“In June 1969, U.S. engineers diverted the flow of the Niagara River away from the American side of the falls for several months.
“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.
“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.
To achieve this the army had to build a 600ft dam across the Niagara River, which meant that 60,000 gallons of water that flowed ever second was diverted over the larger Horseshoe Falls which flow entirely on the Canadian side of the border.
“The dam itself consisted of 27,800 tons of rock, and on June 12, 1969, after flowing continuously for over 12,000 years, the American Falls stopped. Over the course of the next six months thousands of visitors flocked to the falls to witness the historic occasion.
“Once the engineers had removed the collected rocks from the falls base and made geological testing to make safe the rest, the falls were re-watered on November 25 in front of 2,650 onlookers.”