Tidal Constants Derivation for Imo River

Abstract

Tides play critical role in coastal processes, marine operations and navigation. Determination of tidal characteristics and prediction of water levels require knowledge of tide harmonic constants (amplitudes and phase lags) of all relevant tidal constituents. 37 days hourly water level observation was taken at established tide gauge station along Imo River and analysis of observed data using harmonic method implemented with T_Tide. 35 tidal constituents were generated and used for water level prediction. Tidal constants of four principal tidal constituents (K1, O1, M2 and S2) were used to compute tidal form factor and water level datum for the river. The analyses revealed that M2 constituent was the most dominant tidal constituent with amplitude of 0.7375. Computed form factor (0.2076) revealed Imo River to have a semidiurnal tidal regime which is the characteristics of Nigerian coastal waters. The river has a tidal range of 2.231m and mean water level of 1.660m. Comparison of predicted and observed tide gave root mean square error of 0.0177 and correlation coefficient of 0.9943. Results obtained from the study indicated that derived tidal constants are reliable for prediction of Imo River water levels and tide.