Glaciers - Grande Dixence

Question 1

Where is Grande Dixence Dam?

Answer 1

Val des Dix in Switzerland

Question 2

How much of Switzerlands power comes from fossil fuels?

Answer 2

less than 5% of power comes from FF

Question 3

What type of power does Grande Dixence generate?

Answer 3

Hydroelectric

Question 4

how many homes does Grande Dixence power?

Answer 4

Grande Dixence Dam generates power for 400,000 Swiss Homes

Question 5

How large is Grande Dixence Dam?

Answer 5

290m high, 15m wide at top
Stores 400 million m3 of water.

Question 6

Where is the pumping for the hydroelectric power done in the Grande Dixence Dam?

Answer 6

All hydroelectric generation is done underground to reduce lightening natural environment

Question 7

How many Valais glaciers feed into the Grande Dixence Dam?

Answer 7

• 35 Valais glaciers
• 50% water only from 4 glaciers though

Question 8

What is glacial water inputs used for in the Grande Dixence Dam?

Answer 8

85% for hydroelectric generation.
15% for flushing out accumulated sediments.

Question 9

Negatives of the Grande Dixence Dam

Answer 9

• Pipe burst killing 3 and wiping out a hamlet, in December 2000 due to high pressure (maintenance quality debated?)
• 30cm/yr deposit released which pollutes water eg. at Des Haudére.
• During ablation periods, some water released = more energy for hydraulic action = increases deposits and blocks irrigation channels

Question 10

Describe the impact of the pipe bursting in Grande Dixence Dam

Answer 10

• Killed 3
• Hamlet destroyed
• Unreliable maintenance = stakeholders unhappy.
• Economic losses
• High pressure pipes, unsafe for communities.

Question 11

What impact does the Grande Dixence Dam have on water quality at Les Haudére?

Answer 11

• Reduced discharge of the Borgne River
• Collects more deposits
• Pollutes the water at Les Haudére.

Question 12

During ablation periods, water is released from Grande Dixence Dam.
How can this impact communities?

Answer 12

• More water for irrigation
• But increases hydraulic action = more deposits = block irrigation channels = crop failure
• Blocking drainage channels = flood risks due to saturated overland flow on soil.

Question 13

How may the Grande Dixence Dam be affected in the future?

Answer 13

• Climate change increasing ablation rates
  = more thawing so more meltwater.
  ST = more power because more turbines to power generators.
  LT = equilibrium shifts because of less meltwater leading to less hydroelectric energy generated.

Question 14

In last 2 years, how much has the Swiss Alps shrunk and why is this significant to Grande Dixence Dam?

Answer 14

• Swiss Alps have shrunk by 10% in last 2 years
• Increases meltwater stores in long term, but supply is finite so long term may reduce hydroelectric energy generation.