Oxbow lakes geographic facts history

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By Amber Pariona on April 25 in Environment. An oxbow lake is a U-shaped body of water, originally a curve in a river. That curve has been separated from the rest of the river and, as an oxbow lake, is now a free-standing body of water. Oxbow lakes can be found all over the world. In Australia, they are known as billabong. Oxbow lakes are formed after a river carves away a curve in the river bank. Over time, this curve becomes more pronounced due to continuous erosion and hydraulic action.

The curve consists of two river banks: the inner, or smaller one and the outer, or a larger one. The inner bank collects more sediment, pushing water further out and into the outer bank. The outer bank experiences more erosion and undercutting, becoming wider. The outer bank is now very close to a neighboring outer bank and the two are separated only by a small strip of land.

oxbow lakes geographic facts history

Extremely forceful water, such as during a flood, eventually breaks through this small strip of land and creates a straight section of the river.

This process leaves the curved area, or meander, cut off from the rest of the river. Over time, sediment is deposited at the breakaway point, resulting in an oxbow lake. It was created in Prior to this year, Carter Lake was actually a curve in the Missouri River.

Flooding in the summer of cut off the Saratoga Bend from the rest of the river, resulting in Carter Lake. It later became a beach resort. Kaber Taal Lake located in India is one of the largest oxbow lakes in Asia. Today, this lake has been protected as the Kanwar Lake Bird Sanctuary. It is home to around resident bird species and provides shelter to at least 60 recorded migratory birds.

The lake and its ecosystem are threatened by pollution, like excessive chemicals which are used to capture birds. Many of the bird species here are endangered or threatened, including the: long-billed vulture, oriental white-backed vulture, lesser kestrel, and greater spotted eagle. Reelfoot Lake, located in the US state of Tennessee, is another example of an oxbow lake. This lake is unique in that it was created after an earthquake, rather than flooding. The to New Madrid earthquakes caused several landform changes throughout the area, including cutting off Reelfoot Lake from the Mississippi River.

Today, it is considered a shallow, swamp-like lake. The area is protected as a state park and is home to bald eagles and bald cypress trees.

Cuckmere Haven in Sussex, England is a floodplains area. It is home to the Cuckmere River, considered a winding river. Additionally, this area has several oxbow lakes that are believed to have once been part of the Cuckmere River. Cuckmere Haven displays a unique ecology, with a mix of domesticated animals and wildlife.Oxbow lakesmall lake located in an abandoned meander loop of a river channel. It is generally formed as a river cuts through a meander neck to shorten its course, causes the old channel to be rapidly blocked off, and then migrates away from the lake.

oxbow lakes geographic facts history

If only one loop is cut off, the lake formed will be crescent shaped, whereas if more than one loop is cut off, the lake will be serpentine or winding. Eventually, oxbow lakes are silted up to form marshes and finally meander scarsmarked by different vegetation or the absence of cultivation. The lakes commonly are filled with clay-sized sediment that is less easy to erode than surrounding material and thus may cause a more complex meandering system in its parent stream.

Oxbow lake Article Media Additional Info. Print Cite. Facebook Twitter. Give Feedback External Websites. Let us know if you have suggestions to improve this article requires login. External Websites. Missouri Botanical Garden - Oxbow Lake. The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree See Article History.

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Learn More in these related Britannica articles:. Silt deposits will eventually fill the lake to form a marsh or meander scar. History at your fingertips. Sign up here to see what happened On This Dayevery day in your inbox! Email address. By signing up, you agree to our Privacy Notice.

Oxbow lake

Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox.Answers 2. Symantha 4 February, 0. Answer: meanders oxbow lakes waterfalls Explanation: River erosion is the carving of the earth's surface by a river.

There are four major ways that a river erodes; attrition, solution, abrasion and hydraulic action. Waterfalls are mainly found upstream because the water moves at higher velocity as a result of higher gradient in watershed regions hence the water has a higher vertical erosion.

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Meanders and oxbow lakes are formed downstream where the gradient is low and water has a stronger horizontal erosion than vertical erosion. The rest of the choices are due to surface runoff erosion, especially on soil with no vegetation to break the running water. Clarion 4 February, 0. Answer: meanders oxbow lakes waterfalls Explanation: i just did the assignment.

Know the Answer? Not Sure About the Answer? Check all that apply. Help with Questions in Geography. The weight of the lithosphere keeps the mantle in a semi-solid state. Summarize Describe the main characteristics of cirrus, cumulus, and stratus clouds. Although the heliocentric model of the solar system was originally proposed by. The original location of an earthquake is also known as the A.

New Questions in Geography. How has the Fertile Crescent changed over time.

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Which place is a region outside of France but with French speaking people identity. A volcanic eruption produces a large amount of smoke which affects the lungs of animals. Which of these Earth systems interact during this event? A rock formed from liquid magma at temperatures above degrees Celsius and then cooled and hardened.

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What type of rock is it? Select one: a.An oxbow lake is a U-shaped lake that forms when a wide meander of a river is cut offcreating a free-standing body of water. In south Texasoxbows left by the Rio Grande are called resacas.

