German rivers suffered record low water levels in 2025-26, researchers report

German rivers ran persistently low through much of the past hydrological year, with water levels falling to levels researchers describe as far more frequent than in previous years. An analysis released by the Science Media Center covering the hydrological year 2025/26, which runs through October 31, found that soils, groundwater reserves and rivers across the country are entering winter with substantial deficits.

Winter is typically the season when Germany's water stores recover, largely because evaporation drops sharply during the colder months. But this year's shortfall has left water managers watching closely to see whether the usual replenishment will occur.

The Science Media Center drew on figures from the Low Water Information System, known by its German acronym NIWIS, which tracks river discharge across the country. According to that data, nine major river basins in Germany experienced sustained low water conditions over the hydrological year.

By January 2026, roughly one fifth of measured river discharge, the volume of water passing a given point per second, was classified as either "very low" or "extremely low." That share climbed further as the year progressed, reaching 35 percent in August and September.

NIWIS determines those categories by comparing current discharge figures against historical data from the same time of year between 1991 and 2020. A flow is labeled "very low" if it falls within the lowest five percent of historical values for that period, and "extremely low" if it drops below the lowest one percent.

Soil conditions followed a similar pattern. The winter of 2025/26 was already drier than usual, researchers found, and by summer an "extreme drought" had taken hold across large parts of the country, with southern Germany particularly affected.

Enno Nilson, a hydrologist at the Federal Institute of Hydrology, known as the BfG, told the Science Media Center that low water events on the Rhine were historically a winter phenomenon, typically triggered by severe cold, ice and snow. He said the shift toward summer low water driven by heat and drought matches patterns long forecast under climate change.

"That we now experience low water on the Rhine almost exclusively because of heat and drought in summer fits the picture we projected under the conditions of advancing climate change," Nilson said.

He noted that the winter now beginning is normally the period when rivers and groundwater refill, but cautioned that it remains to be seen whether that recovery will actually take place this year. Sustained, heavy rainfall over land would be required to meaningfully restore water levels, he said.

Looking further ahead, Nilson said projections suggest Germany is likely to continue receiving substantial rainfall over the course of a full year in the foreseeable future, but that the distribution across seasons is expected to become increasingly uneven. He said more pronounced droughts and low water periods during the summer half of the year could be partly offset, on an annual average basis, by higher rainfall and river flows during winter months.

"This would not necessarily create a water quantity problem, but rather a distribution problem between regions and between seasons," Nilson said.

The findings add to a growing body of hydrological data pointing to shifting seasonal water patterns in Germany, with implications for agriculture, shipping and drinking water supplies that depend on steady river flows throughout the year.