Catalan Water Research Institute research and innovation for the sustainable use of water


01/12/2022 - 30/11/2024

City runoff pollution impacts on river biodiversity under extreme climatic events (CityPoll)

Urban areas are growing worldwide, with significant consequences for the natural ecosystems that surround them and for global biodiversity and climate. In addition to domestic and industrial wastewater, runoff from impervious urban surfaces alters local hydrology and can contribute a wide variety of pollutants, the effects of which on receiving river ecosystems are poorly understood but are likely to increase as a result of ongoing climate change.

CityPoll addresses this information gap through multidisciplinary research combining hydrology, environmental chemistry, ecotoxicology and ecology, in two contrasting case studies. With this aim, first of all, it will create a hydrological model of both case studies, integrating the sewer and the receiving river systems, to jointly analyze and control the passage of water and pollutants between urban areas and receiving rivers during rain events. Second, it will combine automatic sampling of natural rainfall events with experimental rainfall monitoring and the most advanced analytical tools to monitor the chemical characteristics of urban runoff, including suspended materials, nutrients, regulated and emerging micropollutants and microplastics. It will prioritize pollutants according to their occurrence and toxicity, and associate specific pollutants with specific types of urban areas. Thirdly, by means of micro and mesocosm studies, the ecotoxicological effects of these runoff on a series of organisms, from microbes to invertebrates, will be studied. It will also analyze the ecological effects of urban runoff by measuring the structural and functional response of receiving rivers by looking at biofilm, invertebrates, as well as a range of ecosystem processes, from nutrient dynamics to greenhouse gas emissions greenhouse With this information, CityPoll will produce multimetric indices of the ecological impact of urban runoff. Fourthly, the capacity of buffer zones (urban parks, riparian vegetation, etc.) to mitigate pollution derived from urban runoff will be assessed, thus pointing out the most suitable natural solutions for this purpose. Finally, CityPoll will devote a great deal of effort to the transfer and dissemination of the multi-layered evidence collected to a wide range of targets, from urban and water managers to scientists to the general public, through the development of guidelines, protocols, scientific articles, press releases and a video documentary. These guidelines and protocols will be useful beyond CityPoll’s specific case studies. Likewise, it will contribute to the development of new digital solutions for monitoring runoff, strengthening European industry once new procedures and strategies are transposed to global standards.

CityPoll combines 3 sub-projects: sub-project 1 (ICRA) focuses on hydrology, chemistry and their effects on biofilms; subproject 2 (UB) focuses on the ecotoxicological effects on invertebrates and on the emission of greenhouse gases; subproject 3 (EHU) focuses on the functioning of ecosystems and the mitigating effects of buffer zones.