a A representative profile of Tidal fluctuation at Jharkhali over the period of one month, showing mixed semidiurnal tidal pattern, with two consecutives spring tide nearly 15 days interval with a neap phase in between. Maximum tidal range on Day 07 (6.1 metre) coincides with Blue moon event on Day 06. Subsequent highest peak on Day 22, having average tidal range 5.1metre corresponds to next new moon event. b Tidal current at Jharkhali for the period of one month, showing highest speed on Day 07 with velocity 140 cm/ sec, coinciding with maximum tidal range of Blue moon period and next highest speed attains on Day 22, matches on New moon event on the same day. c Distribution of monthly precipitation (mm) in Sundarbans. The precipitation data was averaged over 9 years (2002-2011) showing highest in July (21%) and lowest in December (0.4%).