Urban Green Corridor Optimization for Flood Resilience in Mid-Sized Cities

Thesis Abstract

Urban flood risk in mid-sized cities is exacerbated by fragmented green spaces and insufficient integration of ecological infrastructure into urban planning, underscoring the need for a systematic optimization of green corridors to enhance flood resilience. This study addresses the gap between theoretical green infrastructure benefits and practical urban design in non-metropolitan contexts by evaluating how corridor configuration, connectivity, and multi-functional vegetation influence stormwater attenuation, peak discharge reduction, and environmental equity. The aim is to develop an evidence-based framework for optimizing green corridors to improve flood resilience in mid-sized cities. Specific objectives are (1) to quantify relationships between green corridor characteristics (width, connectivity, vegetation structure) and hydrological performance using empirical data from three mid-sized cities; (2) to assess the social dimension by examining public perception, accessibility, and equity of green corridor benefits across socio-economic groups; (3) to test the applicability of the IURD (Integrated Urban Resilience Design) framework and the Green Infrastructure Planning Theory in guiding corridor optimization; (4) to formulate a practical optimization model linking land-use planning, green space allocation, and flood mitigation outcomes; and (5) to deliver policy recommendations and a decision-support toolkit for municipal planners. The methodology adopts a mixed-methods design anchored in a pragmatic philosophical stance to enable actionable insights for planning practice. The population comprises municipal planning datasets, hydrological and land-use records, and residents from three mid-sized cities with comparable climatic regimes and known flood events. A stratified multi-stage sampling approach selects 60 neighborhoods (20 per city) representing varying corridor densities and socio-economic profiles. Data collection instruments include a GIS-based hydrological dataset capturing catchment areas, imperviousness, drainage networks, and green corridor metrics; field surveys and transect measurements of vegetation structure and soil infiltration rates (n=180 plots); structured questionnaires administered to 1,200 residents focusing on perceived flood risk, access to green spaces, and willingness to use corridors; and key informant interviews with 25 city planners and landscape architects. Instrument validity and reliability are established through pilot testing, expert review, and Cronbach alpha assessments (>0.7 for multi-item scales). Data analysis proceeds in three interconnected streams. Hydrological performance is evaluated via multiple regression and generalized additive models to relate corridor attributes to flood indicators (peak discharge, runoff volume, and time to peak) at sub-catchment scales, supplemented by hydrological simulations using SWMM. Social dimensions are examined through descriptive statistics, ANOVA, and structural equation modeling to explore pathways between corridor attributes, accessibility, and perceived flood resilience. The integration of physical and social findings is supported by a convergence coding matrix and a thematic analysis of interview transcripts to identify governance constraints and enablers. A corridor optimization model is developed to maximize flood attenuation and accessibility under budgetary and land-use constraints, employing a multi-objective linear programming approach with Pareto frontier analysis. The study also tests the applicability of the IURD framework and Green Infrastructure Planning Theory in explaining observed outcomes and guiding optimization. Expected findings indicate that corridor width, longitudinal connectivity, and native vegetation diversity significantly reduce peak flows and delay runoff, with diminishing returns beyond threshold levels; equitable distribution of access to green corridors enhances perceived resilience and community adoption of flood-mighting practices; the optimization model yields practicable configurations balancing flood mitigation with land acquisition costs and social equity. The study contributes to knowledge by empirically linking green corridor design parameters to hydrological performance in mid-sized urban contexts, validating an integrated planning framework that combines ecological infrastructure with social equity considerations, and delivering a replicable methodology and toolkit for municipal planning departments. The main conclusion posits that strategically configured, well-connected green corridors can materially enhance urban flood resilience in mid-sized cities when complemented by inclusive access policies and data-driven land-use optimization. Policy recommendations include adopting corridor-specific design guidelines, integrating green infrastructure into zoning and capital improvement plans, prioritizing community engagement to address equity gaps, and implementing a decision-support toolkit for iterative spatial planning under climate uncertainty.