Monitoring of rivers is fundamental not only for classifying their status and for identifying the main sources of pollution, but also for defining suitable intervention strategies for their restoration. The processes that affect the evolution in space and time of rivers’ water quality develop differently in space and time. Following the Water Framework Directive (2000/60/CE), European nations developed water monitoring programs, which are mostly on a large spatial scale. However, to evaluate the effects of local actions a different spatial density of monitoring station and sampling frequency may be needed. Numerical models calibrated on this data may be useful not only to identify the processes involved but also to forecast effects of local intervention. Here, the small-scale water quantity and quality monitoring system, developed between 2021 and 2023 to assess the impact of the combined sewer system of the city of Treviso (North-East Italy) on the quality status of the Sile River, is presented. The city is currently characterized by a combined sewer system and an ongoing project aims at separating it. Thus, to better assess the improvements derived by the new project, it is fundamental to achieve an in-depth knowledge of the current and future status of the river, by quantifying the impact of the urban area in dry periods and during rainfall events, and identifying pollution sources coming also from the surrounding. The monitoring system consists of 6 stations each one of them equipped with radar sensors to continuously retrieve water level and discharge data; 3 stations out of 6 are equipped with multiparametric probes and refrigerated samplers, while two additional portable samplers allow quality data to be collected at other locations. In this work, after a brief description of the monitoring system setup, the analysis of data collected up to now is presented, together with an overview of the inter seasonal behavior of the water quality of the river Sile and on the pollution contributes during rainfall events.
Giulia et al. (Wed,) studied this question.