75-461: A dijkgraaf ( lit. ' dike -warden, dike-reeve ' ), sometimes called a watergraaf , is the chair of a Dutch water board . The dijkgraaf is the equivalent of a mayor in local government and a King's Commissioner in provincial government, chairing both the legislative and executive council, while having both ceremonial and representational roles as well as their own portfolios. The term goes back to medieval days. Literally
150-596: A slippery slope scenario in his style guide that, "if we do end by casting aside the AD/BC convention, almost certainly some will argue that we ought to cast aside as well the conventional numbering system [that is, the method of numbering years] itself, given its Christian basis." Some Christians are offended by the removal of the reference to Jesus, including the Southern Baptist Convention . The abbreviation BCE, just as with BC, always follows
225-414: A breach may experience flooding similar to a natural event, while damage near a breach can be catastrophic, including carving out deep holes and channels in the nearby landscape. Under natural conditions, floodwaters return quickly to the river channel as water-levels drop. During a levee breach, water pours out into the floodplain and moves down-slope where it is blocked from return to the river. Flooding
300-400: A controlled inundation by the military or a measure to prevent inundation of a larger area surrounded by levees. Levees have also been built as field boundaries and as military defences . More on this type of levee can be found in the article on dry-stone walls . Levees can be permanent earthworks or emergency constructions (often of sandbags ) built hastily in a flood emergency. Some of
375-612: A distance of some 610 km (380 mi). The scope and scale of the Mississippi levees has often been compared to the Great Wall of China . The United States Army Corps of Engineers (USACE) recommends and supports cellular confinement technology (geocells) as a best management practice. Particular attention is given to the matter of surface erosion, overtopping prevention and protection of levee crest and downstream slope. Reinforcement with geocells provides tensile force to
450-422: A dyke may be a drainage ditch or a narrow artificial channel off a river or broad for access or mooring, some longer dykes being named, e.g., Candle Dyke. In parts of Britain , particularly Scotland and Northern England , a dyke may be a field wall, generally made with dry stone . The main purpose of artificial levees is to prevent flooding of the adjoining countryside and to slow natural course changes in
525-648: A generic sense, to refer to "the common era of the Jews". The first use of the phrase "before the common era" may be that in a 1770 work that also uses common era and vulgar era as synonyms, in a translation of a book originally written in German. The 1797 edition of the Encyclopædia Britannica uses the terms vulgar era and common era synonymously. In 1835, in his book Living Oracles , Alexander Campbell , wrote: "The vulgar Era, or Anno Domini;
600-444: A high suspended sediment fraction and thus are intimately associated with meandering channels, which also are more likely to occur where a river carries large fractions of suspended sediment. For similar reasons, they are also common in tidal creeks, where tides bring in large amounts of coastal silts and muds. High spring tides will cause flooding, and result in the building up of levees. Both natural and man-made levees can fail in
675-626: A matter of convenience. There is so much interaction between people of different faiths and cultures – different civilizations, if you like – that some shared way of reckoning time is a necessity. And so the Christian Era has become the Common Era. Adena K. Berkowitz, in her application to argue before the United States Supreme Court , opted to use BCE and CE because, "Given the multicultural society that we live in,
750-547: A natural wedge shaped delta forming, a " birds-foot delta " extends far out into the ocean. The results for surrounding land include beach depletion, subsidence, salt-water intrusion, and land loss. Common Era Common Era ( CE ) and Before the Common Era ( BCE ) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar ), the world's most widely used calendar era . Common Era and Before
825-428: A number of ways. Factors that cause levee failure include overtopping, erosion, structural failures, and levee saturation. The most frequent (and dangerous) is a levee breach . Here, a part of the levee actually breaks or is eroded away, leaving a large opening for water to flood land otherwise protected by the levee. A breach can be a sudden or gradual failure, caused either by surface erosion or by subsurface weakness in
