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, in hydrology
flood, inundation of land by the rise and overflow of a body of water. Floods occur most commonly when water from heavy rainfall, from melting ice and snow, or from a combination of these exceeds the carrying capacity of the river system, lake, or the like into which it runs. Usually the combined flow of several water-swollen tributaries causes flooding along a river bank or shoreline. Accounts of floods that destroyed nearly all life are found in the mythology of many peoples (see Deluge). Not all floods are destructive, however. The annual floodwaters of the Nile and some other larger rivers historically deposited fertile soil along the surrounding floodplain, which is used extensively for agriculture. The damming of the Nile and other rivers in modern times, however, often has greatly reduced this deposition.

Flood Characteristics and Control

The rise and fall of the water level in a river is called the flood wave. Its highest point, or crest, travels progressively downstream. In the upstream portions of a river the flood crest passes quickly. Further downstream the greater volume of water causes slower passage of the flood crest, resulting in floods of longer duration. In many regions, annual floods follow the thaws and rains of spring; flooding also may occur because of thawing ice jamming narrower and shallower parts of a river. In the Arctic regions, especially in the basins of northward flowing rivers, the floods are caused by the thawing of the southern portion of the basin before the ice blocking the lower course of the river melts. Less predictable are floods resulting from ocean waves, called storm surges, pushed onshore by an advancing hurricane, and from sudden torrential flows, called flash floods, following a brief, intense rainstorm or the bursting of a natural or constructed dam or levee. In addition to the duration and quantity of rainfall, the nature of the soil (permeability; state of saturation) of an area affects the frequency of floods.

Generally, flood control measures along a river are attempted at both its headwaters and its low-lying floodplains. Runoff can be detained in the headwaters by planting ground cover on the slopes, building terraces to increase soil infiltration and prevent soil erosion, and building small check dams or retaining ponds to reduce the flow of water. Flood control on the lower floodplains involves building levees to contain the flow and straightening or dredging the channel to improve flow characteristics. Concern over the affects of channelization on rivers in floodplains has led to the development of flood-control approaches that attempt to combine the way floodplains naturally handle floodwaters with traditional methods that restrict those waters greater spread. Such an approach might involve increasing the distance of levees from a river's channel along with the creation of wetlands to absorb floodwaters. The relocation of residences and business from flood-prone areas has also been used as a means of diminished the human and economic impact of recurrent flooding. Among the chief flood-control projects in the United States are the flood control works along the Mississippi River, the installations of the Tennessee Valley Authority, the Glen Canyon and Hoover dams on the Colorado River, and the systems of dams in the Columbia River basin (including Grand Coulee Dam) and in the Missouri River basin.

Notable Floods

A flood of the Tiber was recorded in 413 B.C. Records of floods on the Danube date from A.D. 1000. In China some of the world's most disastrous floods have been caused by the unstable Huang He (Yellow River). The river, which flows at or above the level of the bordering land, is contained in part by levees; however, because its channel has gradually become filled with deposited sediment, any appreciable increase in its volume causes the river to overflow and flood the surrounding area. The Netherlands, dependent on its dikes for protection from inundation, has suffered many disastrous floods from the sea and the Rhine and Meuse rivers. In 1970, 1985, and 1991, hundreds of thousands of people in Bangladesh were killed when the combination of high tides and a tropical cyclone (see hurricane) storm surge caused widespread flooding of the low-lying delta of the Ganges and Brahmaputra rivers.

In the United States the Johnstown, Pa., flood of 1889, in which thousands of lives were lost, was caused by the breaking of an earth dam above the city. Even greater loss of life occurred (1900) in Galveston, Tex., when tide and storm surges engulfed the city after a hurricane. The hurricanes of 1938 on the New England and Long Island coasts and Hurricane Donna in 1960 along the Atlantic coast from Florida to the Long Island Sound were also followed by storm surges. In June, 1972, extremely heavy rainfall associated with a tropical storm inundated the basins of the Chemung and Susquehanna rivers of New York and Pennsylvania, causing severely damaging floods in Corning and Elmira, N.Y., and Wilkes-Barre and Harrisburg, Pa. In July, 1979, Hurricane Claudette deposited a U.S. record of 43 in. (109 cm) of rain in Alvin, Tex., in 24 hours. Hurricane Katrina in Aug., 2005, led to extensive and devastating storm-surge flooding along the Louisiana and Mississippi coasts, and the failure of several levees in the New Orleans area resulted in hundreds of deaths. The worst floods in the United States from river overflow were in 1913 on the Miami River (a tributary of the Ohio), in 1927, 1937, 1973, and 2011 on the Mississippi River and some of its tributaries, in 1935–36 on several New England rivers, and in 1993 on the Missouri, Mississippi, and some of their tributaries.


See P. Briggs, Rampage (1973); C. Clark, Flood (1982).

The Columbia Electronic Encyclopedia™ Copyright © 2022, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



the inundation of an area by water as a result of a rise in the water level of a river, lake, or sea owing to various factors.

