Causes of Flooding in Bangladesh

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Photo: CGZ

Bangladesh is one of the world most densely populated country and one of the most susceptible countries to flood disasters. It also has one of the three most powerful rivers passing though it Ganges, Meghna and Brahmaputra. About one half of the land area in Bangladesh is at an elevation of less than 8 meters above sea level.  Up to 30% of the country has been covered with flood waters.  In 1991 more 200,000 deaths resulted from flooding and associated tropical cyclones.

 

 

 

 

 

 

 

 

 

 

 

 

 

Photo: USAID

There are many physical and human causes that allowed the floods to be worse; such as:

The Physical Causes of the Floods:

• Most of the country consists of a huge flood plain and delta.
• Snowmelt from the Himalayas takes place in late spring & summer.
• 70% of the total area is less than 1 meter above sea level.
• 10% of the land area is made up of Lakes and Rivers.
• Bangladesh experiences heavy monsoon rains, especially over the highlands.
• Tropical storms bring heavy rains and coastal flooding.
• The main cause was the above average & long period of heavy rain which caused all 3 rivers to have their peak flow at the same time.
• In the spring, melting snow from the Himalayas further increases the flood risks as torrents of melt water enter the rivers at their source.

The Human Causes of the Floods:

• Deforestation in Nepal and the Himalayas increases run off and add to deposition and flooding downstream.
• Urbanization of the flood plain has increased magnitude & frequency of floods.
• Global warming is blamed for sea level rise, increased snow melt & increased rainfall in the region.
• The building of dams in India has increased the problem of sedimentation in Bangladesh.
• Poorly maintained embankments (levees) leak & collapse in times of high discharge.
• Increasing population pressure in Bangladesh itself has resulted in the sinking of many new wells resulting in the lowering of the water table and the subsequent subsidence of land making it even more prone to flooding.