Design and Evaluation of Sustainable Drainage Systems for Urban Flood Management

Thesis Abstract

Urban flooding has become an increasingly pervasive challenge in rapidly expanding cities, driven by intensified urbanization, climate change, and inadequate drainage infrastructure. Traditional drainage systems often fail to sustainably manage stormwater runoff, leading to frequent flood events, environmental degradation, and economic losses. This study aims to design and evaluate sustainable drainage systems (SuDS) tailored for urban flood mitigation, focusing on enhancing system resilience, environmental integration, and socio-economic viability. The specific objectives include assessing existing drainage vulnerabilities, developing innovative SuDS designs that incorporate green infrastructure elements, and evaluating their hydrological performance through empirical and simulation-based approaches. A mixed-methods research design was employed, combining quantitative hydrological analyses with qualitative stakeholder insights. The study was conducted in the Metropolitan City of Nova, which experiences recurrent urban flood episodes. The population comprised urban drainage engineers, city planners, and residents, with a total sample size of 150 stakeholders selected via stratified random sampling. Data collection involved structured questionnaires, semi-structured interviews, field measurements of stormwater flow during selected rainfall events, and laboratory testing of proposed green infrastructure components, such as bio-retention cells and permeable pavements. Instrument validity and reliability were ensured through pilot testing, Cronbach’s alpha analysis (yielding a value of 0.87), and calibration of measurement devices. Hydrological data were analyzed using regression analysis to model runoff characteristics, while comparative evaluation of different SuDS designs employed Analysis of Variance (ANOVA) to determine statistically significant differences in flood reduction performance. A hydrological model was developed using EPA SWMM (Storm Water Management Model) to simulate the impacts of proposed systems under varied rainfall scenarios. Additionally, thematic analysis was applied to qualitative data to capture stakeholder perceptions regarding the feasibility and social acceptance of SuDS interventions. Expected findings include specific design parameters for optimized SuDS configurations, demonstrating substantial reductions in peak flow rates (averaging 35%) and total runoff volume (up to 40%) during storm events compared to conventional drainage systems. The study also anticipates identifying best practices for integrating green infrastructure within existing urban contexts, supported by empirical data and stakeholder feedback. The evaluation highlights that SuDS can significantly improve flood resilience while providing ancillary benefits such as improved water quality, urban cooling, and enhanced aesthetic value. The contribution of this research to existing knowledge lies in providing a comprehensive framework for designing context-specific, sustainable drainage solutions validated through empirical and modeling methods. It advances theoretical understanding by applying the Hydrological Response Unit (HRU) concept and the DPSIR (Drivers-Pressures-States-Impacts-Responses) framework to urban flood contexts, offering a practical, scalable approach for urban planners and engineers. The study concludes that the adoption of well-designed SuDS markedly mitigates urban flood risks and promotes sustainable urban development. It recommends integrating these systems into city planning policies, emphasizing community engagement in design and maintenance, and fostering capacity-building for local authorities. Future studies should explore long-term performance monitoring, socio-economic cost-benefit analyses, and the integration of emerging technologies such as smart sensors and artificial intelligence for real-time flood management. This research underscores the critical role of interdisciplinary approaches in advancing urban flood resilience through sustainable drainage infrastructure.