FOSS4GNL 2025

Urban areas pose significant challenges for hydrological modeling due to their modified landscapes and often flat topography, which disrupt natural drainage and create zones where water cannot flow or discharge effectively. Using QGIS, we can identify such stagnant areas where water accumulates without natural outflow. For these trapped water zones, conventional drainage is impractical, necessitating alternative strategies such as targeted infiltration systems, permeable surfaces, or green infrastructure to manage runoff.

Moreover, through stream network generation and catchment delineation, we can identify vulnerable residential structures and backyard areas due to high accumulation while determining their exact contributing drainage zones. This analysis reveals both accumulation hotspots and their specific upstream source areas. Such comprehensive understanding enables development of coordinated solutions that simultaneously address flood-prone sites and their contributing catchments, leading to more effective urban water management.