|This set of images made available Friday, Sept. 2, 2005 by the U.S. Geological Survey shows the same area of the Chandeleur Islands, approximately 100 kilometers east of New Orleans, La. The first image, taken in July 2001, shows narrow sandy beaches and adjacent overwash sandflats, low vegetated dunes, and backbarrier marshes broken by ponds and channels. The second image shows the same location on August 31, 2005, two days after Hurricane Katrina made landfall on the Louisiana and Mississippi coastline. (AP Photo/USGS, FILE)|
Chandeleur Islands said not rebuilding
CHANDELEUR ISLANDS, La. --Last year's hurricanes did so much damage to these barrier islands in Breton Sound they may disappear altogether in the not so distant future, scientists say.
Wind, waves and tides have always moved sand around the islands but they always found an equilibrium, said Mark Kulp, a University of New Orleans geologist mapping the islands.
But Hurricane Katrina was "a major event that moved volumes of sediment" that "tampered with the equilibrium," Kulp said.
Kulp said the usual sand and sediment patterns that normally rebuilt the Chandeleur Islands after big storms are not present.
Hurricanes like Camille in 1969 and Ivan in 2004 pushed sand to the rear of the islands in what is known as "overwash fans," or splays of sand in the shape of an open folding fan.
After each monster storm the island chain slowly rebuilt itself on those fans, just a little smaller than before each storm.
There's another worry: There's evidence of unprecedented landslides on the seafloor slopes on the islands' Gulf of Mexico side.
The now-deeper water might increase the size of some of the waves hitting and eroding the remnants of the islands, Kulp said.
Shea Penland, another UNO geologist mapping the islands, said a 1980s survey found the islands fairly stable "and we thought they would still be around in 300 years. Now, we are saying, maybe a decade."
The islands are part of the Breton National Wildlife Refuge, the nation's second oldest refuge.
President Theodore Roosevelt declared the islands a bird reservation because the islands' brown pelican populations were being plundered by plume hunters looking for fancy hat feathers. Raids by plume hunters had prompted Roosevelt a year before to declare Pelican Island in Florida a refuge, the first of what would become the national wildlife refuge system.
A lot has changed on the islands in the past century since it became a refuge. Once, there was a fishing settlement with a school and homes. It was destroyed by a powerful hurricane in 1915. And at one time, there were trees, and people even farmed there.
But since the late 1800s, the islands have shrunk, losing much of their surface.
Information from: The Advocate, http://www.theadvocate.com