#ModellingMonday – Granollers and the ICM InfoWorks Model: Building Climate Resilience Through Smarter Water Management 

To respond, Granollers has begun redesigning its urban systems with a strong focus on flood resilience. As part of the EU-funded Horizon Europe project KNOWING, the city is using ICM InfoWorks, an advanced modelling tool, to anticipate and reduce flood risks in a changing climate.

 ICM InfoWorks: Simulating Reality to Prevent Disaster 

Figure 1: Even in a heavy rain event, occurring only every ten years, large parts of the city of Granollers will be flooded with the current drainage network. Credit: Aquatec 

At the core of Granollers’ climate adaptation strategy is a 1D+2D hydrological and hydrodynamic model. ICM InfoWorks simulates how water moves both through underground drainage systems (1D) and across the surface of streets and rivers (2D). This is critical for a city like Granollers, where both stormwater runoff and river flooding pose significant threats. 

The model supports decision-making by creating detailed hazard maps that show flood depths and flow speeds. It also estimates material damages, such as infrastructure losses, and helps evaluate the cost-effectiveness of various adaptation strategies. Importantly, ICM InfoWorks supports land use planning, disaster response, and long-term recovery strategies, all through a climate risk lens. 

Three Scenarios for a Wetter Future 

To prepare for the future, Granollers has modeled three distinct scenarios using ICM InfoWorks: 

1. Current drainage system – showing today’s vulnerabilities. 
2. Land use change according to the city’s CoCoNat25 renaturalisation project – projecting shifts in impermeable surfaces. 
3. Nature-based solutions (NbS) – including sustainable urban drainage systems (SUDS) and future rainfall under climate change projections. 

Each scenario was tested for extreme rainfall events that statistically occur every 10, 100, and 500 years (T10, T100, T500). These simulations provided a robust understanding of what Granollers could face as climate extremes become more frequent and intense. 

Figure 2: Modellations show that land use change according to the city’s plan can reduce the flooding risk significantly. Credit: Aquatec 

Key Findings: Infiltration Beats Intervention Upstream 

The modelling revealed several critical insights: 

• Reducing impermeable surfaces upstream significantly increases effective water infiltration, cutting flood risk. 

• Nature-based solutions can slightly reduce accumulated flood volumes. Additional retention areas will be necessary in case of heavy flooding events. 

These findings help city planners make informed, cost-effective decisions. Instead of expensive interventions in the wrong places, Granollers is now focusing efforts where they matter most: impermeable surfaces upstream and water retention areas for heavy flooding events. 

From Flood Risk to Urban Opportunity 

At the same time, river interventions modeled with ICM InfoWorks, such as riverbank restoration and green public spaces, offer more than just flood protection. They improve urban liveability, store carbon, and reduce heat, helping mitigate and adapt to climate change simultaneously. This systems-level thinking is central to KNOWING, which links models like ICM InfoWorks with others in the project, including energy demand (MAED-City), urban climate (PALM-4U), and infrastructure optimization (IESopt).  

Finally, all the results are brought together in the KNOWING System Dynamics Model. This model depicts complex interactions between climate change, social developments, political measures and technical interventions and makes it possible to develop robust climate paths for regions such as Granollers.