5 Years After Katrina, Gulf Ecosystems On the Ropes

Section of the Chandeleur Islands, before and after Hurricane Katrina. The storm stripped up to 85 percent of of islands away.

(Image: © USGS)

Flying over the remote Chandeleur Islands east of New Orleans off the Louisiana coast soon after Hurricane Katrina hit, coastal scientist Abby Sallenger of the U.S. Geological Survey was struck by the extent of the devastation to the coastal landscape.

«What happened there is extraordinary,» Sallenger said. «Following the storm, all the dunes were completely destroyed. All the sand was stripped from the hawaiian islands.»

The uninhabited 19-mile-long (31-kilometer) chain was among most of the so-called barrier islands off the Louisiana coastline which were the first elements of the Gulf Coast to feel the wrath of Katrina.

The storm made landfall over southeast Louisiana on Aug. 29, 2005, as a solid Category 3 storm, with winds of 125 mph (201 kph). Storm surges of 10 feet (3 meters) socked a huge selection of miles of coastline. Southeast of New Orleans, surges up to 20 feet (6 m) crashed ashore. The city’s levees gave way to the onslaught of water, flooding the town built on sand below sea level and leaving it flooded for weeks.

A lot more than 1,800 people died because of this of Hurricane Katrina, 1,600 of these in Louisiana. The storm ripped apart a lot more than 90,000 square miles (233,100 square kilometers) of land, an area almost the size of the state of Oregon.

Five years later, scars from the storm remain noticeable on the Gulf Coast’s delicate ecosystems, including its barrier islands. Katrina’s ferocious winds and waves washed away these islands, killed vast sums of trees and transformed marshlands into giant lakes.

The destruction took place in ecosystems that were already slipping away due to unsustainable development; Katrina added fuel to the fire simply. Today these fragile features are just starting to heal. However they won’t be the same, say scientists. And they’ll be sustainable only when they may be reconnected with their lifeblood — the Mississippi River.

«We discuss restoration on a regular basis, but individuals who don’t focus on it 24/7 think we will put it back enjoy it was before,» said coastal ecologist Denise Reed of the University of New Orleans. «But it isn’t about this, it’s about which makes it better in the years ahead.»

Bare barriers

Louisiana’s Chandeleur Islands, that have been developed by river sediment, lost about 85 percent of their surface during Hurricane Katrina. What valuable habitat was left was hurt, Sallenger said.

Five years later, the Chandeleur Islands «aren’t even close» to recovering that land, leaving them susceptible to future hurricanes, Sallenger told OurAmazingPlanet.

Aerial elevation and photography maps reveal how little has changed in your community in five years. Before Katrina, the common elevation above sea level on the Chandeleur Islands was 13 feet (4 meters). That dropped to 5 feet (1.5 m) following the storm. The common elevation over the islands has increased only 8 inches (20 centimeters) since.

Pictures taken prior to the storm show the dunes and sand of the mostly healthy Chandeleur Islands. Pictures following the storm show muddy, sand-starved clumps of earth that seem to be drowning.

«It is rather sad,» Sallenger said. «It’s such a lovely, wild, remote, untouched place.»

Restoring the Chandeleur Islands is a tough sell. Seventy-five miles (121 km) from New Orleans, they are definately not people’s houses, and restoration money is normally reserved for rebuilding barrier islands that could create a genuine barrier.

For instance, two islands nearer to the mainland appear to have been rebuilt by the state beneath the Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA). A third project at East Grand Terre, 50 miles (80 km) from New Orleans, would be the largest barrier island restoration project to date, rebuilt beneath the Coastal Impact Assistance Program, at a price of $31 million.

But building these islands back up won’t guarantee their long-term survival; scientists say that if the reconstructed islands are to last, coastal engineers must reconnect them to the silt-providing Mississippi.

The barrier islands built by the Mississippi River no more get a healthy dose of sediment to create new marshland. Due to dams and other diversions of the river, sediment that could replenish the hawaiian islands is lost to the Gulf coast of florida at the average rate of 120 million tons (109 metric tons) each year, which may be the major reason the hawaiian islands are sinking and eroding slowly. Insufficient sediment is to arrive to displace what storms and tides are washing away.

«We’ve starved the machine of sediment so much that, for just about any chance at being rebuilt, we need to rebuild them,» said Chris Macaluso, spokesperson for the Louisiana Wildlife Federation, a non-profit conservation group.

Wetlands and marshes

River sediments are also the lifeblood of coastal wetlands in the Gulf. Just like the barrier islands, these wetlands were devastated by Katrina; a huge selection of square miles were lost through the storm.

«The marshlands to the east of the Mississippi Delta were really hammered,» said ecologist Harry Roberts of Louisiana State University in Baton Rouge.

A wholesome marsh acts much just like a barrier island, blocking storm surges while creating areas for fish to spawn and birds to nest also. As sediments accumulate in the wetlands, rich soil forms, and plants and other vegetation take root and keep carefully the marsh’s head above water. So when you walk on a wholesome marsh, you are walking on the roots of plants actually.

