Contemporary picture of the flood that struck the North Sea coast of Germany and Denmark in October 1634.

People seeking refuge from flood in Java. ca. 1865-1876.

Flooding of a creek due to heavy monsoonal rain and high tide in Darwin, Northern Territory, Australia.

Jeddah Flood, covering King Abdullah Street in Saudi Arabia.

Flooding near Key West, Florida, United States from Hurricane Wilma's storm surge in October 2005.

Flash flooding caused by heavy rain falling in a short amount of time.

Dozens of villages were inundated when rain pushed the rivers of northwestern Bangladesh over their banks in early October 2005. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured the top image of the flooded Ghaghat and Atrai Rivers on October 12, 2005. The deep blue of the rivers is spread across the countryside in the flood image.

A flood is an overflow of an expanse of water that submerges land.^[1] The European Union (EU) Floods Directive defines a flood as a covering by water of land not normally covered by water.^[2] In the sense of "flowing water", the word may also be applied to the inflow of the tide. Flooding may result from the volume of water within a body of water, such as a river or lake, which overflows or breaks levees, with the result that some of the water escapes its usual boundaries.^[3]

While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, it is not a significant flood unless such escapes of water endanger land areas used by man like a village, city or other inhabited area.

Floods can also occur in rivers, when flow exceeds the capacity of the river channel, particularly at bends or meanders. Floods often cause damage to homes and businesses if they are placed in natural flood plains of rivers. While flood damage can be virtually eliminated by moving away from rivers and other bodies of water, since time out of mind, people have lived and worked by the water to seek sustenance and capitalize on the gains of cheap and easy travel and commerce by being near water. That humans continue to inhabit areas threatened by flood damage is evidence that the perceived value of living near the water exceeds the cost of repeated periodic flooding.

The word "flood" comes from the Old English flod, a word common to Germanic languages (compare German Flut, Dutch vloed from the same root as is seen in flow, float; also compare with Latin fluctus, flumen). Deluge myths are mythical stories of a great flood sent by a deity or deities to destroy civilization as an act of divine retribution, and are featured in the mythology of many cultures.

Principal types and causes[link]

Riverine[link]

• Slow kinds: Runoff from sustained rainfall or rapid snow melt exceeding the capacity of a river's channel. Causes include heavy rains from monsoons, hurricanes and tropical depressions, foreign winds and warm rain affecting snow pack. Unexpected drainage obstructions such as landslides, ice, or debris can cause slow flooding upstream of the obstruction.
• Fast kinds: include flash floods resulting from convective precipitation (intense thunderstorms) or sudden release from an upstream impoundment created behind a dam, landslide, or glacier.

Estuarine[link]

• Commonly caused by a combination of sea tidal surges caused by storm-force winds. A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category.

Coastal[link]

• Caused by severe sea storms, or as a result of another hazard (e.g. tsunami or hurricane). A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category.

Catastrophic[link]

• Caused by a significant and unexpected event e.g. dam breakage, or as a result of another hazard (e.g. earthquake or volcanic eruption). See outburst flood.

Human-induced[link]

• Accidental damage by workmen to tunnels or pipes.

Muddy[link]

• A muddy flood is produced by an accumulation of runoff generated on cropland. Sediments are then detached by runoff and carried as suspended matter or bed load. Muddy runoff is more likely detected when it reaches inhabited areas. Muddy floods are therefore a hill slope process, and confusion with mudflows produced by mass movements should be avoided.

Other[link]

• Floods can occur if water accumulates across an impermeable surface (e.g. from rainfall) and cannot rapidly dissipate (i.e. gentle orientation or low evaporation).
• A series of storms moving over the same area.
• Dam-building beavers can flood low-lying urban and rural areas, often causing significant damage.

Effects[link]

Primary effects[link]

• Physical damage – Can damage any type of structure, including bridges, cars, buildings, sewerage systems, roadways, and canals.

Secondary effects[link]

• Water supplies – Contamination of water. Clean drinking water becomes scarce.
• Diseases – Unhygienic conditions. Spread of water-borne diseases.
• Crops and food supplies – Shortage of food crops can be caused due to loss of entire harvest.^[4] However, lowlands near rivers depend upon river silt deposited by floods in order to add nutrients to the local soil.
• Trees – Non-tolerant species can die from suffocation.^[5]
• Transport - Transport links destroyed, so hard to get emergency aid to those who need it.

