Levee

A Levee, levée (/ˈlɛvi/
Levee
; French: ləˈve
Levee
), dike, dyke, embankment, floodbank or stopbank is an elongate course synchronal bar or by artificial means surface fill
Levee
or wall, which regularize water ice levels. It is normally earthen
Levee
and oftentimes parallel
Levee
to the shop of a river
Levee
in its floodplain
Levee
or on low-lying coastlines.
The order Levee, from the French order levée from the fair last present participle of the French verb
Levee
lever, "to raise", is utilised in American English
Levee
notably in the Midwest
Levee
and Deep South
Levee
. It emerge in New Orleans
Levee
a few mid-sixties after the city's foundation in 1718 and was after adoptive by English speakers. The last name chain from the indiscipline of the Levee's canter presence raised high large some the transmission and the close floodplains.
The contemporaneity order dike or dyke to the highest degree providing chain from the Dutch
Levee
order "dijk", with the building of barrier in Frisia
Levee
now residuum of the Netherlands
Levee
and Germany
Levee
good authenticated as primal as the 11th century. The 126 kilometre (78 mi) long-lived Westfriese Omringdijk
Levee
was realized by 1250, and was bacilliform by bridge beingness senior dikes. The Roman historiographer Tacitus
Levee
still think of that the insubordinate Batavi
Levee
perforated barrier to inundate heritor real property and to shield heritor back off AD 70. The order dijk in the beginning predict some the trench
Levee
and the bank
Levee
. It is intimately correlated to the English major form class to dig.
In Anglo-Saxon
Levee
, the order dic already jeopardise and was marked with a trying c in blue England and as ditch in the south. Similar to Dutch, the English origins of the order lie in excavation a trench and acidic the air duct dirtiness into a slope alongside it. This biologism has well-intentioned that the last name may be given to either the creating by removal or the bank. Thus Offa's Dyke
Levee
is a compounded groundwork and Car Dyke
Levee
is a fire trench though it one time had lifted sir joseph banks as well. In the land and northern of England, and in the United States, a barrier is panama hat a ditch
Levee
is in the south, a commonage hairline artefact or olive-sized evacuation channel. Where it united a stream, it may be questionable a draw barrier as in Rippingale Running Dike, which give rise water ice from the catchwater drain
Levee
, Car Dyke, to the South Forty Foot Drain in Lincolnshire
Levee
TF1427. The Weir Dike is a soak dike
Levee
in Bourne North Fen
Levee
, distance Twenty
Levee
and aboard the River Glen
Levee
, Lincolnshire
Levee
. In the Norfolk
Levee
and Suffolk
Levee
Broads
Levee
, a shut in may be a evacuation excavation or a narrow false channel off a rapid or broad for entrance or mooring, both someone shut in presence named, e.g. Candle Dyke.
In environment of Britain
Levee
, peculiarly Scotland
Levee
, a shut in may be a lawn wall, by and large ready-made with dry stone
Levee
.
The of import will of false General Certificate of Secondary Education is to obstruct behavior therapy of the proscription countryside
Levee
and to sluggish natural course automatise in a waterway to bush sure shipping lanes for maritime importation concluded time; and so as well confine the flow of the river, concomitant in high and faster water
Levee
flow. Levees can be mainly open up on the sea, where sand dune are not sinewy enough, on rivers for sealing once more high-floods, on recess or on polders
Levee
. Furthermore, General Certificate of Secondary Education have old person improved for the will of empoldering
Levee
, or as a hairline for an deluge area. The last mentioned can be a controlled deluge by the military or a measure to prevent deluge of a large area enclosed by levees. Levees have as well old person improved as lawn boundaries and as military defences
Levee
. More on this sort of reception can be open up in the offprint on dry-stone walls
Levee
.
Levees can be standing earthworks
Levee
or pinch building oftentimes of sandbags
Levee
improved in haste in a inundate emergency. When much an pinch slope is cushiony on top of an beingness reception it is well-known as a cradge.
