First, oil destroyed the wetlands from the inside: Since the middle of the last century oil companies have dredged straight-as-an-arrow canals and thrown aside the spoil to create spoil banks that lace the Louisiana wetlands. Should a canal go east and west water flowing south, it always flows south in Louisiana, it pooled behind the the spoil bank, think levee, drowning the wetlands behind it. The wetlands in front of it starved for in puts of freshwater. Should a canal go north and south it sped freshwater out of the wetlands and funneled saltwater into the brackish and fresh marshes. The State of Louisiana estimates that the oil industry and its canals have led to the loss of 1/3 of the 2,100 square miles of land lost along the Louisiana coast. I explained this much better in a January 28, 2010 post.
Now, oil is attacking the wetlands from the outside: The BP oil gusher is headed to the barrier islands that front the Barataria Basin west of the Mississippi. The westward-trending longshore currents in the Gulf of Mexico could carry the oil as far west as Point au Fer Island, just short of Atchafalaya Bay. LaCoastPost, which does daily updates on what is going on with the oil gusher, has a post about Gov. Bobby Jindal’s efforts to rebuild the barrier islands fast, now, and have BP pay the $500 million cost.
The barrier islands have always been the first line of defense against hurricanes. Why not the first line of defense against oil? Beefing up the barrier islands could save BP the cost of cleaning up the wetlands, which could add up to billions.
In the meanwhile Louisiana has opened all its diversion structures–Davis Pond, the Naomi Siphon, the West Point a la Hache siphon along the Mississippi that flush freshwater into the Barataria Basin and the Caernarvon structure at English Turn along the Mississippi to flush freshwater into Breton Sound. And they are considering opening the old, (1924) Bohemia siphon way down, past the end of the main line levee, to flush still more freshwater into Breton Sound.
Before the construction of the main line levee and before the construction of oil canals that lace the Louisiana wetlands, freshwater, spilling over from the flooded Mississippi, flushed out salt water the washed into the wetlands on fall and winter tides. So if freshwater can flush out salt water, why not see if freshwater can flush out oil and prevent it from coating and killing the coastal grasses and the tiny creatures who live in the marshes and provide food for the larger critters.
Finally, the Corps of Engineers estimates that the Nashville flood was a 1000-year event. All that water, which destroyed the Grand Old Opry, is streaming down the Mississippi and could push back some of the oil that is streaming towards the Louisiana wetlands, where it might spill over into Breton Sound near Bohemia. Perhaps Nashville’s misfortune can mitigate Louisiana’s misfortune.