Relaxing at the Achensee
The Achensee is a lake north of Jenbach in Tyrol, Austria. It is the largest lake within the federal state, and has a maximal depth of 133 metres. Together with the Achental valley it parts the Karwendel mountain range in the west from the Brandenberg Alps in the east.
Water quality is near drinking water, with sight up to 10 m below the surface. An alpine lake, water temperature is accordingly low, rarely above 20 °C. Its size and wind conditions make it suitable for surfing.
Since 1924 the Achensee is managed by the Tiroler Wasserkraft AG (TIWAG), which was founded for this purpose.
Originally, its only outflow was the Achen Bach feeding the Isar. Since 1927, when a powerplant in Jenbach was finished, it primarily feeds the Inn, at a level difference of 380 m below. Eight pelton wheels at 500 rpm produce a total of 96 MW.
In winter the level of the lake is lowered by up to 6 metres, accordingly the size of the lake keeps changing. At maximum level the reservoir can store 66 million m³ of water.