Estuarine and Ocean Circulation Dynamics in the Niger Delta, Nigeria: Implications for Oil Spill and Pollution Management

Abstract

The Niger Delta is a fan-shaped sedimentary environment located between the Benin River in the west and the Imo River in the east (longitudes 5o4′00″E and 7o 40′00″E), extending a few kilometres south of the village of Aboh at the point where the Niger bifurcates into several rivers with estuaries opening into the Gulf of Guinea. Within the estuaries, circulation patterns are dictated mainly by the tidal regimes and fluvial flows superimposed on the ebb and flood currents. The ebb tidal currents are usually stronger than the flood tidal currents, with water fluxes during the ebb tide almost twice those of the flood tides. Offshore circulation is predominantly along-shelf and is oscillatory in nature with a fortnightly component. The across-shelf circulation, which is more subdued, is both tide and wind dependent. Understanding the circulation patterns both in the estuaries and in the open ocean has implications for oil spill management and the resulting health of the estuaries, which serve as breeding grounds for a wide variety of fish and floral species.