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#1732780870589900-715: A period of 138 years in which the traditional BC/AD dating notation was used. BCE/CE is used by the College Board in its history tests, and by the Norton Anthology of English Literature . Others have taken a different approach. The US-based History Channel uses BCE/CE notation in articles on non-Christian religious topics such as Jerusalem and Judaism . The 2006 style guide for the Episcopal Diocese Maryland Church News says that BCE and CE should be used. In June 2006, in
975-799: A property-boundary marker or drainage channel. Where it carries a stream, it may be called a running dike as in Rippingale Running Dike , which leads water from the catchwater drain , Car Dyke, to the South Forty Foot Drain in Lincolnshire (TF1427). The Weir Dike is a soak dike in Bourne North Fen , near Twenty and alongside the River Glen , Lincolnshire . In the Norfolk and Suffolk Broads ,
1050-525: A ridge and increasing the river channel's capacity. Alternatively, levees can be artificially constructed from fill , designed to regulate water levels. In some circumstances, artificial levees can be environmentally damaging . Ancient civilizations in the Indus Valley , ancient Egypt, Mesopotamia and China all built levees. Today, levees can be found around the world, and failures of levees due to erosion or other causes can be major disasters, such as
1125-412: A shorter route to the ocean and begin building a new delta. Wave action and ocean currents redistribute some of the sediment to build beaches along the coast. When levees are constructed all the way to the ocean, sediments from flooding events are cut off, the river never migrates, and elevated river velocity delivers sediment to deep water where wave action and ocean currents cannot redistribute. Instead of
1200-421: A shorter time interval means higher river stage (height). As more levees are built upstream, the recurrence interval for high-water events in the river increases, often requiring increases in levee height. During natural flooding, water spilling over banks rises slowly. When a levee fails, a wall of water held back by the levee suddenly pours out over the landscape, much like a dam break. Impacted areas far from
1275-608: A tyrant who persecuted Christians. He numbered years from an initial reference date (" epoch "), an event he referred to as the Incarnation of Jesus. Dionysius labeled the column of the table in which he introduced the new era as " Anni Domini Nostri Jesu Christi " (Of the year of our Lord Jesus Christ]. This way of numbering years became more widespread in Europe with its use by Bede in England in 731. Bede also introduced
1350-447: A waterway to provide reliable shipping lanes for maritime commerce over time; they also confine the flow of the river, resulting in higher and faster water flow. Levees can be mainly found along the sea, where dunes are not strong enough, along rivers for protection against high floods, along lakes or along polders . Furthermore, levees have been built for the purpose of impoldering, or as a boundary for an inundation area. The latter can be
1425-537: Is electrical resistivity tomography (ERT). This non-destructive geophysical method can detect in advance critical saturation areas in embankments. ERT can thus be used in monitoring of seepage phenomena in earth structures and act as an early warning system, e.g., in critical parts of levees or embankments. Large scale structures designed to modify natural processes inevitably have some drawbacks or negative impacts. Levees interrupt floodplain ecosystems that developed under conditions of seasonal flooding. In many cases,
1500-480: Is a direct reference to Jesus as Lord . Proponents of the Common Era notation assert that the use of BCE/CE shows sensitivity to those who use the same year numbering system as the one that originated with and is currently used by Christians , but who are not themselves Christian. Former United Nations Secretary-General Kofi Annan has argued: [T]he Christian calendar no longer belongs exclusively to Christians. People of all faiths have taken to using it simply as
1575-429: Is an elevated ridge , natural or artificial, alongside the banks of a river , often intended to protect against flooding of the area adjoining the river. It is usually earthen and often runs parallel to the course of a river in its floodplain or along low-lying coastlines. Naturally occuring levees form on river floodplains following flooding, where sediment and alluvium is deposited and settles, forming
