A flood is an overflow of water, an expanse of water submerging land, a deluge.
Since prehistoric times people have lived by the seas and rivers for the access to cheap and quick transportation and access to food sources and trade; without human populations near natural bodies of water, there would be no concern for floods.
However fertile soil in a river delta is subject to regular inundation from normal variation in precipitation.
Floods from the sea can cause overflow or overtopping of flood-defenses like dikes as well as flattening of dunes or bluffs.
Land behind the coastal defence may be inundated or experience damage.
A flood from sea may be caused by a heavy storm (storm surge), a high tide, a tsunami, or a combination thereof.
As many urban communities are located near the coast this is a major threat around the world.
In western countries, rivers prone to flooding are often carefully managed.
Defenses such as levees, bunds, reservoirs, and weirs are used to prevent rivers from bursting their banks.
Coastal flooding has been addressed in Europe with coastal defenses, such as sea walls and beach nourishment.
Levee A levee, floodbank or stopbank is a natural or artificial embankment or dike, usually earthen, which parallels the course of a river. The main ... >
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Floodplain A floodplain, or flood plain, is flat or nearly flat land adjacent to a stream or river that experiences occasional flooding. It includes the ... >
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Coastal management Coastal management or coastal defence is used throughout the world for many different purposes, but predominantly to reduce coastal erosion and ... >
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Storm surge A storm surge is an onshore rush of water associated with a low pressure weather system, typically a tropical cyclone. Storm surge is caused ... >
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Estuary An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ... >
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Coast The coast is defined as the part of the land adjoining or near the ocean. A coastline is properly, a line on a map indicating the disposition of a ... >
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Catastrophe modeling Catastrophe modeling (also known as cat modeling) is the process of using computer-assisted calculations to estimate the losses that could be ... >
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Monsoon A monsoon is a periodic wind, especially in the Indian Ocean and southern Asia. The word is also used to label the season in which this wind blows ... >
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Surface runoff Surface runoff is water, from rain, snowmelt, or other sources, that flows over the land surface, and is a major component of the water cycle. Runoff ... >
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