Distinguishing between your marshland damage from Hurricane Katrina and the damage from Hurricanes Rita, Ivan and Gustav (which struck within four years) is tricky. Based on the USGS, the region of wetlands lost from all storms totaled 340 square miles (881 sq. km). Katrina and Rita alone destroyed 220 square miles (570 sq. km) — a location almost 10 times how big is Manhattan.

Intense storms blow away all of the vegetation and soil from a marsh typically, leaving behind a huge body of water. Katrina was no exception.

At the White Kitchen Preserve close to the Pearl River, a floating marsh that took more than 100 years to create was «just shoved to the north as an accordion,» said Nelwyn McInnis, program manager for the north shore field office of the type Conservancy, a non-profit conservation organization. «It’s still a lake even today.»

In the Breton Sound Basin, southeast of New Orleans, Hurricane Katrina converted roughly 39 square miles (100 sq. km) of wetlands into open water. At Big Branch Marsh National Wildlife Refuge, 1,500 acres of marsh (2 square miles, 6 sq. km) was converted into a lake. A close by 200-acre (0.3-square mile, 0.8-sq. km) marsh is currently referred to as Lake Katrina.

The Mississippi Delta marshes suffered the most damage because they, just like the barrier islands, were already ailing just before the storm because their way to obtain sediment has been blocked off. Since 1900, some 1,900 square miles (4,900 sq. km) of wetlands in coastal Louisiana have already been lost — a location how big is Delaware — at rates of as high as 39 square miles (100 sq. km) each year.

Katrina accelerated the disappearance simply, making restoration even more daunting.

CWPPRA projects are slowly nursing the region back again to health. In 2008, employees started «plugging» 400 acres (0.6 square miles, 1.6 sq. km) of new marsh in Big Branch, with the purpose of creating another 1,400 acres (2.2 square miles, 5.7 sq. Plugging identifies filling the open water with sandy and muddy vegetation.

«We’re rushing nature up to get vegetation so that it won’t erode from various other storm,» said Daniel Breaux, refuge manager at Big Branch Marsh National Wildlife Refuge.

Recovery of the marshlands is not simple to measure, said University of New Orleans’ Reed. These wetlands weren’t sitting still before Katrina plus they have not been still since. Oil spills, more hurricanes and man-made levees mold the coastal wetlands constantly. The ecosystem that emerges from any rebuilding won’t be like it had been before.

«This is actually the tale of coastal Louisiana; something is happening,» Reed said in a telephone interview. «It is rather dynamic. Really what goes on is that whenever we lose a marsh, it’s gone — unless we take deliberate regenerative action.»

Tree loss

Katrina also took its toll on the Gulf Coast’s tree population, with an increase of than 320 million trees killed to the east of New Orleans through the storm, according to a 2007 study.

At White Kitchen Preserve, a flyover fourteen days following the bottomland was showed by the storm hardwood forests looking like «matchsticks laying on the floor,» said the type Conservancy’s McInnis.

Yet, there are signs these forests are bouncing — even regrowing vigorously back, said Jeffrey Chambers of Tulane University, a known person in the study team on the 2007 report. Chambers recently revisited the scholarly study site and was shocked by the brand new growth.

«It had been probably the most exhausting hikes I’ve ever been on in my own life,» Chambers said. «It’s just so hard to go through due to the incredibly dense vegetation.»

Katrina didn’t just knock down trees, though, in addition, it created a chance for invasive species to restructure the forests. Trees just like the Chinese tallow are thriving now, Chambers said, which is «an indicator of a fresh ecosystem in the making.»

Regardless of the destruction they wreak, hurricanes are portion of the natural life of a Gulf Coast forest. The forests have become up with storms hammering them once in awhile, and the storms help drive out the old trees to create method for younger ones. From destroying wildlife habitats Aside, the increased loss of forest cover could have a lasting effect on the carbon dynamics of forests, said ecologist Rattan Lal of Ohio State University.long as there were hurricanes in forests

As, trees have already been dying. For old forests just like the Amazon, however, the carbon assimilated by trees roughly balanced out the carbon released when the trees died and decomposed.

The majority of the forests hit by Katrina were relatively young because of a hundred years of logging. These forests certainly are a «slow sink,» Chambers said. They slowly pull the carbon out from the atmosphere, but quickly release it if they die.

«I’d suspect that the websites hit by Katrina are carbon sources, and their peak in carbon loss is approximately right now,» Chambers said.

If storms like Katrina are more frequent later on — as some scientists predict — plus they kill an incredible number of trees every time one hits land, the carbon release and uptake dynamic will be tipped and only carbon being lost from forests. A weakening of forests will be equal to upping emissions, Chambers said.

Restoring the forests can keep that carbon loss in balance potentially, Lal said. «We certainly cannot spend enough; they need to be restored,» Lal said. «It’s a long-term solution, tomorrow not at all something you can show.»

  • A BRIEF HISTORY of Destruction: 8 Great Hurricanes
  • Infographic: Hurricane Katrina History and Numbers
  • IMAGINE IF A Hurricane Hit New Orleans Today?

Brett Israel is an employee writer for OurAmazingPlanet, a sister site to LiveScience.

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5 Years After Katrina, Gulf Ecosystems On the Ropes