What will the water supply of the future look like in Germany, given the climate crisis and industrial change? Because the Spree is carrying less and less water, Berlin is researching methods to quench the city’s thirst.
Berlin’s drinking water supply depends on the Spree. The water from the Spree and Havel seeps into groundwater, which makes up around 60 percent of Berlin’s drinking water. But the water level of the Spree has been falling for years. One reason is the drought of recent years.
Another is the coal phase-out: groundwater from the opencast mining areas of Lusatia is pumped out so that the opencast mines do not fill up. This is the only way the coal can be mined. The majority of the pumped water masses are discharged into the Spree. This is how the drinking water supply in the capital was and is secured.
With the decline of the coal industry in recent years and the impending phase-out of coal, this water will be missing in the future and the Spree will increasingly suffer from water shortages. Even more than now. The Spree is increasingly falling below the critical value that ensures Berlin’s drinking water supply in the long term.
So far, water from the Lusatian district has been channeled into the Spree.
The end of an era
With the end of coal mining in Lusatia, drinking water production will also stop. Although it will be decades before the last pumps in the south of Brandenburg stand still, experts are already calling on politicians to act.
“We are at a turning point that requires a realignment of the drinking water supply. It is time to develop innovative solutions to meet the long-term need for water in Berlin,” says Ulf Miehe, Berlin Water Competence Center.
Falling water levels
Especially in dry summer months, there is a possibility that drinking water in Berlin and Brandenburg could become scarce in the future, experts say. At the same time, the need for drinking water is increasing.
The Berliner Wasserbetriebe must provide more water for more and more residents and new businesses. Four million people could soon be living in Berlin. The current demand of around 540 million cubic meters of drinking water per year is likely to skyrocket.
Politicians must now quickly find solutions to a problem that has not been addressed for a long time, say scientists. Irina Engelhardt from TU Berlin calls for long-term solutions and better cooperation between science, politics and industry: “Short-term assumptions are not enough to overcome the complex challenges in the area of water resources.”
New concepts are being explored
With three million euros in funding, the “SpreeWasser:N” project under Engelhardt’s leadership is researching new possibilities for the use of drinking water. Modern water treatment systems are an important component. Such systems can remove various pollutants and impurities from the water and treat it to drinking water quality.
So-called reverse osmosis systems can separate water from dissolved substances using a semi-permeable membrane. This enables the water to be highly purified, including even the smallest particles and pollutants.
The technology can be used for both groundwater treatment and wastewater reuse. The resource water can be used particularly efficiently.
Groundwater recharge like in London
Groundwater enrichment through alternative water sources such as rainwater is therefore more promising, says project manager Irina Engelhardt. “That means I collect heavy rainfall, store the rainwater and bring it into the aquifer. The city of London does that, the entire Mediterranean region does it and it’s also very common in France,” says the hydrogeologist.
Switching to alternative water sources brings challenges: it requires careful planning and technological innovation and political will to ensure the quality and safety of drinking water in the future.
Ulf Miehe from the Berlin Water Competence Center emphasizes the importance of research and development: “We have to invest in new technologies in order to master the challenges of the future.”