Tertiary and long-term effects[link]

Economic – Economic hardship, due to: temporary decline in tourism, rebuilding costs, food shortage leading to price increase, etc.

Control[link]

Main article: Flood control

Autumn Mediterranean flooding in Alicante (Spain), 1997.

The River Berounka, Czech Republic, burst its banks in the 2002 European floods and houses in the village of Hlásná Třebaň, Beroun District, were inundated.

Pittsburgh floods in 1936

Floods in Bangladesh 2009

In many countries across the world, rivers prone to floods are often carefully managed. Defenses such as levees,^[6] bunds, reservoirs, and weirs are used to prevent rivers from bursting their banks. When these defenses fail, emergency measures such as sandbags or portable inflatable tubes are used. Coastal flooding has been addressed in Europe and the Americas with coastal defences, such as sea walls, beach nourishment, and barrier islands.

Europe[link]

Remembering the misery and destruction caused by the 1910 Great Flood of Paris, the French government built a series of reservoirs called Les Grands Lacs de Seine (or Great Lakes) which helps remove pressure from the Seine during floods, especially the regular winter flooding.^[7]

London is protected from sea flooding by the Thames Barrier, a huge mechanical barrier across the River Thames, which is raised when the sea water level reaches a certain point.

Venice has a similar arrangement, although it is already unable to cope with very high tides; a new system of variable-height dikes is under construction. The defences of both London and Venice would be rendered inadequate if sea levels were to rise.

The Adige in Northern Italy was provided with an underground canal that allows to drain part of its flow into the Garda Lake (in the Po drainage basin), thus lessening the risk of estuarine floods. The underground canal has been used twice, in 1966 and 2000.

The largest and most elaborate flood defences can be found in the Netherlands, where they are referred to as Delta Works with the Oosterschelde dam as its crowning achievement. These works were built in response to the North Sea flood of 1953 of the southwestern part of the Netherlands. The Dutch had already built one of the world's largest dams in the north of the country: the Afsluitdijk (closing occurred in 1932).

Currently the Saint Petersburg Flood Prevention Facility Complex is to be finished by 2008, in Russia, to protect Saint Petersburg from storm surges. It also has a main traffic function, as it completes a ring road around Saint Petersburg. Eleven dams extend for 25.4 kilometres and stand eight metres above water level.

In Austria, flooding for over 150 years, has been controlled by various actions of the Vienna Danube regulation, with dredging of the main Danube during 1870–75, and creation of the New Danube from 1972–1988.

In Northern Ireland flood risk management is provided by Rivers Agency.

North America[link]

Another elaborate system of floodway defences can be found in the Canadian province of Manitoba. The Red River flows northward from the United States, passing through the city of Winnipeg (where it meets the Assiniboine River) and into Lake Winnipeg. As is the case with all north-flowing rivers in the temperate zone of the Northern Hemisphere, snowmelt in southern sections may cause river levels to rise before northern sections have had a chance to completely thaw. This can lead to devastating flooding, as occurred in Winnipeg during the spring of 1950. To protect the city from future floods, the Manitoba government undertook the construction of a massive system of diversions, dikes, and floodways (including the Red River Floodway and the Portage Diversion). The system kept Winnipeg safe during the 1997 flood that devastated many communities upriver from Winnipeg, including Grand Forks, North Dakota and Ste. Agathe, Manitoba. It also kept Winnipeg safe during the 2009 flood.

In the U.S., the New Orleans Metropolitan Area, 35% of which sits below sea level, is protected by hundreds of miles of levees and flood gates. This system failed catastrophically, in numerous sections, during Hurricane Katrina, in the city proper and in eastern sections of the Metro Area, resulting in the inundation of approximately 50% of the metropolitan area, ranging from a few centimetres to 8.2 metres (a few inches to 27 feet) in coastal communities.^[8] In an act of successful flood prevention, the Federal Government of the United States offered to buy out flood-prone properties in the United States in order to prevent repeated disasters after the 1993 flood across the Midwest. Several communities accepted and the government, in partnership with the state, bought 25,000 properties which they converted into wetlands. These wetlands act as a sponge in storms and in 1995, when the floods returned, the government did not have to expend resources in those areas.^[9]

Asia[link]

In India, Bangladesh and China, flood diversion areas are rural areas that are deliberately flooded in emergencies in order to protect cities.^[10]

Many have proposed that loss of vegetation (deforestation) will lead to a risk increase. With natural forest cover the flood duration should decrease. Reducing the rate of deforestation should improve the incidents and severity of floods.^[11]

Africa[link]

In Egypt, both the Aswan Dam (1902) and the Aswan High Dam (1976) have controlled various amounts of flooding along the Nile river.

