Modelling the adoption of combined sewer overflow monitoring technology in Switzerland

Combined Sewer Overflows (CSOs) release untreated wastewater during heavy rain, but their impact on water quality and even their magnitude is poorly understood due to limited monitoring. This study develops a prototype of an Agent-Based Model (ABM) to test policies for increasing sensor adoption in CSO monitoring in Switzerland. The ABM simulates the behaviour of key stakeholders, including municipalities, wastewater treatment plant operators, engineers, and cantonal authorities, using the Theory of Planned Behaviour and the Bounded Confidence Model. It evaluates three strategies: professional events, mandatory sensor installation, and improved sensor technology. Results suggest mandatory installation is the most effective, though findings should be interpreted cautiously due to limited data. The modelling process improved our understanding of the socio-technical system and highlighted the role of social dynamics in technology adoption. Our model integrates multiple knowledge sources, includes a social network structure, and is openly accessible for further development. Key limitations include simplified human behaviour and static assumptions, but ABMs remain valuable to test policies and analyse complex systems.