Published on Wednesday, the study showed that some 384,000 people in Germany could be severely affected by flooding in the coming years, DPA reported.
Of these, around 190,800 reside along the Rhine River and its tributaries, while about 98,800 people living near the Elbe River are also identified as high-risk.
The study, commissioned by the Greens parliamentary group, is based on flood risk management plans from Germany's states.
The authors said that the figures may shift with future changes, noting that past floods, such as those on the Oder River, suggest the current estimates might be conservative.
In February, a separate study commissioned by the German Insurance Association (GDV) indicated that over 300,000 buildings in Germany could face flooding risks.
The UfU researchers stressed the need to enhance current precautionary measures. "Although heavy rain events can only be predicted at short notice, the development of monitoring systems and forecasting models remains important," they said.
Julia Verlinden, deputy leader of the Greens' parliamentary group, described the findings as "alarming" and stressed the urgent need to "adapt flood protection measures to address the climate crisis" more effectively.