The water level in the lower Paraíba do Sul river estuary was assessed in order to evaluate the effects of the astronomical tide co-oscillation, river discharge and meteorological events. Water level data was recorded hourly from October 2000 until February 2003 at a gauge station nearby the estuarine inlet. The water level is controlled mainly by the astronomical tide co-oscillation during periods of low river discharge, and eventually by meteorological tides. Even during periods of higher river discharge the water level is controlled by astronomical co-oscillation, although during low tide phase the river discharge effects are observable. During periods of extreme high discharge the low frequency water level is mainly driven by the river inflow. The tidal wave was mostly symmetrical during the low river discharge periods, and asymmetries were observed during meteorological events, with shorter flood and longer ebbs. Although, such effects were not corroborated by astronomical tidal constituents M2 and M4 relationship, which suggests ebb dominance. Stronger distortions were observed during high discharge periods, with tide attenuationeither at neap as in spring tide periods. During these periods the asymmetries were corroborated by M2 and M4 relationship.
tidal asymmetry; meteorological tides; river discharge
