Insights gained from stormwater e-monitoring in Viimsi, Estonia

The Baltic Sea is at risk from urban societies' diffuse pollution, which includes harmful substances, nutrients, and marine debris. Stormwater, the primary means by which these pollutants are transported, is typically evaluated through the collection and analysis of grab samples, which show the water quality at a particular moment in time. This method, however, is ineffective at capturing instances of high pollutant concentrations, which makes it more difficult to accurately assess the pollutant load or the impact of the pollutants on the environment. In order to better monitor fluctuations in stormwater quality, an e-monitoring station based on surrogate water quality parameters was built in Viimsi, Estonia. The developed system was based on variables such as pH, turbidity, dissolved oxygen, electrical conductivity, flow rate, and water level. The developed system was successful at capturing high frequency data (5-minute time step) over a three-month period, missing only 15% of the data collected and capturing extreme values that would otherwise not be captured (with traditional grab sampling). The gathered data opens up new avenues for stormwater management and investigations (such as identifying unauthorized connections), as having high frequency and real-time data is the first step towards creating a smart stormwater system that can be controlled in real-time in accordance with water quality criteria.