The Niagara Falls are the most powerful waterfalls in North America.These voluminous waterfalls are situated on the Niagara River, which drains Lake Erie into Lake Ontario and forms the international border between the Canadian province of Ontario and the U.S. state of New York. The falls are 17 miles (27 km) north-northwest of Buffalo, New York and 75 miles (121 km) south-southeast of Toronto, Ontario, between the twin cities of Niagara Falls, Ontario, and Niagara Falls, New York.
Niagara Falls is composed of two major sections, separated bởi Goat Island: the Horseshoe Falls on the Canadian side and the American Falls on the American side. The smaller Bridal Veil Falls are also located on the American side, separated from the main falls bởi 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.
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. thêm than 6 million cubic feet (168,000 m3) of water falls over the crest line every một phút in high flow,and almost 4 million cubic feet (110,000 m3) on average.
The Niagara Falls are renowned both for their beauty and as a valuable nguồn of hydroelectric power. Managing the balance between recreational, commercial, and industrial uses has been a challenge for the stewards of the falls since the 19th century.
The Horseshoe Falls drop about 173 feet (53 m), while the height of the American Falls varies between 70–100 feet (21–30 m) because of the presence of giant boulders at its base. The larger Horseshoe Falls are about 2,600 feet (790 m) wide, while the American Falls are 1,060 feet (320 m) wide.
The volume of water approaching the falls during peak flow season may sometimes be as much as 202,000 cubic feet (5,700 m3) per second.Since the flow is a direct function of the Lake Erie water elevation, it typically peaks in late spring hoặc early summer. During the summer months, 100,000 cubic feet (2,800 m3) per một giây of water actually traverses the falls, some 90% of which goes over the Horseshoe Falls, while the balance is diverted to hydroelectric facilities. This is accomplished bởi employing a đập đắp ngang con sông, đập, weir with movable gates upstream from the Horseshoe Falls. The falls flow is further halved at night, and during the low tourist season in the winter, remains a flat 50,000 cubic feet (1,400 m3) per second. Water diversion is regulated bởi the 1950 Niagara Treaty and is administered bởi the International Niagara Board of Control (IJC).
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 bởi the erosive force of the Niagara River itself. The current rate of erosion is approximately 1 foot (0.30 m) per năm down from a historical average of 3 feet (0.91 m) per year. However, it is estimated that 50,000 years from now, even at this reduced rate of erosion, the remaining 20 miles (32 km) to Lake Erie will have been undermined and the falls will cease to exist.
The features that became Niagara Falls were created bởi the Wisconsin glaciation about 10,000 years ago. The same forces also created the North American Great Lakes and the Niagara River. All were dug bởi a continental ice sheet that drove through the area, deepening some river channels to form lakes, and damming others with debris.[7] Scientists believe that there is an old valley, buried bởi glacial drift, at the approximate location of the present Welland Canal.
Aerial view of Niagara Falls, hiển thị parts of Canada (left) and the United States (upper right).
When the ice melted, the upper Great Lakes emptied into the Niagara river, which followed the rearranged topography across the Niagara Escarpment. In time, the river cut a gorge through the north facing cliff, hoặc cuesta. Because of the interactions of three major rock formations, the rocky giường did not erode evenly. The hàng đầu, đầu trang rock formation was composed of erosion-resistant limestone and Lockport dolostone. That hard layer of stone eroded thêm slowly than the underlying materials. The aerial bức ảnh on the right clearly shows the hard caprock, the Lockport Formation (Middle Silurian), which underlies the rapids above the falls, and approximately the upper third of the high gorge wall.
Immediately below the hard-rock formation, comprising about two thirds of the cliff, lay the weaker, softer, sloping Rochester Formation (Lower Silurian). This formation was composed mainly of shale, though it has some thin limestone layers. It also contains ancient fossils. In time, the river eroded the soft layer that supported the hard layers, undercutting the hard caprock, which gave way in great chunks. This process repeated countless times, eventually carving out the falls.
Submerged in the river in the lower valley, hidden from view, is the Queenston Formation (Upper Ordovician), which is composed of shales and fine sandstones. All three formations were laid down in an ancient sea, their differences of character deriving from changing conditions within that sea.
About 10,900 years ago, the Niagara Falls was located between present-day Queenston, Ontario, and Lewiston, New York, but erosion of their crest has caused the waterfalls to retreat approximately 6.8 miles (10.9 km) southward. The Horseshoe Falls, which are approximately 2,600 feet (790 m) wide, have also changed their shape through the process of erosion; evolving from a small arch, to a horseshoe bend, to the present ngày gigantic inverted V. Just upstream from the falls' current location, Goat Island splits the course of the Niagara River, resulting in the separation of the Canadian Horseshoe Falls to the west from the American and Bridal Veil Falls to the east. Engineering has slowed erosion and recession.
