Louisiana is sinking, faster than you might think. Every hour, it loses more than a football field-sized chunk of land to the ocean. Or, to use ProPublica’s more evocative words, it’s like “a layer cake made of Jell-O, floating in a swirling Jacuzzi of steadily warming, rising water.” To save its disintegrating coastline, Louisiana will need a “moon shot” plan and somehow come up with $US50 billion.
The restoration of the Mississippi River delta, detailed in an article from ProPublica and The Lens, will be a project of unprecedented scale. Dredging by oil companies has reshaped the river’s flow and starved it of sediment that would naturally offset the ocean’s encroach. If we don’t do something, we’ll all suffer the consequences. Water will swamp the refineries and pipelines that account for 30 per cent of the U.S.’s oil and gas.
The plan has two options, neither of them ideal. The first simpler option is dredging up sediment from the riverbed and offshore areas to pipe into eroding marshlands. It has the advantage of being faster and cheaper, but one major disadvantage: It’s only temporary. The second option is diverting sediment by controlling the flow of the river itself.
The idea is to move some of the freshwater and sediment in the Mississippi River to where it’s needed most. When the river is high, specially designed gates would be opened in the river levee, allowing freshwater and sediment to wash over nearby areas.
These diversions would build land over decades, not months. Theoretically, they would work as long as the river flows.
The disadvantage of sediment diversions? We’ve never done it before, and it’s supposed to take at least 50 years. Neither method can restore Louisiana’s coast to its former glory — there simply isn’t enough sediment in the river anyway. If you have an appetite for dire situations, be sure to read the entire piece at ProPublica. It’s too late to save everything, but perhaps we can still save something. [ProPublica]
Picture: Louisiana Coastal Protection and Restoration Authority