JAILCD2026-017: Optimizing Urban Green Infrastructure Patterns to Mitigate Urban Floods: A Spatial Morphology Approach in Fukuoka City

Abstract

Increasingly frequent extreme rainfall events have intensified urban flood risks in many rapidly growing cities. While urban green infrastructure (UGI) is recognized as a nature-based solution for stormwater management, the specific influence of its spatial configuration on flood mitigation remains insufficiently explored. This study applies a spatial morphology approach, using Fukuoka City, Japan, as a case study, to analyze and optimize UGI patterns for enhanced urban flood resilience. We quantified UGI spatial characteristics through GIS-based landscape metrics—including connectivity, patch density, and corridor continuity—and evaluated their hydrological performance using a stormwater model under 10-year and 50-year design storms. The results demonstrate that UGI configurations with higher structural connectivity and lower fragmentation significantly improve stormwater retention and reduce peak discharge, particularly in low-lying central districts. Connectivity metrics showed the strongest correlation with flood reduction. The scenario analysis further revealed that enhancing green corridors along hydrological pathways is more effective than increasing green area alone. This study provides a morphology-based framework for designing spatially optimized UGI networks to mitigate urban flooding.