Assessing the Impact of Green Infrastructure on Urban Flood Management

Thesis Abstract

Urban flooding has become an increasingly severe challenge in contemporary cities due to rapid urbanization, climate change, and inadequate drainage systems, necessitating sustainable and resilient flood management solutions. This study aims to evaluate the effectiveness of green infrastructure (GI) in mitigating urban flood risks and to understand how specific GI components influence flood behavior and resilience. The primary objectives include identifying the types and distribution of existing green infrastructure within the study area, quantifying the extent of flood reduction attributable to GI, and assessing community perceptions and stakeholder engagement in GI implementation. The study adopts a mixed-methods approach, integrating quantitative spatial analysis with qualitative stakeholder interviews to provide a comprehensive understanding of GI’s impact. The research design involves selecting a representative urban area with a diverse mix of green infrastructure features—such as rain gardens, green roofs, permeable pavements, and urban forests—covering a geographic extent of approximately 150 square kilometers. The population includes local government agencies, city planners, environmental organizations, and residents, with a sample size of 200 households for surveys and 30 key informant interviews selected through purposive sampling. Data collection instruments consist of spatial data analysis using Geographic Information System (GIS), hydrological modeling with Stormwater Management Model (SWMM), structured questionnaires, and semi-structured interviews. The validity and reliability of survey instruments are established through pilot testing, Cronbach’s alpha, and expert validation. Quantitative data are analyzed using regression analysis to identify the relationship between green infrastructure extent and flood mitigation, while thematic analysis is employed for qualitative insights, guided by the Theory of Urban Resilience and the Green Infrastructure Performance Framework. The anticipated findings suggest a statistically significant inverse relationship between green infrastructure coverage and flood severity, demonstrating that areas with higher GI implementation experience reduced flood peaks and delayed runoff. Additionally, the study expects to reveal perceptual and operational barriers to GI adoption, as well as facilitators that can enhance its effectiveness. The research contributes to existing knowledge by empirically quantifying GI’s stormwater management benefits in an urban context and linking technical flood mitigation outcomes with community perceptions and institutional capacity. These insights offer valuable guidance for urban planners, policymakers, and environmental engineers seeking to optimize green infrastructure deployment for flood resilience. The study concludes that strategic integration of diverse GI elements significantly alleviates urban flood risks and enhances system resilience, emphasizing the importance of policy frameworks, stakeholder engagement, and ongoing maintenance. Recommendations include adopting integrated urban water management policies, incentivizing green infrastructure investments, and enhancing community awareness and participation. It is suggested that future research explore long-term performance monitoring of GI systems under climate variability and urban growth scenarios, and comparative studies across different climatic zones to generalize findings. Overall, the study underscores the vital role of green infrastructure as a sustainable, multifunctional approach to urban flood management and resilience building, advocating for its mainstream incorporation into city development plans to foster adaptive, resilient urban environments.