20 November 1980: The Lake Peigneur disaster

How do you turn a ten-foot deep freshwater lake into a saltwater one over a thousand feet deep? The residents of Lake Peigneur in Louisiana found out on 20 November 1980.

That day, oil giant Texaco had been drilling in the lake, when it pierced the bottom. Directly below the water was a salt mine operated by The Diamond Crystal Salt Company, which yielded around 100,000 tons of salt a year.

Just as what happens when you pull the plug in your bath – but on a far larger scale – the water gushed into the hole and created a giant whirlpool. The drilling platform was the first to go, followed by several barges loaded with rock salt.

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Many locals made a living from a shrimp industry on the lake – their boats disappeared down the hole as well. As did Live Oak Gardens, a plant nursery and tourist attraction. Around $1m-worth of plants and trees were lost to the maelstrom.

A listed house that belonged to 19th century actor Joseph Jefferson was left clinging to the edge of the crater three-quarters-of-a-mile-wide. It continued to widen as the salt dissolved.

The lake had until then emptied into the Gulf of Mexico via the Delcambre Canal. But so much water poured into the salt mine that day that the canal began to flow the other way, dragging salt water from the gulf into the lake, and turning the water saline.

Miraculously, nobody was killed. However, hundreds of jobs were lost as the salt mining and shrimping industries disappeared and the ecosystem was permanently changed.

Today, natural gas is stored in caverns around the lake. In September 2014, a local pressure group, Save Lake Peigneur, was successful in overturning a decision to expand the gas storage facilities. There have been signs, they say, of bubbling in the water.