Lake Constance is changing: floods are hitting historic lows!

Lake Constance is changing: floods are hitting historic lows!

A lot has changed on Lake Constance in recent years - and at a rapid pace. Many communities still suffered from flooding in 2024, while the level of Lake Constance was lower in the spring of 2025 than it had been for a long time. A look back shows the dramatic extreme weather events that shaped this change. According to that South Courier In early summer 2024, riverside paths were closed and walkers struggled through flooded paths. In June 2024, the situation in Konstanz was particularly precarious: the water level in the city garden threatened to overflow, while in spring 2025 the water had receded significantly.

The changing water levels are due to a number of factors, including the amounts of rain and snow that feed Lake Constance. The International Water Protection Commission for Lake Constance (IGKB) emphasizes that the Rhine supplies around 62 percent of the water and that the water levels depend heavily on these tributaries. It is noteworthy that the average water level is around 40 centimeters lower today than in recent decades. This is a direct effect of climate change, which also affects flood levels, such as Watson reported.

The extreme weather situation in numbers

The contrast in the water levels is shocking. In Radolfzell, for example, the bronze statue El Niño was almost completely submerged in water in December 2023, while it could be walked around dry in spring 2025. The banks in Gaienhofen also show a similar picture: in the summer of 2024 the water was up to the bank path, and a year later this area was largely dry. These drastic changes are not only noticeable for the residents, but also for the entire flora and fauna around Lake Constance.

• Juni 2024: Hochwasser in Konstanz, bedrohlicher Wasserstand im Stadtgarten.
• Frühjahr 2025: Wasser hat sich zurückgezogen, Uferbefestigungen werden sichtbar.
• Radolfzell: Vereinsheim der Wäschbruck war im Wasser, im Frühjahr 2025 trocken.
• Bodman-Ludwigshafen: Kiosk im Juni 2024 fast im Wasser, ein Jahr später trocken.

Long-term impact and research

The AGKB underlines the concern about the invasive quagga mussel, which is increasingly being detected in Lake Constance. This mussel can occur in densities of up to 10,000 specimens per square meter and its impact on the ecosystem is currently difficult to estimate. The IGKB is aware of its responsibility and recently launched a new research project entitled “SeeWandel-Klima” to better predict the consequences of climate change and invasive species. At the 2025 Commission meeting, the water balance was discussed intensively and the pressing challenges brought about by climate change were pointed out.

Overall, it can be seen that Lake Constance is changing dramatically not only in numbers, but also in its ecological diversity. How long can the region continue to defy these challenges? Lake Constance remains a natural paradise, but the signs of the times are obvious. The question is how we can respond to this and preserve Lake Constance as a habitat with all its beauty and diversity, while at the same time getting climate change under control.