On June 12, 1969, engineers turned off the American Falls at Niagara so they could study and if necessary, do repairs of the rock bed from all that water. The flow was returned on November 25th.
What they did was build a dam in the part of the river that is heading for the American Falls. This exposed a huge rock pile at the bottom of the Falls. The rock falls, or breaking away from the crest of the Falls happened in 1931 and 1954. The concern was two-fold. The height of the water to the rok below made the American Falls less spectacular to tourists and the erosion threatened to turn the Falls into a downhill river (flatten the Falls) making the American Falls disappear.
In the four months that the work was done, they didn’t move the rock out of the bottom area of the Falls. It was near impossible. So they cleaned up the area, and did some work on the flat rock bed to help insure no more rock collapses occurred over the next few decades.
But wait, there’s more!
As I write this in 2021, 52 years after the “turn off” of 1969, it seems that it may happen again sometime soon.
There are two bridges that connect the mainland of Niagara Falls, New York to Goat Island, which houses part of the Niagara Falls State Park and many tourist attractions on the U.S. side of the border. These bridges are not in good shape, indeed might collapse and be swept of the Falls.
The State is still making the final decision if they will turn off the American Falls or rebuild these bridges another way. It’s going to be a $24 million dollar (or more) project and is still a few years away from beginning.
Pictures are from the CBC and the Niagara Falls Review archives. Aerial photo from 2001 shot by David Duprey and from Associated Press or AP.