55-Years-Ago This Month, The Mighty Niagara Falls Was Turned Off

It's hard to believe that one of the world's largest and most majestic waterfalls has an off-switch, but it does... Sort-of... And way back in 1969, US Government officials decided it was time to flip that switch to see Niagara Falls, which no one had ever seen before.

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For many years, geologists and members of the US Army Corps of Engineers, along with local and state government officials, had worried about the condition of Niagara Falls. To help keep things going in a positive direction, several preservation efforts had been made, some going as far back as the late 1800s when Frederick Law Olmsted and Calvert Vaux issued a report detailing some steps that could be taken to preserve and improve the Niagara Falls and the surrounding area.

However, as improvements were made to Niagara Falls and more visitors descended on the world wonder, many began to become concerned about the large deposit of boulders at the bottom of the American Falls—more than 3.5 million cubic feet of boulders that are more than ten stories tall.

Erosion control is constantly on the mind of geologists at Niagara Falls, but how could you possibly study how erosion impacts Niagara Falls when more than 5.9 million cubic feet of water flows over the falls every minute before dropping more than 160 feet? Well, according to the US Army Corps of Engineers, you just turn the falls off and start studying it, and in June 1969, they did just that.

With more than 1,000 dump trucks at their command, Army Corps officials dumped over 28,000 tons of rock into the Niagara River, creating a rock cofferdam that was more than 600 feet wide.

Water that would have flowed over the American and Bridal Veil Falls was diverted to the Horseshoe Falls, and for the first time in more than 12 millennia, Niagara Falls ran dry.

For the next five months, engineers and geologists studied the rocks at the bottom of the falls and repaired parts of the riverbed by installing large metal plates to help slow erosion. Several bodies were also recovered once the falls were dewatered, the unfortunate result of people jumping into them. Hundreds of workers studied the falls, while more than 100,000 people checked them out from Niagara Falls State Park and Queen Victoria Park in Ontario.

When all the research was completed, it was decided to leave most of the boulders as officials were concerned moving them would actually increase the erosion of the falls.

After five months of intense research, the cofferdam was removed on November 25, 1969, and the Niagara River again flowed over Niagara Falls.

Plans are underway to shut the falls off again shortly for the same reason: for research and preservation. While it may not happen in the next couple of years, it could happen relatively soon after that.