From 1922 to 2014: The vanishing wetlands
The Mississippi Delta has been a story of disappearance. In 1922, you can see the 1922 coastline in the banner graphic to this entry outlined in grey. This was before development of the wetlands and the coastline; before the Army Corps of Engineers built their levee system after the devastating 1927 floods that extended from just south of where the Ohio and Mississippi Rivers merge to the Gulf of Mexico; before the petrochemical industry lined up refineries between Baton Rouge and New Orleans, because land was cheap and 49.1% of the residence were black and probably wouldn’t notice; and before the same industry began siphoning off oil from beneath the wetlands starting in 1926. By 1990, there were 500 or more oil and natural gas wells in the wetlands south of the Mississippi River.
These human activities resulted in 1800 or so square miles of wetland sinking beneath the encroaching ocean water between 1922 and 2014. In my banner graphic, you can see the extent of these lost wetlands in dark blue between the 1922 shoreline and the colors representing the 2014 land surface. The red areas within the wetlands represent expected losses of land from 2014 through 2054, while the green areas represent gains in land during the same period.
The View from Buras, LA
At one time, the view from Buras, LA looking to the south was rich with wetlands supporting cypress stands, marshes, and low ridges that acted to separate bodies of water into bayous and bays. Fishing camps were set up through the area for sportsmen to catch speckled trout, flounder and red snapper. The marshes were even fresh enough to attract wintering ducks. The bays produced large catches of salty oysters and large shrimp for restaurants in the French Quarter to make into tasty dishes.
Even before the 2010s, the marshes, cypress swamps and ridges separating the bayous and bays had washed away, leaving one large, open body of water. All the small bodies of water between Buras and the Gulf of Mexico were removed from nautical maps by NOAA in 2013. You can see where they once were (red dots annotated with former names) in the map below from 2009.
Areas of Wetland Growth: The Atchafalaya River and Wax Lake Canal Deltas
Yes, there are areas where wetlands are actually building, but first, a few quick words on how deltas are formed. Silt to build and maintain wetlands is brought from a river watershed to its delta and deposited, especially during flood events. What has gone wrong in the Mississippi delta is the establishment of flood control. Levees and canals have cut existing wetlands off from the river, causing them to sink because they are starved for silt. The Mississippi delta is sinking at one of the fastest rates of any coastal landscape on the planet.
One area going against the trend, however, is the Atchafalaya River delta, about 70 miles west of the Mississippi River delta. Here, unencumbered by levees, the Atchafalaya — which flows off the Mississippi north of Baton Rouge — has been building two new deltas for decades, as can be seen in the following graphic.
One of them, the Wax Lake Outlet delta, is the result of the 1942 dredging of a new canal above Morgan City, LA to mitigate flooding threats to that city. This canal removes 30 percent of the water from the Atchafalaya and shunts it straight to the Gulf, without levees and with plenty of silt.
These building deltas gave Louisianans an idea. So to save the wetlands of the Mississippi Delta, the Federal Government and the State of Louisiana formed the Coastal Protection and Restoration Authority (CPRA) in 2006. Based on the evidence from the Atchafalaya, Louisiana’s Coastal Protection and Restoration Authority (CPRA) developed a 50-year plan to reconnect the sediment-rich Mississippi to the sinking delta basins that were cut off by levees in the 1930s and deprived of silt by gas and oil company canals starting in the 1940s. Details of this plan can be seen on CPRA+’s webpage here. I’m not disciplined enough to explore the CPRA site fully, but suffice it to say a cursory look at projects in operation includes infrastructure repair; freshwater, marsh, ridge and barrier island restoration; marsh creation, storm resilience, and others.
These projects, and the $1+ billion per year allocated to them by federal, state and local government, could be a basis for hope. It appears that the knowledge and capability to make the necessary repairs exist, but is enough money being allocated?
CPRA Budget
Expenditures will be about $3.5 Billion for FYs 2023-25, but almost $2.5 Billion if for Deepwater Horizon remediation, which leaves about $1 billion over the period for wetland restoration and related projects. It appears that once the infrastructure is finished, which would include silt diversion, marsh restoration, and barrier island/marsh ridge buildup, the maintenance would be easier to budget. It also appears that there is a long term commitment being made to restore and protect the Mississippi delta. The question is and will always be, is it enough, and soon enough?
As Rachel Maddow always says, “Watch this space” (literally).