CAUSE OF FLOODING
Natural Causes of Floods
High rainfall
Heavy rainfall raises the water level. When the water level is higher than the river bank or the dams, the water comes out from the river,there will be flooding.
Relief
Flooding often occurs in lowlands. This is because rivers flow more slowly in low-lying areas. If the water volume increases suddenly, floods occur.
Coastal flooding
Flooding always occurs in coastal areas. High tides or storms cause the water level to rise. If the water level is higher than the level of the coastal lowland, flooding will occur.
Human Causes of Floods
Deforestation
Large areas of forests near the rivers have been cleared. The lands are used to make room for settlement, roads and farmland. Less vegetation protects the soil, the soil is quickly lost to rivers and the sea.This raises the river bed, so the river overflows its banks easily.
Poor farming
Some farming practices can damage the vegetation cover, so the soil will be washed into the river easily.
Overgrazing
People want more food and money. They graze too many animals on the land and the pasture is eaten away quickly. Less vegetation cover results in soil washed into the rivers easily.
Over cultivation
When a piece of land has been used for farming for a long period of time, the soil may became so infertile that no vegetation can grow on it. The land is less fertile than before so the soil washed into the rivers more easily
Poor water management
When the dams are poorly constructed or maintained ,they can easily collapse and this results in flooding. Moreover, poor plan of city construction can also cause flooding as the water can't flow out easily.
Population pressure
Because of large amounts of people, everything needs more, like wood, land and food……
Soil erosion happens more often and increases the risk of flooding.