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#17327808705891650-546: Is below mean sea level. These typically man-made hydraulic structures are situated to protect against erosion. They are typically placed in alluvial rivers perpendicular, or at an angle, to the bank of the channel or the revetment , and are used widely along coastlines. There are two common types of spur dyke, permeable and impermeable, depending on the materials used to construct them. Natural levees commonly form around lowland rivers and creeks without human intervention. They are elongated ridges of mud and/or silt that form on
1725-420: Is important in order to design stable levee and floodwalls . There have been numerous studies to investigate the erodibility of soils. Briaud et al. (2008) used Erosion Function Apparatus (EFA) test to measure the erodibility of the soils and afterwards by using Chen 3D software, numerical simulations were performed on the levee to find out the velocity vectors in the overtopping water and the generated scour when
1800-485: Is in particularly common use in Nepal in order to disambiguate dates from the local calendar, Bikram or Vikram Sambat. Disambiguation is needed because the era of the local calendar is quite close to the Common Era. In 2002, an advisory panel for the religious education syllabus for England and Wales recommended introducing BCE/CE dates to schools, and by 2018 some local education authorities were using them. In 2018,
1875-451: Is permanently diverted through the gap. Sometimes levees are said to fail when water 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. Among various failure mechanisms that cause levee breaches, soil erosion is found to be one of the most important factors. Predicting soil erosion and scour generation when overtopping happens
1950-573: Is prolonged over such areas, waiting for floodwater to slowly infiltrate and evaporate. Natural flooding adds a layer of sediment to the floodplain. The added weight of such layers over many centuries makes the crust sink deeper into the mantle , much like a floating block of wood is pushed deeper into the water if another board is added on top. The momentum of downward movement does not immediately stop when new sediment layers stop being added, resulting in subsidence (sinking of land surface). In coastal areas, this results in land dipping below sea level,
2025-599: The Gregorian calendar without the AD prefix. As early as 1825, the abbreviation VE (for Vulgar Era) was in use among Jews to denote years in the Western calendar. As of 2005 , Common Era notation has also been in use for Hebrew lessons for more than a century. Jews have also used the term Current Era . Some academics in the fields of theology , education , archaeology and history have adopted CE and BCE notation despite some disagreement. A study conducted in 2014 found that
2100-723: The National Trust said it would continue to use BC/AD as its house style. English Heritage explains its era policy thus: "It might seem strange to use a Christian calendar system when referring to British prehistory, but the BC/AD labels are widely used and understood." Some parts of the BBC use BCE/CE, but some presenters have said they will not. As of October 2019, the BBC News style guide has entries for AD and BC, but not for CE or BCE. The style guide for The Guardian says, under
2175-525: The Nile Delta on the shores of the Mediterranean . The Mesopotamian civilizations and ancient China also built large levee systems. Because a levee is only as strong as its weakest point, the height and standards of construction have to be consistent along its length. Some authorities have argued that this requires a strong governing authority to guide the work and may have been a catalyst for
2250-614: The date of birth of Jesus . Since the year numbers are the same, BCE and CE dates should be equally offensive to other religions as BC and AD. Roman Catholic priest and writer on interfaith issues Raimon Panikkar argued that the BCE/CE usage is the less inclusive option since they are still using the Christian calendar numbers and forcing it on other nations. In 1993, the English-language expert Kenneth G. Wilson speculated
2325-596: The BCE/CE notation is not growing at the expense of BC and AD notation in the scholarly literature, and that both notations are used in a relatively stable fashion. In 2011, media reports suggested that the BC/AD notation in Australian school textbooks would be replaced by BCE/CE notation. The change drew opposition from some politicians and church leaders. Weeks after the story broke, the Australian Curriculum, Assessment and Reporting Authority denied
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2400-579: The Christian Era, it was sometimes qualified, e.g., "common era of the Incarnation", "common era of the Nativity", or "common era of the birth of Christ". An adapted translation of Common Era into Latin as Era Vulgaris was adopted in the 20th century by some followers of Aleister Crowley , and thus the abbreviation "e.v." or "EV" may sometimes be seen as a replacement for AD. Although Jews have their own Hebrew calendar , they often use
