On 31 March 2018, an oil spill accident polluted Balikpapan Bay. A failure occurred in a pipeline running from Penajam to Balikpapan Oil Refinery, East Kalimantan, Indonesia. Leaking pipeline caused the total estimated volume of leaked oil to approximate 44,000 Barrels of crude oil. MoTuM was used to simulate the dispersion of oil in the area. The modeling results indicate that a strong dynamic tidal current in the Bay controls the oil’s movement. The MoTuM software is suitable for spill combating, contingency plans, and backtracking. MoTuM is developed in Windows System, which integrates 3D Non-Orthogonal Boundary Fitted Ocean Hydrodynamics Model, Trajectory, Fates, Stochastic, Backtracking in Geographic Information System. This paper presents a further study of the effect of non-linear waves on the dispersion of oil in the Bay. The simulation results were validated by comparing the model with a satellite image. The agreement between the result of simulation and satellite image is excellent and shows that the non-linear wave is an essential factor for oil spill dispersion.

The flood model (MuFlood) had been developed and applied as a flood early warning system in Jakarta, Indonesia. The low land Jakarta faces flood threat because of a significant land-use change in the upstream region, especially in the Katulampa catchment area. Katulampa, Bogor, is located 350 meters above Mean Sea Level (MSL). The distance from Katulampa to Manggarai Gate in Ciliwung River is approximately 91 km. The flood arrival time is about 12 hours. The output of MuFlood is as input for the ocean hydrodynamics model (MuHydro3D) using the 3D Non-Orthogonal Boundary Fitted. The paper presents the integrated model results to simulate flood events from Katulampa and the local catchment area of Jakarta. The comparison between observation and model prediction from the MuFlood hydrodynamic model is excellent for the 21-22 September 2020 case. MuHydro3D predicted that from 21-22 September 2020 case cause the water level increases up to 19 cm on West Flood Canal (KBB), and the closer the bay, the water level will gradually smaller and as same as the tide.

Water pollution problem in Jakarta has been going on for a long time. The existence of some rivers that are not directly connected to upstream in the tidal area can speed up the occurrence of water pollution and slow the circulation of polluted waste that affects water quality in river-estuary. Since 2010 after Kanal Banjir Timur (KBT) operated, Sunter River streamflow was divided by KBT, changes flow rate and water quality pattern. The study area is the main channel of the Sunter River which has 17 km lengths includes Duren Sawit, Pulo Gadung, Kelapa Gading, Plumpang, Rawa Badak and Tanjung Priok Area where the average water load is 624 mg/L. The simulation is divided into 2 scenarios with a flowrate configuration of 5 m3/s and 100 m3/s (with a raining condition of 1 hour). MuQuald3D, a three-dimensional water quality model, has been employed in this research. The merit of this model is that it can accurately predict water pollution load within the surface layer and the bottom layer and can be shown in contour profile which is effective and efficient guidance to solve the water quality problems along Sunter river-estuary. The model results show the effect of salinity will gradually reduce BOD concentration, and the existence of permanent construction around estuary (breakwater, port) changes pollutant distribution to the West and East area and increases the time of decomposition in waters, especially in low flowrate conditions.

Fine-grained cohesive sediments dominate sedimentation in the lowland area. In the Density Induced Current process, where seawater intrusion occurs, the fine-grained cohesive sediment will be easily flocculated by saltwater and settles rapidly. There are complex problems related to sedimentation in the rivers of Jakarta in the downstream area, which is influenced by tides and the dominance of cohesive sediment. Due to the complex process in the estuary, salinity intrusion will affect the settling velocity. And then, the flocculation process, the river’s geometry, will also affect sediment deposition. A proper model is needed to simulate the sedimentation in this area. This study aimed to investigate the distribution of cohesive sedimentation using 3D hydrodynamic and sediment transport model called MuSed 3D. This model will be applied to the Kanal Banjir Barat (KBB) river, Jakarta. The model result shows salinity values in the range of field observations for TSS and salinity. Salinity model present from 1 till 10 ppt and TSS present from 9,8 until 14,2 ppm. This study concludes that the dispersion of sediment cohesive on river and estuary affected by Density Induced Current also depends on salinity and TSS value.

The port-channel and the availability of piers are strongly influenced by physical environmental conditions such as sea current, sea tide, sediment transport, and wave. The best size of vessel and pier length depends on the location’s demand and sea environment. The uncertainty of these environmental factors results in the low efficiency of port infrastructure, the load factor for back cargo, and the reliability level of port users. This paper presents the role of MuHydro3D and MuSed3D software, a three-dimensional hydrodynamic, and sedimentation models to determine the best vessel size. Using a non-orthogonal curvilinear coordinate technique, also known as the boundary-fitted technique, MuHydro3D and MuSed3D can accurately and quickly simulate the environmental conditions at the port. Knowledge of environmental conditions is expected to be an accurate basis in determining the depth and dredging duration, pier length, ship size, or the need of breakwater. The Port of Kuala Tanjung is one of Indonesia’s designated international hubs and was chosen as the case study in this paper. The result shows that the sedimentation rate of dredging for a vessel with up to 3,000 TEUs capacity is not too sensitive. Moreover, a vessel design with an approximate capacity of 3,000 TEUs is the optimum size from the pier length aspect.