Mekong

Question 1

How many nations does the Mekong cross?

Answer 1

• 6 nations

Question 2

What is the source of the Mekong River?

Answer 2

• Tibetan Plateau
• meltwater
• also sustained by monsoon rainfall

Question 3

Why is the Mekong important?

Answer 3

• Supports 60 million people directly
• many more indirectly
• Hosts rich biodiverse community
• Used for HEP generation

Question 4

Who manages the Mekong?

Answer 4

• only lower course is managed
• by Mekong River Commission
• China is not a member
• proposed 10 year ban on building of dams
• has very limited funds
• thus has no way of actually enforcing
• China has held back water from flowing through member states when it is most needed

Question 5

How large is the scale of HEP construction on the Mekong River?

Answer 5

• China has completed 8 dams
  
  • 5 more under construction
  • 11 planned
• Laos and Cambodia have 2 under construction
  
  • 9 planned

Question 6

What benefits do dams come with?

Answer 6

• HEP
• generates income
• can be essential for landlocked countries such as Laos

Question 7

What are the downsides of HEP in the Mekong?

Answer 7

• Only meets 8% of projected power needs
• Harms ecosystems
  
  • migratory fish cannot move freely
  • hinders natural processes
• Pollutants are not flushed out downstream
  
  • less fertile sediment carried by river downstream
  • worse for farmers as they depend on sediment to act as fertiliser
• other farmland may be flooded instead
• may increase regional tensions between countries

Question 8

How has an increasing population in Vietnam affected the Mekong?

Answer 8

• 90% of Vietnamese forest has been cut down
  
  • severely increased local runoff levels

Question 9

What effect has China’s building of dams had on the Mekong?

Answer 9

• reduced sediment load in the lower Mekong from 160MT to 75MT in 15 years
• causes widespread riverbank erosion
• less sediment carried by river
• less settles on floodplain when flooding
• reduced floodplain fertility

Question 10

How has the water quality of the Mekong been changed?

Answer 10

• Lanping Lead-Zinc mine
  
  • Mercury and arsenic have been released
  • Mekong dolphins have died from bacterial illnesses caused by these chemicals
• Phnom Penh
  
  • Urban sewage and rubbish has been dumped into the Mekong
  • resulted in cultural eutrophication
  • build up of nitrogen and phosphorus in water
• Pesticides run off from fields
  
  • resulted in algal blooms
  • water hyacinth outbreaks
  • reduce water oxygen levels
  • resulted in carp and shrimp levels dropping off in Vietnam, Cuulong Delta
  • bad for subsidence fishers

Question 11

How has the flow of the Mekong been changed and what affect has it had?

Answer 11

• Mekong flow has reduced
  
  • By damming + use of water
  • flow into Tonle Sap lake has been reduced
  • harder for people in Phnom Penh to get fresh drinking water

Question 12

How has trade been enhanced along the Mekong?

Answer 12

• Sandbars and rocks within river have been cleared
• allows ships and large ferries to travel along Mekong
• However, results in devastating floods as these structures would have obstructed water flow

Question 13

What effect has building had on the Mekong Delta?

Answer 13

• 17 million people live in delta
• 18cm subsidence in delta over past 25 years
• resulting in seawater encroachment into rice padddies

Question 14

What is cultural eutrophication?

Answer 14

• Eutrophication due to human induced disposal of rubbish