1 EQ4 - Grande Dixence Scheme

Switzerland

What is the general info for the dam?

* Located in Switzerland
* Provides hydroelectric power
* It cost ==1600 million Swiss Francs== at the time
* Half of the water in the dam comes from ==35 glaciers== that provide seasonal meltwater
* The dam has formed the $‘Lac de Dix’$ (a lake)

How does the dam generate electricity? What are the stats for electricity?

* The water inside the lake drives the turbines of the ==four== power stations
* It generates enough electricity to power ==400,000== Swiss households annually
* It operates by storing meltwater during the summer and then using it to generate electricity during the winter
* Around ==1/3== of Swiss electricity comes from storage power stations
* Less than ==5%== of electricity comes from fossil fuels

How does the dam impact the physical environment?

* The environmental impact of the project has been minimised to ensure that the area remains attractive to hikers and bikers
* The power stations are largely built $underground$

What is the water in the dam used for?

* ==85%== of the water is used for electricity generation
* The rest of it is used to deal with issues with sedimentation
* This is caused by the deposition of sediment from the water flowing into the dam
* To solve this issue, some of the water is used to purge the sediment and move it downstream
* There is then a $high concentration of sediment$ in the river for a short time which can suffocate fish and block light for photosynthesis

What is the impact on river channels?

* \
* The trapping of sediment behind the dam means that the river channels below it are much clearer
* The reduced discharge can cause the below-dam rivers to virtually $dry up$ during summer
* The amount of sediment flowing into Lake Geneva has ==halved== since the construction of the dam
* The reduced flow of water in the $Borgne River$ has resulted in $increased concentrations of pollutants down stream$

What impact will climate change have on the dam?

* In the near future, $increased global temperatures are likely to increase the glacial meltwater$ flowing into the lake
* This increases the hydropower capacity of the dam
* However on a longer term scale, climate change could have a much more negative impact on the dam as the $glaciers are likely to shrink significantly$
* The meltwater supply will diminish significantly