Author(s): N. Saichenthur; K. Murali; V. Sundar

Linked Author(s):

Keywords: Pick-up; Drop; Sediment transport rate; Field measurements; Bed evolution

Abstract: The morphodynamics in rivers and estuaries due to several dynamic parameters, like tide, waves, river discharges and winds, is a perennial problem. The contemporary practice is to predict the changes through numerical modelling and field measurements. Morphodynamic modeling is a multi–model problem, with different physical mechanisms acting as per their space and time response. The physical processes involved are the hydrodynamics, sediment transport and bed evolution. The empirical relations to be adopted for the sediment transport calculations form an integral part of the morphodynamic models. Along with these empirical relations, additional sub-models like pick up model and sediment deposition model also contribute significantly in modeling the morphodynamics in rivers and estuaries. In the present study, pick-up and drop functions suggested in literature are evaluated based on their contribution in modeling the bed level change of a navigational bar in Hooghly estuary, the largest estuary in India, which drains into the Bay of Bengal. The hydrodynamic model accounts for tide induced simulations, the tide being the dominant forcing in this estuary. The sediment transport equation for predicting the quantity of sediment transport rate is through the renowned, Ackers and White (1973), total load transport empirical relation. The pick-up and drop functions are subjected to a review in line with the bed evolution modeling of a navigational bar, through statistical approaches, to find the most suitable formulation for the Hooghly domain. The results are validated with the field measurements and an appropriate pick up and drop relations are evaluated using Brier Skill Scores (BSS).

DOI: https://doi.org/10.3850/IAHR-39WC252171192022897

Year: 2022