Flood (洪水, cultural language: big water) refers to a phenomenon in which generally dry land is submerged due to flooding of water. It is a natural phenomenon in which large water or river water overflows, and is a type of flood. It is also called a water ripple or big water.
Types of Flood
Estuarine floods Catastrophic floods
It occurs when it rains a lot at once or when snow and ice suddenly melt. A flash flood occurs when a small river or stream suddenly overflows due to heavy rain. Flash floods occur mostly in mountainous areas. But even in the desert, occasional heavy rains cause raging torrents to flow into the wadi, causing flooding. In 1887, a flood in Huanghe, China, killed about 1 million people.
In Korea, as of August 2020, 98% of flood damage in the country occurs in small rivers. The local river maintenance rate is 45%, and the local government manages it, but the progress is slow due to lack of budget. 98.4% of the rivers affected by flooding in 2018-2019 were local streams. The national river maintenance rate is 80%.
It is a phenomenon that occurs when a typhoon or strong storm is raging and the water from the beach rushes deep into the land. Huge waves hit the Bangladesh coast, killing about 270,000 people and displacing up to a million people. Meanwhile, on the coast of Western Europe, flooding occurs due to low pressure developed in the sea. In 1953, strong winds in the Netherlands caused a big wave to break the embankment blocking the seawater, submerging more than 4% of the country. Earthquakes and volcanic eruptions also generate waves high enough to cause flooding in coastal areas. These waves are called tsunamis or tsunamis. In 1883, Krakatau Volcano in the Sunda Strait in western Java Island exploded, causing a tsunami with a height of 35 m.
Impact of the Flood
Physical Hazards: Hazards can span structures such as bridges, automobiles, buildings, roads, and canals.
Coincidence: People and livestock can drown and die. It can also lead to contagious diseases or diseases.
Supply of water: Water is polluted, making clean water scarce.
Disease: Water-borne diseases occur under unsanitary conditions.
Economy: Economic hardship (especially for the poor) can arise from temporary declines in tourist numbers, reconstruction costs and rising prices due to food shortages.
Advantages of Flood
Floods have numerous devastating effects on the human environment and economic activity. However, floods make the soil more fertile and provide nutrients to areas that are undernourished. Periodic flooding was essential for the well-being of ancient civilizations such as the Tigris-Euphrates, Nile, Indus, Ganges, and Yellow Rivers. In areas prone to flooding, the ability to survive is higher due to the development of hydraulics based on sources that can resume life, that is, the science of managing water, such as state transition.
Floods with the most deaths
Below is a list of flood events that have killed more than 100,000 people worldwide.
river in korea
Wikimedia Commons has media related to flooding.
Flood - Doosan World Encyclopedia
(English) Flood Disaster Database
(English) Flood Risk Assessment website