MAUSAM. ... . (Oc1obe , 1997). 531-540

551.465.755 : 556.535.3 : 551.466.7

River discharge, storm surges and tidal interactions in theMeghna river mouth in Bangladesh

ANWAR All and HAFIZUR RAHMAN

Bangladesh Space Research and Remote Sensing Organiuuion (SPARRSO). Agargaon,Sher-e-Bangia Nagar, Dhaka 1207, Bangladesh

and

SYED SAZZA D HAIDER CHOWDHURY

Department af Physics, University of Dhaka, Dhaka , Bangladesh

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ABST RACT. Interactions among river discharge. storm surges and tides in the Mcghna riverestuary in Bangl adesh have been studied by using a two-di mensional vertical ly integ rated numericalmodel of the northern Bay of Bengal The study considers the interactions mostly in terms of flow

across the river mouth under the three forcings, individually and in different combinations of them.River discharge and tidal flow across lhe river mouth act both positively and negatively dependingon the tidal phase. positively during high tide and negatively during low tide. This is also true forthe combination of all the three forces. On me other hand. in most of the ca.ses, river discharge actsin opposi tion to the storm surges. Under certain conditions and on rare occasions they act positively.The interactions between river discharge and storm surges. however. depend on their relative magnitudes.In respect of total elevation in the estuarial region. river discharge lends to increase the surge height.However. away from the estuary. the effect of river discharge is hardly discernible.

Key wee ds - Interaction, River discharge. Storm surges. T ides. Meghna river. Rangladesh.

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