Systemic blue-green-red urban development (URBAN LE) – A Helmholtz Solution Lab

The URBAN LE project advances climate-resilient urban development by establishing an integrated blue-green-red (BGR) infrastructure framework that reinforces water security and supports sustainable urban transformation. Based in Leipzig and involving five Helmholtz Centers (UFZ, HZDR, HIOH/HZI, GFZ, and KIT), it integrates inter- and transdisciplinary research with co-designed implementation alongside the City of Leipzig and a broad network of municipal, national, and international cities. URBAN LE addresses stormwater management, water-energy coupling, water quality, and governance innovation through real-world pilot implementations at the UFZ campus, and at different sites throughout city. Using functional digital twins and co-designed planning tools, the project evaluates scalable solutions for reducing potable water demand, enhancing water retention and treatment, and integrating aquifer thermal energy storage (ATES). A central focus is the identification of chemical and microbial pollutants mobilized during extreme weather events, including their quantification, accumulation, fate, and transport within BGR systems. Functional digital twins enable comprehensive urban system analysis by combining numerical modeling of hydrological and hydrothermal processes, scenario integration of climatic, demographic, and economic drivers, and infrastructure planning and optimization—such as evaluating interactions between irrigation methods and thermal networks in sponge-city scenarios.

URBAN LE contributes to “Urban Blue-Green-Red Water Systems” and tackles challenges such as decentralized infrastructure planning, digitalization, and institutional governance. Its systemic design positions Leipzig as a model city and facilitates replication in at least ten further German and European cities. By merging rigorous scientific innovation with municipal co-creation, URBAN LE delivers robust tools for climate adaptation, energy transition, and urban water reuse, ensuring long-term impact.