Pham Van, Chien
[UCL]
Gourgue, Olivier
[UCL]
Sassi, Maximiliano
[Wageningen University]
Hoitink, Ton
[Wageningen University]
Deleersnijder, Eric
[UCL]
Soares Frazao, Sandra
[UCL]
Suspended sediment is an inherent component of riverine and marine waters. However, in a continuum such as a river-delta-coastal system, understanding of suspended sediment transport processes is limited by the lack of field measurements and the difficulty to obtain such measurements due to the high spatial and temporal variability of the phenomena. This variability results from various factors, e.g. human activities, availability of sediment sources, changes of land use and soil texture in contributing area, water discharge, tides, in the system. As regards the modelling of such processes, a global system approach, which allows a presentation of the transfer of sediment from the river to the coastal ocean and the deep margin, is essential and still a challenging task. Whereas existing studies primarily investigate sedimentary processes locally, it is becoming computationally feasible to adopt such a global system approach, without excessive simplification of the physical processes resolved by the model. The Second-generation Louvain-la-Neuve Ice-ocean Model (SLIM, www.climate.be/slim) is an unstructured mesh, finite-element model of environmental and geophysical fluid flows, which is under development to include the simulation of suspended sediment transport in the continuum river-delta-coastal system. This model allows coupling of a 1D model for the riverine environment with a more complex 2D depth-averaged model for the coastal environment. It was applied in the present study to the transport of suspended sediments and their transformation at the interface between freshwater and ocean of the Mahakam land-sea continuum. The 2D depth-averaged model was applied to the Mahakam Delta, the adjacent ocean, and to three lakes in the upstream region of the delta while the 1D section-averaged model was employed for the Mahakam River and its four tributaries. Using the available observations of suspended sediment concentration at five locations in the system, a sensitivity analysis regarding the choice of the suspended sediment transport formulations, including fine-grained and non-cohesive sediment models was performed. The modelling parameters were first determined in a calibration step by using the field observed sediment data at all five locations, for a given period of time. Then, a validation step was performed using data related to another period of time. From there, the best sediment transport formulation to reproduce the observed suspended sediment distribution in the delta is determined. The spatial distribution of sediment concentration in the delta and the temporal variation of sediment concentration are finally presented and discussed.
Bibliographic reference |
Pham Van, Chien ; Gourgue, Olivier ; Sassi, Maximiliano ; Hoitink, Ton ; Deleersnijder, Eric ; et. al. Simulations of suspended sediment transport in the river-delta-coastal continuum, East Kalimantan, Indonesia.Joint Numerical Sea Modelling Group Conference - JONSMOD 2014 |
Permanent URL |
http://hdl.handle.net/2078.1/145565 |