising elevations used in Galveston a century ago is not possible in today’s urban infrastructure, but a viable alternative has been proposed by Murdoch and Leonid Germanovich, a professor in Georgia Tech’s School of Civil and Environmental Engineering.
This concept is called Solid Injection to Raise Ground Elevation (SIRGE). The SIRGE process was evaluated in a peer-reviewed journal, Proceedings of the Royal Society, which found that applications could be feasible in Venice, New Orleans, New York City and other areas prone to flooding.
The novel technique raises elevations by injecting sediment-laden slurry into flat-lying layers at depth beneath the city. The injection process would be repeated to create a network of overlapping layers filled with solid material. Injecting sediment over large lateral distances would cause a lasting surface uplift that is roughly equal to the thickness of injected sediment.
A program of field-testing, theoretical analysis and refinement is required to evaluate whether the technique could be an important contributor to the flood-protection arsenal.
“Most forecasts predict rising sea levels, and the frequency of large storms has increased over the last few decades, so a new method for raising ground elevations without disrupting surface infrastructure could have an important place in safeguarding the cities of the future,” said Murdoch.