Some aspects of circulation and mixing in lower reaches of Periyar estuary, west coast of India

Abstract

Monthly synoptic field observations of vertical profiles of velocity and salinity were made at 9 stations alone sections in the estuary from January-December 1985. Value of dimensionless stratification and circulation parameters were worked out from the observed salinity and velocity. Residual salinity structure showed that the estuary can be classified as salt wedgae and density gradient depending on the logitudinal distance from the estuary and the river discharge. There was a net seaward flow of water with varying degree of magnitude from season to season. Stratification was confined only to the lower region of the estuary during monsoon, while the upper reaches were well mixed during postmonsoon (October-December) and premonsoon (January-April) seasons, however, stratification to a lesser degree was observed throughout the estuary.