2475-711: The Common Era are alternatives to the original Anno Domini (AD) and Before Christ (BC) notations used for the same calendar era. The two notation systems are numerically equivalent: "2024 CE" and "AD 2024" each describe the current year; "400 BCE" and "400 BC" are the same year. The expression can be traced back to 1615, when it first appears in a book by Johannes Kepler as the Latin : annus aerae nostrae vulgaris ( year of our common era ), and to 1635 in English as " Vulgar Era". The term "Common Era" can be found in English as early as 1708, and became more widely used in
2550-495: The Gregorian Calendar as BCE and CE without compromising their own beliefs about the divinity of Jesus of Nazareth." In History Today , Michael Ostling wrote: "BC/AD Dating: In the year of whose Lord? The continuing use of AD and BC is not only factually wrong but also offensive to many who are not Christians." Critics note the fact that there is no difference in the epoch of the two systems—chosen to be close to
2625-638: The Mississippi, stretching from Cape Girardeau , Missouri , to the Mississippi delta . They were begun by French settlers in Louisiana in the 18th century to protect the city of New Orleans . The first Louisiana levees were about 90 cm (3 ft) high and covered a distance of about 80 km (50 mi) along the riverside. The U.S. Army Corps of Engineers, in conjunction with the Mississippi River Commission, extended
2700-625: The United States, the Kentucky State School Board reversed its decision to use BCE and CE in the state's new Program of Studies, leaving education of students about these concepts a matter of local discretion. The use of CE in Jewish scholarship was historically motivated by the desire to avoid the implicit "Our Lord" in the abbreviation AD . Although other aspects of dating systems are based in Christian origins, AD
2775-657: The catastrophic 2005 levee failures in Greater New Orleans that occurred as a result of Hurricane Katrina . Speakers of American English use the word levee , from the French word levée (from the feminine past participle of the French verb lever , 'to raise'). It originated in New Orleans a few years after the city's founding in 1718 and was later adopted by English speakers. The name derives from
2850-637: The city of Vancouver , British Columbia , there are levees (known locally as dikes, and also referred to as "the sea wall") to protect low-lying land in the Fraser River delta, particularly the city of Richmond on Lulu Island . There are also dikes to protect other locations which have flooded in the past, such as the Pitt Polder, land adjacent to the Pitt River , and other tributary rivers. Coastal flood prevention levees are also common along
2925-488: The development of systems of governance in early civilizations. However, others point to evidence of large-scale water-control earthen works such as canals and/or levees dating from before King Scorpion in Predynastic Egypt , during which governance was far less centralized. Another example of a historical levee that protected the growing city-state of Mēxihco-Tenōchtitlan and the neighboring city of Tlatelōlco,
3000-588: The earliest levees were constructed by the Indus Valley civilization (in Pakistan and North India from c. 2600 BCE ) on which the agrarian life of the Harappan peoples depended. Levees were also constructed over 3,000 years ago in ancient Egypt , where a system of levees was built along the left bank of the River Nile for more than 1,000 kilometers (600 miles), stretching from modern Aswan to
3075-468: The early 20th century. The phrase "common era", in lower case , also appeared in the 19th century in a "generic" sense, not necessarily to refer to the Christian Era, but to any system of dates in common use throughout a civilization. Thus, "the common era of the Jews", "the common era of the Mahometans", "common era of the world", "the common era of the foundation of Rome". When it did refer to
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3150-479: The earth together. On the land side of high levees, a low terrace of earth known as a banquette is usually added as another anti-erosion measure. On the river side, erosion from strong waves or currents presents an even greater threat to the integrity of the levee. The effects of erosion are countered by planting suitable vegetation or installing stones, boulders, weighted matting, or concrete revetments . Separate ditches or drainage tiles are constructed to ensure that
