Engineering Geological Constraints in the Design of Sustainable Stormwater Retention and Reuse Systems for Residential Developments: A Case Study from Kraków

Progressive climate change and rapid urbanization are placing increasing pressure on water resources, highlighting the need for local stormwater retention and reuse in residential areas. This study aimed to evaluate the influence of geological-engineering and geotechnical conditions on the design of stormwater management systems and to develop a conceptual solution for a residential property in Kraków, Poland. Geological, hydrogeological, hydrological, and topographic conditions were assessed using archival data verified through field investigations. Rainfall data from the Kraków-Balice meteorological station (2014–2023) were used to estimate rainwater harvesting potential and evaluate system performance. The proposed system consists of surface and subsurface drainage, two storage tanks, and an infiltration well. The first tank collects roof runoff for non-potable domestic use, whereas the second stores water from the drainage system and paved surfaces for irrigation. The annual rainwater harvesting potential was comparable to the non-potable water demand of a five-person household, while water collected from the drainage system and paved surfaces was sufficient for irrigation. Monthly precipitation analysis revealed pronounced seasonal variability, with winter shortages and summer surpluses. Integrating the storage tanks with the infiltration well enabled effective management of excess stormwater while supporting groundwater recharge. The results demonstrate that consideration of geological-engineering conditions is essential for the effective and sustainable design of residential stormwater management systems.