Block-based planning to retain stormwater in urban catchments

We explore the potential for block-based interventions to improve stormwater management and comply with the European Urban Wastewater Directive by reducing combined sewer overflow (CSO). Urban blocks—defined as polygons enclosed by cleaned road networks serve as spatial units for identifying suitable Low Impact Developments (LIDs). Using UrbanWaterBlocks, an open-source Python toolkit, we automate the delineation of urban blocks, calculation of key spatial and demographic attributes, and assessment of decentralization potential for stormwater interventions. The methodology was demonstrated on two districts of Leipzig, Germany—Mitte and Süd—where LID types such as bioretention cells and infiltration shafts were considered. Our approach supports scalable, reproducible, and data-driven pre-feasibility studies for decentralized stormwater management in urban catchments with limited data.