Louisiana : Nurturing Nature
Louisiana has lost about a third of its 3.2 million acres of wetlands since 1930, but the state is working hard to turn the tide.
LOST LAKE, LA.—A handsome stretch of marsh rises up in the distance, ringed by a levee just beginning to green up with spring foliage. To an untrained eye, this 1,100-plus-acre sprawl might seem unremarkable—except that it's brand new.
It was completed in January at a cost of $36 million, incorporating a technique known as a slurry-sludge pipeline to pump millions of cubic feet of sediments from the bottom of Lost Lake to rebuild the wetland to a level about 1.25 feet above mean high tide.
It is being planted with native vegetation and is held together with more than 300,000-linear feet of man-made levees and interspersed with winding, man-made tidal channels that integrate it into the natural tidal cycle. Gated weirs on an interconnecting bayou to the west will allow operators to seasonally steer replenishing, silt-rich fresh water to the new marshes to keep them healthy—replicating the natural cycle that built this delta in the first place.
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The project, about 20 miles southwest of the seafood and oil port town of Houma in Terrebonne Parish, was financed by a mix of federal and state dollars and comes not too soon for an area that sits in the epicenter of Louisiana's coastal subsidence. Known as the Barataria-Terrebonne Basin, the coastal marshes between the Mississippi River on the east and the Atchafalaya River on the West are disappearing at a rate faster than any other part of the state's coastal plain.
"Hydraulic dredging is expensive but it's fast and effective and definitely one of the tools we need if we're going to turn the tide and sustain our coast," says Simone Theriot Maloz, executive director of Restore or Retreat, a Thibodaux, La.-based grassroots organization that lobbies for coastal restoration efforts. "We like the momentum of this and we need to keep it going because our situation is so dire and stark that we have a long way to go."
Louisiana, its delta for decades starved for silt by the channelization of the Mississippi and its marshes opened to salt water intrusion by massive channelization for oil and gas development, has lost about a third of its 3.2 million acres of wetlands since 1930 and they continue to erode at a rate of about 15,000 acres a year. Sea-level rise and the compaction of the coastal plain's underlying geology are also factors in the state's marsh collapse. But the cries of despair of a decade ago have finally turned to guarded expressions of optimism as the Lost Lake Restoration and hundreds of projects like it begin to ever so slowly turn back the march of subsidence.
Since work began in earnest in 2007, the state's Coastal Restoration and Protection Agency (CPRA), created by the Louisiana legislature in 2005, estimates that it has rebuilt more than 46,000 acres of marsh, restored 60 miles of barrier islands and beach fronts and in the process pumped and dredged more than 150 million cubic feet of sand and fill. Moreover, projects like Lost Lake, and a $200 million, 14-mile-long beach restoration in neighboring Lafourche Parish completed in 2016, are more important than their parts, says Maloz, because they represent a strategic plan to knit back together marshes and beaches in a way that slows or stops further upland erosion.
"We can't rebuild everything, but if we do things in a smart manner we can magnify the impact of the projects we complete," says State Sen. Norby Chabert of Houma, who sits on the Louisiana Senate's coastal restoration committee.
The fate of Louisiana's coast isn't just a Louisiana problem. The state holds 40 percent of America's remaining wetlands and is a critical annual stop over for millions of migratory birds. Its annual commercial seafood harvest is second only to Alaska's. As a working coast, the Louisiana estuary shelters $150 billion in critical oil field infrastructure. About 18% of the nation's oil production and 24% of its natural gas production is processed or transported through coastal Louisiana.
One difference is there is now money to do this. Counting state and federal recovery dollars that flowed in after Hurricane Katrina in 2005, fines and settlements from the 2010 BP Deepwater Horizon oil spill and Louisiana's share of offshore oil revenues that have been dedicated to coastal restoration, the state has raised about $21 billion.
About two thirds of that has gone to hurricane-proofing New Orleans with massive levees and a sophisticated pumping system as well as important restoration elements, like the sealing off of the Mississippi River Gulf Outlet, a navigation channel blamed for destroying thousands of acres of freshwater marshes and swamps by allowing massive intrusions of killer salt-water tides.
That $21 billion is still short of the $50 billion that the state estimates it needs to complete a 50-year master restoration plan. Still, Chabert and others are happy with the restoration spending momentum though the senator has urged CPRA to pick up the pace. For the fiscal year starting July 1, CPRA has earmarked $748 million toward 108 projects, 58 of which will begin construction with the remainder going into planning, engineering and design. "We've been building nonstop since we began implementing projects in 2007," a CPRA spokesman says.
One encouraging sign is that doubts about some measures, like the longevity and resilience of barrier island restoration, are being allayed by systematic studies of previous restorations. One CPRA report by CPRA coastal scientist Darren Lee notes, for example, that a 20-year monitoring of the restoration of the historic Isles Dernieres chain of barrier islands off the coast of Terrebonne Parish "did not find the land loss we expected."
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