Clean-up safety[link]

Clean-up activities following floods often pose hazards to workers and volunteers involved in the effort. Potential dangers include: water polluted by mixing with and causing overflows from sanitary sewers, electrical hazards, carbon monoxide exposure, musculoskeletal hazards, heat or cold stress, motor vehicle-related dangers, fire, drowning, and exposure to hazardous materials.^[12] Because flooded disaster sites are unstable, clean-up workers might encounter sharp jagged debris, biological hazards in the flood water, exposed electrical lines, blood or other body fluids, and animal and human remains. In planning for and reacting to flood disasters, managers provide workers with hard hats, goggles, heavy work gloves, life jackets, and watertight boots with steel toes and insoles.^[13]

Benefits[link]

There are many disruptive effects of flooding on human settlements and economic activities. However, floods (in particular the more frequent/smaller floods) can also bring many benefits, such as recharging ground water, making soil more fertile and providing nutrients in which it is deficient. Flood waters provide much needed water resources in particular in arid and semi-arid regions where precipitation events can be very unevenly distributed throughout the year. Freshwater floods, particularly play an important role in maintaining ecosystems in river corridors and are a key factor in maintaining floodplain biodiversity.^[14] Flooding adds a lot of nutrients to lakes and rivers which leads to improved fisheries for a few years, also because of the suitability of a floodplain for spawning (little predation and a lot of nutrients).^[15] Fish like the weather fish make use of floods to reach new habitats. Together with fish also birds profit from the boost in production caused by flooding.^[16]

Periodic flooding was essential to the well-being of ancient communities along the Tigris-Euphrates Rivers, the Nile River, the Indus River, the Ganges and the Yellow River, among others. The viability for hydrological based renewable sources of energy is higher in flood prone regions.

Computer modelling[link]

While flood modelling is a fairly recent practice, attempts to understand and manage the mechanisms at work in floodplains have been made for at least six millennia.^[17] The recent development in computational flood modelling has enabled engineers to step away from the tried and tested "hold or break" approach and its tendency to promote overly engineered structures. Various computational flood models have been developed in recent years either 1D models (flood levels measured in the channel) and 2D models (flood depth measured for the extent of the floodplain). HEC-RAS,^[18] the Hydraulic Engineering Centre model, is currently among the most popular if only because it is available for free. Other models such as TUFLOW^[19] combine 1D and 2D components to derive flood depth in the floodplain. So far the focus has been on mapping tidal and fluvial flood events but the 2007 flood events in the UK have shifted the emphasis onto the impact of surface water flooding.^[20]

Deadliest floods[link]

Below is a list of the deadliest floods worldwide, showing events with death tolls at or above 100,000 individuals.

See also[link]

	Environment portal
	Ecology portal

References[link]

Bibliography[link]

• O'Connor, Jim E. and John E. Costa. (2004). The World's Largest Floods, Past and Present: Their Causes and Magnitudes [Circular 1254]. Washington, D.C.: U.S. Department of the Interior, U.S. Geological Survey.
• Thompson, M.T. (1964). Historical Floods in New England [Geological Survey Water-Supply Paper 1779-M]. Washington, D.C.: United States Government Printing Office.
• Powell, W. Gabe. 2009. Identifying Land Use/Land Cover (LULC) Using National Agriculture Imagery Program (NAIP) Data as a Hydrologic Model Input for Local Flood Plain Management. Applied Research Project. Texas State University – San Marcos.

