Sustainable Urban Drainage Design Principles: Professional Application for Nigerian Cities

Sustainable Urban Drainage Systems (SUDS), which use nature-based approaches to manage stormwater at source rather than conveying it rapidly to receiving water bodies, offer significant potential for improving flood management in Nigerian cities, but their professional application in the Nigerian context requires adaptation for local conditions. This study develops a professional application guide for SUDS principles in Nigerian urban drainage design. A professional synthesis methodology was adopted, drawing on international SUDS design guidance from CIRIA and SUSDRAIN, and adapting principles to the Nigerian tropical rainfall regime, soil conditions, and urban planning context. Case study evaluation of three pilot SUDS installations in Port Harcourt, Ibadan, and Enugu assessed the performance of green roof, bioretention, and permeable pavement installations under Nigerian conditions. Interviews with 20 drainage engineers and urban planners from the three cities provided professional context. Results indicate that bioretention systems in lateritic soil contexts achieve peak flow attenuation of 40 to 60 percent for events up to the 2-year return period. Green roof installations in Lagos reduce peak roof runoff by 35 percent on average. Permeable pavement is effective in low-traffic residential applications but requires surface maintenance to prevent clogging by fine tropical soils. The study produces a Nigerian SUDS Design Manual addressing five system types with climate, soil, and maintenance specifications adapted for Nigerian cities.

Keywords: sustainable urban drainage, SUDS, stormwater management, Nigerian cities, nature-based solutions