Assessment of the Effects of Heavy Rainfall on the Environment and Human Health in Eti-Osa Local Government Area, Lagos State, Nigeria

Heavy rainfall and the resulting floods are prominent manifestations of climate variability in low-lying coastal urban areas, with significant implications for environmental quality and public health. This study assessed the environmental and health effects of heavy rainfall on residents of Eti-Osa Local Government Area (LGA), Lagos State, Nigeria. A cross-sectional survey was conducted using structured questionnaires administered to 100 residents (20 per community) across five communities: Abraham Adesanya, Lekki, Sangotedo, Okun-Ajah and Ogombo. Data were analysed using descriptive statistics in SPSS version 20 and Microsoft Excel. Most respondents (95%) perceived rainfall intensity as high. Damage to buildings and loss of property (55%) was identified as the most significant environmental impact, followed by disrupted transportation and water pollution (25%). Common cold (64%), typhoid (18%), malaria (11%), and diarrhoea (7%) were the most frequently reported health problems, while mosquito infestation (90%) and malaria-like symptoms (91%) were widely reported after rainfall events. Town hall meetings (40%) were considered the most effective awareness strategy, while clearing drainage channels (60%) and constructing durable drainage systems (51%) were the preferred mitigation measures. The study concludes that heavy rainfall poses substantial environmental and public health challenges in Eti-Osa LGA, worsened by poor drainage and indiscriminate waste disposal, and contributes community-level evidence on flood risk in Lagos's coastal LGAs. Strengthening drainage infrastructure, enforcing environmental sanitation laws, and promoting community-based awareness programmes are recommended to reduce flood-related risk.