Empirical Study of Post-Disaster Building Damage Assessment Following Flooding in Anambra State

Flooding is the most destructive natural hazard affecting buildings in Anambra State, South East Nigeria, and empirical assessment of building damage patterns following flood events provides essential data for flood risk management and flood-resilient construction standards. This study empirically documented building damage patterns in three communities severely affected by the 2022 Nigeria flood disaster in Anambra State: Ogbaru, Otuocha, and Aguleri. Building damage assessment was conducted using the European Macroseismic Scale building damage assessment protocol adapted for flood damage, covering 480 buildings across the three communities. Damage was classified into five grades: no damage, minor damage, moderate damage, substantial damage, and destruction. Building characteristics (construction material, age, storeys, foundation type, and location) were recorded. Logistic regression was used to identify building characteristics significantly associated with higher damage grades. Results showed that 38% of assessed buildings suffered moderate to substantial damage, and 12% were classified as destroyed or requiring demolition. Single-storey mud brick buildings suffered the highest rates of destruction (54%), compared to 9% for equivalent concrete block buildings. Buildings with raised floor levels (above 0.6m) experienced significantly lower damage grades (OR = 0.31, p < 0.001). Age above 20 years was also significantly associated with higher damage severity. Foundation type (strip versus pad) was not significant. The study recommends that Anambra State Building Regulations incorporate minimum finished floor level requirements of 0.9m above adjacent ground level for buildings in flood-hazard zones. Keywords: post-disaster assessment, building damage, flooding, Anambra State, flood resilience