The effects of dry phases on groundwater vary
Type: News, Date: 13.07.2026, Topic: General information , Topic: Groundwater
The effects of longer dry periods on groundwater levels vary considerably across Germany. While some aquifers recover after just a few months, others are characterised by low groundwater levels for years after a dry period. These findings are presented in a study published by the BGR, together with the environmental agencies and state geological services of the federal states, as well as the Karlsruhe Institute of Technology (KIT), in the journal Grundwasser.
The effects of longer dry periods on groundwater levels vary considerably across Germany. While some aquifers recover after just a few months, others are characterised by low groundwater levels for years after a dry period. These findings are presented in a study published by the BGR, together with the environmental agencies and state geological services of the federal states, as well as the Karlsruhe Institute of Technology (KIT), in the journal Grundwasser.
The study is based on an analysis of groundwater levels across Germany. For this analysis, data from around 5,900 groundwater monitoring sites was used. The long-term development during the climatological reference period of 1991 to 2020, as well as the impact of dry periods from 2018 onwards, were examined. The results revealed clear differences in the behaviour of the aquifers. In fast-reacting systems, the effects of dry phases are noticeable at an early stage. However, these aquifers usually recover comparatively quickly. Dry periods last a median of around two months.
In the case of groundwater systems, however, which are generally more sluggish, the effects of dry periods are experienced with a time lag. While they can better buffer dry phases in the short term, they require significantly more time to regenerate after prolonged drought. Dry phases there last a median of almost ten months. Following the dry phase that began in 2018, around 60 percent of the monitoring sites still had persistently low groundwater levels five years later.
As part of a trend analysis, the long-term development of groundwater levels was examined, in addition to the short-term effects of dry and wet phases. For the reference period from 1991 to 2020, the overall situation was predominantly balanced. At around 69 percent of the monitoring sites, no or only minor long-term changes were detected. Groundwater levels decreased at 22 percent of the monitoring sites and increased at 9 percent.
The study provides an important framework for assessing current developments in groundwater levels in Germany. BGR also provides up-to-date information and forecasts on the development of groundwater levels nationwide via the GRUVO groundwater level service.