Evaluation of Drainage and Stormwater Control Measures in Asaba Metropolis, Delta State, Nigeria

Abstract

The city of Asaba, in Delta State, Nigeria, faces recurrent flooding driven by rapid urbanization, climate change, and inadequate drainage infrastructure, threatening public safety, property, and economic stability. This study examines the drainage and flood control challenges in Asaba, drawing on a synthesis of literature, field assessments, and stakeholder consultations, and develops an engineered stormwater drainage solution for the city. An engineering survey mapped the project area and identified vulnerable zones, while over 25 years of rainfall data were used to characterise rainfall intensity, patterns, and return period. An intensity-duration-frequency (IDF) curve was developed for a 10-year return period and used to determine peak discharge, forming the basis for the hydraulic analysis and design of a stormwater drainage system capable of mitigating flooding during intense rainfall events. Key challenges identified include inadequate drainage infrastructure, unplanned urban development, encroachment on waterways, and ineffective flood management policies, with socio-economic disparities heightening the vulnerability of marginalized communities. 

The findings highlight the need for integrated water management strategies, community participation, policy reform, and investment in resilient infrastructure, alongside the specific engineered channel design proposed in this study.