The Impact of Urbanization and Infrastructure Development on Local Flood Risk in Tomaszkowo: Hydrological Analysis and Spatial Planning

Urbanization significantly alters the hydrological balance of an area by increasing surface runoff, reducing infiltration, and intensifying the risk of local flooding. This study examines the impact of urbanization on the water budget and local flood risk in Tomaszkowo, Poland—a rapidly developing suburban village near Olsztyn. The research analyzes hydrological changes over the period 2003–2023 using precipitation data, evapotranspiration estimates, surface runoff modelling, and soil structure assessments. The findings indicate that the region’s predominantly clay and loam soils hinder water absorption, while low terrain slopes further limit natural drainage. Despite a decline in precipitation since 2014, surface runoff levels have remained stable or increased, highlighting the influence of intensified urban development and impervious surface expansion. Seasonal variations in the water budget show “BELOW NORMAL” values in summer and “ABOVE NORMAL” values in other seasons, emphasizing the need for improved stormwater management strategies. The study underscores the importance of integrating hydrological analysis into spatial planning to mitigate urban flood risks and maintain a sustainable water balance.