External links[link]

Wikimedia Commons has media related to: Flood

Wikinews has related news: Flood

This article's use of external links may not follow Wikipedia's policies or guidelines. Please improve this article by removing excessive or inappropriate external links, and converting useful links where appropriate into footnote references. (January 2011)

• Website on the Great Flood of Paris in 1910
• U.S. Centers for Disease Control and Prevention (CDC) Healthy Water – Flood Water Exposure Health risks, cleanup of flood waters, and links to flood resources
• American Water Resources Association
• Associated Programme on Flood Management from World Meteorological Organization
• Dartmouth Flood Observatory
• Decision tree to choose an uncertainty method for hydrological and hydraulic modelling, Choosing an uncertainty analysis for flood modeling.
• DeltaWorks.Org Flood protecting dams and barriers project in the Netherlands
• Video: Monsoon flooding, in Phnom Penh, Cambodia
• Europe floods 2006
• Flood Risk Management Research Consortium
• International Flood Initiative
• International teaching module "Integrated Flood Risk Management of Extreme Events" (Floodmaster)
• Predictions Off for Global Warming Flood Risk – Study.
• Protecting against the Next Katrina – Scientific American Magazine (October 2005)
• Related articles at Appropedia, a wiki for non-Wikipedia (projects & practical "how to") content.
• Safecoast Knowledge exchange on coastal flooding and climate change in the North Sea region
• Social & Economic Benefits/Costs of Heavy Rain & Flooding NOAA Economics
• Riversagencyni.gov.uk, Rivers Agency of Northern Ireland
• UN-CECAR research and courses on flood disaster risk management and climate change adaptation

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2008)

News is the communication of selected^[1] information on current events which is presented by print, broadcast, Internet, or word of mouth to a third-party or mass audience.

Etymology[link]

One theory claims that the English word "news" developed in the 14th century as a special use of the plural form of "new". In Middle English, the equivalent word was newes, like the French nouvelles and the German neues. Similar developments are found in the Slavic languages – the Czech and Slovak noviny (from nový, "new"), the cognate Polish nowiny and Russian novosti – and in the Celtic languages: the Welsh newyddion (from newydd) and the Cornish nowodhow (from nowydh).

History[link]

Before the invention of newspapers in the early 17th century, official government bulletins and edicts were circulated at times in some centralized empires.^[2]

The first documented use of an organized courier service for the diffusion of written documents is in Egypt, where Pharaohs used couriers for the diffusion of their decrees in the territory of the State (2400 BC).^[3] This practice almost certainly has roots in the much older practice of oral messaging and may have been built on a pre-existing infrastructure.

In Ancient Rome, Acta Diurna, or government announcement bulletins, were made public by Julius Caesar. They were carved in metal or stone and posted in public places.

In China, early government-produced news sheets, called tipao, circulated among court officials during the late Han dynasty (second and third centuries AD). Between 713 and 734, the Kaiyuan Za Bao ("Bulletin of the Court") of the Chinese Tang Dynasty published government news; it was handwritten on silk and read by government officials. In 1582 there was the first reference to privately published newssheets in Beijing, during the late Ming Dynasty.^[4]

In Early modern Europe, increased cross-border interaction created a rising need for information which was met by concise handwritten newssheets. In 1556, the government of Venice first published the monthly Notizie scritte, which cost one gazetta.^[5] These avvisi were handwritten newsletters and used to convey political, military, and economic news quickly and efficiently to Italian cities (1500–1700) — sharing some characteristics of newspapers though usually not considered true newspapers.^[6] Due to low literacy rates, news was at times disseminated by town criers.

Relation aller Fürnemmen und gedenckwürdigen Historien, from 1605, is recognized as the world's first newspaper.^[7]

The oldest news agency is the Agence France-Presse (AFP).^[8] It was founded in 1835 by a Parisian translator and advertising agent, Charles-Louis Havas as Agence Havas.

In modern times, printed news had to be phoned in to a newsroom or brought there by a reporter, where it was typed and either transmitted over wire services or edited and manually set in type along with other news stories for a specific edition. Today, the term "breaking news" has become trite as commercial broadcasting United States cable news services that are available 24-hours a day use live satellite technology to bring current events into consumers' homes as the event occurs. Events that used to take hours or days to become common knowledge in towns or in nations are fed instantaneously to consumers via radio, television, mobile phone, and the Internet.

