Year by year, wetlands near the mouth of the Mississippi River grow smaller and smaller. Those unfamiliar with the vast habitat loss that’s been taking place for nearly a century are shocked when they learn just how big the problem is.
“About 12 square miles of wetland habitat loss occurs each year,” said Larry Reynolds, waterfowl program manager for the Louisiana Department of Wildlife and Fisheries.
Since the 1930s, nearly 1,900 square miles, or 1.2 million acres, of wetland habitat has been destroyed. That’s equivalent to the state of Rhode Island disappearing.
What’s even more shocking is that the habitat loss isn’t just due to natural disasters or oil spills. Much of it is caused by the dredging of sediment out of the Mississippi River and dumping it where it can’t be used to rebuild wetlands.
One thing’s for sure: The extensive habitat loss is slowly choking the life out of many waterfowl.
“Over 10 million waterfowl either winter or stop over here on their way to their wintering grounds,” explained Ben Weber, national sportsman’s outreach coordinator for Vanishing Paradise (www.vanishingparadise.org), a coalition of several conservation groups. “If we’re not good conservation stewards down here, then the duck and geese populations suffer and won’t be as strong as they need to be when they head north next spring.”
What’s happening at the mouth of the Mississippi affects all waterfowl hunters, so it’s time we all take notice.
An Area in Peril
Located where the muddy waters of the Mississippi connect with the Gulf of Mexico, the Mississippi River Delta (or Bird’s Foot Delta) is one of the nation’s most important ecosystems for fish and wildlife. The delta’s wetlands, cypress forests and barrier islands gradually formed over thousands of years by the shifting course of the Mississippi River and its annual floods.
The U.S. Army Corps of Engineers (USACE) is charged by Congress with preventing flooding in the region. To do so, the USACE maintains a litany of levees running from the mouth of the Mississippi 100 miles upstream. The levees stop nutrient-rich sediment from reaching wetlands, which are constantly eroding.
The USACE is also tasked with keeping the mouth of Mississippi open for maritime commerce. New Orleans, the second-busiest port in the world, is an invaluable gateway to North America. Losing the waterway would spell economic disaster. The Port of New Orleans estimates that a shutdown would cost the U.S. economy $300 million a day.
To keep the waterway open, a channel 700 feet wide and 45 feet deep must be constantly dredged, removing sediment, silt and sand out of the river.
“When we talk about the navigation industry and dredging at the mouth of the Mississippi River, we mainly focus on Southwest Pass,” explained Weber. “This is the main navigation channel used by the navigation industry and international sea-going vessels, and therefore the focal point of dredging activity and expenditures.”
Dredging the waterway takes enormous effort and beaucoup bucks. According to USACE records, in 2010, 17,738,108 cubic yards (Yd3) of sediment was dredged out of Southwest Pass, at a cost of more than $50 million. Between 1997 and 2010, Congress spent $370 million dredging the pass.
Almost none of the sediment removed is used to rebuild shrinking wetlands. Sediment dredged upstream is dumped at disposal sites, while sediment removed at the mouth of the river is actually put on a barge, hauled past the Continental Shelf and dumped into the Gulf.
To be fair, the USACE does some wetland restoration projects (less than 500 acres a year) and isn’t given unlimited funding to rebuild bogs and marshes. But Chris Macaluso, coastal outreach coordinator for the Louisiana Wildlife Federation, says the USACE shouldn’t be let off the hook.
“The Army Corps claims that they dispose of the sediment in the least expensive way, but if you look at the cumulative effect of throwing away the sediment, that’s not the case,” Macaluso explained. “Because other federal agencies are trying to conduct wetland restoration work, and they could really use the sediment. When agencies like the U.S. Fish and Wildlife Service, National Oceanic and Atmospheric Administration, and the Natural Resources Conservation Service go to do a wetland restoration, they have to search for sediment deposits.”
Getting to the Nitty Gritty
Two types of dredges are used to keep the navigation channel open: hopper dredges and cutterhead dredges. A hopper dredge is a mobile vessel that excavates sediment, stores it in a holding tank and then dumps it at a predetermined location. A cutterhead dredge removes sediment, transports it through a long pipeline and deposits it elsewhere.
