Low Water 2025

Spring and summer 2025 were marked by exceptionally low water levels at Lake Constance. This article aims to put the event into context and explore some cultural and curious aspects.

First, an overview of the annual progression:

Context

Starting from an unusually high water level in early February, the level dropped continuously until mid-April. On the long-term average, March typically sees rising water levels at Lake Constance as snowmelt and increasing precipitation set in. Very low precipitation from February to April caused the lake’s water level to remain exceptionally low throughout the period from early April to late July 2025.

In the media, the low water level was primarily discussed in April. Some rather curious headlines from that time are listed below. However, the water level was actually at its most extreme between 6 and 8 July (338 cm, 337 cm, 339 cm). Since 1888, there have been only two years when the water level of Lake Constance was lower at this time of year: 1949 and 1976, with 1976 holding the record low for this time of year. Admittedly, the water level was already very low in April. Between 19 and 21 April (277 cm as daily average on all three days), there were only three years since 1888 when the level was lower at this time: 1921, 1976, 1996. For 19 April, 1921 holds the record low (267 cm). For 20 and 21 April, the records stand at 267 cm and 268 cm respectively, both reached in 1976.

This graph shows the water level in relation to the number of years in which the level was equally low or lower:

In July, a discussion arose about a “sad record” because the water level in Konstanz had remained below 400 cm for nearly 365 days. In fact, this has occurred 15 times between 1888 and 2025. The longest such period stretched from July 1971 to July 1973 (738 days). The level also remained below the 4-metre mark between September 2021 and May 2023.

Cultural Aspects - Shoals in the Lower Lake

At very low water levels, three shoals emerge above the surface of the Lower Lake (Untersee). They are called Stuhlrain, Bradlenrain, and Straßenrain. Though on Reichenau Island, locals would rather say “Stulroa”, “Bradler Roa”, and “Stroße Roa”. I have marked the three shoals on this map:

The photos were taken on 2025-04-23 at a water level of 278 cm in Konstanz. Allegedly, the discrepancy between the water level in the Upper Lake (Obersee) and the Lower Lake has increased in recent years. Seagrass in the Konstanz Funnel and along the course of the Schwanenhals is said to be responsible. However, I have not yet looked into this difference in detail.

Straßenrain (navigation marker on OSM):

Stuhlrain (navigation marker on OSM):

Bradlenrain (navigation marker on OSM):

West of the Stuhlrain, some larger stones become visible at low water levels. These are even recorded on OpenStreetMap (example on OSM). Allegedly, these are stones from the construction of the monastery on Reichenau Island. Many of the stones were apparently transported across the lake. It is quite conceivable that a stone occasionally went overboard. However, I have no evidence for this story.

Open-Air Concert 1972

In March 1972, the Bürgermusik (citizens’ band) of Reichenau Island performed an open-air concert on the exposed lakebed (Straßenrain). In the book commemorating the 100th anniversary of the carnival association “Grundel”, the following account can be found:

While the band played, the gymnasts’ wives sold radishes and freshly fried Lake Constance fish on the shore, while girls in traditional costume served Reichenau wine. The schoolchildren sold paperweights that had been painted at school. Still others sold the first spring flowers, donated by the basketful from local gardeners. Naturally, the obligatory sausage sale, organized by the carnival association, was not missing either. In total, over 6200 DM could be transferred to “Aktion Sorgenkind” [a charity for children in need]. German television and the international press reported on this event, to whose success the carnival association “Grundel” had also made a significant contribution.

German original:

Während die Musik spielte, verkauften die Turnerfrauen am Ufer Radieschen und an Ort und Stelle gebackene Bodenseefische, während die Trachtenmädchen Reichenauer Wein ausschenkten. Die Schulkinder verkauften Briefbeschwerer, die in der Schule bemalt worden waren. Wieder andere brachten die ersten Frühlingsblumen, die von Gärtnern körbeweise gestiftet wurden, an den Mann. Selbstverständlich fehlte auch der obligatorische Wurstverkauf unter der Regie des Narrenvereins nicht. So konnten der Aktion Sorgenkind über 6200.- DM überwiesen werden. Das deutsche Fernsehen und die internationale Presse berichteten über dieses Ereignis, zu dessen gutem Gelingen auch der Narrenverein „Grundel" maßgeblich beigetragen hatte.

Thanks to Matthias Graf for the look into the archives.

Quite impressive, what people managed to put together spontaneously back then. Adjusted for inflation, 6,200 DM in 1972 corresponds to just under 10,000 euros today.

Here are images of a postcard that could be purchased as a souvenir and donation.

In memory of the concert by the Reichenau Civic Band, in aid of “Aktion Sorgenkind,” on March 26, 1972, on the exposed lakebed in the Untersee, at a water level of 2.37 m.

German original:

Zur Erinnerung an das Konzert der Bürgermusik Reichenau, zugunsten der » Aktion Sorgenkind «, am 26. März 1972, auf dem Straßenrain im Untersee, bei einem Pegelstand von 2,37 m.

Here they apparently referred to the water level in Radolfzell. The photos above were taken at a water level of 243 cm in Radolfzell (278 cm in Konstanz).

Curiosities

And then there was the silly season in the media. Here are three examples of absurd articles served up to the public. I must admit that I only know the headlines. But I don’t think there can be much more to them than that.

“Bodensee trocknet weiter aus” (EN = “Lake Constance continues to dry up”) on schwaebische.de, 2025-04-07
“Tauchen jetzt 103 Leichen auf?” (EN = “Will 103 bodies surface now?”) on schwaebische.de, 2025-04-13
“Mehr als 100 Tote in den Tiefen: Gibt der Bodensee jetzt seine Leichen frei?” (EN = “More than 100 dead in the depths: Will Lake Constance now release its bodies?”) on focus.de, 2025-04-15

“Bodensee trocknet weiter aus” (EN = “Lake Constance continues to dry up”) - headline on schwaebische.de, 2025-04-07.

“Tauchen jetzt 103 Leichen auf?” (EN = “Will 103 bodies surface now?”) - headline on schwaebische.de, 2025-04-13.

“Mehr als 100 Tote in den Tiefen: Gibt der Bodensee jetzt seine Leichen frei?” (EN = “More than 100 dead in the depths: Will Lake Constance now release its bodies?”) - headline on focus.de, 2025-04-15.