According to the Baden-Württemberg State Institute for the Environment, the water level in Constance was only 3.20 metres on 4 August. The previous negative record from the years 1949 and 1876 of 3.17 metres according to the ZDF will probably be undercut this week according to the authority's forecasts, as there are no major rainfall amounts in sight.
The low water level is already causing problems in many harbours. Numerous marinas are already dry, especially on the lower lake. Berths are becoming scarce in the remaining harbours, as many owners want to move their boats to deeper areas.
The low water level is nothing unusual for Lake Constance, but the time of year is problematic. Normally, the lake is well filled in summer due to the melting snow and the rain in spring. As there was little snow in winter and spring was relatively dry, there is now a lack of water.
Harbours in the Untersee fall dry
The situation is particularly dramatic on Untersee, the western part of Lake Constance between Constance, Radolfzell and the outflow of the Rhine. The harbour master of the Reichenau marina, Franz Egenhofer, reports: "We have already had to take 50 boats out of the water, especially those with a draught of over 1.20 metres. In one to two weeks, it will be the turn of those with a draught of more than one metre, they just have a reprieve." Nevertheless, motorboats from the even more severely affected harbours in Moos, Iznang and Horn are also finding shelter in Reichenau. However, 20 moorings have already had to be shut down completely.
According to Egenhofer, the Lower Lake currently has a level 58 centimetres lower than the Upper Lake. He believes that one of the causes is the silting up of the Seerhein, which connects the Upper Lake to the East with the Lower Lake and forms a bottleneck for the water flow. Twenty years ago, the difference was only 20 centimetres. And the sand is also causing him problems on site in Reichenau, resulting in ever shallower water depths in the harbour. At the same time, large volumes of water are constantly flowing out via the Rhine Falls, which are then missing from the Lower Lake. "The Untersee is haemorrhaging," says Egenhofer.
The marinas in Lake Constance are getting crowded
Things are currently looking better at the Ultramarin Marina in Kressbronn am Obersee, the larger eastern part of Lake Constance. "As we are a former gravel pit, the depth is still unproblematic in most places," says Patricia Reuthe, assistant to the management. It is only at the edges close to land that things are slowly becoming critical. Many owners from other harbours on Lake Constance are currently making enquiries, but the marina is currently at full capacity during the holiday season. An easing of the situation is only in sight when the holidays end.
The most critical point in Kressbronn is the entrance and exit of the harbour, where the water depth is roughly the same as the water level in Constance. And the prospects? "If it's a rainy September, as we've often had, then the situation will ease. But a short shower every two days, like at the moment, is not enough."
Harbour master Egenhofer is also hoping for rain. At the moment, you could almost go for a "mudflat hike". The future belongs to dinghies and other shallow-draft boats, at least in the Untersee.
