Rapids are sections of a river where the river bed has a relatively steep gradient, causing an increase in water velocity and turbulence.
Rapids are hydrological features between a run (a smoothly flowing part of a stream) and a cascade . Rapids are characterised by the river becoming shallower with some rocks exposed above the flow surface. As flowing water splashes over and around the rocks, air bubbles become mixed in with it and portions of the surface acquire a white colour, forming what is called "whitewater". Rapids occur where the bed material is highly resistant to the erosive power of the stream in comparison with the bed downstream of the rapids. Very young streams flowing across solid rock may be rapids for much of their length. Rapids cause water aeration of the stream or river, resulting in better water quality.
Rapids are categorized in classes, generally running from I to VI.A Class 5 rapid may be categorized as Class 5.1-5.9. While Class I rapids are easy to navigate and require little maneuvering, Class VI rapids pose threat to life with little or no chance for rescue. River rafting sports are carried out where many rapids are present in the course.
A waterfall is an area where water flows over a vertical drop or a series of steep drops in the course of a stream or river. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Whitewater forms in a rapid context, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and white.
The Cossatot River is an 89-mile-long (143 km) river in Howard, Polk and Sevier counties in the U.S. state of Arkansas.
The Youghiogheny River, or the Yough for short, is a 134-mile-long (216 km) tributary of the Monongahela River in the U.S. states of West Virginia, Maryland, and Pennsylvania. It drains an area on the west side of the Allegheny Mountains northward into Pennsylvania, providing a small watershed in extreme western Maryland into the tributaries of the Mississippi River. Youghiogheny is a Lenape word meaning "a stream flowing in a contrary direction".
The Nolichucky River is a 115-mile (185 km) river that flows through Western North Carolina and East Tennessee, in the southeastern United States. Traversing the Pisgah National Forest and the Cherokee National Forest in the Blue Ridge Mountains, the river's watershed is home to some of the highest mountains in the Appalachians, including Mount Mitchell in North Carolina, the highest point in the eastern United States. The river is a tributary of the French Broad River, and is impounded by Nolichucky Dam near Greeneville, Tennessee.
The Chattooga River is the main tributary of the Tugaloo River.
The Futaleufú River, located in northern Patagonia, is one of the premier whitewater rivers in the world. One of only two rivers to cross the 5,308 kilometer Chile-Argentina border, the Futaleufú headwaters can be found in the glacial snow melt of the UNESCO protected Los Alerces National Park in Argentina. The river gorge drops as low as 1,700 metres (5,600 ft) below the surrounding glaciated peaks. The name Futaleufú is an indigenous Mapuche word meaning "Big River.” Locals refer to the valley as "un paisaje pintado por Dios"—a landscape painted by God.
The international scale of river difficulty is an American system used to rate the difficulty of navigating a stretch of river, or a single rapid. The scale was created by the American Whitewater Association to evaluate rivers throughout the world, hence international in the title. It should not be confused with the internationally used whitewater scale, which is published and adapted by a committee of the International Canoe Federation (ICF). The grade reflects the technical difficulty and skill level required associated with the section of river. The scale is of use to various water sports and activities, such as rafting, riverboarding, whitewater canoeing, stand up paddle surfing, and whitewater kayaking.
The Dumoine River is a river in western Quebec with its source in Machin Lake near La Vérendrye Wildlife Reserve. From Dumoine Lake, the river flows almost due south off the Canadian Shield and empties into the Ottawa River, just west of Rapides-des-Joachims, Quebec, or Rolphton, Ontario. The river is 129 kilometres (80 mi) long and drains a watershed of 5,380 square kilometres (2,080 sq mi). This relatively short river compared to its drainage area indicates that the Dumoine has a strong current and many steep-gradient rapids.
Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland.
Difficult Run is a 15.9-mile-long (25.6 km) tributary stream of the Potomac River in Northern Virginia in the United States. The area has had many historical uses dating back to the early 1800s. Today, the area is used recreationally by visitors interested in the watershed's variety of options including hiking, biking, fishing, boating, climbing, and bird watching. The wildlife at Difficult Run is vast as 163 different species can be seen depending on the season. There are 41 different soil types found on the trail and alongside the stream. The stream is part of the greater 57.7- square-mile Drainage basin, or watershed, located in the north-central portion of Fairfax County and drains directly to the Potomac River.
Creeking is a branch of canoeing and kayaking that involves descending very steep low-volume whitewater. It is usually performed in specialized canoes and kayaks specifically designed to withstand the extreme whitewater environment in which the activity occurs. In addition, the canoes and kayaks give the paddler improved performance and maneuverability needed to avoid river obstacles.
The geography of New York state varies widely. Most of New York is dominated by farms, forests, rivers, mountains, and lakes. New York's Adirondack Park is larger than any U.S. National Park in the contiguous United States. Niagara Falls, on the Niagara River as it flows from Lake Erie to Lake Ontario, is a popular attraction. The Hudson River begins near Lake Tear of the Clouds and flows south through the eastern part of the state without draining lakes George or Champlain. Lake George empties at its north end into Lake Champlain, whose northern end extends into Canada, where it drains into the Richelieu River and then the St. Lawrence. Four of New York City's five boroughs are on the three islands at the mouth of the Hudson River: Manhattan Island, Staten Island, and Brooklyn and Queens on Long Island.
The Middle Fork of the Salmon River is a 104-mile-long (167 km) river in central Idaho in the northwestern United States. It is a tributary to the Salmon River, and lies in the center of the 2.5-million-acre Frank Church-River of No Return Wilderness Area.
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.
Whitewater canoeing is the sport of paddling a canoe on a moving body of water, typically a whitewater river. Whitewater canoeing can range from simple, carefree gently moving water, to demanding, dangerous whitewater. River rapids are graded like ski runs according to the difficulty, danger or severity of the rapid. Whitewater grades range from I or 1 to VI or 6. Grade/Class I can be described as slightly moving water with ripples. Grade/Class VI can be described as severe or almost unrunnable whitewater, such as Niagara Falls.
The Flambeau River is a tributary of the Chippewa River in northern Wisconsin, United States. The Chippewa is in turn a tributary of the upper Mississippi River. The Flambeau drains an area of 1,860 square miles (4,800 km2) and descends from an elevation of approximately 1,570 feet (480 m) to 1,060 feet (320 m) above sea level. The Flambeau is an important recreational destination in the region. It is notable among canoeists in the Midwest for outstanding canoe camping, including excellent scenery, fishing and whitewater. The river and its forks have a variety of possible trip lengths from short day outings, to overnight camping, to voyages of a week or more.
The Boonton Gorge is a river gorge in Boonton, New Jersey where the Rockaway River drops over several waterfalls, and travels for slightly over a mile before emptying into the Jersey City Reservoir.
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