Analysis of Sedimentation Rate at Royoq Port (Kutai Barat, Kalimatan Timur) with Hydrodynamic Modeling

Abstract Sedimentation in port areas can have a significant impact on port operations and shipping safety. The accumulation of sediment material in the harbor area can cause a decrease in depth, limiting the size of ships that can enter the harbor. Our research aims to analyze the flow patterns and sedimentation rates in Royoq Harbor, a crucial step toward maintaining the safety and smooth operation of the harbor. The model simulation was conducted on a 75-kilometer stretch of the Mahakam River that was separated into three monitoring locations at Royoq Port for 2023. The research method used is hydrodynamic modeling with Delft3D. The results showed that the existence of the harbor decreased current velocity to 0.5 m/s on the west side and 0.2 m/s on the east side, as well as a change in current direction around the harbor as it headed from upstream to downstream. This phenomenon triggers the formation of stagnation zones that increase the risk of sedimentation. The sedimentation rate in the study area is 96.29 m3/year or 34 tons/year. The sedimentation rate in the west of the harbor has a value of 5.49 m3/year, while in the east of the harbor it is 97.9 m3/year. In addition, the Delft3D modeling results for six months showed a change in the morphology of the water bottom in the port, with sedimentation ranging from 0.03 m to 0.4 m on the west and east sides and erosion between −0.002 m to −0.01 m on the north side. To maintain the safety and smooth operation of the harbor, it is recommended that regular monitoring of the water depth and dredge sediments be conducted if necessary, supporting SDG 9 on building resilient infrastructure.