Flooding

Causes of Flooding

The Causes of Flooding can be divided into

Physical factors and Human Factors

Physical Factors

• Heavy rainfall

Many areas have an uneven distribution of rainfall. Very often, most of them receive only heavy rainfall for a few months of teh year.

The effect of tropical storms also bring a huge amount of rainfall. Tropical storms are very low pressure systems. They bring violent winds and heavy rain to the afftected areas.

• Low relief

Most of the frequently flooded areas are located at the low relief. It is because the sudden increase in the amount of rainfall.

• Coastal flooding

Some of the flood area are located near the coast, When there is a tsunami or hurricane took place, coastal flooding will be easily occured to coastal areas, e.g. Dhaka in Bengladesh.

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• Snowmelt

In winter, there is snow on the top of the mountains, e.g. the Himalaya. When summer comes, snow melts. There is a sudden increase of water flow into the rivers nearby, i.e. the Chang Jiang in China and the Ganges in Bangladesh. Since the banks of rivers cannot hold the large amount of the increased water, water overflows from the river banks. Flooding is then occured.