7.1 How do the Power Entities (Ontario Power Generation and the New York Power Authority) get water from the Chippawa-Grass Island Pool to their respective hydro-electric plants at Queenston, ON and Lewiston, NY?
Both OPG and NYPA divert water from the CGIP above the INCW. Water is carried by gravity through a difference in head to the hydroelectric facilities. The OPG carries water to a forebay by a set of three tunnels and an open channel, whereas the NYPA use two covered conduits for water diversion to its power plant forebay. From the forebay, water may be either discharged through the plants to the Niagara River or pumped to a storage reservoir and later used by the main plants.
Ontario Power Generation constructed a third tunnel that was put into operation in 2013 to increase its diversion capacity from the Niagara River to be able to better use Canada’s share of the water of the Niagara River. The Falls flow minimums specified in the 1950 Niagara Treaty remain in force, as do the limits in the GIP.
7.3 Can the flow over the Falls be stopped completely?
No, the International Niagara Control Works does not extend entirely across the Niagara River and therefore it cannot stop the flow completely.
7.4 I have seen pictures of Niagara Falls being dry, doesn’t this prove that the Falls flow can be stopped completely?
In the summer and fall of 1969, the American Falls were dewatered in order to study the erosion that had been happening on the American Falls and to develop options to prevent further erosion. Although many pictures were taken during this time and these give the impression that the Falls were shut off, flow over Horseshoe Falls continued during this period.
No, however topographic maps produced by the US Geological Survey (USGS) in 1980 and 1995 showed an incorrect location of the crest of the Horseshoe Falls. These maps gave the incorrect impression that 1/3rd of the Horseshoe Falls was actually in US territory. More recent topographic maps produced by the USGS show the proper location of the crest of Horseshoe Falls. On these maps, the international border crosses the crest of Horseshoe Falls very close to where it meets Terrapin Point, resulting in almost the entire crest of the Horseshoe Falls being located in Canada.