Niagara Falls is 19 miles downstream from Lake Erie. Goat Island divides the Niagara River into two channels, separating Niagara Falls into American Falls on the American side and Horseshoe Falls on the Canadian side.

Public concern arose in the mid-1960s regarding the talus (rock fragments) accumulation at the base of the American Falls, which many felt detracted from its natural beauty. Three major rockfalls occurred in 1931, 1954 and 1959, depositing about 130,000 cubic yards of rock at the Falls' base.

In 1965, Congress authorized the U.S. Army Corps of Engineers to study the measures needed to preserve and enhance the beauty of the American Falls. The results of the Corps' study were submitted to the International Joint Commission (IJC) which, at the request of the American and Canadian governments, began an independent inquiry in 1967. The Commission established the American Falls Study Board, which included representatives from the Corps, Environment Canada, and eminent landscape architects to consider possible alternatives for preserving American Falls' future.

The IJC recommended to both countries that American Falls be temporarily dewatered to facilitate a timely and thorough study. The governments agreed, and on June 12, 1969, a rock cofferdam stopped the flow over American Falls. The Falls remained dry until November 25, 1969, when a backhoe removed the cofferdam.