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Flood Plain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrology), discharge.Goudie, A. S., 2004, ''Encyclopedia of Geomorphology'', vol. 1. Routledge, New York. The soils usually consist of clays, silts, sands, and gravels deposited during floods. Because of regular flooding, floodplains frequently have high soil fertility since nutrients are deposited with the flood waters. This can encourage farming; some important agricultural regions, such as the Nile and Mississippi Basin, Mississippi Drainage basin, river basins, heavily exploit floodplains. Agricultural and urban regions have developed near or on floodplains to take advantage of the rich soil and freshwater. However, the Flood risk, risk of inundation has led to increasing efforts to Flood control, control flooding. Formation Most floodplai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraná River Floodplain
Paraná, Paranã or Parana may refer to: Geology *Paraná Basin, a sedimentary basin in South America Places In Argentina *Paraná, Entre Ríos, a city *Paraná Department, a part of Entre Ríos Province In Brazil *Paraná (state), a state in the South of Brazil *Paraná, Rio Grande do Norte, a town *Paraná Province, one of the provinces of the Empire of Brazil *Paranã, a city in the state of Tocantins *Ji-Paraná, a city in the state of Rondônia Rivers *Paraná River, a river that flows through Brazil, Paraguay, and Argentina **Paraná Delta, at the mouth of Paraná River *Paranã River, a river in the state of Goiás, Brazil *Paraná Urariá, a river in the state of Amazonas, Brazil Other *ARA Paraná, ARA ''Paraná'', several ships of the Argentine Navy *Ji-Paraná Futebol Clube, a football team from Ji-Paraná, Rondônia state *Paraná Clube, a football team in the Vila Capanema district of Curitiba, Paraná *Paraná (footballer), Brazilian association footballer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meanders
A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank or river cliff) and deposits sediments on an inner, convex bank which is typically a point bar. The result of this coupled erosion and sedimentation is the formation of a sinuous course as the channel migrates back and forth across the axis of a floodplain. The zone within which a meandering stream periodically shifts its channel is known as a meander belt. It typically ranges from 15 to 18 times the width of the channel. Over time, meanders migrate downstream, sometimes in such a short time as to create civil engineering challenges for local municipalities attempting to maintain stable roads and bridges.Neuendorf, K.K.E., J.P. Mehl Jr., and J.A. Jackson, J.A., eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. Charlton, R., 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluvial Terrace
Fluvial terraces are elongated Terrace (geology), terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplain, other fluvial terraces, or uplands by distinctly steeper strips of land called "risers". These terraces lie parallel to and above the river channel and its floodplain. Because of the manner in which they form, fluvial terraces are underlain by fluvial sediments of highly variable thickness. River terraces are the remnants of earlier floodplains that existed at a time when either a stream or river was flowing at a higher elevation before its channel downcut to create a new floodplain at a lower elevation. Changes in elevation can be due to changes in the base level (elevation of the lowest point in the fluvial system, usually the drainage basin) of the fluvial system, which leads to headward erosion along the length of either a stream or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Incision
River incision is the narrow erosion caused by a river or stream that is far from its base level. River incision is common after tectonic uplift of the landscape. Incision by multiple rivers result in a dissected landscape, for example a dissected plateau. River incision is the natural process by which a river cuts downward into its bed, deepening the active channel. Though it is a natural process, it can be accelerated rapidly by human factors including land use changes such as timber harvest, mining, agriculture, and road and dam construction. The rate of incision is a function of basal shear-stress. Shear stress is increased by factors such as sediment in the water, which increase its density. Sediment transport#Depth-slope product, Shear stress t is proportional to water mass, gravity, and WSS: ::t = \rho gD\sin where t is shear stress (N/m2), ρ is density of flowing water, g is gravity on Earth, D is average water depth, and WSS is Water Surface Slope. This is analogous to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braid Bar
Braid bars, or mid-channel bars, are river bars typically present in braided river channels. These formations have many names, including medial, longitudinal, crescentic, and transverse bars, as well as the more colloquial sandflat. Braid bars are distinguished from point bars due to their presence in the middle of a flow channel, rather than along a bank of the river channel. Formation Braid bars often originate from remnants of point bars or the growth of mid-channel unit bars in braided rivers. These features typically form in rivers with a high sediment load, within channels characterized by a large bed load and easily-eroded bank material. There are several mechanisms of formation. One explanation is that flow in the river may be redirected over a point bar, wherein the bar may be separated from the bank and thus become isolated within the channel. This forms a small ‘island’ of sediment, which can evolve into a braid bar. Alternatively, an obstacle such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2008 Bihar Flood
