A Planning Framework for Sustainable Stormwater Management Using Blue–Green Infrastructure in Lublin Streetscapes

Sustainable urban stormwater management requires planning tools that quantify local retention potential while accounting for limited street space and existing infrastructure. This study develops a planning-level framework for selecting and preliminarily sizing blue–green infrastructure (BGI) to support sustainable water and land management in existing streetscapes. A section of Henryka Wolińskiego Street in Lublin, Poland, was divided into 26 sub-catchments. Runoff was estimated from land cover, runoff coefficients, and a 15 min design rainfall depth of 16.13 mm with an annual exceedance probability of 20%, obtained from the PMAXTP model. Rain gardens, infiltration swales, stormwater curb extensions, and bioretention basins were allocated according to spatial, environmental, and infrastructure constraints. Calculated runoff was equivalent to 7.4 mm over the study area. The proposed facilities provided 6.8 mm of design storage and could accommodate 6.6 mm, or 89.4% of calculated runoff, under the adopted assumptions; 0.8 mm, or 10.6%, required sewer discharge. Unused storage coexisted with local deficits, demonstrating the importance of storage location and feasible hydraulic connections. The framework contributes a transparent decision-support procedure for assessing the water-management dimension of urban sustainability through runoff accommodation, residual sewer discharge, and BGI space requirements. These are design estimates, not measured environmental benefits or a comprehensive sustainability assessment. Application elsewhere requires local input data, field verification, and subsequent performance monitoring.