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Regaining Ground: In aftermath of Katrina and Rita, scientists make case for coastal recovery balancing ecology with economy

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Charles Groat has spent plenty of time during the last few decades thinking about the consequences of a hurricane slamming into the Gulf Coast. The one-time director of both the U.S. Geological Survey (USGS) and Louisiana Geological Survey is part of a group of scientists who for years recognized that New Orleans and other towns were dangerously vulnerable to a major storm.

In 2001, when Groat was the USGS director, he said that unless coastal development slowed and ecological restoration kicked into gear New Orleans “will likely be on the verge of extinction” within 100 years. Hurricane Katrina was just a little ahead of schedule—on a geologic time scale—but it validated the analysis of Groat and others that the loss of natural buffers like wetlands, marshes and barrier islands had left the coastline at risk.

Charles Groat
Dr. Charles Groat, former director of the U.S. Geological Survey and current professor at the Jackson School of Geosciences, says now is the time for scientists to make their voices heard on the best plans for the Gulf Coast.

In the aftermath of hurricanes Katrina and Rita, the scientific community may finally have policymakers’ attention. Groat, now director of the Center for International Energy and Environmental Policy at the Jackson School of Geosciences (where he is also a chaired professor and director of the Energy and Mineral Resources graduate program), is one of the more prominent national voices calling for a restoration effort that will balance the region’s economic and social needs with its environmental conditions.

Groat says there are a number of related factors, natural and human, that have amplified hazards. Land subsidence and sea-level rise are geophysical processes occurring since the last ice age. But oil and gas development in the gulf may also accelerate subsidence as industry removes fossil fuels. Residential and commercial growth along the coastline has also sped up the effects of erosion and saltwater intrusion and contributed to a rising sea level by developing or removing wetlands, marshes and barrier islands.

The resulting changes to the natural landscape during the last century have been considerable. Below-sea-level New Orleans sinks three feet every 100 years, a rate eight times greater than the worldwide average. In the last five decades, the entire Louisiana coast has lost 24 square miles, or about 16,000 acres, of wetlands each year due to development.

This suite of factors “makes New Orleans more vulnerable to sea level rise and not just hurricanes,” says Groat. The everyday benefits of these natural features are particularly important but Groat and others fear they’re overlooked or underestimated, especially after the hurricanes. As politicians consider a restoration plan and allocate money, Groat believes the Jackson School’s Center for International Energy and Environmental Policy has a role to play in helping policymakers and the public recognize, understand and restore these coastal geophysical processes.

Communicating the science

Satellite views of Louisiana's wetlands before and after Hurricane Katrina
Satellite views of Louisiana’s wetlands before and after Hurricane Katrina. Source: NASA MODIS. The images, which reveal extensive flooding post-Katrina, illustrate how coastal wetlands protect inland regions from destructive storm surges. Without its wetlands, Louisiana would have suffered far worse damage during Katrina as the storm surge and flooding penetrated further inland. See larger images with explanation at Yubanet.

“The challenge for the scientific community,” wrote Groat in a Sept. 20, 2005, column for the geoscience weekly EOS, “is to be organized, reasonable in its expectations, effective in its communications and persistent in engaging those responsible for [the] next steps in the recovery and rebuilding of New Orleans and affected Gulf Coast areas.”

Groat’s comments in EOS were “right on the mark,” says Robert Twilley, director of Louisiana State University’s Wetland Biogeochemistry Institute. Twilley is working through the Coastal Louisiana Ecosystem Assessment and Restoration approach to link the recovery of social and environmental systems and “calibrate” restoration efforts accordingly. This is exactly the challenge Groat was writing about.

If restoration just focuses on rebuilding New Orleans and fortifying its levees, Groat continues, the larger ecosystem will suffer and future floods will be even more severe. Levees don’t decrease storm surges. Beach nourishment projects—where sand is pumped onto disappearing coasts and dunes—don’t stem erosion. Even though the hurricanes’ effects may have confirmed geoscientists’ theories, the emotional response to the destruction of New Orleans could direct recovery to the further detriment of the environment.

“I think the biggest issue around coastal restoration in Louisiana is the scope or magnitude,” says Groat.

Twilley agrees that restoration based primarily around bigger and better engineering fixes would cause more problems than it would solve, but he worries that the present debate over recovery is pitting wetlands versus levees. While environmental degradation happened over 50 or so years, social degradation in New Orleans unfolded in just 24 hours and the public is rightly sympathetic with the people of the Gulf.