A river may flood because of a sharp increase in the amount of water as a result of the melting of snow and glaciers in its basin or as a result of heavy precipitation. Many floods are caused by a rise in the water level when the river channel is jammed with ice owing to an ice drift (ice jam) or when the channel beneath an immobile sheet of ice is blocked by ice that accumulates under the sheet, forming a barrier.

Floods are often caused by winds that drive water inland from the sea, raising the level of a river by backing up the water at the mouth. This type of flood has occurred in Leningrad (1824 and 1924) and the Netherlands (1952). Along seashores and on islands floods may result from the inundation of the coastal zone by a wave formed during earthquakes or volcanic eruptions in the ocean (tsunamis). Floods of this type occur frequently on the shores of Japan and other Pacific islands. Breaks in dams or protective dikes may cause floods.

Floods occur on many rivers in Western Europe, including the Danube, the Seine, the Rhone, and the Po; on the Yangtze and Huang Ho in China; and on the Mississippi and Ohio in the USA. In the USSR there have been heavy floods on the Dnieper (1931) and the Volga (1908 and 1926). The most effective method of combating floods is the construction of reservoirs to regulate the flow of rivers.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

What does it mean when you dream about a flood?

Because water is a universal symbol for the unconscious, a flood dream can indicate being overwhelmed by unconscious material, such as repressed emotions. It can also represent a feeling of being overwhelmed by circumstances in one’s life. Floods are related to initiation, in the sense that they can symbolize the destruction or washing away of the old in preparation for something new. Finally, a flood, as the bursting forth of fluids, can be a sexual symbol.

The Dream Encyclopedia, Second Edition © 2009 Visible Ink Press®. All rights reserved.


To direct a large-area flow of electrons toward a storage assembly in a charge storage tube.
To cover or fill with fluid.
The condition that occurs when water overflows the natural or artificial confines of a stream or other body of water, or accumulates by drainage over low-lying areas.
(mechanical engineering)
To supply an excess of fuel to a carburetor so that the level rises above the nozzle.
The highest point of a tide.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


for his evilness, man perishes by inundation. [O.T.: Genesis 6: 5–8; 7:4]
Allusions—Cultural, Literary, Biblical, and Historical: A Thematic Dictionary. Copyright 2008 The Gale Group, Inc. All rights reserved.


a. the inundation of land that is normally dry through the overflowing of a body of water, esp a river
b. the state of a river that is at an abnormally high level (esp in the phrase in flood)
a. the rising of the tide from low to high water
b. (as modifier): the flood tide
3. Theatre short for floodlight (sense 1)


Henry. 1732--91, Anglo-Irish politician: leader of the parliamentary opposition to English rule


Old Testament the. the flood extending over all the earth from which Noah and his family and livestock were saved in the ark. (Genesis 7--8); the Deluge
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005


Various denial-of-service techniques that saturate a critical resource, leading either to system failure or to the exclusion of legitimate access. See email bomb, Fraggle attack, smurf attack and SYN-flood attack.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.


Heavy rain and the melting of snow usually cause floods. Water in any form, including rain and snow, symbolizes emotions. Dreaming about being in a flood is an indication that the dreamer is currently experiencing powerful emotions that may be overwhelming. The flood in your dream could represent a very powerful, or even violent, emotionally cleansing experience. But don’t worry, just like in an actual flood, waters recede and so do emotions. Water at times represents the flow of life and this dream may point to your feelings of being overwhelmed by it. Depending on the content of the dream and your emotional experience in it, the flood could also represent sexuality and be a sexual dream symbol.
Bedside Dream Dictionary by Silvana Amar Copyright © 2007 by Skyhorse Publishing, Inc.
References in periodicals archive ?
As many as 1000 rescuers have been conducting continues, search rescue and evacuation operations at 46 special flood posts in flood-hit districts of the Punjab during day and night timings since 19th August 2019 of the recent flash floods.
Are younger homeowners more likely to protect their property by buying flood coverage?
Millennials - those born between 1981 and 1996 - are nearly three times more likely to have purchased flood insurance than their older Baby Boomer counterparts born between 1944 and 1964, a new survey finds.
Daniel Kanieski, deputy administrator of the Federal Emergency Management Agency said advised people in the high risk areas to have a flood insurance and also stressed on the importance of flood preparedness.
Protect sockets, switches, breakers, and wiring in a home by placing them at least one foot above the expected flood level in your area, offers the Insurance Institute for Business & Home Safety.
In order to ensure the menace remains a hazard and not a disaster by averting flooding disasters, the Oyo state government has done a lot to ensure that the issue of flooding remains a thing of the past in Ibadan by expending billions of naira on construction of bridges and culverts in flood prone areas, dredging and expansion of rivers as well as clearing of drainages and water across the states.
Flood in Nala-i-Dek in Chahoor, Sialkot inundated several villages, while the flooded Nala-i-Baeen swamped hundreds acre crops in Shakargarh.
Emphasizing its goal of seeing affordable flood insurance made available for all U.K.
The flood levels were between 0.3m and 0.6m, while the sea level was at 1.95m as at 2.21am.
The Environment Agency has today issued the flood warning as it launches an action campaign aimed at younger people.
Funded by the Northumbria Regional Flood and Coastal Committee (NRFCC) for the next four years, the officers are working alongside partner organisations to help support communities.