Dynamic Morphology of the Sittaung Estuary, Myanmar

A detailed investigation and modelling of rapid bank erosion

Master thesis (2021)

Authors

H. de Haas Civil Engineering & Geosciences

Contributors

Zhengbing Wang Coastal Engineering - CEG (supervisor 1)
T.A. Bogaard Water Resources - CEG (supervisor 1)
E. Mosselman Rivers, Ports, Waterways and Dredging Engineering - CEG (supervisor 1)
J Cleveringa ARCADIS Nederland (supervisor 1)
Faculty
Civil Engineering & Geosciences
Copyright: © 2021 Huck de Haas
Dynamic Morphology, Bank Erosion, Estuary, Modelling, Delft3D, Satellite Analsysis, Modelling Analysis, Tidal Bore, Sittaung Estuary, Myanmar
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Published Date

29-01-2021

Language

English

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Faculty

Civil Engineering & Geosciences

Abstract

The Gulf of Mottama, located in the southwest of Myanmar, is home to morphologically interesting processes. An entrance of around 100 km wide narrows into a funnel­shaped bay towards the Sittaung River in the north. The entire estuary region is subject to strong dynamic morphological activity which is alleged to be driven by the large tidal energy and sediment inputs. The dynamics of the tidal channels in the Sittaung estuary have resulted in rapid bank erosion of up to 3 km/y. The Sittaung estuary harbours a unique set of characteristics. This has made the question of which processes and mechanisms cause the bank erosion a complex one for which no clear cut answer is currently available. The knowledge of the main processes and mechanisms is valuable to improve the understanding of morphological functioning in dynamic estuaries. The main research question has thus been formulated as: • What is the effect of the large incoming tide and storm events on the bank erosion of the Sittaung estuary and to what extent can this erosion be simulated with a numerical model? The research objectives have been achieved through a literature analysis, system analysis, satellite analysis and modelling simulations. Main conclusions of the research have been as follows: The satellite analysis has shown little to no correlation between the wet season discharge increase and the bank erosion rates. It also showed large differences between erosion rates at different heights of the estuary. Modelling results indicate a prominent role but cannot substantiate a quantitative impact of the tidal forcing and associated tidal bore. River discharge fluctuations were shown to have little effect on the bank erosion. • The results of both the satellite and numerical modelling analysis have shown no additional implications on the dynamic morphology caused by large incidental storm events. Long­term simulations with respect to the bank erosion resulted in several hindrances. Heightened levels of channel incision occurred through a fault in the numerical schematization. The representation of bank erosion in the model has also been subject to stalling.