But Twilley says the states and Congress should heed Groat’s message and look at big-picture recovery for people and the environment.

“That’s very problematic now because not everyone buys that paradigm” that restoration can benefit both ecological and economic systems, adds Twilley.

Making the case in Texas

“You can make the argument [for ecological restoration] economically,” says Jim Gibeaut of the Bureau of Economic Geology in Texas. He says environmental restoration can mitigate damage to oil and gas infrastructure, help protect fisheries and the seafood industry by creating nursery habitat and diminish future storm surges. One study has indicated that for every square mile of wetland that is restored, the storm surge in adjacent inland areas is reduced by one foot.

Jim Gibeaut
Dr. Jim Gibeaut, coastal research specialist at the Jackson School’s Bureau of Economic Geology, believes the economic case for environmentally sound coastal policies is compelling and deserves more attention.

Gibeaut, who studies the Texas coast, says coastal development in Texas has been a little more recent than in Louisiana, but the same factors and risks are at work.

“The Upper Texas coast has been eroding over the last hundred years and there’s also been marsh-wetland loss,” he says.

Cities like Galveston, which sits on a large barrier island, Beaumont and Houston are much more susceptible to flooding from a storm than they were 100 years ago, adds Gibeaut.

“The Texas coast, like the Mississippi Delta,” says Gibeaut, “is set up to be quite the catastrophe.”

If Hurricane Rita had followed forecasters’ projected course and maintained its peak intensity, Galveston would have been entirely inundated. (View LiDAR and satellites featurette for more information and images.) The difference between New Orleans and Galveston is that Galveston is above sea level and could drain naturally. Only one-third of the island relies on a seawall for protection.

As a coastal management specialist, Gibeaut points out that the geophysical elements of a hurricane that tend to cause people the most concern—fierce winds, huge waves and storm surges—are not actually a “catastrophe” for wetlands and marshes because they decrease salinity, improve water quality and create fishery habitat. One implication is that public policy should focus on preserving the beneficial, natural functions of hurricanes while protecting lives and property.

Eye for the Eyes

How Texas researchers use LiDAR
and satellites to visualize storm damage

Sequence of images showing impact on the Galveston region of hypothetical storm surges varying in intensity from 4.5 to 19.0 feet
Sequence of images showing impact on the Galveston region of hypothetical storm surges varying in intensity from 4.5 to 19.0 feet
Sequence of images showing impact on the Galveston region of hypothetical storm surges varying in intensity from 4.5 to 19.0 feet

Long-time Gulf Coast residents have typically reacted to hurricane forecasts like sightings of alligators in their backyards: They might not walk outside but they probably aren’t going to abandon their homes either.

Hurricanes Katrina and Rita may have changed all that. In Texas, residents were particularly aware of Rita’s potential for danger thanks in part to visualizations created by the Center for Space Research at The University of Texas at Austin, drawing on a range of data including surveys from the university’s Bureau of Economic Geology.

Continue reading the LiDAR and satellites featurette and view series of images showing impact on the Galveston region of hypothetical storm surges varying in intensity from 4.5 to 19.0 feet.

Will the recent storms reshape Texas’ approach to coastal management? Gibeaut isn’t convinced that Katrina and Rita will lead to drastic changes in land-use planning and the reliance on stopgap measures, like beach nourishment, “but I also see more attention paid to the idea that maybe we shouldn’t be developing those highly susceptible areas.”

The challenge for geoscientists

Researchers within the Jackson School and its Center for International Energy and Environmental Policy will continue to support such scientifically prudent ideas, and encourage local citizens and politicians to look beyond just preventing damage from a Category 5 storm.

Groat and colleagues like LSU’s Twilley point to the Coast 2050 Initiative and the Louisiana Coastal Area ecosystem restoration plan as a good place to start. Released last November, the programs offer a blueprint for system-wide restoration. Measures include connecting the Mississippi River with its delta and removing some canals and manmade structures that impede the protection of natural features. But these projects require $14 billion from Congress for coastal restoration of wetlands, marshes and barrier islands in addition to $12 billion to shore up levees.

The hefty price tag is a tough sell, but Groat and others recognize that the Gulf Coast will get one shot at a recovery package. The area and its residents will then have to live with the priorities that are set.

“The scientific community needs to step up and bring some muscle,” says Groat, “because they’re the ones that will make the case” for ecological restoration.

BY Joshua Zaffos

PHOTOS of Dr. Groat and Dr. Gibeaut: Christina Murrey

Banner image of coastal wetlands: NOAA

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  Updated 24 April 2006
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