3225-428: The entry for CE/BCE: "some people prefer CE (common era, current era, or Christian era) and BCE (before common era, etc.) to AD and BC, which, however, remain our style". In the United States, the use of the BCE/CE notation in textbooks was reported in 2005 to be growing. Some publications have transitioned to using it exclusively. For example, the 2007 World Almanac was the first edition to switch to BCE/CE, ending
3300-938: The foundation does not become waterlogged. Prominent levee systems have been built along the Mississippi River and Sacramento River in the United States , and the Po , Rhine , Meuse River , Rhône , Loire , Vistula , the delta formed by the Rhine, Maas/Meuse and Scheldt in the Netherlands and the Danube in Europe . During the Chinese Warring States period , the Dujiangyan irrigation system
3375-486: The fourth year of Jesus Christ, the first of which was but eight days", and also refers to the common era as a synonym for vulgar era with "the fact that our Lord was born on the 4th year before the vulgar era, called Anno Domini, thus making (for example) the 42d year from his birth to correspond with the 38th of the common era". The Catholic Encyclopedia (1909) in at least one article reports all three terms (Christian, Vulgar, Common Era) being commonly understood by
3450-450: The impact is two-fold, as reduced recurrence of flooding also facilitates land-use change from forested floodplain to farms. In a natural watershed, floodwaters spread over a landscape and slowly return to the river. Downstream, the delivery of water from the area of flooding is spread out in time. If levees keep the floodwaters inside a narrow channel, the water is delivered downstream over a shorter time period. The same volume of water over
3525-462: The inland coastline behind the Wadden Sea , an area devastated by many historic floods. Thus the peoples and governments have erected increasingly large and complex flood protection levee systems to stop the sea even during storm floods. The biggest of these are the huge levees in the Netherlands , which have gone beyond just defending against floods, as they have aggressively taken back land that
3600-549: The laboratory tests, empirical correlations related to average overtopping discharge were derived to analyze the resistance of levee against erosion. These equations could only fit to the situation, similar to the experimental tests, while they can give a reasonable estimation if applied to other conditions. Osouli et al. (2014) and Karimpour et al. (2015) conducted lab scale physical modeling of levees to evaluate score characterization of different levees due to floodwall overtopping. Another approach applied to prevent levee failures
3675-528: The levee system beginning in 1882 to cover the riverbanks from Cairo, Illinois to the mouth of the Mississippi delta in Louisiana. By the mid-1980s, they had reached their present extent and averaged 7.3 m (24 ft) in height; some Mississippi levees are as high as 15 m (50 ft). The Mississippi levees also include some of the longest continuous individual levees in the world. One such levee extends southwards from Pine Bluff , Arkansas , for
3750-420: The levee. A breach can leave a fan-shaped deposit of sediment radiating away from the breach, described as a crevasse splay . In natural levees, once a breach has occurred, the gap in the levee will remain until it is again filled in by levee building processes. This increases the chances of future breaches occurring in the same location. Breaches can be the location of meander cutoffs if the river flow direction
3825-475: The levees in the area, created for the purpose of farming the fertile tidal marshlands. These levees are referred to as dykes. They are constructed with hinged sluice gates that open on the falling tide to drain freshwater from the agricultural marshlands and close on the rising tide to prevent seawater from entering behind the dyke. These sluice gates are called " aboiteaux ". In the Lower Mainland around
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#17327808705893900-543: The main channel, this will make levee overtopping more likely again, and the levees can continue to build up. In some cases, this can result in the channel bed eventually rising above the surrounding floodplains, penned in only by the levees around it; an example is the Yellow River in China near the sea, where oceangoing ships appear to sail high above the plain on the elevated river. Levees are common in any river with
3975-445: The majority of The Lake being drained in the 17th century. Levees are usually built by piling earth on a cleared, level surface. Broad at the base, they taper to a level top, where temporary embankments or sandbags can be placed. Because flood discharge intensity increases in levees on both river banks , and because silt deposits raise the level of riverbeds , planning and auxiliary measures are vital. Sections are often set back from
