Modeling of Flow Patterns and Sediment Transport in the Malili River Estuary East Luwu Regency
Mahatma Lanuru, Amir Hamzah Muhiddin, Mustono

Department of Marine Science
Faculty of Marine Science and Fisheries
Hasanuddin University
Indonesia

Abstract

The river estuary of Malili is one of the estuarine waters that flow directly into the sea waters of Bone Bay. The interaction between water flow from rivers and tidal currents from the sea affects the hydrodynamic and sediment transport processes at the river estuary of Malili. Sedimentation in the river estuary is relatively high and large enough to cause siltation. As a result, the ship^s channel is sometimes blocked so port managers carry out dredging in part of the estuary. According to the Regulation of the Minister of the Environment No. 5 of 2012, Dredging activities have the potential to impact the hydrological and ecological systems at that location, such as increasing turbidity and sedimentation that can have far-reaching impacts on the sea. Therefore, it is necessary to model current patterns and sediment transport to see the extent of the hydrological effects.
The research method used is to create a current pattern model and a sediment transport model.
Current circulation pattern modeling is carried out using a model processing application by entering bathymetry data, shoreline/river line, tides, and river water discharge at the study location. The results of the current hydrodynamic model will be the basis for making sediment transport models. The current measurement results show that the speed and direction of the current varied with time in the range of 0.028 - 0.578 m/s. The current pattern model shows that when the water recedes, the highest current velocity reaches 0.578 meters/second with the dominant current direction to the southwest due to the influence of river discharge that has flowed towards the estuary. Meanwhile, at high tide, the highest speed reaches 0.238 m/s with the dominant current direction to the northeast. The results of sediment transport modeling show that the distribution of sediment downstream is influenced by high tides, thereby reducing sediment concentration when it goes to the river mouth. However, with the flow of river

Keywords: sediment, river estuary, transport, water flow, modelling, oceanography, Malili

Topic: Oceanography (International)