Reasons for urban water utilities’ hesitance towards dynamic system operation – and solutions to mitigate these

Dynamic operation of urban water infrastructure has many times been demonstrated as an efficient way to manage storm- and wastewater flows with a minimum of cost and material resources, and to improve the health of surface water environments by reducing, for example, combined sewer overflows. Adopting dynamic, real-time control strategies become even more important as climate change is challenging existing water infrastructure with increasing precipitation intensities and volumes. Nevertheless, urban water managers are hesitant to adopt such strategies and rather fall back to upgrading the infrastructure with e.g. underground basins and tunnels. Based on a series of semi-structured interviews and workshops with operators and planners from six Danish utilities, we can demonstrate that many aspects make utility employees feel uncomfortable with dynamic control schemes, e.g.:

• lack of knowledge on the environmental improvements that can be achieved with dynamic operation
• lack of understanding of the algorithms in applied control schemes
• lack of experience with dynamic operation
• lack of knowledge of the effect of system changes (e.g. construction work) on the dynamic control performance
• lack of collaboration across different departments within the utility
• lack of motivation from the operators

Furthermore, there is a general lack of time of the interviewed employees to engage in these aspects.

While the identified issues span across different stages of the planning and operation process, several issues (such as the lack of knowledge on potential environmental improvement, or the lack of collaboration between disciplines) arise in initial planning stages where strategic decisions are made. For this purpose, we have developed an automated screening approach for the potential environmental effects of dynamically operating urban water systems, where the approach and visualizations were developed iteratively and in close collaboration with the stakeholders.

Environmental improvements are in scientific literature often reported for the entire catchment (e.g. the total potential overflow volume reduction); however, a key learning from our work is that the environmental effects need to be visualized for each individual control point in the system. This makes it much more tangible for stakeholders to compare the potential environmental effect with the needed effort and cost, and the detailed result visualization of the dynamic control thus aligns much better with the decision-making process of the stakeholders. Furthermore, the stakeholders prefer simple, understandable control algorithms, even if these don’t fully exploit the potential of dynamic operation. This preference stands in direct contradiction to academic literature, which focuses on advancing control algorithms rather than making sure that existing algorithms are implemented.

Our results are currently implemented in a dashboard for screening the potential of dynamic operation of urban water systems, and will form the basis for generic rule-based operation strategies for urban water systems.