City and Water Risk: Accumulated Runoff Mapping Analysis as a Tool for Sustainable Land Use Planning

The complex integration of water and flood risk management, climate change adaptation, and sustainable planning requires advanced, dynamic tools that are unavailable to most planning offices. This paper aims to demonstrate that the available GIS technologies and large, variable, and diverse datasets (big data) already allow us to create effective, easy-to-use, and, most importantly, cross-sectorial and holistic tools that integrate issues related to planning, flood risk management, and adaptation to climate change. Resulting from an interdisciplinary study of districts in Krakow, Poland, which have been heavily affected by pluvial floods in recent years, the accumulated runoff mapping analysis method proposed in this paper can be considered an effective planning tool that can be used at the initial stage of pluvial flood risk assessment and, above all, for spatial planning analysis and urban design. The proposed tool accounts for a correlation of development, land cover, and hydrological conditions, as well as their impact on vulnerability and the urban climate, while integrating environmental, urban, and social amenities. Intended for preliminary planning phases, it uses open-source software and data, which, although giving approximate runoff volumes, do not require advanced hydrological calculations or costly and time-consuming field research. The method allows studying alternative scenarios that can support the cross-sectorial, inclusive, and interdisciplinary discussion on new developments, sustainable planning, and adaptation to climate change. Most importantly, it can reduce, if not eliminate, issuing decisions that may have negative impacts on urban areas and enhance their resilience before more sophisticated, detailed, and advanced methods are ready for implementation.