LSU researchers find surprising erosion evidence.
One of the biggest issues facing Louisiana is the preservation of its coastal regions. Loss of coastal areas impacts hurricane safety, wildlife and fisheries, and private property. For years, conventional wisdom has held that hurricanes, oil and gas activity, and the Mississippi River levees were the principle culprits responsible for coastal erosion. Louisiana is seeking as much as $14 billion from the federal government to address the problem. A constitutional amendment is on the September 30 ballot to lock up any new federal revenue coming from offshore oil and gas activities, and current legislation in Washington is the best hope in decades for Louisiana to gain a significant amount of new federal oil and gas revenue.
It is extremely important that any funds available for coastal restoration be used in programs that will actually solve the problem. Interestingly, two different analyses from scientists at LSU are challenging the conventional wisdom about the causes of coastal erosion at a time when major funding may be forthcoming. Both of the LSU studies have created a significant amount of controversy, but both deserve to be a part of the debate about the best use of dollars to address the degradation of Louisiana’s coast.
A study recently released by the LSU Coastal Ecology Institute concludes that the Mississippi River levees’ channeling of silt away from the coastal wetlands is not as big a factor as once thought. The most shocking contention of the study is that the silt deposited beyond the mouth of the river finds its way back to the wetlands by a most unlikely agent: hurricanes. The controversial study claims that Katrina and Rita deposited 131 million tons of silt and sediment in the coastal wetlands, and 280 million more in shallow coastal waters. According to the study, this total is more than 200 times the sediment diverted into the marsh in the Caernarvon project and five times more than the marsh received annually before the lower levees were completed. If this study is even remotely correct, it has supreme significance in planning coastal restoration projects.
The other scientific study coming out of LSU is controversial as well; but it, too, deserves careful consideration when planning extremely expensive coastal restoration projects. Dr. Roy Dokka, director of the Louisiana Spatial Reference Center, has conducted high-tech research on the issue of subsidence in the coastal regions of the Gulf of Mexico. There is no doubt that the land in many areas of the Gulf Coast is sinking, sometimes dramatically. Dokka’s research is interesting for two reasons. His measurements indicate that subsidence in Louisiana’s coastal regions most susceptible to hurricane damage is more severe than measured by historic indicators.
Levees themselves, according to Dokka, are not as high in many areas as the Corps of Engineers believes them to be. Dokka’s findings depart from conventional wisdom in that he identifies subsidence as the major cause. His thesis is that the sedimentation load of the river over the course of centuries has, by its sheer weight, depressed the earth beneath it over a wide region. This theory clashes with the view held by others that oil and gas extraction is the major cause of the surface of the earth sinking.
These two schools of scientific thought emanating from LSU definitely have their critics. Considering, however, how important it is to get a proper solution to the coastal erosion problem, the information in those studies deserve a high level of consideration. If billions of dollars are spent getting it wrong, no more billions will likely be coming from Washington to try again.