There's long been much ado about the ongoing loss of coastal wetlands in south Louisiana.
Angst about coastal issues overall increased considerably after Hurricane Katrina led to breaches in parts of the levee system protecting New Orleans.
The ensuing deluge of water was almost surreal.
Louisiana is a busy working coast, rife with oil industry pipelines, floating rigs, boats, ports, fisheries and more. Both the state and the United States in general benefit economically from activity here.
Unfortunately, the region is also a frequent target for the many hurricanes and tropical storms that enter the Gulf of Mexico.
The coastal wetlands are a buffer of sorts to storm surges and subsequent land loss, which can jeopardize flood protection infrastructure.
There has been considerable finger pointing in the effort to zero in on the culprit(s) responsible for the disappearing land.
Not surprisingly, many fingers point to the oil and gas industry with its several thousand linear miles of pipelines in the region.
The Usual Suspects
A state-proposed Coastal Master Plan designed to sustain the coastline debuted in 2012, carrying an estimated minimum price tag of $50 billion, some of which would be covered by the BP Macondo spill payout money.
Spurred by the encouragement of activist and author John Berry, the South Louisiana Flood Protection Authority East sued numerous oil companies operating in the state, claiming they bear responsibility for all of the lost land area and, therefore, the cost of restoration.
The lawsuit is currently being appealed.
The commonly held contention that the oil and gas industry is responsible for 36 percent of wetlands loss can be tied back to the publication of U.S.G.S. Open File Report 00-418 in 2000. That report titled "Process Classification of Coastal Land Loss Between 1932 and 1990 in the Mississippi River Delta Plain, Southeast Louisiana" was a map publication with minimal text. The report attributed 11 percent of land loss to direct removal by oil and gas canals and 25 percent to altered hydrology due to submergence and associated with oil and gas activity.
There was no process-based discussion of how the association of the areas of land loss was linked to the location of the oil and gas activities; it was simply an observation of the coincidence of location. In 2011, Open File Report 00-418 was replaced by U.S.G.S. Scientific Investigations Map 3164 titled “Land Area Change in Coastal Louisiana from 1932 to 2010.” The latter report removed all reference to cause, and simply provided an investigation of the patterns of land loss over time.
So the question became: What did cause the land loss?
Blame Mother Nature, specifically subsidence, say a number of experts.
Chris McLindon, deepwater exploration geologist at Lafayette-headquartered Stone Energy, has studied the subject in detail, much of the effort on his own time.
He has shared his research findings through numerous papers and presentations at professional gatherings. Recently, he appeared as a guest expert on a segment of Al Jazeera America's program focused on the 10th anniversary of Hurricane Katrina.
"Subsidence has been a topic of discussion in south Louisiana for 20 years or so," he said. "It's been in a state of flux owing to the evolution of technology to measure the rate of subsidence."
When the Levee Breaks
Katrina apparently served as a wake-up call to the scientific community.
McLindon remarked that a study conducted by noted scientists concluded that it's likely the catastrophic levee failure in New Orleans was caused by subsidence due to faulting.
"They didn't come right out and say it," he said, "but it's clear what they meant.
"They were using satellite imaging technology to measure subsidence right there," he noted. "Rates also can be measured using tidal gauges and geodetic leveling.
"Efforts to measure how much elevation benchmarks have subsided created a whole new batch of data," he added.
"I have made the case that we have been able to measure land loss since 1932 because of the earliest vintage of aerial photography we have to measure the change," McLindon said. "If we could have measured the change over the past 5,000-6,000 years, we would have measured 30,000 square miles of land loss.
"This is only the most recent manifestation of what has been a natural component of the construction of the marsh, which is the delta cycle.
"Deltas built and then were abandoned, and the abandoned delta ultimately subsided below the surface, and the entire area of the delta that may have existed 3,000 years ago has been 'lost.' All we're seeing now is a manifestation of a process that has been going on for millions of years, but we're only able to measure it over the last 80 years.
"The public is left with the impression that (the huge) figures quoted as land loss are only applicable to the last 80 years, when they actually are the most recent expression of what has been a natural process all along."
Industry Involvement
The New Orleans Geological Society (NOGS) is working on a proposal to study subsidence and the effect of geological faults on subsidence.
Rather than acquiring oil and gas company 3-D surveys, NOGS determined the best approach is to get the surveys donated to universities so that researchers could implement the effort.
"Industry has the capability to offer to other entities a much more detailed and accurate assessment tool than they have available otherwise by getting 3-D surveys into the hands of institutions and having them produce faulting and subsidence interpretations that result in a predictive model of where relative sea level rise will have the greatest impact," McLindon said.
"Successful mapping of faults and subsidence across the coast could have broad applications for infrastructure planning," he emphasized.
The initial seismic donation was a 500 square-mile 3-D in Plaquemines Parish, which went to the University of Texas at Austin, courtesy of WesternGeco.
"They mapped 28 faults and found very distinct surface expressions basically causing land loss at the surface," McLindon said. "It was a strong premise to move forward with this."
NOGS has arranged for a second donation of an industry survey to go to the Coastal Research Laboratory at the University of New Orleans.