The largest of the three Falls at Niagara, the Canadian Horseshoe Falls is 2,200 feet wide at the crest, which is 670 metres. The Canadian Falls plunges 188 feet, or 57 metres into the Niagara Gorge below. During the high tourist season, the amount of water that goes over the Falls every second is 100,000 cubit feet which is 2,832 cubic metres, which in turn translates to 2,832 tonnes of water per second cascading over Niagara Falls. It’s been doing this, and more for 12,000 yeas and will keep doing it for at least another 50,000 years.
The Canadian Horseshoe Falls are not the largest or highest Falls in the world. It’s the volume of water and their location that makes the Falls so spectacular. Niagara Falls is situated in the heart of the largest population in North America. New York City a few hours by car to the east, Chicago a few hours to the west, Toronto and Montreal a quick car ride to Niagara Falls and a ton of other cities between.
Over 168,000 cubic metres, or 6 million cubic feet of water goes over the crest of the falls every minute during peak daytime tourist hours. It is stated this way because at night they reduce the flow over the Falls, moving more water to the hydro generating stations downriver. The reduction also assists in reducing erosion of the Falls which is currently about a foot a year.
The amount of water that can be diverted for power generation is contained in a treaty between the Governments of Canada and the United States originally dated 1950, thus it is called the “1950 Niagara Treaty.” The treaty requires that during the daylight hours of the tourist season (0800 to 2200 hours local time, April 1st to September 15th and 0800 to 2000 hours local time September 16th to October 31st), the flow over Niagara Falls must not be less than 2,832 cubic metres per second (cubic m/s) [100,000 cubic ft. per second (cfs)]. At all other times, the flow must not be less than 1,416 cu m/s (50,000 cfs).
The treaty also specifies that all water in excess of that required for domestic and sanitary purposes, navigation and the falls flow may be diverted for power generation. If the river was allowed to return to natural levels, it would rise another 5 metres, however, the erosion of the falls would greatly increase as a result.
The rapids above the falls climbs to 40 km/hr or 25 mph. The fastest water speed is at Falls itself, where it has been recorded at 68 mph. The green colour of the Niagara River is because about 60 tons of dissolved minerals are swept over Niagara Falls every minute. The colour comes from the dissolved salts and “rock flour,” which is finely ground rock.