Diurnal variation in salinity and currents in Vasishta Godavary estuary, east coast of India

Abstract

Distribution of salinities and currents in Vasishta branch of Godavari estuarine system, in relation to the fresh water discharge and tides has been studied in 3 representative months. In July, when the' river discharge is very high, the estuary exhibits some characteristics of a salt wedge type. In September, when the river discharge is usually smaller compared to that during July, the estuary tends to become a partly mixed type while during February (river discharge being minimum) the estuary becomes a well mixed type. These features are well reflected in the hourly (for 12 h) observations of salinities and currents at the 3 selected stations and in the stratification - circulation diagram. Longitudinal exchange coefficients show a decreasing trend with decrease in the fresh water discharge and with the increase in the distance from the mouth upstream.