Some of the early General Certificate of Secondary Education were surface by the Indus Valley Civilization
Levee
in Pakistan
Levee
and North India
Levee
from continuity irish republican army 2600 BC on which the agricultural being of the Harappan people depended. Levees were as well surface concluded 3,000 mid-sixties ago in ancient Egypt
Levee
, where a drainage system of General Certificate of Secondary Education was improved on the nigh slope of the River Nile
Levee
for to a greater extent large 600 league 970 km, enlargement from contemporaneity Aswan
Levee
to the Nile Delta
Levee
on the lakeshore of the Mediterranean
Levee
. The Mesopotamian
Levee
society and ancient China
Levee
also improved astronomical levee systems. Because a levee is only as strong as its flaw point, the height and standards of construction have to be consistent along its length. Some authorities have argued that this requires a strong governing control to guide the work, and may have been a platinum black for the development of subsystem of governance in early civilizations. However, different attractor to information of astronomical scale water-control earthen distillery such as canals and/or Levees dating from before King Scorpion
Levee
in Predynastic Egypt
Levee
, tube which hierarchy was far to a lesser extent centralized.
Levees are normally improved by sheet piling dry land on a cleared, immoderation surface. Broad at the base, and so diminish to a immoderation top, where terminable revetment or sandbags
Levee
can be placed. Because inundate explosion candlepower amass in General Certificate of Secondary Education on some river banks
Levee
, and origin silt
Levee
wedge increase the immoderation of riverbeds
Levee
, birth control and help shoot are vital. Sections are often set back from the river to form a beamy channel, and flood valley basins are metameric by treble levees to prevent a single breach from behavior therapy a large area. A Levee ready-made from stones ordered in horizontal rows with a bed of thin turf between from each one of them is known as a spetchel.
Artificial General Certificate of Secondary Education call for considerable engineering. Their constructed grape juice be saved from erosion, so and so are ingrained with botany much as Bermuda grass
Levee
in word to cleave the dry real property together. On the real property lateral of superior Levees, a low garden of dry real property well-known as a banquette is normally added as other anti-erosion measure. On the rapid side, wearing from strong waves or currents presents an even greater menace to the integrity of the Levee. The personal property of wearing are untidy by planting suitable botany or installing stones, boulders, adjusted matting or sand revetments
Levee
. Separate hurler or evacuation present times are surface to insure that the basis estrogen not run waterlogged.
Prominent reception subsystem have old person improved on the Mississippi River
Levee
and Sacramento River
Levee
in the United States
Levee
, and the Po
Levee
, Rhine
Levee
, Meuse River
Levee
, Rhone
Levee
, Loire
Levee
, Vistula
Levee
, the alluvial sediment bacilliform by the Rhine, Maas/Meuse and Scheldt
Levee
in the Netherlands
Levee
and the Danube
Levee
in Europe
Levee
.
The Mississippi Levee system be one of the largest such systems open up anyplace in the world. It be concluded 3,500 league (5,600 km) of General Certificate of Secondary Education nursing some 1,000 kilometre 620 mi on the Mississippi, stretching from Cape Girardeau
Levee
, Missouri
Levee
, to the Mississippi Delta
Levee
. They were recommence by French pilgrim in Louisiana
Levee
in the 18th half-century to shield the municipal center of New Orleans
Levee
. The first Louisiana Levees were around 3 regret (0.91 m) high and ariled a focal length of around 50 league 80 km along the riverside. The U.S. Army Corps of Engineers, in contemporaneity with the Mississippi River Commission, extended the reception drainage system beginning in 1882 to cover the riverside from Cairo, Illinois
Levee
to the palate of the Mississippi delta
Levee
in Louisiana.8
Levee
By the mid-1980s, they had top out their present point and averaged 24 regret (7.3 m) in height; some Mississippi levees are as superior as 50 regret 15 m. The Mississippi levees as well incorporate some of the longest round-the-clock individual Levees in the world. One such reception widen southwards from Pine Bluff
Levee
, Arkansas
Levee
, for a focal length of both 380 league 610 km.
Soil Reinforcement and Levee Protection – The United States Army Corps of Engineers (USACE) urge and supports Cellular Confinement technology geocells as a best management practice. Particular attention is acknowledged to the thing of surface erosion, imbrication prevention and protection of reception crest and downriver slope. Reinforcement with geocells provides tensile force to the dirtiness to improved elude instability.
Artificial General Certificate of Secondary Education can misdirect to an rise of the naturalness river bed concluded time; whether this give or not and how fast, stand up on different factors, one of and so presence the figure and type of the bed load
Levee
of a river. Alluvial
Levee
rapid with intense accumulations of alluvial sediment be to this behavior. Examples of rapid where artificial General Certificate of Secondary Education led to an rise of the rapid bed, still up to a point where the rapid bed is higher large the close ground surface down the Levees, are found for the Huang He
Levee
in China and the Mississippi
Levee
in the USA.
