Oil and the Louisiana Coastal Wetlands

No matter how we extract energy from the landscape, we change the landscape for good or for ill, mostly for ill. I have already addressed this in two posts: A Riff on the Kaskaskia River and the Peabody River King Wildlife Management Area, about strip mining in Southwestern Illinois. Oil exploration and extraction has been devastating for the Louisiana Coast.

To understand why oil exploration and extraction from the Louisiana Coastal Wetlands has been so destructive , you have to first understand how tidal exchange nourished the wetlands before the construction of the Mississippi River levees after the Flood of 1927.

Before the levees the Mississippi, fed by winter snow melt and spring rains, washed over its banks, flushed out saltwater that crept into the marshes on fall and winter tides when the river stayed within its banks. The levees, extending to the Gulf of Mexico, broke this seasonal exchange of freshwater for saltwater. The wetlands shifted  from river-dominated systems to tidal-dominated systems and became dependent on rainwater for freshwater. Gulf tides washed saltwater into brackish and freshwater marshes.

What you must understand is freshwater flowed south from the river and saltwater washed north on tides from the Gulf of Mexico. Meandering bayous distributed the freshwater through the marshes. Marshy landbridges like the Barataria Landbridge in the Barataria Basin retarded the flow of salt water into freshwater marshes and swamps.

Louisiana has made several attempts to restore the flow of freshwater to the marshes with diversions from the river at Naomi, West Point a la Hache, and Davis Pond in the Barataria Basin west of the Mississippi and at Caernarvon in Breton Sound east of the Mississippi, but its not enough.

Bayous in the Barataria Basin

Barataria Landbridge at Bayou Rigolettes where the Natural Resources Conservation Service is installing a wall to prevent erosion of the landbridge.

The Louisiana wetlands cap a sea of oil, which was first discovered at the end of the nineteenth century. In the mid-twentieth century, oil companies obtained permits to explore and extract oil from coastal Louisiana. In doing so they dredged canals through the wetlands and threw the spoil into artificial banks–levees–that disrupted the remnants of tidal exchange.

Oil Canals off Bayou Terrebonne

Canals that ran north and south sped freshwater out of brackish and freshwater marshes and conveyed salt water in.

The spoil banks on the canals that ran east and west stopped the flow of water south altogether. Wetlands north of the levees drowned as water pooled behind the levees; wetlands south of the levees starved from inputs of freshwater, what there was of it after construction of the Mississippi levees.

From The Mississippi: “At the beginning of the twenty-first century, oil companies were paying the Federal government $5 billion dollars a year to drill along the Louisiana coast, but the State of Louisiana saw little of it. In 2003 Senator Mary Landrieu (D-Louisiana) added a provision to the pending energy bill that would funnel some of that money back to the state of coastal reconstruction. When passed and signed in August 2005, the energy bill returned $250 million annually between 2007 and 2010 to be divided up between the six eligible states: Alaska, Alabama, California, Louisiana, Mississippi, and Texas.

“Louisiana began taking proposals for use of the funds and in February 2007 issued the draft of its Louisiana Coastal Impact Assistance Plan, the blueprint for spending the $523 million the State would receive between 2007 and 2010. The plan, if approved by the U.S. Minerals Management Service, would enhance management of Mississippi River water and sediment, protect and restore critical land bridges, protect and restore barrier islands shorelines, protect interior shorelines, and conserve Louisiana’s coastal forests in its swamps and along its natural levees.”

A group of religious organizations are asking that the oil companies, beginning with ConocoPhillips, meet their obligation to restore some of the damage their exploration and extraction activities have caused in the wetlands and change the way they operate in the wetlands.

Read more about The Mississippi: How the river was formed by glacial action, how we have changed it, and how we are trying to restore it.