NUMERICAL MODELING ANALYSIS OF HYDRODYNAMICS AND SEDIMENT TRANSPORT IN THE SEMI-ENCLOSED WATERS OF BERAU AND BINTUNI BAY, WEST PAPUA

• Main Author: Dwi Pramulya, Andi
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86816
• Institution: Institut Teknologi Bandung

Bintuni Bay is a semi-enclosed body of water that does not directly connect to the open ocean but is separated by Berau Bay, with a distance of approximately 200 km from its mouth to the open sea. This study utilizes numerical methods to model hydrodynamics and sediment transport, employing the Delft3D software to evaluate the hydrodynamic conditions and sediment transport processes within the study area. The research follows a descriptive methodology, with sediment sampling sites selected using purposive sampling techniques. Primary data, including elevation, current velocity, and bathymetry, were collected through field measurements and satellite imagery. Sensitivity analysis was conducted using four parameters: bathymetry data, river discharge, wind, and wave conditions. The analysis revealed that bathymetry and wind are the most critical factors influencing the model results. Simulations were performed over a 61-day period, spanning November 1 to December 31, 2019. Tidal currents dominate the study area, with average velocities ranging from 0.5 to 1 m/s. The current velocity decreases toward the bay mouth, primarily due to the influence of river discharge in the estuary. Maximum current speeds at the estuary reach 1 m/s, tapering off to a maximum of 0.1 m/s near the bay entrance. During neap tide at the lowest ebb, water from the estuary flows outward, while simultaneously, water from the surrounding area flows inward toward the bay. Model results indicate that the convergence of these opposing water flows occurs within the bay, limiting the outward movement of water masses. The sediment transport model shows higher sedimentation rates in the Tangguh area compared to certain locations at the Bintuni Bay estuary. The calibration of the model’s water surface elevation against field measurements, using the Root Mean Square Error (RMSE) method, resulted in a 23.69% error, while the calibration of current data showed an error of 28.23%.