Das Projekt RainDrop entwickelt ein hydrodynamisches Planungstool, mit dem blau-grüne Infrastrukturen über reale klimatische Langzeitreihen dimensioniert werden. Um eine kostenoptimierte Auslegung eines Mulden-Rigolen-Elements je zulässiger Überlaufhäufigkeit mit dem Planungstool bestimmen zu können wurde wird ein deterministischer Bisektions-Optimierer vorgestellt (R-Paket kwb.raindrop). Für die Standorte Wien und Bad Aussee (15-jährige Klimareihen 2011-2025) findet der Optimierer mit rund einem Fünftel der Simulationsläufe durchweg günstigere Designs (im Median -6,5 %, bis -16 %) als die beste Rasterzelle in einem Lösungsraum mit äquidistaner Parametervariation, da Muldenfläche, Muldentiefe und Rigolen-Speicherhöhe stufenlos gesucht werden. Ein Suchpfad-Monte-Carlo bestätigt die Robustheit der gefundenen Optima.

Für das Wassermanagement urbaner Gewässersysteme werden schnelle und zugleich ausreichend belastbare Modellansätze benötigt, um beispielsweise Stoffeinträge, Abwasseranteile oder Auswirkungen zukünftiger Randbedingungen bewerten zu können. Am Beispiel Berlins wurde hierfür das Berlin Water Model als vereinfachtes dynamisches Mischungsmodell entwickelt, das für 35 Gewässerabschnitte Durchflüsse, Stoffkonzentrationen sowie Anteile von gereinigtem Abwasser, Regenabfluss und Mischwasserüberläufen in stündlicher oder täglicher Auflösung berechnet. Die Validierung mit Ergebnissen hydrodynamischer Modelle und Messdaten zeigt eine gute Übereinstimmung, auch bei Sonderfällen wie Fließumkehr. Mit dem Modell können Hotspots und Überschreitungshäufigkeiten identifiziert und die Ergebnisse als Karte dargestellt werden. Das Modell eignet sich somit für Substanzmapping und Szenarien-rechnungen zur Unterstützung des Berliner Wassermanagements.

Berlin's groundwater is the city's primary drinking water source and closely linked to surface water via riverbank filtration and groundwater augmentation. Climate change, lower summer flows, increasing treated wastewater shares, stormwater runoff and combined sewer overflows pose growing challenges for water supply and ecological quality. Its interconnected lakes and rivers, flat topography and occasional flow reversals have traditionally required computationally intensive hydrodynamic models, limiting rapid long-term and scenario assessments.

We present the Berlin Water Model, a simplified dynamic mixing model that efficiently represents key quantitative and qualitative dynamics of Berlin’s surface waters. Implemented as an emulator, it describes the river-lake-canal network as interconnected, continuously mixed

sections and simulates flows, source contributions and substance concentrations at hourly or daily resolution. It integrates long-term data on upstream inflows, wastewater treatment plant (WWTP) discharges, stormwater runoff, combined sewer overflows, waterworks abstractions

and meteorological boundary conditions. Calibration against hydrodynamic simulations enables reproduction of key hydraulic features, including flow splitting and temporary flow reversals, while maintaining runtimes suitable for scenario analysis.

Beyond surface water dynamics, we are extending the model towards groundwater-related processes. Dynamic bank-filtration shares for single well galleries were integrated into the Berlin Water Model via regression functions from groundwater modelling studies, extended by KWB model runs within IMPETUS. Ongoing automation of Berliner Wasserbetriebe’s steady-state FEFLOW models via the Python interface (IFM) will provide these relationships consistently for changing recharge and abstraction rates. This enables assessment of climate-change impacts, altered abstraction regimes, and temporal dynamics in contributing areas and catchment water balances. Crucially, WWTP-derived effluent loads can be traced from discharge through surface waters and bank filtration to abstraction, supporting evaluation of measures from Berlin’s Masterplan Wasser.

The presentation will introduce the framework and show how the combined approach supports scenario analysis, impact assessment and decision-making for a resilient urban water cycle.

The SmartWater project is developing a digital urban planning tool – the Blue-Green Infrastructure Planner (BGI Planner) – to integrate decentralised stormwater management measures into planning processes at an early stage. The aim is to strengthen the climate resilience of urban areas, mitigate flood risks, reduce urban heat and lessen the pollution of Berlin's waterways. The BGI Planner is based on a modular structure and links geodata, checklists and effect simulations. In two pilot areas in Berlin, the effects of blue-green infrastructure are being analysed using models – in terms of flooding, water pollution, urban climate and water balance. Established modelling tools such as InfoWorks ICM, GERRIS/HYDRAX/QSim, ENVI-met and ABIMO are being used. Initial simulation results confirm the effectiveness of selected measures and form the basis for simplified evaluation models in the tool. In future, the BGI Planner will be used as a digital tool in Berlin's administration to support sustainable and climate-adapted urban development.

SmartWater is a Berlin-wide initiative that integrates blue and green infrastructure measures into urban planning through three digital tools. The tools are being tested in two contrasting districts and comprise of a planning tool, a digital game and a flood information portal. These prototypes demonstrate the potential of blue-green infrastructure to reduce flood risk, mitigate heat stress and enhance urban climate resilience. The development process has been meticulously structured to facilitate a collaborative co-design process involving administrations, utilities, experts and residents. This approach has been instrumental in elucidating the governance needs, data requirements and communication pathways. The findings illustrate the efficacy of coordinated modelling and shared digital infrastructures in facilitating decision-making processes, enhancing public comprehension, and providing a transferable framework for urban areas aspiring to enhance climate adaptation through integrated and pragmatic approaches.