“Cutterhead dredges require a week of setup time and can get in the way of ships, so it’s not an efficient way to dredge sediment unless you have a sediment build-up that’s a mile or more long,” said Michelle Spraul, operations manager for the USACE. “We place dredge material in the most economical and environmentally acceptable manner possible.”
But who decides which dredging technique is the most economically and environmentally acceptable? You guessed it: the USACE.
When I pushed the Army Corps on this issue, staff members admitted that they could make more use of cutterhead dredges to rebuild wetlands.
“Cutterhead dredges could be exclusively used to maintain the Southwest Pass and discharged dredged material for coastal habitat restoration,” said USACE environmental resources specialist Edward Creef. “But the New Orleans District’s commitment to navigation to provide full channel dimensions all year round generally precludes permitting the channel to shoal to depths that would make use of cutterhead dredges productive and cost-effective.”
Despite the fact that the Mississippi Delta is disappearing at a rate of one football field every hour, nearly all of the dredged sediment is wasted. Conservationists have long known that coastal Louisiana is at the heart of waterfowl wintering grounds. The area hosts 70 percent of all the waterfowl that use the Central and Mississippi flyways for seasonal migration. As wetland habitat is reduced, the number of waterfowl that can winter in the area also goes down.
“Ducks Unlimited did a study that found between 1970 and 2007, about 3 million fewer birds were using coastal habitat along the Gulf Coast,” added Macaluso. “The primary reason is loss of wetlands.”
Loss of marsh habitat not only displaces waterfowl, but puts stress on those that still winter in the Delta.
“Some studies suggest that northern pintail are delaying spring migration by two weeks to accumulate enough energy to return north,” said Bob Dew, manager of conservation programs for Ducks Unlimited (www.ducks.org). “But we don’t know how much of a negative effect the loss of wetlands is having on waterfowl.”
While Louisiana still has excellent duck hunting statewide—hunters took 2.8 million ducks in 2011-2012—wetland destruction has ruined duck and goose hunting in some areas. According to Dew, the Southern Terrebonne Parish is a good example. In the 1970s it was a duck hunting hotspot, teeming with waterfowl. Today it’s entirely underwater.
The Pass A Loutre Wildlife Management Area is one of the finest public waterfowl hunting grounds in Louisiana. But dredging and dredge disposal are slowly choking off marshes and hampering public access to the area.
“People care so much about the BP oil spill and what it did to the waterfowl and fish down here,” said duck hunter and retired shrimper Augustus Leland. “But no one’s talking about all the wetland that’s disappearing, which is having a greater effect on ducks and geese than the oil spill did.”
One way to stem the tide of wetland destruction is large-scale sediment diversion.
“We want to see some portions of the levees strategically opened, which would allow us to mimic the natural spring cycle of flooding and rebuild wetlands,” Dew explained. “The sediment diversions would also help to reduce sediment build-up at the mouth of the Mississippi.”
Besides cutting holes in levees to allow sediment to feed starving wetlands, dredge spoils could be dumped at key locations along the Mississippi to rebuild marshes.
“When you complete a dredge spoil project, you get solid marsh, which slowly erodes to create ideal duck habitat,” Reynolds said.
This year the Louisiana Legislature passed the 2012 Coastal Master Plan, which outlines 109 high-performing projects that would result in significant wetland restoration. Not surprisingly, many of the projects directly contradict the work the USACE performs. Sadly, the plan calls for abandoning current wetland restoration projects at the mouth of the river and build a new delta 50 miles upstream.
“Our engineers have told us that the Bird’s Foot Delta isn’t sustainable because of all the destruction that’s occurred,” Reynolds explained. “In 50 years it’s going to disappear entirely.”
Nationally, the North American Wetlands Conservation Act (which is now part of the NRA-backed Sportsmen’s Act of 2012) provides funding for waterfowl conservation and wetland restoration throughout the country.
Dew notes that major policy changes must occur on a national scale to stop managing sediment as a nuisance, and instead as a resource. Macaluso agrees.
“These are supposed to be the best engineers in the world,” said Macaluso. “There’s no reason that they can’t manage the river for more than navigation and flood control. There’s no reason that there shouldn’t be an ecological aspect to managing the Mississippi River.”
The future of thousands of miles of wetlands—and the waterfowl that depend on them—hangs in the balance.