Monitoring and modeling of rivers crossing urban areas: The case of the Sile River in Treviso (Italy)

A significant factor in compromising receiving water standards required by the EU Water Framework Directive is the use of plant protection products and fertilizers in agriculture and the diffuse urban pollution. Changes in the built environment and climatic forces contribute to the increase of combined sewer system (CSS) overflows and of stormwater directly conveyed to water bodies that, together with rural discharges, are responsible of their contamination. Here the case of the river Sile, one of the longest European wellspring rivers and part of a protected area located in the Nord-Est of Italy is addressed. To assess the impact of rural and urban pollution discharges on the quality of the main river and some of its tributaries crossing the city of Treviso (Figure), a monitoring system consisting of 6 discharge measurement stations and 4 sampling systems, together with 3 multiparametric probes, will soon be realized. To identify the most common pollutants and quantify rural and urban area’s drainage system outflows during both rainfall events and dry conditions continuous probe monitoring and lab analysis of automatic water samples will be developed. Monitored discharges and collected quality data will be analysed and used together with the results of a currently under development 1D-2D hydrodynamic model of natural and artificial channel network. The hydrodynamic model, using as input the data acquired over time, will allow us to determine the nowadays conditions, identify and quantify the main sources of pollution and suggest possible mitigation strategies to improve the current status of the Sile River. These activities will enable the promotion of responsible agricultural practices and the assessment of the effects of an ongoing project aimed at separating the CSS. Moreover, to solve pollution generating from urban areas runoff, Sustainable Drainage Systems solutions will be tested with a laboratory equipment in a fully controlled environment, to analyse the main physical processes and assess the solutions’ efficiency both in the short and long-term. If the laboratory model gives satisfactory results, a full-scale test will be developed on an experimental area of the municipality of Treviso, to verify the effectiveness of the solutions adopted through the installed monitoring system.