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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] |
Floodplain
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] |
Meander Cutoff
A meander cutoff is a natural form of a cutting or cut in a river occurs when a pronounced meander (hook) in a river is breached by a flow that connects the two closest parts of the hook to form a new channel, a full loop. The steeper drop in gradient (slope) causes the river flow gradually to abandon the meander which will silt up with sediment from deposition. Cutoffs are a natural part of the evolution of a meandering river. Rivers form meanders as they flow laterally downstream (see sinuosity). Meandering rivers flow higher and hence with more total flow, pressure and erosion on the outside of their bends due to forming a vortex as in a stirred coffee cup and consequently the river erodes more the outer bank. On the inside bend of a river, the level is lower, secondary flow moves sand and gravel across the river bed creating shallows and point bars, and friction of air and perturbances of the bed act against a higher proportion of the column of water, being shorter, slowin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watercourse
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large streams are usually called rivers, while smaller, less voluminous and more intermittent river, intermittent streams are known, amongst others, as brook, creek, rivulet, rill, run, tributary, feeder, freshet, narrow river, and streamlet. The flow of a stream is controlled by three inputs – surface runoff (from precipitation or meltwater), daylighting (streams), daylighted subterranean river, subterranean water, and surfaced groundwater (Spring (hydrology), spring water). The surface and subterranean water are highly variable between periods of rainfall. Groundwater, on the other hand, has a relatively constant input and is controlled more by long-term patterns of pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Bar
A point bar is a depositional feature made of alluvium that accumulates on the inside bend of streams and rivers below the slip-off slope. Point bars are found in abundance in mature or meandering streams. They are crescent-shaped and located on the inside of a stream bend, being very similar to, though often smaller than, towheads, or river islands. Point bars are composed of sediment that is well sorted and typically reflects the overall capacity of the stream. They also have a very gentle ''slope'' and an elevation very close to water level. Since they are low-lying, they are often overtaken by floods and can accumulate driftwood and other debris during times of high water levels. Due to their near flat topography and the fact that the water speed is slow in the shallows of the point bar they are popular rest stops for boaters and rafters. However, camping on a point bar can be dangerous as a flash flood that raises the stream level by as little as a few inches (centimet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabo
Strabo''Strabo'' (meaning "squinty", as in strabismus) was a term employed by the Romans for anyone whose eyes were distorted or deformed. The father of Pompey was called "Gnaeus Pompeius Strabo, Pompeius Strabo". A native of Sicily so clear-sighted that he could see things at great distance as if they were nearby was also called "Strabo". (; ''Strábōn''; 64 or 63 BC) was an ancient Greece, ancient Greek geographer who lived in Anatolia, Asia Minor during the transitional period of the Roman Republic into the Roman Empire. He is best known for his work ''Geographica'', which presented a descriptive history of people and places from different regions of the world known during his lifetime. Additionally, Strabo authored historical works, but only fragments and quotations of these survive in the writings of other authors. Early life Strabo was born to an affluent family from Amasya, Amaseia in Kingdom of Pontus, Pontus in around 64BC. His family had been involved in politics s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miletus
Miletus (Ancient Greek: Μίλητος, Mílētos) was an influential ancient Greek city on the western coast of Anatolia, near the mouth of the Maeander River in present day Turkey. Renowned in antiquity for its wealth, maritime power, and extensive network of colonies, Miletus was a major center of trade, culture, and innovation from the Bronze Age through the Roman period. The city played a foundational role in the development of early Greek philosophy and science, serving as the home of the Milesian school with thinkers such as Thales, Anaximander, and Anaximenes of Miletus, Anaximenes. Miletus's prosperity was closely linked to its strategic coastal location and the productivity of its surrounding rural hinterland, which supported thriving agriculture and facilitated wide-ranging commercial activity. The city established dozens of colonies around the Mediterranean Sea, Mediterranean and Black Sea, significantly shaping the Ancient Greece, Greek world’s expansion. Archae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graben
In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 'trench'. The first known usage of the word in the geologic context was by Eduard Suess in 1883. The plural form is either ''graben'' or ''grabens''. Formation A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side by side with Horst (geology), horsts. Horst and graben structures indicate tensional forces and crustal stretching. Graben are produced by sets of normal faults that have parallel fault traces, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bend2
Bend may refer to: Places Canada * Bend, British Columbia, a railway point United States * Bend, California * Bend, Missouri * Bend, Oregon * Bend, South Dakota * Bend, Texas Science, technology and engineering * Bending, the deformation of an object due to an applied load * Bend, a curvature in a pipe, tube, sheet, cable or hose; see Bend radius * Bend (knot), a type of knot used to tie two ropes together Music Techniques * Bend (guitar), a guitar technique * Note bending, a glide from one pitch to another Albums and songs * ''Bend'' (8stops7 album), 2006 * ''Bend'' (The Origin album), 1992 * "Bend" (song), a 2015 song by Chet Faker People with the surname Bend * George H. Bend (1838–1900), American banker and financier * Lin Bend (1922–1978), Canadian ice hockey player * Robert Bend (1914–1999), Manitoba politician Other uses * Bend (heraldry), a diagonal band used as a heraldic charge * Curl (association football), a playing technique also called "bend" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Flow
In fluid dynamics, flow can be decomposed into primary flow plus secondary flow, a relatively weaker flow pattern superimposed on the stronger primary flow pattern. The primary flow is often chosen to be an exact solution to simplified or approximated governing equations, such as potential flow around a wing or geostrophic current or wind on the rotating Earth. In that case, the secondary flow usefully spotlights the effects of complicated real-world terms neglected in those approximated equations. For instance, the consequences of viscosity are spotlighted by secondary flow in the viscous boundary layer, resolving the tea leaf paradox. As another example, if the primary flow is taken to be a balanced flow approximation with net force equated to zero, then the secondary circulation helps spotlight acceleration due to the mild imbalance of forces. A smallness assumption about secondary flow also facilitates linearization. In engineering, secondary flow also identifies an additi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicoidal Flow
Helicoidal flow is the cork-screw-like flow of water in a meander. It is one example of a secondary flow. Helicoidal flow is a contributing factor to the formation of slip-off slopes and river cliffs in a meandering section of the river. The helicoidal motion of the flow aids the processes of hydraulic action and corrasion on the outside of the meander, and sweeps sediment across the floor of the meander towards the inside of the meander, forming point bar deposits. See also *Laminar flow *Turbulent flow In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by Chaos theory, chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disrupt ... * Baer's law * Secondary flow in river bends References Bibliography Journal of Geophysical Research, Volume 107 (2002) Rivers {{Fluiddynamics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Greece
Classical Greece was a period of around 200 years (the 5th and 4th centuries BC) in ancient Greece,The "Classical Age" is "the modern designation of the period from about 500 B.C. to the death of Alexander the Great in 323 B.C." ( Thomas R. Martin, ''Ancient Greece'', Yale University Press, 1996, p. 94). marked by much of the eastern Aegean and northern regions of Greek culture (such as Ionia and Macedonia) gaining increased autonomy from the Persian Empire; the peak flourishing of democratic Athens; the First and Second Peloponnesian Wars; the Spartan and then Theban hegemonies; and the expansion of Macedonia under Philip II. Much of the early defining mathematics, science, artistic thought (architecture, sculpture), theatre, literature, philosophy, and politics of Western civilization derives from this period of Greek history, which had a powerful influence on the later Roman Empire. Part of the broader era of classical antiquity, the classical Greek era ended after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
