Lagos State is endowed with international commerce, industry and infrastructure excellence drives. In
Lagos State, traffic situation is chaotic and socio-economically unfriendly due to ills in multitransportation
modal functions. Urgent research and development attention is required to arrest total
collapse of the entire modal system. In this study, a framework is developed for efficient utilization of
Lagos waterway system as a complement to other transportation modes such as the dominating road
mode. The paper has used passengers travel distances, travel times, travel delays and speed variations
on road and water transportation systems in Lagos State to design a geographic information system
(GIS) of waterway transportation system. This attempt has formed its base on graph theory, spatial
interaction and urban transit capacity. The study has also designed a vector-based GIS for four (4)
different spatial locations of the water transportation route network. Consequently, the water
transportation at a peak hour commuter service that would complement existing bus, car and taxi in
order to reduce the demand for road transportation in Lagos Metropolis was examined. From the study,
water transport is found to have caused a reduced journey time by an average of 46.33%.