The 2008 Bihar flood was one of the most disastrous floods in the history of Bihar, an impoverished and densely populated state in India. The Koshi embankment near the Indo-Nepal border (at Kusaha VDC, Sunsari district, Nepal) broke on 18 August 2008. The river changed course and flooded areas which had not been flooded in many decades. The flood affected over 2.3 million people in the northern part of Bihar. Incident On 18 August 2008, heavy monsoon rains and poor maintenance caused a breach in the Kosi embankment. Water passed through the breach at an estimated 3675 cubic meters per second (129,800 cusecs), flooding many villages in Nepal and hundreds of villages in northern Bihar. The flood submerged most of the Kosi alluvial fan area, which is very fertile, with a dense agrarian population. Background The Kosi River's upper basin in southern Tibet and eastern Nepal drains some 60,000 km2 of mountainous terrain, a region that tectonic forces are elevating by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1851–1855 Yellow River Floods
The 18511855 Yellow River floods were a series of natural disasters along the Yellow River in China, culminating in the 1855 channel change event. Some data is missing from this period, especially 1854. but it seems that water levels were high for most of 1851-1855.Fei, J., Lai, ZP., He, HM. et al. Limnology (2012) 13: 117. https://doi.org/10.1007/s10201-011-0361-5 The Yellow River had flowed along various courses south of the Shandong Peninsula since the 1194 Yellow River flood, disastrous floods of 1194. These mid-19th century floods reversed that, shifting the river into a path north of Shandong once again and causing it to empty into the Bohai Sea near Tianjin rather than the Yellow Sea on the Jiangsu coast. This natural disaster is thought to have been a major cause of the Taiping Rebellion and Nian Rebellion. See also * Yellow River flood (other), Floods of the Yellow River References 1851 in China 1852 in China 1853 in China 1854 in China 1855 in China Ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxbow Lake
An oxbow lake is a U-shaped lake or stream pool, pool that forms when a wide meander of a river is meander cutoff, cut off, creating a free-standing body of water. 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. It takes its name from an oxbow which is part of a harness for oxen to pull a plough or cart. In South Texas, oxbows left by the Rio Grande are called ''resaca (channel), resacas''. In Australia, oxbow lakes are called billabongs. Geology An oxbow lake forms when a meandering river erodes through the neck of one of its meanders. This takes place because meanders tend to grow and become more curved over time. The river then follows a shorter course that bypasses the meander. The entrances to the abandoned meander eventually silt up, forming an oxbow lake. Oxbow lakes are stillwater lakes, with no current flowing through them, which causes the lake bed to gradually accumulate silt, becoming a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggradation
Aggradation (or alluviation) is the term used in geology for the increase in land elevation, typically in a river system, due to the deposition of sediment. Aggradation occurs in areas in which the supply of sediment is greater than the amount of material that the system is able to transport. The mass balance between sediment being transported and sediment in the bed is described by the Exner equation. Typical aggradational environments include lowland alluvial rivers, river deltas, and alluvial fans. Aggradational environments are often undergoing slow subsidence which balances the increase in land surface elevation due to aggradation. After millions of years, an aggradational environment will become a sedimentary basin, which contains the deposited sediment, including paleochannels and ancient floodplains. Aggradation can be caused by changes in climate, land use, and geologic activity, such as volcanic eruption, earthquake An earthquakealso called a quake, tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Delta
A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creation of a river delta occurs at the '' river mouth'', where the river merges into an ocean, a sea, or an estuary, into a lake, a reservoir, or (more rarely) into another river that cannot carry away the sediment supplied by the feeding river. Etymologically, the term ''river delta'' derives from the triangular shape (Δ) of the uppercase Greek letter delta. In hydrology, the dimensions of a river delta are determined by the balance between the watershed processes that supply sediment and the watershed processes that redistribute, sequester, and export the supplied sediment into the receiving basin. River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crevasse Splay
A crevasse splay is a sedimentary fluvial deposit which forms when a stream breaks its natural or artificial levees and deposits sediment on a floodplain. A breach that forms a crevasse splay deposits sediments in similar pattern to an alluvial fan deposit. Once the levee has been breached the water flows out of its channel. As the water spreads onto the flood plain sediments will start to fall out of suspension as the water loses energy. The resulting deposition can create graded deposits similar to those found in Bouma sequences. In some cases crevasse splays can cause a river to abandon its old river channel, a process known as avulsion. Breaches that form a crevasse splay deposits occur most commonly on the outside banks of meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhine River
The Rhine ( ) is one of the major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Swiss-Austrian border. From Lake Constance downstream, it forms part of the Swiss-German border. After that the Rhine defines much of the Franco-German border. It then flows in a mostly northerly direction through the German Rhineland. Finally, the Rhine turns to flow predominantly west to enter the Netherlands, eventually emptying into the North Sea. It drains an area of 185,000 km2. Its name derives from the Gaulish ''Rēnos''. There are two German states named after the river, North Rhine-Westphalia and Rhineland-Palatinate, in addition to several districts (e.g. Rhein-Sieg). The departments of Bas-Rhin and Haut-Rhin in Alsace (France) are also named after the river. Some adjacent towns are named after it, such as Rheinau, Stein am Rhein, Rheineck, Rheinfelden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
