Their plan was to remove the large amount of loose rock from the base of the waterfall, an idea which they eventually abandoned due to expense in November of that year. During the interim, they studied the riverbed and mechanically bolted and strengthened a number of faults to delay the gradual erosion of the American Falls.
The team, made up of U.S. Army Corp of Engineers, blew up their temporary dam in November 1969 and six million cubic feet of water once again thundered over the falls' sides every minute.
Now, after lying unseen for more than four decades, a set of images showing the eerie calm at the American Falls that year have been unearthed by a man from Connecticut.
Russ Glasson recently stumbled across the pictures, which were taken by his in-laws, and had been left in an old shoebox in their garage for over four decades. Mr Glasson said: 'My in-laws took these pictures during the six months through June to November that the Army was working to improve the health of the American Falls.'
Two rockslides from the plate of the falls in 1931 and 1954 had caused a large amount of rock to be collected at the base.
In 1965, reporters at local newspaper Niagara Falls Gazette revealed that the America Falls would eventually cease to flow and stop altogether if the rocks were not removed.
Four years later, the U.S. Army Corp of Engineers were charged with de-watering the falls to clean the river bed and to remove any loose rock at the bottom of the falls.
Source: mailonline