Water is diverted from the Niagara River above the Falls by an open-cut canal, as well as three tunnels (the latest tunnel was built between 2011 and 2013) that pass through and under the city of Niagara Falls to the Sir Adam Beck Generating Plants. The plants are located in Queenston, Ontario about 9 kilometres north of the Falls near the Flower Clock.
You might find it interesting to know some people who own homes directly above these tunnels will swear they still hear the water flowing at night below their homes.
On the American side of the border, water is diverted through tunnels to the Robert Moses Power Generating Plant in Lewiston, New York, downriver of the Falls.
If the Niagara River was allowed to flow without any diversion of water, approximately 200,000 cubic feet of water per second would go down the Niagara River and over the Falls. Between 9 p.m. and 8:00 a.m. each day these plants draw water, reducing the rate of water over the Falls to 50% of the normal flow.
Another 50,000 cubic feet of water is diverted from November 1 and March 31 reducing the flow of water to about 25 % over the Falls.
The Niagara River Water Diversion Treaty of 1950 set these limits,” to preserve and enhance the scenic beauty of Niagara Falls and the Niagara River while providing for the most beneficial use of the river waters”.
About 4.4 million kilowatts of power is generated from these plants. That’s enough power to light 24 million 100-watt bulbs!