Morphological Characteristics of the Bonny and Cross River (Calabar) Estuaries in Nigeria: Implications for Navigation and Environmental Hazards

Abstract

The Bonny and Cross River estuaries are two major estuaries along the eastern coast of Nigeria. These estuaries are characterized by deep and shallow channels with semi-diurnal tides that generate tidal currents in phase with the tidal directions. The mouths of these estuaries are used extensively by a wide range of vessels and boats with varying sizes ranging from small dinghies and powerboats to merchant ships and commercial fishing boats. The morphology of these estuaries is being shaped by high tidal oscillations superimposed on waves and high volumes of sediment brought in by the rivers and creeks that flow into their drainage basins. The estuaries serve as navigational ways to the Bonny, Onne, Port Harcourt, Okrika and Calabar ports which are of high socio-economic importance to Nigeria. Navigational and environmental problems facing these estuaries include strong currents, occurrence of sandbars or shoals around the mouth, and erosion.