Exploring the relationship between mobile positioning data and wastewater flows: evidence from five Swiss catchments.

Emissions from urban drainage systems can have unwanted consequences for human and environmental health. Unfortunately, traditional water quality monitoring in sewers is expensive and not comprehensive enough to provide detailed data on pollution across an entire catchment. However, with the increasing digitization of society, alternative data sources such as mobile positioning data offer new opportunities to assess wastewater production and dynamics. In this study, we investigate the relation between mobile positioning data and wastewater flows in five catchments in Switzerland with different characteristics and sizes, using data from the largest Swiss telecom provider and simple multiple linear regression models. The initial results of this study are promising although the degree of correlation observed between mobile positioning data and wastewater production is rather low (R² between 0 and 0.73) and varies greatly from catchment to catchment. As expected, we find nonlinear effects in the data that indicate that advanced models - incorporating factors like flow distances and dynamic travel times - are needed for reliable predictions. Also, data privacy issues limit its use in small catchments, highlighting the need for domain-specific preprocessing. This approach holds potential for urban drainage, wastewater treatment, drinking water, epidemiology, and climate adaptation.