Landscape Urbanism and the Design of Ecological Infrastructure in Nigeria’s Flood-Prone River Cities

Nigeria's major river cities including Lokoja, Onitsha, Makurdi, and Yola occupy fluvial landscapes whose ecological character has been systematically erased by conventional urban development, creating flood vulnerability, urban heat amplification, and loss of biodiversity that are structurally related to the design exclusion of landscape and ecological infrastructure from urban form composition. This dissertation develops an original landscape urbanism framework for the design of ecological infrastructure in Nigeria's flood-prone river cities, making theoretical contributions to landscape urbanism as applied to West African riverine urban contexts and developing a practical design methodology validated through case applications. The theoretical contribution adapts landscape urbanism theory from its origins in North American and European deindustrialised landscape contexts to the specific conditions of West African river cities, introducing three original conceptual contributions: a fluvial landscape succession model that incorporates seasonal flood dynamics as a positive urban design resource rather than an engineering problem to be excluded; a riverine ecological infrastructure matrix that integrates flood retention, biodiversity provision, thermal comfort, and urban agriculture in a single spatial framework calibrated to Nigerian river city scales; and a social-ecological connectivity theory relating the physical design of ecological corridors to the livelihoods and spatial practices of riverside communities. The empirical programme conducts spatial analysis of flood vulnerability and ecological condition in all four case cities, develops detailed ecological infrastructure design frameworks for each, and tests their flood risk reduction and urban heat mitigation performance through hydraulic and climatic simulation. Keywords: landscape urbanism, ecological infrastructure, flood-prone cities, Nigeria, river cities.