Niagara Falls Niagara River, Canada

Niagara Falls is the collective name for three waterfalls that straddle the international border between the Canadian province of Ontario and the U.S. state of New York. They form the southern end of the Niagara Gorge. From largest to smallest, the three waterfalls are the Horseshoe Falls, the American Falls and the Bridal Veil Falls. The Horseshoe Falls lie on the Canadian side and the American Falls on the American side, separated by Goat Island. The smaller Bridal Veil Falls are also located on the American side, separated from the other waterfalls by Luna Island. The international boundary line was originally drawn through Horseshoe Falls in 1819, but the boundary has long been in dispute due to natural erosion and construction.

Located on the Niagara River, which drains Lake Erie into Lake Ontario, the combined falls form the highest flow rate of any waterfall in the world, with a vertical drop of more than 50 m. Horseshoe Falls is the most powerful waterfall in North America, as measured by vertical height and also by flow rate. The falls are located 27 km north-northwest of Buffalo, New York and 121 km south-southeast of Toronto, between the twin cities of Niagara Falls, Ontario, and Niagara Falls, New York. Niagara Falls were formed when glaciers receded at the end of the Wisconsin glaciation (the last ice age), and water from the newly formed Great Lakes carved a path through the Niagara Escarpment en route to the Atlantic Ocean. While not exceptionally high, the Niagara Falls are very wide. More than 168,000 m3 of water falls over the crest line every minute in high flow, and almost 110,000 m3 on average. The Horseshoe Falls drop about 53 m, while the height of the American Falls varies between 21–30 m because of the presence of giant boulders at its base. The larger Horseshoe Falls are about 790 m wide, while the American Falls are 320 m wide. The distance between the American extremity of the Niagara Falls and the Canadian extremity is 1039 meters. The volume of water approaching the falls during peak flow season may sometimes be as much as 5,700 m3 per second. Since the flow is a direct function of the Lake Erie water elevation, it typically peaks in late spring or early summer. During the summer months, 2,800 m3 per second of water actually traverses the falls, some 90% of which goes over the Horseshoe Falls, while the balance is diverted to hydroelectric facilities. The verdant green colour of the water flowing over the Niagara Falls is a byproduct of the estimated 60 tonnes/minute of dissolved salts and /rock flour/ (very finely ground rock) generated by the erosive force of the Niagara River itself. The current rate of erosion is approximately 0.30 m per year down from a historical average of 0.91 m per year. However, it is estimated that 50,000 years from now, even at this reduced rate of erosion, the remaining 32 km to Lake Erie will have been undermined and the falls will cease to exist.

/Wikipedia.org/

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