Griessee (Switzerland)

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Griessee and Bättelmatthorn in the canton of Valais in Switzerland.jpg
Location: SwitzerlandSwitzerland Switzerland
Canton of ValaisCanton of Valais Valais
Tributaries: nameless stream from the Gries glacier
Drain: Mändelibach → Griesseebach → Ägene → Rhone
Larger places nearby: Ulrichen
Griessee (Canton of Valais)
Coordinates 671551  /  145554
Data on the structure
Lock type: Gravity dam
Construction time: 1963-1966
Height of the barrier structure : 60 m
Height above the river bed : 66 m
Height of the structure crown: 2387.5  m above sea level M.
Building volume: 251 000  m³
Crown length: 400 m
Slope slope on the air side : from bottom to top:
1: 0.85
1: 0.72
1: 0.68
1: 0.25
Slope slope on the water side : perpendicular
Power plant output: 1st level: Altstafel 9.2 MW
2nd level: Bavona
3rd level: Cavergno
4th level: Verbano
Operator: Kraftwerk Aegina AG
owned by:
- Rhonewerke AG: 50%
- OFIMA : 50%
Data on the reservoir
Altitude (at congestion destination ) 2386.3
Water surface 59.4 hadep1
Reservoir length 1.2 km
Reservoir width 700 m
Maximum depth 66 m
Storage space 18 million m³
Total storage space : 18.6 million m³
Catchment area 10.5 km²
Design flood : 38.8 m³ / s

The Griessee in the canton of Valais is one of the highest reservoirs in Switzerland. The reservoir is used for power generation by the Aegina AG power plant .


The lake is located in the area of ​​the once independent municipality of Ulrichen , which today belongs to the municipality of Obergoms . It is fed by the Gries glacier , the natural outflow of the lake is the Mändelibach, whose water flows over the Griesseebach and the Ägene near Ulrichen into the Rhone .

The reservoir can be reached via the Nufenenpassstrasse . From the west ramp, an approx. 2 km long mountain road leads south to the reservoir. In the south, a mule track leads over the Gries Pass to Italy . In addition to the Griessee, the first turbine at the Gries wind farm was put into operation in 2011 .


After a construction period of three years, the Gries dam was completed in 1966. The lake water is of AG Kraftwerk Aegina used that in half the Rhone works and in half the Maggia power plants belongs It operates the underground power station Altstafel , which has an output of 9.2 MW and 21.6 million kWh of energy feeding into the grid annually . Almost 80% of the energy is generated in the winter half-year. The control center is accessed from the equipment chamber at the base of the dam via an inclined elevator .

The underwater from Altstafel is led through a tunnel under the canton border into the canton of Ticino , where it is further used by Maggia Kraftwerke AG . First it reaches the Lago di Robièi , then it is used by three other centers as far as Lake Maggiore , namely those of Bavona , Cavergno and Verbano near Brissago .

The high usable gradient between the reservoir at 2387.5 m above sea level. M. and the Langensee at 194 m above sea level. M. leads to the fact that the water in the Griessee has a very high value for electricity generation. The 18 million m³ storage capacity can do 15 million kWh of work in Altstafel and a further 63 million kWh in the machine houses of the Maggia power plants on the way to the valley, which results in a total of 78 million kWh. That means one cubic meter of Griessee water can produce 4.3 kWh on the way down into the valley, which is one of the highest energy equivalents in Switzerland.


Web links

Commons : Griessee  - Collection of images, videos and audio files

Individual evidence

  1. a b EnAlpin AG - Kraftwerk Aegina AG. Retrieved June 8, 2020 .
  2. a b Geoserver of the Swiss Federal Administration ( information )
  3. 3988.01 Altstafel power plant cavern center - Griessee dam base. In: Retrieved June 8, 2020 .
  4. ^ Officine Idroelettriche della Maggia SA. Retrieved June 6, 2020 (Official Website).
  5. Andrea Baumer: Gries . Ed .: Swiss Dam Committee. ( [PDF]).