Niagara Falls is composed of two major sections, separated bởi Goat Island: the Horseshoe Falls on the Canadian side and the American Falls on the American side. The smaller Bridal Veil Falls are also located on the American side, separated from the main falls bởi 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.
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. thêm than 6 million cubic feet (168,000 m3) of water falls over the crest line every một phút in high flow,and almost 4 million cubic feet (110,000 m3) on average.
The Niagara Falls are renowned both for their beauty and as a valuable nguồn of hydroelectric power. Managing the balance between recreational, commercial, and industrial uses has been a challenge for the stewards of the falls since the 19th century.
The Horseshoe Falls drop about 173 feet (53 m), while the height of the American Falls varies between 70–100 feet (21–30 m) because of the presence of giant boulders at its base. The larger Horseshoe Falls are about 2,600 feet (790 m) wide, while the American Falls are 1,060 feet (320 m) wide.
The volume of water approaching the falls during peak flow season may sometimes be as much as 202,000 cubic feet (5,700 m3) per second.Since the flow is a direct function of the Lake Erie water elevation, it typically peaks in late spring hoặc early summer. During the summer months, 100,000 cubic feet (2,800 m3) per một giây of water actually traverses the falls, some 90% of which goes over the Horseshoe Falls, while the balance is diverted to hydroelectric facilities. This is accomplished bởi employing a đập đắp ngang con sông, đập, weir with movable gates upstream from the Horseshoe Falls. The falls flow is further halved at night, and during the low tourist season in the winter, remains a flat 50,000 cubic feet (1,400 m3) per second. Water diversion is regulated bởi the 1950 Niagara Treaty and is administered bởi the International Niagara Board of Control (IJC).
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 bởi the erosive force of the Niagara River itself. The current rate of erosion is approximately 1 foot (0.30 m) per năm down from a historical average of 3 feet (0.91 m) per year. However, it is estimated that 50,000 years from now, even at this reduced rate of erosion, the remaining 20 miles (32 km) to Lake Erie will have been undermined and the falls will cease to exist.
The features that became Niagara Falls were created bởi the Wisconsin glaciation about 10,000 years ago. The same forces also created the North American Great Lakes and the Niagara River. All were dug bởi a continental ice sheet that drove through the area, deepening some river channels to form lakes, and damming others with debris.[7] Scientists believe that there is an old valley, buried bởi glacial drift, at the approximate location of the present Welland Canal.
Aerial view of Niagara Falls, hiển thị parts of Canada (left) and the United States (upper right).
When the ice melted, the upper Great Lakes emptied into the Niagara river, which followed the rearranged topography across the Niagara Escarpment. In time, the river cut a gorge through the north facing cliff, hoặc cuesta. Because of the interactions of three major rock formations, the rocky giường did not erode evenly. The hàng đầu, đầu trang rock formation was composed of erosion-resistant limestone and Lockport dolostone. That hard layer of stone eroded thêm slowly than the underlying materials. The aerial bức ảnh on the right clearly shows the hard caprock, the Lockport Formation (Middle Silurian), which underlies the rapids above the falls, and approximately the upper third of the high gorge wall.
Immediately below the hard-rock formation, comprising about two thirds of the cliff, lay the weaker, softer, sloping Rochester Formation (Lower Silurian). This formation was composed mainly of shale, though it has some thin limestone layers. It also contains ancient fossils. In time, the river eroded the soft layer that supported the hard layers, undercutting the hard caprock, which gave way in great chunks. This process repeated countless times, eventually carving out the falls.
Submerged in the river in the lower valley, hidden from view, is the Queenston Formation (Upper Ordovician), which is composed of shales and fine sandstones. All three formations were laid down in an ancient sea, their differences of character deriving from changing conditions within that sea.
About 10,900 years ago, the Niagara Falls was located between present-day Queenston, Ontario, and Lewiston, New York, but erosion of their crest has caused the waterfalls to retreat approximately 6.8 miles (10.9 km) southward. The Horseshoe Falls, which are approximately 2,600 feet (790 m) wide, have also changed their shape through the process of erosion; evolving from a small arch, to a horseshoe bend, to the present ngày gigantic inverted V. Just upstream from the falls' current location, Goat Island splits the course of the Niagara River, resulting in the separation of the Canadian Horseshoe Falls to the west from the American and Bridal Veil Falls to the east. Engineering has slowed erosion and recession.