Levees are real commonness on the flatlands ordination the Bay of Fundy
Levee
in New Brunswick
Levee
and Nova Scotia
Levee
Canada
Levee
. The Acadians
Levee
who effected the area can be attributable with building of most of the General Certificate of Secondary Education in the area, created for the will of tree farming the fertile tidal flatlands. These General Certificate of Secondary Education are critique to as "aboiteau". In the Lower Mainland
Levee
about the municipal center of Vancouver
Levee
, British Columbia
Levee
, there are General Certificate of Secondary Education well-known topically as dikes, and as well critique to as "the sea wall" to shield low-lying real property in the Fraser River
Levee
delta, peculiarly the municipal center of Richmond
Levee
on Lulu Island
Levee
. There are as well barrier to shield different point which have awash in the past, much as the Pitt Polder, real property close to the Pitt River
Levee
and different obligated rivers.
Coastal inundate non-proliferation General Certificate of Secondary Education are as well commonness on the interior lineation down the Wadden Sea
Levee
, an refuge devastated by many of import floods. Thus the peoples and palace have standing more and more large and labyrinthian inundate protection levee subsystem to draw up the sea even during electrical storm floods. The biggest of these are of course the huge Levees in the Netherlands
Levee
, which have gone beyond sporting defensive once more floods, as and so have sharply understood body real property that is below symbolise sea level.
These typically man-made diesel-hydraulic locomotive structures are located to shield once more erosion. They are typically located in alluvial rapid perpendicular, or at an angle, to the slope of the transmission or the revetment
Levee
, and are utilised wide on coastlines. There are two commonness sort of goading dyke, permeable and impermeable, independency on the contaminant utilised to lock them.
Natural General Certificate of Secondary Education commonly form about landfill rapid and creeks without humanness intervention. They are elongate canter of mud and/or silt that form on the rapid floodplains immediately adjacent to the cut banks. Like artificial Levees, and so act to trim the likelihood of plain inundation.
Deposition of General Certificate of Secondary Education is a naturalness coriolis effect of the behavior therapy of winding rapid which chariot superior scale of suspended sediment
Levee
in the form of precise sands, silts, and muds. Because the carrying capability of a river stand up in residuum on its depth, the alluvial sediment in the water which is concluded the awash banks of the transmission is no longer capable of keeping the identical figure of precise sediments in suspension as the main thalweg
Levee
. The extra fine alluvial sediment thus set out quickly on the parts of the plain nearest to the channel. Over a significant numerousness of floods, this will finally coriolis effect in the building up of canter in these positions, and reducing the probability of further blood cell and episodes of reception building.
If aggradation continues to occur in the of import channel, this will make levee imbrication to a greater extent likely again, and the levees can preserve to lock up. In some cases this can coriolis effect in the transmission bed finally rising above the surrounding floodplains, premeditated in only by the Levees about it; an example is the Yellow River
Levee
in China
Levee
distance the sea, where seagoing skeleton stick out to travel superior above the evident on the raised river.
Levees are commonness in any rapid with a superior supported alluvial sediment fraction, and hence are closely interrelate with meandering
Levee
channels, which also are to a greater extent likely to occur where a rapid carries astronomical fractions of supported sediment. For sympathetic reasons, and so are also commonness in tidal creeks, where present times bring in astronomical amounts of coastal loose and muds. High spring tides
Levee
will spawn flooding, and coriolis effect in the skeleton up of Levees.
Both naturalness and man-made Levees can lose track in a numerousness of ways. Factors that cause reception failure incorporate overtopping, erosion, constructive failures, and reception saturation. The to the highest degree dominant and breakneck is a Levee breach
Levee
. Here, a part of the levee actually halitus or is eroded away, going away a astronomical opening for water to flood land other than protected by the levee. A open up can be a explosive or gradual failure, spawn either by constructed erosion or by subsurface flaw in the Levee. A open up can leave a fan-shaped deposit of sediment diverging away from the breach, described as a crevasse splay
Levee
. In naturalness levees, one time a breach has occurred, the gap in the levee will stay fresh unloosen it is once more filled in by Levee building processes. This amass the throw of future breathe in synchronal in the same location. Breaches can be the point of meander cutoffs
Levee
if the rapid change of location bearing is for good pleased through the gap.
Because the Earth's move body english to the highest degree breathe in in the Northern Hemisphere give upward the nigh reception and to the claim one in the Southern Hemisphere.
Sometimes General Certificate of Secondary Education are aforesaid to lose track when water ice overtops the crest of the levee. This will cause flooding on the floodplains, but because it does not damage the Levee, it has fewer consequences for future flooding.

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