How does human activity cause change within glaciated and periglacial landscape systems? Flashcards
What is the Alyeska pipeline?
A pipeline that transports oil from Prudhoe Bay to Valdez, Alaska
It runs 1300 km and transports about 500,000 barrels of oil per day
What are the effects of gravel extraction in periglacial landscapes?
Alters rates of gravel transport and affects equilibrium in river systems
This can lead to changes in erosional and depositional processes
What is thermokarst?
A landscape dominated by surface depressions due to thawing of ground ice
Characterized by hummocky ground and waterlogged hollows
What causes solifluction lobes?
Downslope movement of the thawed active layer
Resulting from heat from buildings or infrastructure
What is the Grande Dixence Scheme?
The highest gravity dam in the world, constructed for hydroelectric power
Located in southwest Switzerland, it was completed in the 1960s
What is the height of the Grande Dixence dam?
285 meters
It stores over 400 million m3 of water each year
What is the width of the Grande Dixence dam at its base?
200 metres
What is the width of the Grande Dixence dam at the top?
15 metres
What is used to make the foundation soil of the Grande Dixence dam watertight?
A deep grout curtain
What is the catchment area of the Grande Dixence dam?
Just over 350 km2
What percentage of the catchment area is derived from glaciers?
Half of the catchment area is from 35 glaciers
How many pumping stations are involved in sending water to the Lac des Dix?
Four pumping stations
What is the main purpose of the Grande Dixence dam?
To optimize the water level for maximum availability before heavy demand periods
What is the annual energy generation capacity of the power stations associated with the Grande Dixence dam?
2000 GWh
How many Swiss households can be powered by the energy generated from the Grande Dixence dam?
400,000 Swiss households
What proportion of Swiss electricity comes from storage power stations?
About one-third
What is the percentage of Swiss electricity production that comes from fossil fuels?
Less than 5 percent
What percentage of the water available at Grande Dixence is used for electricity generation?
85 percent
What is the sediment deposition rate behind the Grande Dixence dam?
20-40 cm/year
What are the sediment concentrations above and below the dam?
> 300 mg/l above the dam, 20-50 mg/l just below the dam, <20 mg/l 3 km downstream
How is sedimentation managed in the Grande Dixence reservoir?
By flushing out sediment with stored water
What environmental impact has the dam had on the Borgne River?
Higher concentrations of pollutants due to reduced flow
What happens to some rivers below the dam during summer?
They virtually dry up
What is a potential risk associated with the storage of excess water in the Grande Dixence?
Sudden and unexpected flooding
What has been a consequence of the construction of the Grande Dixence dam on sediment flow into Lake Geneva?
The amount of sediment flowing into Lake Geneva has halved
What has enhanced tourism in the area around the Grande Dixence dam?
Guided tours and helicopter rides
What occurred in December 2000 at the Grande Dixence dam?
A high-pressure pipeline burst, causing a landslide
How has increased dam storage affected irrigation channels?
Reduced sediment has led to the need for additional measures like channel lining
What future impact might climate change have on glaciers in the Swiss Alps?
Higher rates of glacier melting and increased meltwater supply
