Proposals to fill in La. canals not gaining much traction
“The scale at which the master plan is laid out, there’s no bang for your buck to go around backfilling canals in areas that are doomed in 50 years. It doesn’t fix the harm the canal and spoil bank did in the first place. I don’t think that’s what the state should be spending its money on.” David muth, state director of the National Wildlife Federation’s Louisiana Coastal Campaign
At the heart of a lawsuit against a number of oil and gas companies filed by the Southeast Louisiana Flood Protection Authority — East levee board is the question of how much damage was caused by dredging canals through Louisiana’s coastal wetlands.
But landowners have long opposed one approach to minimizing the damage: backfilling the canals.
“The people who have these canals don’t necessarily want these canals backfilled,” said Don Briggs, the Louisiana Oil and Gas Association’s president. “Some of the best spots to fish are in areas like that.”
Even as early as the 1950s, researchers had concerns about the canals, not only because of the marsh that was disturbed but also because of the spoil banks piled up along each side of the waterways. These small levees of dirt, dug from the canal channels, can impound water in certain areas while the canals let in saltwater and otherwise alter the way the landscape functions.
These indirect effects from the dredging of oil and gas canals compound the direct impact of the canal construction and are considered one of the multiple causes of coastal wetland loss in the state.
State officials, saying these were sins of the past, say the state has changed the way it allows canals to be dredged in the marsh as well as how companies have to “mitigate” or replace the marsh they damage or impact.
In addition, oil and gas canals aren’t needed as often now, thanks to directional drilling technology, Briggs said, and if a canal is needed, industry is required to mitigate any damage.
“If I use 1 acre of land over here, I’ll mitigate 5 acres somewhere else,” Briggs said.
He also said many landowners consider the canals and the spoil banks as a benefit for flood and storm-surge protection as well as a historical means of access to the marsh.
Others involved in coastal research, however, say the state continues to ignore indirect impacts the canals have had and so the required mitigation doesn’t account for the true loss.
Backfilling the canals has been proposed a number of times by scientists and in the Legislature, yet despite some initial interest from the state in the 1980s, the idea hasn’t gotten much traction.
“People were dredging canals and we knew canals were causing land loss back then, so why don’t we look at putting them back?” asked Eugene Turner, Boyd professor and Shell endowed chair in oceanography/wetland studies with the Department of Oceanography and Coastal Science at LSU.
Oliver Houck, professor of law at Tulane University Law School, became interested in oil canals after writing a piece for the Tulane Law Review in 1983. He said there were a number of reports suggesting backfilling of canals be required or at least recommended.
“There were very thorough reports on this done in the 1980s,” he said. “A lot of them were suppressed.”
There was even a report from Joel Lindsey, then administrator of the coastal management section at the Department of Natural Resources, sent to DNR Secretary Frank Simoneaux in 1983, that in part spoke in favor of backfilling canals or at least prohibiting spoil banks by instead pumping dredged material to marsh areas.
The report’s introductory letter states that more research is needed on the efficiency of the technique in different wetland types, “but we feel that this is a positive first step towards the accumulation of a scientific body of data on this subject.”
“They pulled back. They didn’t do it,” Houck said.
Several state legislators also tried to pass legislation that would require backfilling, but the idea didn’t go anywhere, he said.
“They killed it dead. They drove a stake through its heart,” Houck said. “It’s one of those great ideas that just never had a backer.”
So why the resistance?
Houck said he thinks companies or landowners with these canals didn’t favor backfilling them because that would mean admitting the canals and spoil banks were a problem.
Turner has followed up on the approximately 30 backfilled sites that he could find records of, and also designed several backfilling projects at the Barataria Preserve at Jean Lafitte National Historical Park and Preserve.
Research on the effectiveness of backfilling, although limited, has shown mixed results; it appears to work better in freshwater marsh areas. But knocking spoil banks back into the canals won’t completely fill them because organic soils reduce in volume after being exposed to air.
Some coastal areas are crisscrossed by so many canals that backfilling one canal would have little impact on the overall hydrology, or water movement, in the area.
“If you restore the hydrology, you can get marsh back,” Turner said.
Starting in the early 2000s, several projects were conducted at Jean Lafitte Park to determine how effective backfilling canals would be in restoring wetlands and re-establishing the natural flow of water through areas of the park.
David Muth, now the Louisiana state director of the National Wildlife Federation’s Louisiana Coastal Campaign but at the time the cultural and natural resource manager at the Jean Lafitte park, said about 5 miles of canals were filled.
“In 2001, we signed a cooperative agreement with Gene Turner at LSU to design and oversee a canal backfilling project,” Muth said. Researchers took two canal segments and tested different methods on each to determine how the restoration would work over time. On one canal, the spoil banks were knocked into the canal, while the other canal was filled with dirt dredged from a nearby lake.
“After five years, there weren’t dramatic differences between the two canals,” Muth said. “These projects have proven to be very cost-effective. The cost per acre is extremely low compared to other restoration measures.”
However, the practice isn’t widely used for old oil and gas canals for a number of reasons.
“It isn’t done more mainly because of opposition of landowners who want to keep the canals,” Muth said.
The canals provide access to hunting and fishing areas, and from one area of the marsh to another, and some landowners want to keep the canals open in case new oil and gas extraction techniques become available that could make an old well profitable again. In other cases, he said, landowners have used the spoil banks in their water management plans to create duck ponds or as locations for camps.
Although there have been some complaints that backfilling canals wasn’t included in the state’s master plan for coastal restoration, Muth said the master plan is at a much larger scale.
“The scale at which the master plan is laid out, there’s no bang for your buck to go around backfilling canals in areas that are doomed in 50 years,” Muth said about the $50 billion, 50-year plan the state has approved to try to halt coastal land loss. The technique of backfilling canals is appropriate for an individual landowner who wants to keep land in place while waiting for larger projects to be built in the area, he said.
“It doesn’t fix the harm the canal and spoil bank did in the first place,” he said. “I don’t think that’s what the state should be spending its money on.”
In addition, he said, backfilling is included in the master plan but in a manner that might not be obvious.
Within the larger projects included in the master plan, such as diverting sediment and water from the Mississippi River and dredging soil to build marsh, some former canals could be in the way.
“There’s no reason you can’t fill in the canals within that footprint,” Muth said.
Kyle Graham, deputy executive director of the state’s Coastal Protection and Restoration Authority, said canals do get filled in during the course of other restoration projects.
In addition, the state is looking at how to evaluate and prioritize areas where backfilling or other stabilization measures could buy some time until larger restoration projects are put in place, he said. Although details still need to be worked out, that effort could involve offering incentives to landowners or expanding current programs that fund smaller projects, some of which could include the closing in of canals.