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SAVING CAJUN COUNTY: NASA SATELLITES
TO HELP PRESERVE LOUISIANA WETLANDS
by John C. Stennis Space Center
John C. Stennis Space Center,
Stennis Space Center, MS 39529-6000
HANCOCK COUNTY, Miss. — NASA scientists at Stennis Space Center are using satellites to
study the Louisiana wetlands, which are disappearing because of erosion, sinking land and rising sea- levels. The wetlands are shrinking at the speed of 65 to 91 square km (25 to 35 square miles) each year.
Much of the Louisiana wetlands, where blue-crab fisher Michael Comardelle has lived all his
life, are gone. With the wetlands goes the homeland of Comardelle's Cajun culture, as well as the
buried relics of the Native American cultures that came before it.
"That was our playground," Comardelle said. "The swamp and the bayou were right at our
doorstep. All that's eroding away so quick, so fast, it disappears in front of your eyes just about."
Human alteration of the flow of the Mississippi River is the primary culprit. Flood-control
levees along its banks prevent the river from spilling out into the surrounding wetlands. Normally,
the sediment from the river would build up the wetlands and help counter the erosion process, but
without this influx of sediment, erosion goes unchecked.
The loss is particularly worrisome because southern Louisiana is home to 40 percent of the
coastal wetlands in the 48 contiguous states. Beyond the natural functions they serve as water
purifiers, these marshes and estuaries are vital to the local fishing and tourism industries and they
provide a buffer against flooding by storm surges during hurricanes.
For example, during the recent one-two punch of Tropical Storm Isidore and the following
week's Hurricane Lili, Comardelle said that, "people who've been living there 20 or 30 years have
never seen storm surges come up that high."
To counter this loss of wetlands, the Army Corps of Engineers is spearheading an ambitious
restoration project called Coast 2050. The project will extend 50 years into the future to try to restore
20,000 square miles of wetlands. Because the project will require detailed measurements of the
landscape for planning, the Army Corps of Engineers is recruiting data from NASA satellites to help.
Dr. Marco Giardino, acting chief of the Applications Engineering Division for the Earth
Science Applications Directorate at Stennis Space Center, is helping coordinate NASA's
involvement in Coast 2050. "These swamps and marshes are often very dense and hard to get around
in, which makes them difficult to survey," he said. "By using satellite imagery from NASA's fleet of
Earth science sensors, we can supplement traditional surveying techniques and improve decision-
making."
The first target will be the hundreds of ancient Native American sites scattered throughout the
bayou. Most of these are visible only as wide mounds rising just a few feet in elevation.
How can a satellite in orbit spot a subtle mound in a vast swamp?
Satellites distinguish changes in vegetation that can be important clues about the wetland
characteristics — sunlight reflecting off a patch of swamp carries the "fingerprints" of the area's
plant life in its bands of colors, for instance. A patch of oaks will have a different color fingerprint
than a patch of reeds or grasses.
So by looking at the reflected light, the satellites that will be used (NASA's Terra, EO-1, and
Landsat 7 satellites) can map out the raised areas in a large bayou or swamp, and thus identify
candidates for archeological sites.
"The use of satellites will make it possible for archeologists to pinpoint areas to look at on the
ground without having to first undertake extensive terrestrial surveys," said Dave Davis, an
archeologist at Tulane University and a consultant for Coast 2050.
Coast 2050 hopes to preserve the habitat for thousands of species and restore the buffer
between Gulf storm surges and inland cities. They will also help save the bayou that Cajuns like
Comardelle call home, and preserve the relics of Native Americans who called it home ages ago.
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