NBSINFRA City Labs Booklets: Cologne

Cologne City lab Booklet Germany Funded by the European Union 2 Table of contents All the City Labs History and introduction City Lab characterisation NBS in the City Lab Future NBS Key Activities Best Practices 3 6 7 8 9 10 11 Authors Acknowledgments Ali Barrett Udo Nehren Alexander Fekete Christopher Munschauer 3 All the City Labs The NBSINFRA project has five city labs across Europe that are assessing how cities can handle different challenges and stay resilient through Nature-Based Solutions. Each city lab aims to investigate how NBS can protect local infrastructure, preserve biodiversity, restore ecosystems and confront the challenges of climate change. The goal is to deliver tailored solutions and risk indicators for specific locations, contribute to city contingency plans and increase the resilience and sustainability of NBS for future generations. Cologne Germany Fingal Ireland Ruse Bulgaria Aveiro Portugal Prague Czechia 4 Nature Based Solutions stages across City Labs Collaborative assessment of the current conditions and identification of key challenges and opportunities. Co-designing and co-creating nature-based solutions with input from diverse stakeholders. Collaborative implementation of the solutions, ensuring active participation from all involved parties. Ongoing evaluation and monitoring of the solutions effectiveness through collective input and feedback. Expanding or replicating the solutions collaboratively to ensure broader impact and scalability. (Co-) Diagnosis and (Co-) Characterization (Co-) Design and (Co-) Creation (Co-) Implementation (Co-) Evaluation and (Co-) Monitoring (Co-) Amplification or (Co-) Replication 1 2 3 4 5 Visit our website for a more accurate insight on the project’s city labs www.nbsinfra.eu Fingal Ireland NBS stages: 1-2 Cologne Germany NBS stages: 4 Ruse Bulgaria NBS stages: 1 Aveiro Portugal NBS stages: 1-2 Prague Czechia NBS stages: 3-4 5 Cologne Germany 6 Leverkusen located to the north of Cologne City, is an industrial city, and where the Wupper River empties into the Rhine. Rheinisch Bergisher Kreis with an undulating landscape gives rise to many smaller streams which are tributaries to the Wupper. Rhein Erft Kreis to the west is predominantly farmland with many smaller settlements located along the River Erft. There are multiple hazards The city of Cologne, founded in AD50 by the Romans, is a modern city in West Germany with a population of 1.1 million people. The Rhine River flows through the centre of the city and is the focal point of the city. History and introduction affecting the Cologne region. They include ever-present hazards such as Rhine River floods and hazards enhanced by climate change. Increased atmospheric heat and water holding capacity enhance hazards such as pluvial and fast moving fluvial floods in the Wupper and Erft basins, and urban heat island impacts in Cologne City. Cologne City Lab hazards 7 Ecosystems and protected areas Hazards: Floods Hazards: Urban heat islands Critical infrastructure The City Lab’s natural vegetation consist of Atlantic mixed and West European broadleaf forests of Beech, Oak and Hornbeam, historically replaced by coniferous (Spruce) plantations. Protected species in Cologne City consists of remnant hardwood and softwood alluvial Rhine forests, meadow herbs, eutrophic lake species in the north and swamp forest and heath grassland in the southeast. The Wupper Basin includes swamp forests, Alder, Ash and Beech alluvial forests and wet meadows. In the Erft Basin small sections of hardwood alluvial forests are protected. Rhine floods in Cologne City in 1993 and 1995 caused 70 € million and 35 € million worth of damage respectively. Heavy rainfall also caused flooding in the Wupper and Erft basins in July 2021. This resulted in rivers flowing at unprecedented levels and damage to city infrastructure, homes and businesses. An annual average temperature increase of 0.8°C from the 1950s means that many residents of Cologne City are living in buildings where summer temperatures now reach 35 to 40 °C with some warming greater than 40 °C. Human lives, homes and critical services such as hospitals, roads, electricity transformers and fire stations are all affected by hazards in the Cologne District. NBS design must avoid exacerbating damages by considering potential for maladaptation and climate change effects such as drought, pests and disease. City Lab characterisation 8 NBS in the City Lab Where we already find NBS How existing NBS work Flood protection infrastructure in the Cologne District includes both grey infrastructure and NBS. NBS in Cologne City consist of retention basins and remnant floodplains. NBS in the Wupper and Erft basins includes retention basins along with sections of retained floodplain and riparian vegetation in the Wupper Basin. While not strictly in place for flood peak reduction, the Erft River in the Cologne district also contains four sites of meander or riverbank renaturation for natural water retention. Sites along the Wupper River are also identified for renaturation. Floodwater retention in Cologne city is 4.5 million m3 with Worringen Bruch expected to add another 29.5 million m3 by 2027. Floodplains provide room for around 10.7 million m2 floodwater before the city is impacted. Approx. 4.5 million m3 floodwater is retained in the Cologne section of the Erft basin. Only one existing (and two planned) minor retention basins operate in the Cologne RegionWupper Basin, as several large reservoirs also retain floodwaters in the wider basin. Location of NBS in the Cologne City Lab 9 Future NBS The next stages of the project will focus on green roof design and community engagement to address urban heat islands and pluvial flooding in Cologne City, and the issue of NBS for combined fluvial and pluvial floods in the Wupper and Erft catchments. Each stage will be designed using best practice principles of effective and efficient design, co-creation in the community and the maximisation of environmental, social and economic benefits. After research into green roof substrates is completed, workshops will be held to encourage uptake in the community and dissemination of lessons learnt. For NBS in the Wupper and Erft, a selection of tools will be used to investigate the potential for neighbourhood level interventions. Location of NBS in the Cologne City Lab