Assessment of Existing Drainage Infrastructure through Field Measurements in Abuja

Abstract

This study investigates drainage performance and flood resilience along six chronically affected road corridors in Abuja, Nigeria, to quantify the relationship between drainage infrastructure condition and urban road flooding severity. A mixed-methods research design was employed, integrating 412 cross-sectional field measurements, real-time flood observations during the 2025 rainy season, structured questionnaire surveys administered to 184 residents and road users, and simplified Manning-based hydrological modelling. Six flood-prone corridors were purposively selected: Galadima Interchange Slip Road, Apo–Dutse Road, Damagaza Road, Area 3 Road (Garki), Lokogoma District Roads, and Lugbe Trade Moore Estate. Drainage systems were evaluated using three composite indices: the Drainage Condition Index (DCI), Flood Severity Index (FSI), and Appropriate System Performance Index (ASPI). Statistical analysis employed Pearson correlation and multiple regression techniques. Widespread infrastructure failure was confirmed across all corridors, characterised by severe blockage (42–95%), undersized drains, and extensive siltation.