"From June to November 1969 the American Falls were dewatered. This action cut back the normal flow of 60,000 gallons a second to almost nothing. Most of the diverted water was either sent over the Horseshoe Falls or diverted to the Robert Moses generating plant’s upriver intakes. The action enabled Canadian and US power companies and the US Army Corps of Engineers to do on-the-spot inspections and aerial photographs of the river bed’s rock formation. This was all part of a plan to reduce erosion to the Falls."