Published on November 20th, 2012 | by Joshua S Hill0
Storm Surge Defense Alternatives in Wake of Hurricane Sandy
In the wake of the flooding caused by Superstorm Sandy, Governor Andrew Cuomo and other officials called for the building of storm surge barriers to protect Lower Manhattan from future flooding.
But this strategy only protects one area and goes so far as to increase the damage likely in nearby regions.
“If you mitigate to protect Lower Manhattan, you increase the impact in other areas,” says Catherine Seavitt Nordenson, associate professor of landscape architecture in CCNY’s Spitzer School of Architecture.
“Everyone outside of the surge protection zone would be in jeopardy because the water doesn’t get reduced, it just goes somewhere else. It’s an environmental justice issue. You can’t just save Wall Street.”
Instead, Professor Seavitt believes that deploying a storm defence strategy that combines elements of soft infrastructure with the hardening of existing infrastructure such as the subway system, highways, and power plants is the smarter and more effective action.
Seavitt first proposed the development of soft infrastructure in a report she published in 2010 entitled “On the Water/Palisade Bay” which included restoring and enlarging wetlands, creating reefs and archipelagos of artificial islands, and seeding oyster beds.
“We wanted to show how soft infrastructure could be used to transform the coastal edge in order to create a healthier ecology and reduce the extent of storm damage,” Seavitt said. “There are things we can do besides building higher and higher seawalls everywhere. For example, if we replace a wall with a gradient edge that slopes into the water or we give the shoreline a more irregular shape there will be more room to accommodate water.”
The benefits of such actions are numerous: creating reefs and wetlands would minimize the damage caused by flooding by absorbing water and dissipating wave energy; archipelagos and artificial islands would weaken wave energy in the water column; while oysters and other molluscs would biologically filter and cleanse the water.
“Through our research we found that improving water quality and wetlands ecology would improve the area’s resiliency to storm,” she notes. “If you can absorb water in wetland areas, it has a place to go. It can percolate into the earth instead of rebounding from a seawall or overtopping a wall. We can engineer solutions to absorb water and slow its velocity. There may still be flooding, but there will be less damage.”
The cost of developing such soft-infrastructure would only run into the hundreds of millions, rather than the billions necessary to continually building higher storm walls.
Source: The City College of New York