Mumbai (Bombay) harbour receiving effluent waste from the discharge points
located in an adjoining tidal basin is polluted. The concentrations of inor
ganic constituents such as nitrite, nitrate, ammonia acid phosphate monitor
ed for a period of 20 months were near critical values. Chlorophyll a conte
nt was low. The semidiurnal to diurnal tidal flow in the bay characterised
by high velocity movement particularly during ebb-tide, replaces one third
of bay water at every cycle per day. This helps to maintain normal dissolve
d oxygen concentrations as well as to reduce the organic load as the water
moves into the open sea.