Numerical Modeling of Suspended Sediment Concentration and Its Validation for the Hooghly Estuary, India

Abstract

Suspended sediment transport plays an important role in the evolution of coastal environment. Hence, observation and modeling of suspended sediment concentration (SSC) is of immense interest to coastal oceanographers, engineers and coastal zone management authorities. The variation of SSC in an estuary is expected both in space and time scales governed by factors such as freshwater influx, tidal variation and basin geometry. The present study reports on development of SSC model for the tidal dominated Hooghly basin, a tributary of the Ganges River having its discharge in the Bay of Bengal, India. The Hooghly estuary experiences high rates of sedimentation related problems requiring periodic maintenance dredging at various locations in the basin. Being a tidal dominated estuary, varying loads of suspended sediments is distributed along various channels in the estuarine zone. The existing SSC models developed earlier for this region had inherent limitations that tend to over-predict computed SSC. These issues critically investigated in the present study thereby developing an upgraded SSC model. It includes better physical parametrizations compared to existing SSC models developed for this region. Efficacy and robustness of the developed SSC model substantiated with measurements conducted in the Hooghly basin. Validation of model computed SSC performed with all available data that comprises of 15 location specific observations of SSC. The validation results signify that upgraded SSC model performs reasonably well compared to field measurements.