Flooding - Bangladesh - River Ganges - Case Study

Flooding - Bangladesh - River Ganges - Case Study

1. Causes

   • HUMAN CAUSES Deforestation – Population increase in Nepal means there is a greater demand for food, fuel and building materials. As a result, deforestation has increased significantly. This reduces interception and increases run-off. This leads to soil erosion. River channels fill with soil, the capacity of the River Ganges and Brahmaputra is reduced and flooding occurs.
   • Monsoon Rain Melting Snow Tectonic Activity – The Indian Plate is moving towards the Eurasian Plate. The land where they meet (Himalayas) is getting higher and steeper every year (fold mountains). As a result, the soil becomes loose and is susceptible to erosion. This causes more soil and silt in rivers. This leads to flooding in Bangladesh.

2. Effects

   • Erosion of chars (islands) by flooding rivers causes landlessness amongst Bangladesh’s poor; these people end up in major cities such as Chittagong and Dhaka. Death – over 200,000 people died in a cyclone and flood in the 1970s. Loss of agricultural land – a major problem in a country with high natural increase.
     • 2004 Floods The 2004 floods lasted from July to September and covered 50% of the country at their peak. At the time of the July 2004 floods 40% of the capital, Dhaka was under water. 600 deaths were reported and 30million people were homeless. 100,000 people alone in Dhaka suffered from diarrhoea from the flood waters. Bridges were destroyed, the death toll rose to 750 and the airport and major roads were flooded. This hampered relief efforts. The damage to schools and hospitals was estimated at $7billion. Rural areas also suffered, the rice crop was devastated as were important cash crops such as jute and sugar.

3. Responses

   • Bangladesh is a very poor country and so has less money to spend on flood defences than richer countries. Most people in Bangladesh do not earn enough to pay for insurance against flooding, so when there are floods they risk losing everything.
   • Short-term responses to flooding Food aid from the Government and other countries. Water purification tablets. People repaired embankments and helped to rescue people. Free seed given to farmers.
   • Long-term responses Building embankments. Building raised flood shelters. Introducing flood warning systems. Emergency planning. Dams planned. Reducing deforestation.

4. Management

   • Flood action plan – a system of huge embankments along the coast and rivers reinforced by concrete. They increase channel capacity and hydraulic radius but stop floods replenishing fields with nutrients and can stop rainwater escaping into fields. It also causes erosion downstream of the defences and prevents deposition. Improved drainage canals – the clearing of old canals had allowed a more efficient drainage system allowing water to drain away more efficiently. SPARSO and flood satellite imaging systems – allow more warning to be given to Bangladeshis by monitoring cloud cover, hydrographs and rainfall patterns across the river basins.

5. Advantages of living there:Fertile land for farming, especially crops like rice Plenty of water for fishing or aquaculture. This can feed families or provide an economic income. Abundant drinking water Water for cooking, washing, etc. Tourism opportunities Good transport links, possible to trade

6. Disadvantages: Hard to make transport links by roads - regular flooding Areas are at constant risk of flood Vulnerable to rising sea levels - 70% only 1 metre above sea level Water is often dirty and polluted (industry, agriculture, sewers) Mosquitoes are attracted to water (Malaria, Dengue) Storm surges from tropical storms Cost of building defences

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