The Gelmersee was built simultaneously with the Grimselsee (until 1929 ). The Gelmersee has a usable volume of 13 million cubic meters and is located 1850 m above sea level, about 50 m deeper than the Grimsel. The water comes in part from the Grimsel (via a tunnel connection ), partly from the catchment area around the Gelmersee. The water is used in electricity plant Handegg 1

For Gelmersee performs operated by power plants Oberhasli AG Gelmerbahn with 106% steepest funicular railway in Europe.

To the Gelmersee leads a white-red- white -marked mountain trail. On the north side of the road to the steep rock face was carved. The most dangerous places were secured by ropes. However, Absolute sure-footedness is a prerequisite. The road is not suitable for small children. During the snow melt streams can block the way. The Seeumwanderung takes about two hours.

Even before the construction of the dam was at the point a ( much smaller ) lake.

Technical data of the dam

Storage volume: 14 million m³