Flood (อุทกภัย)
The
word "flood" comes from the Old Englishflod, a word common to Germanic
languages (compare GermanFlut, Dutchvloed from the same root as is seen
in flow, float; also compare with Latinfluctus, 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 they are
featured in the mythology of many cultures.
Primary effects
The
primary effects of flooding include loss of life, damage to buildings
and other structures, including bridges, sewerage systems, roadways, and
canals.Infrastructure
damage also frequently damages power transmission and sometimes power
generation , which then has knock-on effects caused by the loss of
power.This
includes loss of drinking water treatment and water supply, which may
result in loss of drinking water or severe water contamination.It may also cause the loss of sewage disposal facilities.Lack
of clean water combined with human sewage in the flood waters raises
the risk of waterborne diseases , which can include typhoid , giardia ,
cryptosporidium , cholera and many other diseases depending upon the
location of the flood.
Damage
to roads and transport infrastructure may make it difficult to mobilise
aid to those affected or to provide emergency health treatment.Flood
waters typically inundate farm land, making the land unworkable and
preventing crops from being planted or harvested, which can lead to
shortages of food both for humans and farm animals.Entire harvests for a country can be lost in extreme flood circumstances.Some tree species may not survive prolonged flooding of their root systems
Secondary and long-term effects
Economic
hardship due to a temporary decline in tourism, rebuilding costs, or
food shortages leading to price increases is a common after-effect of
severe flooding.The
impact on those affected may cause psychological damage to those
affected, in particular where deaths, serious injuries and loss of
property occur.
Benefits of flood
Floods
(in particular more frequent or smaller floods) can also bring many
benefits, such as recharging ground water , making soil more fertile and
increasing nutrients in some soils.Flood
waters provide much needed water resources in arid and semi-arid
regions where precipitation 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.Flooding can spread nutrients to lakes and rivers, which
can lead to increased biomass and improved fisheries for a few years.For
some fish species, an inundated floodplain may form a highly suitable
location for spawning with few predators and enhanced levels of
nutrients or food. Fish, such as the weather fish , make use of floods
in order to reach new habitats.Bird populations may also profit from the boost in food production caused by flooding. 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 of hydropower , a renewable source of energy, is also higher in flood prone regions.
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