Assess The Frequency, Intensity, and Spatial Patterns of Flooding and Erosion Hazards Across Ogbaru Local Government Area, Anambra State, Nigeria

Flooding and erosion are major environmental hazards in Ogbaru Local Government Area (LGA), Anambra State. This study assessed their frequency, intensity, severity, and spatial distribution across eight selected communities: Atani, Ossomala, Ogbakuba, Odekpe, Akili-Ogidi, Mputu, Ogwuikpele, and Okpoko. A mixed-methods design combining questionnaire surveys, field observations, GPS mapping, and GIS analysis was adopted. Of 422 questionnaires administered, 377 were retrieved, representing an 89.34% response rate. Data were analysed using descriptive statistics, weighted means, one-way ANOVA, Tukey HSD, and GIS-based spatial analysis. Odekpe recorded the highest annual flood frequency (3.5 ± 1.2 events), longest inundation duration (25 days), greatest flood depth (1.8 m), and highest perceived flood-intensity score (3.17), while Mputu recorded the lowest values. Flood frequency differed significantly among communities, F(7,369) = 8.64, p < 0.001. Heavy rainfall (92.3%), River Niger overflow (88.6%), and poor drainage (79.8%) were the leading perceived flood drivers. Gully erosion was most prominent in Odekpe (48%), which recorded very high erosion severity. Spatial analysis identified Atani Waterfront and Ossomala Riverbank as very-high flood-risk locations, while Odekpe Gully Site, Ogwuikpele River Margin, and Okpoko Drainage Channel were high-risk areas. The study concludes that flooding and erosion in Ogbaru are recurrent and spatially heterogeneous, requiring community-specific interventions, improved drainage and waterway management, erosion control, environmental restoration, and GIS-supported disaster-risk reduction planning.