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Indian Remote Sensing-P4 (IRS P4) Ocean Color Monitor (OCM) data is used to understand seasonal variations in suspended sediment (SS) dispersal pattern in the near-shore waters of the Central West Coast of India. Four distinct patterns of sediment dispersion are observed. (1) During monsoon, plume-like sediment dispersion seaward is observed especially in the mouths of rivers. (2) As the monsoon progresses, there is northerly transport of sediments with anticlockwise pattern within the plumes. (3) During NE monsoon, sediment concentration is less and its transport is southward. (4) During premonsoon, SS concentration is high in the near-shore water and transport is landward. Sequential OCM data analyses indicated the influence of tidal currents, especially during premonsoon in the vicinity of the river mouths on sediments dispersion. During rising tide, sediments move into the estuary, and during falling tide they flow seaward resulting in erosion and formation of shoals. Sediment-dispersal patterns largely follow wind and wave patterns, a characteristic feature of the mesotidal coast. Presence of a number of mudflats within the estuary along with the siltation in the channels suggests that a net landward transport of sediments occur in the region. [ABSTRACT FROM AUTHOR]

A multilevel breadth-averaged numerical model has been developed and applied it to the Gulf of Khambhat to study the tidal circulation, salinity, and suspended sediment transport. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve mass, momentum, and advection diffusion equations in a vertical plane. A turbulent kinetic-energy scheme is used to parameterize the vertical transfer of momentum, salinity, and suspended sediments. The model is forced by prescribing the tidal elevations along the open boundary of the analysis region. The tide in the gulf is mainly represented in the model by the semidiurnal M2 constituent. A freshwater discharge from the landward end is also considered for this study. The erosion and deposition are computed by empirically developed source and sink terms in the suspended sediment equation. Numerical experiments were carried out to simulate the tidal circulation, salinity intrusion, and suspended sediment transport in the gulf region. The computed M2 tide and salinity at two different sets of coastal stations were validated with the available observations. [ABSTRACT FROM AUTHOR]