[1] The lake feeds the Etzelwerk power station [de], which is located 5 kilometres (3 mi) to the north-east in Altendorf on the upper section of Lake Zürich (the Obersee) and which supplies electricity to the Swiss Federal Railways (SBB).

A concrete dam and two viaducts over the lake were built before 1937 when the valley was flooded.

As a result 107 farms disappeared completely and 1762 persons had to leave their homes.

[2] A failure of the dam could lead, according to studies, to an 8-metre (26 ft) high flood wave through the lower Sihl Valley reaching the Altstadt of the city of Zürich, the biggest city in Switzerland, within 2 hours.

This threat has led the City of Zürich to develop, publish and test evacuation plans for the affected areas of the city, and especially the area around Zürich Hauptbahnhof railway station.