Usable river discharge 30 m³ / s

The Griessee is the highest reservoir of Switzerland and is located in the Canton of Valais in the field of the once independent community Ulrichen, which now belongs to the municipality of Upper Goms VS. It is fed from the Gries glacier.

You can reach the reservoir only through the Nufenenpass. From the pass, a 2 km long mountain road to the south leads to the reservoir. In the south of the Gries Pass leads to Italy.


After a construction period of 3 years, the dam Gries was completed in 1966. The connected power plant produces an average of Aegina 17.8 GWh / year electricity.


  • Lakes in Switzerland: Natural and reservoirs, Federal Office for the Environment FOEN, 2007 → lakes in Switzerland ( PDF)