February 12, 2018

How Humans Sank New Orleans

Richard Campanella—The Atlantic:

What was beginning to happen was anthropogenic soil subsidence—the sinking of the land by human action. When runoff is removed and artificial levees prevent the river from overtopping, the groundwater lowers, the soils dry out, and the organic matter decays. All this creates air pockets in the soil body, into which those sand, silt, and clay particles settle, consolidate—and drop below sea level.

Fascinating geologic history of how New Orleans became the city situated between the river and the sea, below sea level. What began as novel engineering projects resulted in the New Orleans of today; largely a sunken marsh that survives on levee and pump construction and operation.

As the article concludes, these projects can never end. That, or the city must shrink back to the two narrow strips of natural levee along the silt-conveying and -depositing Mississippi River.

#NewOrleans #MississippiRiver #humanEngineering #unintentdedConsequences