4050-423: The mid-19th century by Jewish religious scholars. Since the late 20th century, BCE and CE have become popular in academic and scientific publications on the grounds that BCE and CE are religiously neutral terms. They have been promoted as more sensitive to non-Christians by not referring to Jesus , the central figure of Christianity , especially via the religious terms " Christ " and Dominus ("Lord") used by
4125-399: The ocean migrating inland, and salt-water intruding into freshwater aquifers. Where a large river spills out into the ocean, the velocity of the water suddenly slows and its ability to transport sand and silt decreases. Sediments begin to settle out, eventually forming a delta and extending to the coastline seaward. During subsequent flood events, water spilling out of the channel will find
4200-470: The other abbreviations. Nevertheless, its epoch remains the same as that used for the Anno Domini era. The idea of numbering years beginning from the date that he believed to be the date of birth of Jesus , was conceived around the year 525 by the Christian monk Dionysius Exiguus . He did this to replace the then dominant Era of Martyrs system, because he did not wish to continue the memory of
4275-484: The overtopping water impinges the levee. By analyzing the results from EFA test, an erosion chart to categorize erodibility of the soils was developed. Hughes and Nadal in 2009 studied the effect of combination of wave overtopping and storm surge overflow on the erosion and scour generation in levees. The study included hydraulic parameters and flow characteristics such as flow thickness, wave intervals, surge level above levee crown in analyzing scour development. According to
4350-422: The practice of dating years before what he supposed was the year of birth of Jesus, without a year zero . In 1422, Portugal became the last Western European country to switch to the system begun by Dionysius. The term "Common Era" is traced back in English to its appearance as " Vulgar Era" to distinguish years of the Anno Domini era, which was in popular use, from dates of the regnal year (the year of
4425-399: The rebellious Batavi pierced dikes to flood their land and to protect their retreat (70 CE ). The word dijk originally indicated both the trench and the bank . It closely parallels the English verb to dig . In Anglo-Saxon , the word dic already existed and was pronounced as dick in northern England and as ditch in the south. Similar to Dutch, the English origins of
4500-507: The reign of a sovereign) typically used in national law. (The word 'vulgar' originally meant 'of the ordinary people', with no derogatory associations. ) The first use of the Latin term anno aerae nostrae vulgaris may be that in a 1615 book by Johannes Kepler . Kepler uses it again, as ab Anno vulgaris aerae , in a 1616 table of ephemerides , and again, as ab anno vulgaris aerae , in 1617. A 1635 English edition of that book has
4575-413: The river floodplains immediately adjacent to the cut banks. Like artificial levees, they act to reduce the likelihood of floodplain inundation. Deposition of levees is a natural consequence of the flooding of meandering rivers which carry high proportions of suspended sediment in the form of fine sands, silts, and muds. Because the carrying capacity of a river depends in part on its depth, the sediment in
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#17327808705894650-440: The river to form a wider channel, and flood valley basins are divided by multiple levees to prevent a single breach from flooding a large area. A levee made from stones laid in horizontal rows with a bed of thin turf between each of them is known as a spetchel . Artificial levees require substantial engineering. Their surface must be protected from erosion, so they are planted with vegetation such as Bermuda grass in order to bind
4725-575: The riverbed, even up to a point where the riverbed is higher than the adjacent ground surface behind the levees, are found for the Yellow River in China and the Mississippi in the United States. Levees are very common on the marshlands bordering the Bay of Fundy in New Brunswick and Nova Scotia , Canada . The Acadians who settled the area can be credited with the original construction of many of
4800-595: The rumours and stated that the BC/AD notation would remain, with CE and BCE as an optional suggested learning activity. In 2013, the Canadian Museum of Civilization (now the Canadian Museum of History) in Gatineau (opposite Ottawa ), which had previously switched to BCE/CE, decided to change back to BC/AD in material intended for the public while retaining BCE/CE in academic content. The notation
