
Prognosis
Berlin faces increasing drinking water challenges due to rising demand from population growth and more frequent droughts. An expected 40% reduction in summertime natural surface water runoff by 2040 further complicates water management, necessitating strategies to ensure sustainable water supply and mitigate the impacts of climate change.
Situation
The metropolitan Berlin-Brandenburg region in the north-eastern German lowlands has a relatively high surface area of rivers and lakes, but natural flow is low and increasing temperatures has led to higher evaporation rates and drought periods resulting in reduced river flows. The city of Berlin and its metropolitan region rely on groundwater as the drinking water production source. Treated wastewater is currently released back into the local freshwaters, resulting in a partially closed water management cycle within the city area. Brandenburg state has a higher reliance on water for agriculture and ecosystems. The rising pressure of climate change is impacting the natural water cycle.
Climate related issues

Water stress
Climate change is expected to cause more frequent drought periods, leading to decreased water availability.

Securing drinking water
Urban consumption of drinking water, industrial and agricultural needs, recreational use, and ecological requirements will compete for limited water resources, creating potential points of contention.

New policies required
The Masterplan Water outlines various measures and strategies to ensure a stable and sustainable water supply.
Key actions
We are supporting decision-making processes by calculating scenarios for water resource challenges and mitigation measures and their effects on surface water, groundwater, and drinking water by:
- Applying simplified models to evaluate pollution inputs to surface waters used for drinking water production and scenarios of related measures.
- Identifying the relationship between the ratio of bank filtration and groundwater abstraction rate from drinking water wells with detailed groundwater models.
- Developing and conducting workshops with relevant stakeholders to support decisions on measures to address challenges of reduced water availability.
Contact us

Nasrin Haacke
Kompetenzzentrum Wasser Berlin
nasrin.haacke[@]kompetenz-wasser.de
Events
Date
News
Resources
Relevant sectors:
Municipality
Authorities
Citizens
Water utilities
Industry
Nature conservation associations
Our ambitions
“In the IMPETUS project’s continental demo site, our primary goal is to tackle water scarcity in a city with a semi-closed water cycle. By identifying gaps in the regional water cycle and developing future usage scenarios, we aim to model both surface and groundwater in detail.
Our efforts to simulate water balance scenarios are crucial in reducing uncertainties, supporting strategies, and conducting vulnerability assessments. Moreover, this project supports the creation of a comprehensive regional strategy for water management and climate adaptation, developed by local authorities, to position the region as a national model for effective water strategies and best practices.”
Nasrin Haacke, Kompetenzzentrum Wasser Berlin
The following ambitions have been set:
- Simulate and map the regional water cycle and water balance (quantitative and qualitative).
- Assess cross-sectoral, regional vulnerability of critical conditions in the local water cycle.
- Define and assess scenarios for the development of water resources under future challenges and potential mitigation measures.
- Assess the effect of reduced groundwater recharge rates with detailed groundwater models.
- Preparation and realisation of several workshops for stakeholder engagement that supports decision making, incorporating results of modelled scenarios.
- Development of citizen-centered criteria and indicators to enhance the transparency, comprehensibility, and effectiveness of water-related adaptation measures, informed by prior insights into decision-making processes and prioritization approaches.

Issues
- Drought periods in recent years resulted in low river flows during summer being half of average values.
- Upcoming closure of coal mine south of Berlin and resulting reduction of groundwater discharges to the Spree river further reduces flow to one of Berlinās major rivers considerably.
- Berlinās semi-closed water cycle causes continued challenges for the production of drinking water via bank filtration and securing drinking water quality.
- Longer drought periods in the summer reduce surface water flows substantially resulting in higher shares of treated wastewater in river stretches used for drinking water production via bank filtration.
- For adequate management of different interests.
- To harmonise the approach across the federal states of Berlin and Brandenburg.
- To converge single-aspect policies into an integrated, common strategy.
Region-specific solutions
Integrated mapping and regional watershed modelling



The evaluation of future scenarios such as low flow periods in surface waters, reduced natural groundwater recharge or different discharge routes for treated wastewater, and their effects on water resources is crucial for authorities and water utilities in order to secure drinking water production and a sustainable management of urban water resources.
For this, different modelling approaches are applied in IMPETUS to assess regional water flows, critical shares of treated wastewater and surface water groundwater interactions relevant for drinking water resources. These efforts support decision making including prioritization of measures for the local water management plan “Masterplan Water”.
Our approach:
- Development and application of simplified models to assess water quality and quantity changes in the semi-closed water cycle of Berlin.
- Calculation of scenarios for reduced surface water flows and its effects on water ballances and shares of treated wastewater and stormwater runoff.
- Detailed groundwater and surface water modelling for specific relevant issues in the water cycle (e.g. variability of bankfiltration shares and reverse flows in surface water stretches).
- Visualization of detailed modelling results in easy understandable map views.
Stakeholder Workshops to Support Collaborative Water Management




A participatory format to assess and prioritize sustainable water-related measures.
To support ongoing efforts in sustainable urban water management, the Ecologic Instituteāon behalf of KWBāis organizing a series of multi-stakeholder workshops. These workshops aim to bring together diverse perspectives, strengthen collaboration across sectors, and jointly identify effective and widely supported adaptation measures. Participants from public institutions, utilities, science, civil society, and local initiatives come together to reflect on existing measures, explore future challenges through scenario development, and co-create transparent evaluation approaches. Established formats help create an open and structured dialogue.
Key elements of the approach:
- Focused discussion on selected water-related measures
- Scenario-based exploration of future challenges and needs
- Co-development of criteria and indicators to evaluate measures
- Involvement of a broad range of stakeholders
- Practical recommendations to improve transparency and acceptance
- Workshop outcomes contribute to refining individual measures and support coordinated efforts toward more resilient urban water management.