Wednesday, April 3, 2019

The Control of Nature, Under Water : Can engineering save Louisiana's disappearing coast? New Yorker Magazine, April 1, 2019 by Elizabeth Kolbert

Unlike many articles on water that I have read, this article forced me to confront the question: How much should humans interfere with the forces of nature? Focusing on Plaquemines, land that extends into the Gulf of Mexico "where the river meets the sea" (p. 32), the author explained the natural interplay between the weather, the Mississippi River, and the land in this section of Louisiana. This area, below sea level, could not withstand the fury of Hurricanes Katrina or Rita. Erosion has brought the city of New Orleans twenty miles closer to the Gulf of Mexico. Additionally, New Orleans, below sea-level, continues to sink. "A recent study that relied on satellite data found some sections of New Orleans dropping by almost half a foot per decade" (p. 41). The city's solution of pumping water exacerbates the problem of subsidence; the more the city pumps, the more the city sinks.

Geographically, Louisiana, like Italy, looks like a boot with Plaquemines at its farthermost point of the toe. Describing the degree of erosion of Plaquemines and in Louisiana generally, the author stated:

"And what's happening to Plaquemines is happening all along the coast. Since the days of Huey Long, Louisiana has shrunk by more than two thousand square miles. . . Every hour and a half, Louisiana sheds another football field's worth of land. . . On maps, the state may still resemble a boot. Really, though, the bottom of the boot is in tatters, missing not just a sole but also its heel and a good part of its instep" (p. 34). 

Citing this phenomenon as a "land-loss crisis" (p. 34). Kolbert attributes the problem to the Army Corps of Engineers attempt to manage and control the Mississippi with "thousands of miles of levees, flood walls, and revetments" (p. 34). Kolbert wrote the article to disclose the latest project to control the river, "a huge new public-works project is getting under way--this one aimed not at flood control so much as at controlled flooding, Ten pharaonic structures are planned. The furthest along of these is slated for Plaquemines Parish. . . and, when operating at full capacity, will, by flow, be the twelfth-largest river in the country" (p. 34).

Historically, the Mississippi has dropped sediment in Louisiana. Tracing the rivers history, Kolbert claimed that "In the last seven thousand years, the river has avulsed six time, and each time it has set about laying down a new bulge of land" (p. 34). The author recounts some of these, from the time of the building of the pyramids and the formation of New Orleans to the creation of Western Terrebonne Parrish during the time of Charlemagne. Plaquemines, the most recent of the avulsions, dates about fifteen hundred years old. However, the story does not end there. The sea eventually reclaims the some of the land, "where the river delivers enough sand and clay to make up for the lost volume, the land holds its own. Where compaction outpaces accretion, the land begins to subside until, eventually, the Gulf reclaims it" (p. 35).

The Army Corps of Engineers projects of dredging and diversions hope to thwart another avulsion or crevasse, a breach of a levee, in a race against nature.

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