Effects chain – Example ‘water balance and water management’ | Umweltbundesamt

Climate changes relevant to the action field

State: Drought and heavy rain

Although the mean precipitation amounts have changed little in the course of recent decades, there have been repeated phases regionally of extreme water shortages contrasted with fierce heavy-rain events. Since 2003 there have been particularly frequent incidents of dry phases in summer. As far as the heavy-rain events are concerned, high spatial and temporal variability combined with relatively short data series make reliable trend statements difficult. Dry periods as well as heavy-rain events impact the availability of water (see section precipitation extremes).

Impacts of climate change

Impact: WW-I-2 Groundwater level and spring flow

High evaporation in summer on one hand, and increasing heavy-rain events on the other – with rainwater predominantly running off the surface – entail decreases in the replenishment of groundwater as well as the medium- to long-term diminution of groundwater levels in Germany, especially while the abstraction of water is increasing as a result of rising demand. All over Germany, record shortfalls were identified in the drought years of 2018-2020 revealing the lowest groundwater levels and spring flows recorded at gauging stations for many years. Of particular concern is the situation in northern Germany.

Impact: WW-I-7 Water levels in lakes

The water levels of lakes have been distinctly and significantly receding too. This is true for both, the lakes in the North German Plain, which are essentially fed by groundwater and therefore directly affected by receding groundwater levels, and also for lakes in the Alps-and-foothills, along with the Alpine foreland which are largely dependent on inputs from surface water bodies. During the period of 2018–2020 there were some incidents of massive water loss.

Adaptations – activities and results

Response: National Water Strategy

The National Water Strategy has led to the pooling of water-related measures in all relevant sectors, with the involvement of all relevant stakeholders. As water becomes less readily available, the situation can bring about conflicts regarding the utilisation of water. A guideline is being developed at joint Federal and Länder level to facilitate transparent decision-making regarding the prioritisation of water abstraction. In addition, many Länder are currently developing strategies on how to deal with low-water levels and drought and how to safeguard the water supply. The ANK is used for funding climate-related measures in water management, for developing water bodies and for measures required in respect of water-sensitive urban development.