Grain size of sediments relates to the physical characteristics of the depositional environments. The distribution of sediment grain size is affected by the variations of wave energy and turbulent conditions of depositing environment. Linear Discriminate Analysis (LDA) technique and bi-variate plotting of grain size parameters are used to explain and understand the environment of sediment deposition. Hydrodynamic processes working during the deposition of sediments have been identified by C-M plotting. Sedimentation, in this reach is the result of the spatial and seasonal variation of the interaction between fluvial and marine processes. In non-monsoon season more than 60% of the sediment samples fall under marine environment, but in monsoon season more than 65% of the sediment samples fall under riverine environment. Nearly, 58% of the sediments are deposited under fluvial action and 42% samples are deposited by turbidity action mainly in low to moderate energy condition. Deflection of sluggish riverine discharge towards right by Coriolis force causes more sedimentation towards right bank of the river mainly in non-monsoon season. About 88% sediments are transported by suspension with rolling and graded suspension and are deposited in moderate to lesser violent hydrodynamic condition. The clustering of sediments in PQR segment in C-M plotting indicates the estuarine characteristics of the region.