By Will Martin
Humans have been altering wetlands for thousands of years. From draining and filling, to encroachment and pollution, to levee construction, our wetlands are far from an un-touched, “pristine” environment. For some time, wetlands were considered useless swamps however, today we are learning, or maybe relearning, the important roles wetlands serve, especially when it comes to hurricane protection.
Wetlands are coastlands’ first line of defense against storms. Once a hurricane hits land it looses steam due to the lack of warm water to fuel its movement. Therefore, by traveling over land for sometime, wetlands absorb the brunt of the storm and reduce its strength as it moves inland. However, hurricanes’ destruction in the wetlands is also a blessing in disguise. After Hurricane Katrina, researchers from Louisiana State University found that storms carry large amounts of silt and other inorganic sediments that help further the growth of wetlands. Along with that, wetlands mitigate storm surge that, if not blocked, can lead to intense flooding. It is estimated that around 2.7 miles of wetland can negate one foot of storm surge.
There are three primary causes of the disappearance we are witnessing of the Mississippi Delta: subsidence, erosion, and continental warping. The most prominent is the subsidence caused by the levees surrounding the Mississippi River. Every year, this mighty river deposits 450 billion pounds of sediment. This sediment is intended by nature to replenish the river delta. However, the levees’ blockage of annual floods no longer negates the delta’s sink. Therefore, the silt that created some of the most fertile farmland in North America is now deposited off the edge of the North American continental shelf-a drop so extreme that the silt is lost at sea. The result is a drastically shrinking buffer between Gulf Coast states and hurricanes —at a rate of nearly eight millimeters a year in the New Orleans area.
The biggest dilemma is how to stop the disappearance of our wetlands. We can’t tear down the levees-that would entail displacing hundreds of thousands of local residents. We can’t simulate flooding by trucking sediment in-our urbanization would leave most if not all of this loose sediment prone to erosion. We cannot add to the subsiding parts of the delta.
However, plans are in the making to divert up to 200,000 cubic feet of the Mississippi River down a 60-mile canal to contribute to the existing march and hopefully create two fresh deltas in Terrebonne and Barataria bays. This channel would simulate pre-anthropogenic processes, depositing rich sediment and reclaiming some of the land lost (with no intervention we would lose a land area roughly the size of Delaware between 2010 and 2050). This potential project is estimated to cost $14 billion, and in our current economy, that much money is quite hard to come by-especially since we have yet to see any shipping industries be affected by our shrinking wetlands.
Another drawback of this potential restoration program-called Coast 2050-is it would leave the Port of South Louisiana, the United States’ largest port by volume, useless. There would not be enough water remaining in the Mississippi to allow for large oceangoing ships to pass through. These ports are so valuable they’re essentially monopolistic, so it seems unrealistic to estrange any port-especially the biggest one-for any period of time. Thus, there is a silver lining in the BP oil spill.
80 percent of the Clean Water Act penalties imposed on British Petroleum will be allotted to restoration efforts in the five states most affected by the oil spill: Louisiana, Texas, Mississippi, Alabama, and Florida. For Louisiana, this means a source of funding and therefore fresh hope for Coast 2050. If a precisely-calculated canal is utilized, Coast 2050 could very well present itself to be an ideal model for combating the loss of our wetlands, and thus the replenishing of wetlands on a national and eventually global scale.