Newspapers[link]

Most large cities in the United States historically had morning and afternoon newspapers. As the media evolved and news outlets increased to the point of near over-saturation, most afternoon newspapers were shut down. Morning newspapers have been gradually losing circulation, according to reports advanced by the papers themselves. Commonly, news content should contain the "Five Ws" (who, what, when, where, why, and also how) of an event. There should be no questions remaining. Newspapers normally place hard news stories on the first pages, so the most important information is at the beginning. Busy readers can read as little or as much as they desire. Local stations and networks with a set format must take news stories and break them down into the most important aspects due to time constraints. Cable news channels such as BBC News, Fox News, MSNBC, and CNN, are able to take advantage of a story, sacrificing other, decidedly less important stories, and giving as much detail about breaking news as possible.

News organizations are often expected to aim for objectivity; reporters claim to try to cover all sides of an issue without bias, as compared to commentators or analysts, who provide opinion or personal point-of-view. The result is a laying out of facts in a sterile, noncommittal manner, and then standing back to "let the reader decide" which view is true.^[9] Several governments impose certain constraints or police news organizations against bias. In the United Kingdom, for example, limits are set by the government agency Ofcom, the Office of Communications. Both newspapers and broadcast news programs in the United States are generally expected to remain neutral and avoid bias except for clearly indicated editorial articles or segments. Many single-party governments have operated state-run news organizations, which may present the government's views.

Even in those situations where objectivity is expected, it is difficult to achieve, and individual journalists may fall foul of their own personal bias, or succumb to commercial or political pressure. Similarly, the objectivity of news organizations owned by conglomerated corporations fairly may be questioned, in light of the natural incentive for such groups to report news in a manner intended to advance the conglomerate's financial interests. Individuals and organizations who are the subject of news reports may use news management techniques to try to make a favourable impression.^[10] Because each individual has a particular point of view, it is recognized that there can be no absolute objectivity in news reporting.^[11]

Newsworthiness[link]

Newsworthiness is defined as a subject having sufficient relevance to the public or a special audience to warrant press attention or coverage.^[12]

In some countries and at some points in history, what news media and the public have considered "newsworthy" has met different definitions, such as the notion of news values.^[13] For example, mid-twentieth-century news reporting in the United States focused on political and local issues with important socio-economic impacts, such as the landing of a living person on the moon or the cold war. More recently, the focus similarly remains on political and local issues; however, the news mass media now comes under criticism for over-emphasis on "non-news" and "gossip" such as celebrities' personal social issues, local issues of little merit, as well as biased sensationalism of political topics such as terrorism and the economy. The dominance of celebrity and social news, the blurring of the boundary between news and reality shows and other popular culture, and the advent of citizen journalism may suggest that the nature of ‘news’ and news values are evolving and that traditional models of the news process are now only partially relevant.^[14] Newsworthiness does not only depend on the topic, but also the presentation of the topic and the selection of information from that topic.

New ecology of news[link]

“Everything we thought we once knew about journalism needs to be rethought in the Digital Age”,^[15] professor of Sociology and Communication Michael Schudson points out. Today the work of journalism can be done from anywhere and done well. It requires no more than a reporter and a laptop. In that way, journalistic authority seems to have become more individual- and less institution-based. But does the individual reporter always have to be an actual journalist? Or can journalistic work be done from anywhere and by anyone? These are questions that refers to the core of journalistic practice and the definition of “news” itself. As Schudson has given emphasis to, the answer is not easily found; “the ground journalists walk upon is shaking, and the experience for both those who work in the field and those on the outside studying it is dizzying”.^[15]

Schudson has identified the following six specific areas where the ecology of news in his opinion has changed: 1. The line between the reader and writer has blurred 2. The distinction among tweet, blog post, newspaper story, magazine article, and book has blurred 3. The line between professionals and amateurs has blurred, and a variety of “pro-am” relationships has emerged 4. The boundaries delineating for-profit, public, and non-profit media have blurred, and the cooperation across these models of financing has developed 5. Within commercial news organizations, the line between the news room and the business office has blurred 6. The line between old media and new media has blurred, practically beyond recognition ^[16]

These alterations inevitably has fundamental ramifications for the contemporary ecology of news. “The boundaries of journalism, which just a few years ago seemed relatively clear, and permanent, have become less distinct, and this blurring, while potentially the foundation of progress even as it is the source of risk, has given rise to a new set of journalistic principles and practices”,^[17] Schudson puts it. It is indeed complex, but it seems to be the future.

References[link]

Further reading[link]

• Stephens, Mitchell. "The History of News - 3rd Ed" Oxford University Press, New York, 2007.

External links[link]

• News media by country at the Open Directory Project