In Australiaoxbow lakes are called billabongs. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether or not it is cut off from the main stream. An oxbow lake forms when a river creates a meander, due to the river's eroding bank.

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After a long period of time, the meander becomes very curved, and eventually the neck of the meander becomes narrower and the river cuts through the neck, cutting off the meander and forming an oxbow lake. When a river reaches a low-lying plain, often in its final course to the sea or a lakeit meanders widely. In the vicinity of a river bend, deposition occurs on the convex bank the bank with the smaller radius.

In contrast, both lateral erosion and undercutting occur on the cut bank or concave bank the bank with the greater radius. Continuous deposition on the convex bank and erosion of the concave bank of a meandering river cause the formation of a very pronounced meander with two concave banks getting closer.

The narrow neck of land between the two neighboring concave banks is finally cut through, either by lateral erosion of the two concave banks or by the strong currents of a flood.

When this happens a new, straighter river channel develops—and an abandoned meander loop, called a cutoffforms. When deposition finally seals off the cutoff from the river channel, an oxbow lake forms. This process can occur over a time from a few years to several decades, and may sometimes become essentially static. Gathering of erosion products near the concave bank and transporting them to the convex bank is the work of the secondary flow across the floor of the river in the vicinity of a river bend.

The process of deposition of silt, sand and gravel on the convex bank is clearly illustrated in point bars. River flood plains that contain rivers with a highly sinuous platform are populated by longer oxbow lakes than those with low sinuosity.

oxbow lakes geographic facts history

This is because rivers with high sinuosity have larger meanders, and greater opportunity for longer lakes to form. Rivers with lower sinuosity are characterized by fewer cutoffs and shorter oxbow lakes due to the shorter distance of their meanders.

The effect of the secondary flow can be demonstrated using a circular bowl. Partly fill the bowl with water and sprinkle dense particles such as sand or rice into the bowl. Set the water into circular motion with one hand or a spoon. The dense particles quickly sweep into a neat pile in the center of the bowl. This is the mechanism that leads to the formation of point bars and contributes to the formation of oxbow lakes.

Geography and Geology

The primary flow of water in the bowl is circular and the streamlines are concentric with the side of the bowl. However, the secondary flow of the boundary layer across the floor of the bowl is inward toward the center. The primary flow might be expected to fling the dense particles to the perimeter of the bowl, but instead the secondary flow sweeps the particles toward the center. The curved path of a river around a bend makes the water's surface slightly higher on the outside of the bend than on the inside.

As a result, at any elevation within the river, water pressure is slightly greater near the outside of the bend than on the inside. A pressure gradient toward the convex bank provides the centripetal force necessary for each parcel of water to follow its curved path.They are transitional communities, which have neither the benefits of a traditional tribal community with its medicine man nor the benefits of modern civilization with its available medical care, except for annual immunizations and elementary schooling.

They live on a rich floodplain that annually undergoes drastic environmental change. The river is their life and is used for washing, bathing and fishing, and the water for cooking. Since there are no roads in the forest, the rivers are the roads and highways. Everyone travels by dugout canoes and even young children know how to paddle a canoe at an early age.

Children attend schools in villages along the rivers, sometimes traveling long distances to reach the one-room building where one teacher teaches students in many grades. Farming is the major focus, but fishing, hunting, extraction of forest products, and waged labor are also integral economic pursuits of the Amazon river people.

The primary dietary staples are sweet manioc and plantains although over sixty other plants are raised, including maize, rice, beans, and a number of fruits and vegetables. Despite almost five centuries of European cultural and biological intermixing the outlook of the people and their methods of managing the resources appear not to have changed much and remain essentially native in origin.

Near Iquitos, the primary city ofpeople, the floodplain measures between 15 and 25 km mi in width. The low-lying terrain is composed of fine sediments eroded and transported from the recently uplifted Andean Mountains, and the slightly higher land that rises metres feet above the water level forms the floodplain borders or levees. The ecosystem in this floodplain consists of varied landforms and bodies of water sculpted by the river covered with diverse vegetation that ranges from palm forests and flood forests to grasses and aquatic plants.

These all provide rich habitats for wildlife. Game is preferred to fish, especially large mammals like tapir, deer, peccaries, and rodents such as capybara. However, scarcity due to over-hunting in the past and uncertain seasonal availability cause the inhabitants to seek the more dependable and abundant fish.

These animals, however, also show fluctuations in their populations according to seasons and peak harvests occur during the high-water season when land is scarce. The floodplains of Amazonia have supported a large and dense human population since prehistoric times. High demographic density was enabled by the rich soils and by the abundant fisheries. On the floodplains, fishing plays a role comparable to farming.

As in agriculture, it supplies one of the vital ingredients of food intake, and it also contributes to producing cash. In certain areas, supernatural beings were thought to discourage fishing with nets and canoes in specific locations at specific times. Later developed into taboos, these beliefs assured the local inhabitants a sustainable supply of fish. Some of these culturally conditioned avoidances have led to the exclusion of the atinga Symbrancus marmuratuselectric eel Electrophorus electricuscanero Cetopsis spp.

