The Niagara Falls is divided into the Horseshoe Falls and the American Falls. The Horseshoe Falls drop about 173 feet and are 2,600 feet wide. The American Falls drop 70 feet and are 1,060 feet wide. The volume of water that approaches the falls during the peak season is 202,000 cubic feet per second.
The viewpoints from the American shore are usually from behind the falls or astride. As the falls face directly at the Canadian shore, the most complete view of the Niagara Falls is available from the Canadian shoreline.
The Niagara Falls was created by the Wisconsin glaciations about 10,000 years ago, which was also responsible for the formation of the Niagara River and the North American great lakes. These were dug by the continental ice sheet that moved through the area like a bulldozer deepening the river channels to form lakes.
When all the ice melted, the upper Great Lakes emptied into the Niagara River. Over a period of time, the river cut a gorge through the north facing cliff. The rock structure did not erode in an even manner as it was composed of three varied rock formations. The uppermost rock layer was composed of erosion resistant limestone and dolostone. This layer eroded more slowly than the underlying layers. Immediately below this layer which comprised two-thirds of that cliff, the formation was composed of shale along with some thin limestone layers. Over a period of time the river eroded the softer layers which undercut the hard cap rock leading to a process that eventually carved out the Niagara Falls.
The original Niagara Falls was near present day Queenston, Ontario and Lewiston, New York but due to erosion of their crest, the falls have retreated several miles towards the south. As the erosion continues over the years the falls will eventually recede far enough to drain most of Lake Erie, the bottom of which is higher than the bottom of the falls. Engineers have been working very hard to reduce the rate of erosion to help postpone this eventuality for as long as possible.
Underwater weirs have been used to redirect the most damaging currents. Along with this, the top of the falls have also been strengthened. To provide some examples as to how much work has gone into the entire process, in 1969 the entire Niagara River was diverted from the American Falls for more than a couple of months with the help of a temporary earth rock and a dam. The Horseshoe Falls absorbed all the additional flow and this entire activity gave the American engineers an opportunity to study the riverbed and also mechanically bolt the faults present in the riverbeds which could otherwise hasten the retreat of the Niagara Falls. The temporary wall was destroyed with dynamites in November 1969, and normal flow of water to the American Falls was restored.
Touring the Niagara Falls
The peak tourism season of the Niagara Falls is during the summertime, when the falls are spectacular during the day and evenings. Floodlights illuminate both sides of the falls from the Canadian side for several hours during the evening.
It is expected that about 29 million people visited the falls in 2009. The best known tourist attraction at Niagara Falls is the 'Maid of the Mist' cruise boat (named after an ancient Ongiara Indian Mythical character) that has been around since 1846, which carries the passengers into the whirlpools below the falls.
Niagara Falls has also been a favorite spot for many Hollywood films like Niagara, Superman II and 'Pirates of the Caribbean: At World's End'. It was also an integral part of the Canadian television series, 'Wonderfalls'.