A blue-green veil of water tumbles 51 meters over the rocky precipice of the Niagara Falls in this Ikonos image, acquired on August 2, 2004. Every second, more than two million liters of water plummets over the half-circle of the Canadian/Horseshoe portion of the Niagara Falls, shown here, making it one of the world’s largest waterfalls. The force of the pounding water is sending a cloud of mist up from the bottom of the falls; this same force eats away at the rock behind the falls, pushing them back as much as two meters per year.
Niagara Falls is actually made up of three different falls, the most famous of which are shown in this image. The Niagara River, the narrow strait that connects Lake Erie to Lake Ontario, forks around Goat Island, seen in the lower left corner of the image. The main portion of the river is pushed over the Canadian/Horseshoe Falls, but the diverted water tumbles down American Falls and Bridal Veil Falls farther downstream. All three falls that make up Niagara Falls are visible in the large image. As the names of the individual falls suggest, the river and the falls mark the boundary between the United States and Canada.
Victoria Falls, on the Zambezi River, is one of the most famous tourist sites in subsaharan Africa. Details of the Falls are visible in this image taken with the 800 mm lens by Astronaut Edward Lu from the Space Station on September 4, 2003. The positions of the falls are controlled by linear fault lines in the underlying basalt rocks. The falls have moved upstream (bottom to top) by intense river erosion, elongating the zig-zag gorge in the process. Prior positions of the strongly linear falls can be detected. The earliest on this cropped view may have been the longest (dashed line). The zig-zags represent subsequent positions, all with the characteristic water-worn lip on the upstream side. The falls will continue to erode northward.
The Niagara River forms the U.S.-Canadian Border and allows Lake Erie to drain northwest into Lake Ontario. Lake Ontario is about 100 m lower than Lake Erie; the Falls and the rapids account for most of the elevation difference. The energy derived from water falling over the falls, with average total flows of 750,000 U.S. gallons (2.8 million liters) per second, fuel multiple power plants on the river. Power Plants downstream from the plant generate 4.4 million kilowatts of power for both Ontario and New York.