Formed by mighty glaciers 20,000 years ago, Lake Achensee lies nestled between the Rofan and Karwendel mountains, Tirol's largest nature reserve. The majestic lake is shrouded in myth, and according to legend, it was not formed naturally. In its place, there was once a thriving village. However, its inhabitants lived a dissolute life. As a punishment, immense water masses came over the village, causing it to sink forever, and this is how Lake Achensee was born. Tirol's largest lake is 9 kilometres long, 1.3 kilometres wide and 133 metres at its deepest point. The bright limestone rock causes the surface water to shimmer in hues of stunning turquoise and aquamarine. If you want to immerse yourself in the lake, you should know that the water temperature is relatively low throughout the year. In the summer months, however, Lake Achensee warms up to 22 degrees Celsius – a blissfully refreshing experience on hot days.
Lake Achensee is not only a popular excursion and travel destination. Since 1927, it has also been used as a reservoir to generate electricity. To keep the water level constant despite the use of water, canals and tunnels were built to channel streams into the lake. Nevertheless, the withdrawal of water is noticeable. In winter, the lake’s water level drops by up to five metres. In spring, the southern shoreline is still dry, and in summer the lake is completely refilled. During the construction of a shared-use path for pedestrians and cyclists from Maurach to Pertisau, a dam was built which cuts off a part of the lake. On the southern shore of Lake Achensee, a reed bed has developed, providing a habitat for reeds, colourful marsh irises, purple willows, the carnivorous plant common butterwort, and a variety of native birds. Information about Lake Achensee, its formation and use, and the fauna and flora of its littoral area can also be found on the interpretive panel on the southern lakeshore in Maurach.