Hydrology

The catchment area of the River Reuss to the side weir is 3382 km2 and extends from the Gotthard region through Central Switzerland and Canton Zug, Entlebuch, the upper Freiamt in Aargau and parts of the Knonauer Amt in Zurich. Lake Lucerne acts as a balancing element for all its tributaries. On the one hand, it guarantees a minimum water level even in dry periods, while on the other it effectively damps flood waves from the Gotthard Reuss, Muota and Sarner Aa rivers. Below the city of Lucerne, however, the River Kleine Emme flows unchecked into the Reuss. It reacts like a torrent with extreme fluctuations in water volume. During dry periods, the water flow is a few cubic metres per second, during floods several hundred cubic metres per second. It is therefore almost exclusively the weather conditions in the Entlebuch that are responsible for the extreme floods. The picture was taken during a 2005 flood.

Thanks to the measuring stations of the National Hydrological Survey in Seedorf, Lucerne, Emmen (Kleine Emme), Frauental (Lorze) and especially Mühlau (Reuss) we are well informed about the hydrology. Most of the time our data refer directly to the Mühlau gauge, although between Mühlau and the side weir the River Lorze still flows in, but its water volume is negligible in case of flooding.

If you want to know more about the River Reuss and its floods, you will find valuable information in a Wikipeter article by Peter Eichhorn and can consult the web links about the Reuss.

In the event of impending flooding, our operations group is automatically alerted and the protective measures put in place can be taken. Unfortunately, the turbine plant is not flood-proof, so that damage-causing flooding must be expected in the future.