13th Urban Drainage Modelling Conference Editors’ Notes

The 13th Urban Drainage Modelling Conference (UDM 2025) was held from 15–19 September 2025 at the University of Innsbruck in Innsbruck (Austria), continuing a long-standing tradition of international exchange on advances in urban drainage modelling. The conference, organised in collaboration with the International Working Group on Data and Models (IWGDM) under the Joint Committee on Urban Drainage (JCUD), received 244 submissions from 52 countries and featured 141 oral and 88 poster presentations. Abstracts were reviewed by at least two experts to ensure scientific quality and coherence, and all accepted contributions are published in these Proceedings, with authors able to opt into open-access publication. Finally these proceedings contain 101 submissions. UDM 2025 showcased developments in hydrodynamic and water-quality modelling, real-time control, blue–green infrastructure, digital twins, and the growing role of artificial intelligence. The programme included three keynote lectures, seven technical workshops, and—for the first time—a “Combat on retrofitting drainage networks with nature-based solutions” (NBS Retrofit Combat). Integrated and cross-sectoral approaches linking urban drainage with heat mitigation, drought resilience, and microclimate analysis were prominent throughout. These Proceedings summarise the scientific contributions and emerging trends discussed at UDM 2025 and document the continued evolution of the field toward data-centric modelling, nature-based approaches, and integrated urban resilience.