bangladesh

• • low-lying thus prone to flooding anyway also has a river delta less than 3m above sea level
  • incoming storm surges often meet with outflowing river discharge
  • the coast is made up of unconsolidated fluvial sediment that is easily eroded
  • coastal vegetation like mangroves offer protection but many have been removed
• a vulnerable, low-lying area

  delta made of unconsolidated delta sediment

  funnel-shaped bay of Bengal concentrates wave energy further north

  the Ganges delta covers 2/3 of Bangladesh
• 2007, category 4 storm?

  heavy rain, strong winds, storm surge 6m high

  eye of the storm crosses the coasts near Sundarbans mangrove forest

  coastal districts had highest impacts

  destroyed more than 7000 shrimp farms , estimated loss of $36 million
• Problems with the 2007 category 4 cyclone?

  embankments didn't provide enough heights to prevent overtopping of cyclone storm surge

  many trees planted in the surface layer of embankments were blown down breaking the embankments

  maintenance for the structures has scarcely been executed

  illegal habitation on the structures

  cyclone shelter capacities were inadequate for the population of the service area

  many people neglected cyclone warnings resulting in many deaths
• • Bangladesh is prone to serious and chronic flooding
  • 60% of the country is less than 3m above sea level
• Bangladesh, Tropical Cyclone Sidr 2007:

  • Category 4 cyclone, 6m storm surges
  • Impact worsened by:
  • funnel shape of the Bay of Bengal focussing water on Bangladesh at the bay apex
  • Coastline from unconsolidated delta sediment - easily eroded.
  • Deforestation of mangrove swamps. 
  • 60% of Bangladesh low lying, less than 3 m above sea level
  • 15,000 people killed and 55,000 injured. 1.6 million homes destroyed.
  • Crops destroyed on 600,000 ha of agricultural land
• 80% of the country occupies one of the world's largest delta systems and is criss crossed by thousands of small rivers

  low lying land
• • Population increase forces people onto more marginal land each year.
  • Bangladesh is also in a tropical storm region. This means that monsoon rain and meltwater flooding can be made worse if salt water floods coastal lowlands.
• approximately 20 million people live in areas less than 1m above sea level or less

  a lot of this low-lying land is on the coast where there is a large delta
• hundreds of small islands make up the Bay of Bengal area

  unconsolidated material makes up the majority of the islands

  this material comes from the 3 main rivers as sediment deposits, which makes islands highly unstable and susceptible to flooding

  as sea level rises, more of these islands are at risk
• scientists estimate that 800km2 of land in Bangladesh will disappear if sea level rises 0.3m from its current level
• some of the islands in Bangladesh are more susceptible to flooding due to human actions

  fertile farmland is in increasingly short supply as the population grows, causing some farmers to clear areas of mangrove forest on the delta and drain it to increase farmland

  the delta used to be a site of net deposition but now is a site of net erosion

  this in combination with its low elevation, makes it more vulnerable to flooding from the rising sea level
• what makes Bangladesh so vulnerable to flooding?

  around 50% of the country is at an elevation of 10m above sea level or less

  tropical cyclones regularly cause storm surges on the coast

  unconsolidated material makes up the majority of the islands in the Bay of Bengal area, making the islands highly unstable and susceptible to flooding- as sea level rises more of these islands are at risk
• cyclone sidr?

  15,000 deaths

  55,000 injured

  1.6 million homes destroyed

  6m high storm surge
• how densely populated is Bangladesh?

  it's the 9th most densely populated country in the world with more than 1000 people occupying one square km2

  thus highly vulnerable as more people at risk to coastal flooding
• what is Bangladesh home to?

  the world's 3 most powerful rivers

  Ganges

  Bhramaputra

  Meghna

  an average of 844,000 million cm3 of water flows into thr country through these 3 rivers
• economic losses?

  flooding in Bangladesh causes annual losses of $1 billion (reported by World Bank)

  loss of slums, washed away

  loss of income

  great amount of money to repair the country before another flood occurs

  loss of livestock
• What type of country is Bangladesh?

  a LEDC

  (less economically developed country)
• why is the coastline so easily eroded?

  due to the unconsolidated delta sediment
• how low lying is Bangladesh?

  60% of the country is less than 3m above sea level
• • Bangladesh is in the path of tropical storms
  • due to climate change there is an increased frequency of tropical storms and monsoon rain
  • leading to prolonged rainfall, thus prone to flooding
• rapid population growth?

  1951: 1.8 million

  2024: 172 million
• what has the rapid population growth led to?

  urbanisation

  60% of the land is covered with buildings and roads

  making urbanised cities 6x more at risk to intense flooding

  creates extra pressure on the land
• • Bay of Bengal is funnel shaped and thus concentrates wave energy along the coast
  • eroding the coastline easily as it's made of unconsolidated sediment
• • a 100m belt of mangrove forest reduces wave height by 40%, dissipating wave energy before it reaches the coast