4875-404: The soil to better resist instability. Artificial levees can lead to an elevation of the natural riverbed over time; whether this happens or not and how fast, depends on different factors, one of them being the amount and type of the bed load of a river. Alluvial rivers with intense accumulations of sediment tend to this behavior. Examples of rivers where artificial levees led to an elevation of
4950-524: The term means "Dike count ", like other titles ending in -graaf (equivalent to English: - grave and German : - graf ) of feudal origin, but remained a functional official. The government bodies in the Netherlands today in order of rank are: In medieval times and earlier however, the water boards were the same as municipal, and since it was a country of duchies, the Water board ( Waterschap )
5025-492: The title page in English that may be the earliest-found use of Vulgar Era in English. A 1701 book edited by John Le Clerc includes the phrase "Before Christ according to the Vulgar Æra, 6". The Merriam Webster Dictionary gives 1716 as the date of first use of the term "vulgar era" (which it defines as Christian era). The first published use of "Christian Era" may be the Latin phrase annus aerae christianae on
5100-480: The title page of a 1584 theology book, De Eucharistica controuersia . In 1649, the Latin phrase annus æræ Christianæ appeared in the title of an English almanac. A 1652 ephemeris may be the first instance found so far of the English use of "Christian Era". The English phrase "Common Era" appears at least as early as 1708, and in a 1715 book on astronomy it is used interchangeably with "Christian Era" and "Vulgar Era". A 1759 history book uses common æra in
5175-497: The traditional Jewish designations – B.C.E. and C.E. – cast a wider net of inclusion." In the World History Encyclopedia , Joshua J. Mark wrote "Non-Christian scholars, especially, embraced [CE and BCE] because they could now communicate more easily with the Christian community. Jewish, Islamic, Hindu and Buddhist scholars could retain their [own] calendar but refer to events using
5250-492: The trait of the levee's ridges being raised higher than both the channel and the surrounding floodplains. The modern word dike or dyke most likely derives from the Dutch word dijk , with the construction of dikes well attested as early as the 11th century. The 126-kilometer-long (78 mi) Westfriese Omringdijk , completed by 1250, was formed by connecting existing older dikes. The Roman chronicler Tacitus mentions that
5325-494: The water which is over the flooded banks of the channel is no longer capable of keeping the same number of fine sediments in suspension as the main thalweg . The extra fine sediments thus settle out quickly on the parts of the floodplain nearest to the channel. Over a significant number of floods, this will eventually result in the building up of ridges in these positions and reducing the likelihood of further floods and episodes of levee building. If aggradation continues to occur in
5400-482: The word lie in digging a trench and forming the upcast soil into a bank alongside it. This practice has meant that the name may be given to either the excavation or to the bank. Thus Offa's Dyke is a combined structure and Car Dyke is a trench – though it once had raised banks as well. In the English Midlands and East Anglia , and in the United States, a dike is what a ditch is in the south of England,
5475-642: Was built by the Qin as a water conservation and flood control project. The system's infrastructure is located on the Min River , which is the longest tributary of the Yangtze River , in Sichuan , China . The Mississippi levee system represents one of the largest such systems found anywhere in the world. It comprises over 5,600 km (3,500 mi) of levees extending some 1,000 km (620 mi) along
5550-488: Was constructed during the early 1400s, under the supervision of the tlahtoani of the altepetl Texcoco, Nezahualcoyotl. Its function was to separate the brackish waters of Lake Texcoco (ideal for the agricultural technique Chināmitls ) from the fresh potable water supplied to the settlements. However, after the Europeans destroyed Tenochtitlan, the levee was also destroyed and flooding became a major problem, which resulted in
5625-431: Was in governmental terms the equivalent of a city ( Stad ), and thus also the highest form of government. This article about government in the Netherlands is a stub . You can help Misplaced Pages by expanding it . Levee A levee ( / ˈ l ɛ v i / or / ˈ l ɛ v eɪ / ), dike ( American English ), dyke ( British English ; see spelling differences ), embankment , floodbank , or stop bank
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