Estuarine oceanography of the Vembanad lake Part II : the region between Cochin and Azhikode

Abstract

Some aspects of the estuarine oceanography of the Vembanad lake between Cochin and Azhikode are discussed. Since this part of the lake is in confluence with the Arabian sea at its southern and northern ends, at Cochin and Azhikode, its circulation pattern and other characteristics are different from what they are between Cochin and Vaikom. Because of the position of these two mouths, which are exposed to the same tidal cycles, the high tides and low tides each producing two opposite flows respectively converge and diverge leaving a null zone, almost free of the tidal effect, around Kadakara, situated midway between Cochin and Azhikode. Another significant feature of this pairt of the estuary is an extreme low-salinity i«gion between Karthedam and Cherai during monsoon and early postmonsoon, brought about by the deflected waiters of the Periyar, opening at the northern end of the estuary.