In 1969, the U.S. Army Corps of Engineers temporarily stopped the flow of water over the American Falls for several months to study long-term erosion and the buildup of fallen rock at the base. Authorities wanted to know whether the scenic appearance of the falls should be “restored” by removing the talus (the huge pile of boulders that had accumulated over decades).
Engineers built a 600-foot-long (182 m) temporary dam, or cofferdam, consisting of nearly 28,000 tons of rock and earth, upstream between the U.S. mainland and Goat Island. The water flow was successfully rerouted entirely to the Canadian Horseshoe Falls, reducing the American Falls to a mere trickle. With the riverbed exposed, curious tourists walked on the dry surface, where coins thrown in for wishes and two human bodies were discovered.
The primary goals were to conduct geological surveys, monitor the rock face stability, and determine if the large accumulation of boulders (talus) at the base should be removed. After five months of study, the Army Corps of Engineers decided that removing the boulders would be too expensive and possibly counterproductive to stability, ultimately choosing to leave them in place and let nature take its course.
On November 25, 1969, the temporary dam was dynamited, and water was restored to the American Falls in front of thousands of spectators. The only other instance of the falls going nearly waterless was in 1848, when an ice jam upstream briefly stopped the flow of water over both the American and Horseshoe Falls.
crazy. makes me want to scoop and clean all that slag shit out from the base. :)
ReplyDelete