Simulations of the flow in the Mahakam river–lake–delta system, Indonesia

Simulations of the flow in the Mahakam river–lake–delta system, Indonesia

Pham Van, Chien (Thuyloi University; Université Catholique de Louvain)
de Brye, Benjamin (Free Field Technologies)
Deleersnijder, E.L.C. (TU Delft Mathematical Physics; Université Catholique de Louvain)
Hoitink, A. J F (Wageningen University & Research)
Sassi, Maximiliano (NIOZ Royal Netherlands Institute for Sea Research)
Spinewine, Benoit (Université Catholique de Louvain)
Hidayat, Hidayat (Wageningen University & Research)
Soares-Frazão, Sandra (Université Catholique de Louvain)

2016-01-12

Large rivers often present a river–lake–delta system, with a wide range of temporal and spatial scales of the flow due to the combined effects of human activities and various natural factors, e.g., river discharge, tides, climatic variability, droughts, floods. Numerical models that allow for simulating the flow in these river–lake–delta systems are essential to study them and predict their evolution under the impact of various forcings. This is because they provide information that cannot be easily measured with sufficient temporal and spatial detail. In this study, we combine one-dimensional sectional-averaged (1D) and two-dimensional depth-averaged (2D) models, in the framework of the finite element model SLIM, to simulate the flow in the Mahakam river–lake–delta system (Indonesia). The 1D model representing the Mahakam River and four tributaries is coupled to the 2D unstructured mesh model implemented on the Mahakam Delta, the adjacent Makassar Strait, and three lakes in the central part of the river catchment. Using observations of water elevation at five stations, the bottom friction for river and tributaries, lakes, delta, and adjacent coastal zone is calibrated. Next, the model is validated using another period of observations of water elevation, flow velocity, and water discharge at various stations. Several criteria are implemented to assess the quality of the simulations, and a good agreement between simulations and observations is achieved in both calibration and validation stages. Different aspects of the flow, i.e., the division of water at two bifurcations in the delta, the effects of the lakes on the flow in the lower part of the system, the area of tidal propagation, are also quantified and discussed.

Coupled 1D/2D model
Mahakam River
River–lake–delta system
SLIM

http://resolver.tudelft.nl/uuid:af0d3f20-25b8-45f2-928e-2564edcd8a2d

https://doi.org/10.1007/s10652-016-9445-4

2017-06-30

1567-7419

Environmental Fluid Mechanics, 16 (3), 603-633

Accepted author manuscript

Institutional Repository

journal article

© 2016 Chien Pham Van, Benjamin de Brye, E.L.C. Deleersnijder, A. J F Hoitink, Maximiliano Sassi, Benoit Spinewine, Hidayat Hidayat, Sandra Soares-Frazão