Blue-green-grey infrastructure for climate-resilient cities, cleaner waters and biodiversity

The BLUEgreenLIFE project addresses the critical vulnerability of urban and rural agglomerations to the adverse impacts of climate change, in particular extreme rainfall events and pluvial flash floods, as well as the poor quality of urban water bodies, groundwater moisture deficits and water stress affecting urban greenery. The main objective is to transform the traditional model of linear urban drainage into a circular Sponge City model through the systematic implementation of blue-green-grey infrastructure. In demonstration sites in the Czech Republic (Liberec Zoo and the City of Jablonec nad Nisou), Poland (the Silesian Botanical Garden and the City of Mikołów) and Spain (the University of Girona campus), the project will deploy an integrated system of nature-based solutions. These measures, including wetland systems, rain gardens, floating islands and retention elements, will ensure the decentralised capture of stormwater at the point of impact, thereby reducing the hydraulic overload of combined sewer networks and decreasing the frequency of combined sewer overflows (CSOs) discharging untreated wastewater into receiving waters. An innovative feature of the project is the development and pilot validation of a methodology for prioritising blue-green infrastructure elements in spatial planning. This methodology integrates urban design, water quality monitoring, hydrological data, satellite monitoring and real-time biological and biodiversity surveys. The expected impacts include a measurable increase in biodiversity, reduced impacts of extreme climate events, including heavy rainfall and drought, improved surface water quality affected by pollution from surface runoff and wastewater treatment plants, and the replacement of at least 30% of potable water used for irrigation with harvested rainwater. The project directly implements the requirements of the new Urban Wastewater Treatment Directive (2024/3019) and is fully aligned with the EU Strategy on Adaptation to Climate Change. The project outputs will be replicated through international networks of municipalities and managers of visitor-oriented sites.