International Control Dam

International Control Dam
The dam as viewed from the Canadian side
Opening date	1954

Coordinates: 43°04′20.1″N 79°03′31.0″W / 43.072250°N 79.058611°W / 43.072250; -79.058611

The International Control Dam, also known as the International Control Structure, operated by Ontario Power Generation, is a Weir that controls the water diversions from the Niagara River and dispatches the water between the New York Power Authority and Ontario Power Generation in accordance with the terms of the 1950 Niagara Treaty. It was completed in 1954

To preserve Niagara Falls' natural beauty and to ensure an "unbroken curtain of water" is flowing over the falls, the 1950 treaty was signed by the U.S. and Canada to limit water usage by power plants.

The treaty allows higher summertime diversion at night when tourists are fewer and during the winter months when there are even fewer tourists. The treaty states that during daylight time during the tourist season (April 1 to October 31) there must be 100,000 cubic feet per second (2,800 m³/s) of water flowing over the falls, and during the night and off-tourist season there must be 50,000 cubic feet per second (1,400 m³/s) of water flowing over the falls. This treaty is monitored by the International Niagara Board of Control, using a NOAA gauging station above the falls.

This weir allows water from the upper river to be diverted into the intakes for the American and Canadian power stations. Two tunnels on the American side take water under the town of Niagara Falls, New York and three tunnels on the Canadian side divert water under the town of Niagara Falls, Ontario. Once past these cities, the water flows into two canals and then into two large reservoirs. Behind the Canadian Sir Adam Beck powerplant is a reservoir covering 300 hectares (750 acres) and a similar reservoir on the US side behind the Robert Moses Station.