Author(s): Tanjir Saif Ahmed; Shinji Egashira; Daisuke Harada
Linked Author(s):
Keywords: Estuary; Numerical model; Fine sediment; Sand bar deformation; Channel changes
Abstract: The Sittaung river estuary is 220 km long southwards and 270 km wide and it opens to Gulf of Martaban. Due to a funnel shape of the estuary, tidal bores and associated strong currents take place during spring tides on new moon and full moon. Bed and banks of the estuary are constituted by silt and clay particles with their �50 ranging from 0.02 to 0.04 mm. Therefore, a very active sediment transportation takes place with active channel changes leading to severe bank erosion at the rate of around 1 km every year at most active locations. Present study discusses tidal currents and associated channel changes with sand bar evolution based on numerical results obtained from a newly proposed model. The new model is composed of a sediment transport process model to treat very fine sediment such as silt-clay material in addition to a depth-averaged two dimensional flow model. Numerical results show that tidal bores and associated strong currents are reproduced well. Bed evolution and channel pattern are reproduced for the shape of estuary in recent years. Numerically created morphology agrees well with the recent satellite images extracted during ebb tides.
Year: 2020