Informal urban green spaces are areas of greenery with a history of anthropogenic disturbance, dispersed throughout our cities, and covered with at least partly spontaneous vegetation. Often characterized by an overgrown nature, these informal green spaces provide ecosystem services to citizens, as well as urban flora and fauna. Due to their informal nature, these green spaces offer a unique opportunity to deliver both habitat and cultural ecosystem services simultaneously, especially since they are often found in populated areas with a shortage of green spaces. Research on synergies of cultural and habitat ecosystem services within informal urban green spaces is largely lacking, as these services often counteract each other. This thesis focuses on how these two types of ecosystem services can coexist within an informal urban green space in the culturally diverse K-buurt in Amsterdam; how synergies between these services are identified and how an informal green space can be designed for humans, animals, and plants alike. Through Research-through-Design, this thesis analyzes the current state of the informal green space and reveals its potential. By identifying and applying synergies between proposed design interventions, this design provides both habitat and cultural ecosystem services that not only coexist but benefit from each other’s presence.

This thesis investigates how underutilised urban rooftops can be transformed into productive, multifunctional spaces through the integration of water, energy, and food systems within the Water-Energy-Food (WEF) Nexus framework. By treating rooftops as interconnected ecosystems, the study demonstrates how water harvesting, renewable energy, and urban agriculture can work together to improve resource efficiency, reduce environmental impacts, and contribute to urban resilience. Through case studies, technical guidelines, and best practices, the research provides a practical model for designing multifunctional rooftops tailored to diverse urban contexts. The findings underscore the potential of WEF-integrated rooftops to address sustainability challenges in cities while setting a foundation for future projects and research in urban infrastructure optimisation.