MICROCLIMATE CONDITIONS AND URBAN FORM IMPACTS ON FLOOD AND HEAT VULNERABILITY IN LAGOS INFORMAL SETTLEMENTS

Rapid urbanization and climate change have increased heat stress and flooding in Lagos coastal informal settlements, yet the role of urban form in driving microclimate risk remains under-studied. This study examined the influence of urban form on microclimate conditions and flood vulnerability in three Lagos slums: Makoko, Iwaya, and Ago-Egun Bariga. Using twelve months of field measurements from 24 HOBO loggers, GIS spatial analysis of sky view factor, street width, vegetation, and building density, and ENVI-met microclimate modeling, the research addressed four questions on microclimate variation, urban form constraints, statistical relationships, and design solutions. Results show significant microclimate injustice within settlements. Makoko core recorded 32.4°C mean temperature and 44.8°C heat index, 3.2°C higher than the better-ventilated Makoko edge. All settlements scored 24–37% on a six-indicator resilience grading scale due to sky view factor below 0.35, street width under 3 meters, vegetation under 6%, and density above 75%. Regression analysis revealed that sky view factor, street width, and vegetation explained 74% of temperature variation, with a 0.1 increase in sky view factor reducing night temperature by 0.48°C. ENVI-met scenario testing demonstrated that creating 4-meter ventilation corridors every 50 meters combined with 15% vegetation increase can reduce temperature by 2.4°C and flood depth by 35% without demolition. The study concludes that Lagos coastal slums are not unfixable; incremental “microclimate surgery” can improve resilience while preserving communities. Findings provided an evidence base for no-eviction climate upgrading policy.