NATURE-BASED SOLUTIONS FOR URBAN FLOODING AND WATER REUSE IN IRAQI CITIES: EVALUATING GREEN INFRASTRUCTURE UNDER CLIMATE STRESS

• Rusul A Al-ameri

  Al-Furat Al-Awsat Technical University, Najaf Technical Institute

  Author

Urban flooding is increasingly affecting semi-arid cities where rapid urbanisation, high impervious surface coverage, and climate-driven extreme rainfall events exceed the capacity of conventional drainage systems. Existing studies often evaluate flood hazards or infrastructure upgrades independently, without integrating hydrodynamic modelling, spatial optimisation, climate stress simulation, and stormwater reuse potential within a unified framework. To address this limitation, an integrated SWMM–GIS–NbS framework for urban flood resilience is developed to evaluate the effectiveness of nature-based solutions (NbS) in reducing run-off, improving drainage performance, and supporting stormwater reuse under climate stress conditions in Iraqi cities. The framework combines EPA SWMM hydrodynamic simulation, GIS-based spatial analysis, and green infrastructure scenario modelling using geospatial datasets, including USGS EarthExplorer SRTM Digital Elevation Model (DEM), NASA POWER precipitation records, and the Zenodo global land cover dataset. Terrain analysis, rainfall processing, and impervious surface estimation are integrated to simulate flood behaviour and optimise the placement of green infrastructure such as permeable pavements, bioswales, and green roofs. Simulation results demonstrate that the proposed framework significantly improves flood mitigation performance, reducing peak run-off to 16.75 m³/s, decreasing flooded nodes to 18, achieving 31.7% run-off reduction, and increasing infrastructure efficiency to 76.5% under climate-intensified rainfall scenarios. Additionally, stormwater harvesting from green infrastructure contributes 38.9% reuse potential and enhances climate resilience by 67.8%. The proposed framework provides a scalable decision-support approach for climate-adaptive urban water management in semi-arid regions.

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