NICHES, solutions to end the pollution of aquatic ecosystems in cities 

The project will focus on five cities characterised by different challenges such as Barcelona, Berlin, Boston, Sheffield and Rotterdam.

With a total funding amount of over 21.1 million euros, the call is aimed at projects on "Conservation and restoration of degraded ecosystems and their biodiversity, including a focus on aquatic systems".  

The new NICHES project held its kick-off meeting on 21 April 2022 in Berlin. For two days, the different partners discussed the expectations and scope of the project, and had the chance to get to know each other and set the tone for their future collaborations. ICTA-UAB researchers involved in the project are Johannes Langemeyer and Sara Maestre. 

The overflow of combined waste and rainwater sewer systems in cities are one of the major pollution sources for aquatic ecosystems and threats to marine and freshwater biodiversity in Europe and beyond. Apart from environmental, this problem also has a strong social and economic impact in many urbanized areas. 

Compounded by climate change and increasing heavy rain events, there is an urgent need to increase the evidence around and implementation of restorative nature-based solutions (NBS) to avoid storm-water runoff in urban areas and preserve ecosystem functioning and aquatic system biodiversity. These include solutions such as riverbank restoration, sustainable urban drainage systems, constructed urban wetlands, the regeneration of urban green belts or bioretention ponds. These actions are very necessary considering that urban sewage overflows pollute 38% of Europe's surface waterbodies with bacteria, pathogens, industrial waste, oil and fats, nutrients, organic matter and solid waste. It is estimated that approximately 60% of these waterbodies have failed to achieve good ecological status.  

These overflows in turn produce physical effects (erosion and deposition), aesthetic pollution, decreases in water oxygen content and eutrophication, with cascading effects on nearby aquatic ecosystems as well as impacts on tourism, fishing, sports and recreation activities. Despite these impacts, urban waters are still not sufficiently considered in European monitoring directives such as the Water Framework Directive (WFD) or the EU Nature Directives and reference conditions are lacking in most Member States for all waterbody types (EC2019b). 

The NICHES project, led by Johannes Langemeyer, will analyse and propose restorative nature-based restorative to mitigate the effects of combined sewer overflows in cities and the consequential reduction of their impacts on aquatic systems 

Focusing on five cities characterised by different challenges (Barcelona, Berlin, Boston, Sheffield and Rotterdam, NICHES will address four objectives: to examine the ecological, social and economic impacts from sewer overflows on aquatic ecosystems; develop restorative urban nature-based solutions to estimate runoff mitigation potentials and their co-benefits; assess the integration of restorative NBS within existing urban policy frameworks; and effectively consider trade-offs between the people’s needs across different parts of the urban social-ecological-technical systems (SETS), including the location of NBS implementation and the areas around water bodies receiving overflows.  

To do so, NICHES will examine the biological and biophysical processes critical to avoiding negative impacts on aquatic ecosystems and will model the hydrological and ecological functions of NBS that improve urban runoff and pollution retention capacities under different scenarios to support an increased predictive understanding of biodiversity impacts. NICHES will further address social, institutional and governance systems in cities and acknowledge trade-offs and synergies between targeted benefits and policies for nature conservation and restoration across the entire SETS in order to foster the co-design of sustainable urban transitions and inclusive decision-making processes.