Construction Quality Management Practices in Drainage Infrastructure Projects in Kano State

Drainage infrastructure projects in Kano State in the North West geopolitical zone are critical for managing the annual flood episodes that affect large urban and peri-urban populations, yet construction quality management in this sector is widely acknowledged to be inadequate. This study investigates construction quality management practices in twelve drainage infrastructure projects in Kano Metropolis, examining the planning, implementation, and verification dimensions of quality management in drainage channel, culvert, and detention facility construction. Data were collected through site visits, structured interviews with project engineers, contractors, and state supervising engineers, and review of quality records and inspection registers from the Kano State Ministry of Environment and Climate Change. Quality management maturity was assessed using a six-dimension framework adapted from ISO 9001:2015 principles. Findings reveal that only two of the twelve projects had formally documented quality management plans at contract award, with the remainder relying on informal supervision arrangements. Concrete sampling and testing was conducted in only four projects, and testing frequencies were below the minimum one set per 50 m3 required by the Nigerian Standard for concrete testing in all four cases. Non-conforming concrete pours were not formally rejected in any project, with site engineers relying on post-pour remedial plastering rather than removal and recasting. The study links the prevalence of drainage failures during the first rainy season after construction to the absence of quality management controls. Recommendations include mandatory quality management plan submission as part of contractor bid, independent materials testing laboratories, and third-party construction audits for all state drainage contracts. Keywords: construction quality management, drainage infrastructure, Kano State, concrete testing, ISO 9001.