Plaquemines Parish sits on a 100-mile long spit of land that juts out into the Gulf Mexico like the barb on the head of a Louisiana brown shrimp. In just the past few years, it’s been battered by three hurricanes and the worst oil spill in US history.
One of the things that makes Plaquemines predicament so bad, is that it’s both sinking into the Gulf of Mexico and washing away due to coastal erosion. It’s not just Plaquemines suffering though; between 1932 and 2010 Louisiana lost 1,883 square miles of land. This is roughly an area the size of the state of Delaware. It continues to lose approximately one football field of land every hour.
Bob Marshall, environmental reporter for The Lens NOLA, explains the dire situation for Plaquemines Parish.
Louisiana’s politicians have known about the problem for decades but done little to fix it. With much fanfare, in 2012 the state released the 2012 Coastal Master Plan , in that plan was a never-before-tried solution for rebuilding the coastal marshes: Large-scale sediment diversions.
These large diversion projects attempt to mimic a natural land-building process, which prior to the construction of levees in 1882, was an almost annual occurrence in south Louisiana.
These diversions caused quite a stir in the fishing communities in Plaquemines parish, where 24 of them are planned. To understand why people were so opposed to them, you need a little biology lesson.
One of the main industries in Plaquemines parish is commercial fishing. This includes both fish and oysters. The marshes in upper Plaquemines are mostly saltwater, and the marshes in lower Plaquemines are more brackish, a mix of saltwater and freshwater. These brackish marshes are home to a variety of species of fish, species common to both freshwater and saltwater.
When the diversions go in place, they will pump huge quantities of freshwater into the saltwater and brackish marshes, making the salinity level of the water drop by quite a bit. This isn’t a problem for the fishermen, they can move with the water. For oyster fishermen it’s another matter entirely.
Oysters grow in place, they don’t move. Oyster fisherman lease public land, at a cost of $2/acre, and they need a very specific salinity level[pdf] for oysters to grow, typically about two percent. When these diversions start pumping a massive influx of freshwater into the marshes that are home to these oysters, the salinity levels will be too low for them to survive.
Mark Schleifstein, environmental reporter for the Times-Picayune and NOLA.com, explains how earlier diversion projects have had this same effect and led to a lawsuit against the state by the oyster fisherman.
The parish presidents in both Plaquemines and St. Bernard have come out against the diversion projects arguing they could be economically devastating to an area that has already lost so much.
Plaquemines Parish Council President, Byron Marinovich, spoke with me about the diversions
One plan proposed by the oyster fisherman is dredging sediment from the bottom of the river and pumping that sediment into the marshes and building land that way. It’s a plan that has proven effective at building land before.
David Muth, Director for the Mississippi River Delta Restoration Program for the National Wildlife Federation, said that this was an inefficient way to build land. Muth explained, “The Mississippi River carries a tremendous amount of sediment and 80 percent of it is in suspension, all the time. That’s why the Mississippi is brown and muddy.”
“To give up four-fifths of the sediment that the river could deliver to the delta is insane. If you have a disappearing coastline, if the delta is collapsing, if the whole system is going to become the Gulf of Mexico, why would you give up 80 percent of the potential land building? It doesn’t make any sense, and it’s not sustainable,” said Muth.
Captain Ryan Lambert, owner of Cajun Fishing Adventures, spoke with me about why he thinks this process will be ineffective, and why diversions are a better solution and will provide habitat for fish and other wildlife.
Cajun Fishing Adventures is a guide service that takes fisherman and hunters into the marshes around Buras, LA. Lambert contends that one of the reasons the wetlands on the east side of the river are so productive is because of wetlands built by natural diversions already present there.
“See all this vegetation, you got elephant ears, you got duck potatoes, you got cattail, you got the Roseaus, you got freshwater aquatics, you got peas. See all these vines, that’s wild peas growing, and then you have the buck beads. On the other side the river, none of that, none of it. No vegetation, no habitat, no grass to keep it” said Lambert.
He continued, “when the shrimp larvae come in, and the eggs, and the crabs, there is no place for the juveniles to hide; they are open to predation by everything. If there is nowhere for them to hide, you have so many less of them because everything is eating each other. There is nowhere to get out of anything. There is no grass, so if they are just floating in the bay, a redfish will eat every one of them till he bust open. You’ve got to have a habitat in order to have a fishery.”
Lambert brings up a valid point about habitat. As the state washes away, so does valuable wildlife habitat. One of Louisiana’s nicknames is “the Sportsman’s Paradise”. Increasingly one of those sports is birdwatching.
Even Captain Lambert is considering branching out into tours for birdwatchers. Plaquemines parish is home to 352 species of birds, either as resident species or as a stopping point during migration. Habitat destruction is detrimental to those birds and that activity.
According a 2006 study, the economic impact of non-consumptive fish and wildlife-associated recreation in Louisiana was over $517 million dollars, and that generated $32.3 million dollars in tax revenues for the state and cash-strapped local governments. The total economic impact of commercial fisheries to the state in 2006 was only $317 million dollars, and that was before the BP Oil spill.
Since the BP oil spill, the oyster harvest on the east side of Plaquemines is down 71percent. When you combine this with the sea-level rise Bob Marshall spoke about and the likely effect the diversions will have on the industry; the question we really need to be asking is whether it’s worth trying to save an industry that is by and large already headed for destruction.
If you would like to learn more about this issue and interact with others discussing it, follow my Twitter timeline (embedded below) where I will be curating links to diversion related tweets.