Touching or crossing over the fishing equipment and canoes by women, especially those in menstruation, are thought to bring bad luck. Solitary fishing is possible when using projectiles like gigs and harpoons, but the use of nets and trotlines is commonly done in pairs.

Larger groups, consisting of five to six members, are common during periods of fish migration. These groupings fulfill not only an economic objective but also social needs.Chicot County is a county located in the state of Arkansas.

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Based on the census, the population was 11, The county seat is Lake Village. Chicot County is Arkansas's tenth county, formed on October 25, Chicot county is named after Point Chicot on the Mississippi River. Its name was thought to have come from the French word "chicot" stumpy for the many cypress trees along the river. Chicot County is rich, flat farmland, was created October by the Territorial Legislature from part of Arkansas County.

The county name was thought to have come from the French word "Chicot" stumpy for the many cypress trees along the river. Lake Village is the county seat. Chicot County is the state's southeastern-most county and is well known for its rich, fertile soil that often reaches 1, feet world average seven inches. Agriculture is strong; cotton, rice and soybeans are the big three with catfish farming and processing gaining, with the capabilities of processing up topounds a day.

As reported by the Census Bureau, the county has a total area of square miles 1, km 2of which square miles 1, km 2 is land and 47 square miles km 2 6. Lake Chicot offers many recreational opportunities. The lake is 22 miles long and is the largest oxbow lake in the nation. At the end of the lake, the state park offers cabins, a swimming pool, fishing, boating, camping, tours, picnicking, and many other recreational opportunities.

On stilts in the lake sets the only tourist information center in the state completely heated and cooled by solar energy. Many plantation homes are also located in the county. The courthouse is located on the banks of the lake with the jury room having a spectacular view of the lake.

Landmarks around the county include Lake Chicot, North America's largest oxbow lake and Arkansas's largest natural lake; the site of Charles Lindbergh's first night-time flight; and the legendary burial site of Hernando De Soto, near Lake Village.

Arkansas State Click Image to Enlarge. Arkansas Counties The first of the Arkansas' seventy-five present-day counties created, Arkansas County was formed on 13 Decemberwhen this area was part of the Missouri Territory.

Compare More Colleges and Universities. Find more schools to match to your needs. Start Now. All rights reserved.It is the fifth largest country in the world, exceeded in size only by RussiaCanadaChinaand the United Statesthough its area is greater than that of the 48 conterminous U. Brazil faces the Atlantic Ocean along 4, miles 7, km of coastline and shares more than 9, miles 15, km of inland borders with every South American country except Chile and Ecuador—specifically, Uruguay to the south; ArgentinaParaguayand Bolivia to the southwest; Peru to the west; Colombia to the northwest; and VenezuelaGuyanaSurinameand French Guiana to the north.

Brazil stretches roughly 2, miles 4, km from north to south and from east to west to form a vast irregular triangle that encompasses a wide range of tropical and subtropical landscapes, including wetlands, savannas, plateaus, and low mountains. The country contains no desert, high-mountain, or arctic environments. Rio de Janeiro, in the eyes of many of the world, continues to be the preeminent icon of Brazil.

However, Brazil struggles with extreme social inequalities, environmental degradationintermittent financial crises, and a sometimes deadlocked political system. Brazil is unique in the Americas because, following independence from Portugalit did not fragment into separate countries as did British and Spanish possessions in the region; rather, it retained its identity through the intervening centuries and a variety of forms of government.

At the turn of the 21st century, Brazilians marked the th anniversary of Portuguese contact with a mixture of public celebration and deprecation. The Brazilian landscape is immense and complex, with interspersed rivers, wetlands, mountains, and plateaus adjoining other major features and traversing the boundaries of states and regions.

Its diversified economy includes strong manufacturingagriculture, and service sectors. The region covers roughly one-fourth of Brazil, including forested valleys, semiarid highlands, and vast wetlands. Brazil is a predominantly tropical country famous for its extensive Amazon lowlands; however, highlands cover most of the national territory. Forested mesas and mountain ranges, scenic waterfalls, and white-water rivers characterize the area. The highest point in Brazil is Neblina Peakwhich reaches 9, feet 3, metres along the Venezuelan border in the Serra do Imeri.

The Serra da Pacaraima, farther east, rises to 9, feet 2, metres at Mount Roraimawhere the borders of Venezuela, Guyana, and Brazil meet. The Amazon lowlands are widest along the eastern base of the Andes. Shallow oxbow lakes and wetlands are found throughout the region. The immense Pantanal, an extension of the Gran Chaco plain, is a region of swamps and marshes in northwestern Mato Grosso do Sul and southern Mato Grosso states and, to a lesser extent, in northern Paraguay and eastern Bolivia; it is one of the largest freshwater wetlands in the world, covering some 54, square milessquare km.

The Pantanal is dissected by the effluents of the upper Paraguay Riverwhich overflows its banks during the rainy season, inundating all but the tops of scattered levees and low hills.

See also Drainage. Brazil Article Media Additional Info. Article Contents. Print print Print. Table Of Contents. Facebook Twitter. Give Feedback External Websites.

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