Mud from farmland in the upper Mississippi River valley may soon be transported south to Louisiana to fill in wetlands tattered and punctured by Hurricane Katrina.
Louisiana officials want to bolster the marshes — already badly eroded before Katrina — as a barrier against potential storm surges from future hurricanes. They are in early talks with Illinois to transport by barge or pipeline large amounts of mud to the Louisiana coast.
“The material we have here is very much like what the delta was built up with,” said John Marlin, senior scientist with the Illinois Department of Natural Resources.
The biggest obstacle to the plan may be the cost of the 1,240-mile trip down the Mississippi River.
Last year, officials estimated it would cost $24,000 to bring a barge laden with 1,200 tons of sediment to Louisiana. Since then, the price tag has skyrocketed because of the jump in oil prices.
Beating the next Katrina
Scientists say the loss of the buffer-like marsh over the decades was a big factor in Katrina’s powerful storm surge, which overwhelmed the city’s levees. They say 2.7 miles of marsh knocks out 1 foot of storm surge.
Since the 1950s, more than 8,000 miles of canals have been dug for oil and gas exploration and shipping in the area, causing more than a third of coastal Louisiana’s loss of 1,900 square miles of marsh since the 1930s, experts say.
Storm surge finds its way far inland by traveling up the canals and shipping channels, most of which lead straight to levees that protect homes and businesses.
A lack of sediment is at the heart of the losing fight against hurricanes, experts say.
Before the levees were built, the Mississippi River overflowed in the spring and replenished Louisiana’s marshes and swamps with silt, sand and mud. But today the 200 million tons of sediment that come down the river flow straight into the Gulf — a wasted opportunity that rolls by the Big Easy every Mardi Gras.
“The wetlands for millennia have dealt with hurricanes and won,” said Paul Templet, a professor of environmental studies at Louisiana State University. “What’s gone wrong is that we have stopped the sediment from getting out there” to the wetlands.
The U.S. Army Corps of Engineers is studying ways to let the river run free, but large manmade diversions can take years to build and in the past have been stymied by fishermen wary of having their fishing grounds flooded. Thus, bringing mud down river by barge or pipeline could be a good alternative.
There is an additional benefit: Officials from Illinois say an agreement would result in the removal of mud that is clogging the Illinois waterways.
“Their life’s blood is to get grain to market and it’s New Orleans’ life blood to keep the port open,” said Len Bahr, director of the Louisiana governor’s applied coastal science program.
Louisiana environmental officials are also thinking of building up the marshes by recycling tree limbs and the timber from smashed wood homes.
The debris could be bundled to create fences along the shore that would slow down the wave action that gnaws at the coast. They also could trap sediment. It’s not a new idea — it’s been a wintertime ritual in recent years for New Orleanians to see their old Christmas trees strapped together into brush fences and laid out in the marshes.
Building up coastal reefs also would help weaken potential future storm surge and officials are considering grinding up the estimated 50,000 fiberglass boats destroyed by Katrina and mixing them with cement to create artificial reefs.
“We’re exploring all sorts of options for waste,” said Chuck Brown, an assistant secretary at Department of Environmental Quality.
However, Darryl Malek-Wiley, of the local Sierra Club chapter warned: “We have to make sure we’re not putting toxins into the Gulf.”