Unit 1 - Page 26 - 28

What percentage of Bangladesh is less than 6 meters above sea level?

• 30%

• 50%

• 60%

• 80%

Answer explanation

Answer: c) 60%

• Explanation:
  60% of Bangladesh is very low-lying, meaning it’s close to sea level. This makes it easy for floods to happen when rivers overflow or during storms.

• Example:
  During a cyclone, seawater can easily flood inland because the land is flat and low.

Which three rivers converge in Bangladesh?

• Ganga, Brahmaputra, and Yamuna

• Ganga, Brahmaputra, and Meghna

• Yamuna, Meghna, and Indus

• Brahmaputra, Indus, and Yamuna

Answer explanation

Answer: b) Ganga, Brahmaputra, and Meghna

• Explanation:
  These rivers meet in Bangladesh, creating one of the largest river systems in the world. Their combined flow makes flooding more likely.

• Example:
  Heavy rains upstream in these rivers can cause water levels to rise and flood large areas in Bangladesh.

What is the population density of Bangladesh?

• 800 people/km²

• 1000 people/km²

• 1161 people/km²

• 1500 people/km²

Answer explanation

Answer: c) 1161 people/km²

• Explanation:
  Bangladesh has a very high population density, meaning a lot of people live in a small area. This makes it hard to manage disasters like floods.

• Example:
  Imagine fitting thousands of people into a single square kilometer. When floods happen, evacuation and aid become very challenging.

What is the average gradient of the rivers in Bangladesh?

• 2 cm/km

• 4 cm/km

• 6 cm/km

• 8 cm/km

Answer explanation

Answer: c) 6 cm/km

• Explanation:
  The rivers in Bangladesh flow very slowly because the slope is gentle. Slow-moving rivers are more likely to overflow and cause floods.

• Example:
  Think of water flowing down a flat street versus a steep hill; on a flat street, it spreads out and floods.

What percentage of the population in Bangladesh is employed in agriculture?

• 30%

• 40%

• 47%

• 50%

Answer explanation

Answer: c) 47%

• Explanation:
  Nearly half of the population depends on farming. Floods can destroy their crops, making life very hard.

• Example:
  If a farmer’s rice fields are flooded, their entire income for the year might be lost.

Which area contributes to the high discharge of the Ganges and Brahmaputra rivers?

• The Tibetan Plateau

• The Indian Plains

• The Meghna Basin

• The Bay of Bengal

Answer explanation

Answer: a) The Tibetan Plateau

• Explanation:
  Melting snow and rain from the Tibetan Plateau flow into these rivers, increasing their water levels downstream.

• Example:
  In spring, snowmelt from the mountains can lead to a sudden rise in river water levels in Bangladesh.

What is the sediment load of the Ganga river?

• 500 Mt/year

• 597 Mt/year

• 650 Mt/year

• 729 Mt/year

Answer explanation

Answer: d) 729 Mt/year

• Explanation:
  The Ganga carries a huge amount of sediment (soil and silt). This can raise the riverbed, reducing its capacity to hold water, leading to floods.

• Example:
  Imagine pouring sand into a bucket of water; as the sand builds up, there’s less room for the water.

What is the primary physical cause of flooding in Bangladesh?

• Urbanization

• Deforestation

• Monsoon rainfall

• Poor infrastructure

Answer explanation

Answer: c) Monsoon rainfall

• Explanation:
  Heavy rain during the monsoon season fills rivers beyond their capacity, causing floods.

• Example:
  Think of a bathtub overflowing because too much water is added at once.

What human activity has worsened flooding in Bangladesh?

• Afforestation

• Urbanization

• Improved embankments

• Decreased river sediment

Answer explanation

Answer: b) Urbanization

• Explanation:
  Building cities and roads reduces natural drainage, so rainwater has nowhere to go, increasing the risk of floods.

• Example:
  Paved streets in a city don’t absorb water like soil does, so rain pools and causes waterlogging.

What year did the devastating floods in Bangladesh occur?

• 1988

• 1998

• 2004

• 2014

Answer explanation

Answer: b) 1998

• Explanation:
  The 1998 floods were one of the worst in Bangladesh’s history, affecting more than half the country.

• Example:
  Imagine your home submerged in water for weeks, with no access to food or clean water.