Floods occur on our planet as a consequence of various factors such as natural meteorological phenomena, human constructions, human activities or even climate change.
In this AgroCorrn article, we analyze the causes and consequences of floods , to better understand this problem, which can be more or less dangerous depending on various factors. In addition, we will see that there are situations that are controllable and even predictable and can be avoided, while other times it is totally unexpected and uncontrollable.
What are floods
We define a flood as a massive occupation by water of areas that were dry. The factors that lead to a flood can be a temporary rise in the level of a river, lake or sea . Although sometimes they are unavoidable, sometimes floods can be situations that can be controlled by human activity, due to the poor use of land near waterways.
It is estimated that floods are the catastrophe or natural disaster that causes the most deaths on the planet. During the 20th century, it has been estimated that around 3.2 million people have lost their lives due to this cause, which constitutes more than half of the victims of natural disasters during the same period.
Types of floods
In addition, there are various types of floods , which can be classified as follows:
- Rain floods: this type of flooding occurs as a result of heavy rainfall concentrated in a particular area. The high concentration of rain causes the ground to become saturated and the excess water begins to accumulate, which can last for hours or days, until it begins to evaporate and the ground recovers.
- River floods: this kind of flood occurs when the water in the rivers overflows and reaches the land near the riverbed.
- Coastal floods: they occur as a result of strong winds such as a stormy cyclone. This flood enters the coastal areas and covers large areas of land.
For example, the previous image is a coastal flood, where it can be sensed that a promenade has been completely flooded.
Causes of floods
The main causes of floods are multiple, but in general, we can classify them as natural or as a consequence of human activity:
Natural causes of floods
- Intense precipitations: they can occur by rains, tropical storms or hurricanes . These floods can be produced as a consequence of the increase in river levels. The more water that falls and the longer it rains, the higher the probability of water overflows. To contain these problems, dams or dikes are often built to store large amounts of water from different springs. This water can then be released to supply plantations, irrigated land or generate energy.
- Sediment accumulation : these accumulations form large containment barriers for the water, which as the amount (and pressure) of water increases ends up overflowing, letting large amounts of water flow mixed with mud, logs or stones.
- Melting of snow in high mountains: the snow accumulated during the winter melts normally during the spring, but if there are strong waves of heat, this process accelerates, to the point of being able to increase the levels of the sea or rivers and make them invade the earth.
- Forest destruction .
- Tsunamis: they take place as a consequence of earthquakes in the sea. This causes the marine plates to move, generating large waves of water that can exceed the water levels on the coast and invade the land.
Human causes of floods
- Deforestation: due to human activities, forests and jungles are massively cut down, which is a big problem, because the vegetation retains large amounts of water, which it releases even after the rainfall is over.
- Water pipes in cities that overflow due to rainfall.
- Different constructions in cities carried out in areas too close to the sea or rivers or constructions that are carried out in areas previously occupied by the sea or rivers. As a consequence, when different natural phenomena occur, water can flood the land.
- Dam or levee ruptures , which release large amounts of retained water.
- Discharges of garbage or materials that clog river beds.
- Climate change , which can accelerate other processes such as melting snow.
Many of these phenomena can be classified as natural and human at the same time. In addition, the causes of floods are often a combination of human and natural phenomena, such as tsunamis and buildings that are too close to the sea.
What are the consequences of floods
The consequences of floods can be:
- Economic: floods cause the loss of large amounts of material goods, to which must be added the cost of rebuilding infrastructure. They can also be global, for example, that the damaged country has a great loss of a certain product, which means that there is less supply, prices rise and other countries have to satisfy that demand with their exports. In addition, they can make people homeless, by destroying their homes.
- Environmental: damage to agricultural land, damage to crops and food production. In addition, floods also spread pollution, harming animals and humans.
- Health: Floods increase the risk of fecal-oral diseases and transmit pathogens such as malaria, dengue, leptospirosis, jungle yellow fever or cholera. People can also be injured from downed trees, power lines, or other debris.
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