Study of the Impact of Artisanal Sand Dredging on Waterway Navigation in Lagos Lagoon

Artisanal sand dredging for construction material supply is a widespread activity in the Lagos Lagoon, with significant implications for waterway navigation and environmental stability. This study investigates the impact of artisanal sand dredging operations on navigation conditions and channel morphology in the Lagos Lagoon, focusing on areas between Badore, Ajah, and Ikorodu. A descriptive field survey design was employed, combining bathymetric measurements at ten locations before and after reported dredging activity, review of Lagos Waterways Authority incident records, and structured interviews with forty vessel operators, commercial dredging site managers, and lagoon fishermen. Findings reveal that artisanal sand dredging creates irregular bottom topography with localised deep pits adjacent to shoaling areas, which pose navigation hazards particularly for flat-bottomed ferries during low tide conditions. Dredging vessels operating without lights at night have been involved in multiple collision incidents with passenger ferries and cargo canoes. Turbidity plumes generated by dredging activity reduce underwater visibility at sensitive navigation channels. Several previously charted routes have been rendered unreliable as a result of morphological changes induced by concentrated dredging activity. Recommendations include mandatory dredging site registration, installation of warning buoys at active dredging locations, enforcement of nighttime dredging restrictions in navigation channels, and periodic re-surveying of affected lagoon sections by the Lagos Waterways Authority. Keywords: artisanal dredging, Lagos Lagoon, waterway navigation, channel morphology, safety hazards