Niagara Falls without water

For six months in the summer and fall of 1969, Niagara’s American Falls were“de-watered”, as the Army Corps of Engineers conducted a geological survey of the falls’ rock face, concerned that it was becoming destabilized by erosion.

These stark images reveal North America’s iconic – and most powerful –waterfall to be almost as dry as a desert.

Niagara Falls is the collective name for three waterfalls that straddle the international border between Canada and the United States. From largest to smallest, the three waterfalls are the Horseshoe Falls, the American Falls and the Bridal Veil Falls.

The Horseshoe Falls lie mostly on the Canadian side and the American Falls entirely on the American side, separated by Goat Island. The smaller Bridal Veil Falls are also on the American side, separated from the other waterfalls by Luna Island.

To dewater the Niagara’s American Falls the army had to build a 600ft (182 m) dam across the Niagara River, which meant that 60,000 gallons of water that flowed every 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. The completed dewatering of the American Falls was made easier because only 10% of the water follows that route.

with information from  rarehistoricalphotos.com