HIDRODYNAMIC AND TRAJECTORY MODELLING OF MACROPLASTIC PARTICLES IN JAVA SEA

• Main Author: Nuril Azmi, Parikesit
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/82556
• Institution: Institut Teknologi Bandung

The Java Sea waters are included in WPPNRI 712, which borders the dense settlements in the north of Java Island. Along with the many human activities on Java Island, more and more waste is generated, especially macroplastic waste. Therefore, this study uses a numerical model that aims to describe the hydrodynamic conditions in the Java Sea and simulate the trajectory of macroplastics in the Java Sea originating from DKI Jakarta, Cirebon City, and Surabaya City. The hydrodynamics model simulation uses the Region Ocean Modelling System with a resolution of 1/96o or 1.1 kilometres and long simulation time of 1 year from 1 January 2019 to 31 December 2019 with a time step of 60 seconds. The hydrodynamics simulation results in the form of average ocean current data per 30 minutes are used as input data to model particle trajectories using Opendrift with the assumption that the particle weight is equal to 1 kilogram. Furthermore, the trajectory model will be simulated with 2 scenarios, namely simulation every month and one year by releasing macroplastic particles every hour for scenario 1 and every month for scenario 2 continuously at 3 source points in DKI Jakarta, Cirebon, and Surabaya. In addition, each scenario has 2 different boundary conditions, namely stranded and previous. The results of the hydrodynamics model show that the ocean currents in the Java Sea are dominated by tidal currents with a magnitude of 0.01 - 1 m/s, the direction of the ocean currents is dominated to the east in one year. Particle trajectory simulation results show that in the previous boundary conditions the missing particles were 51.2% (8,599 kg) and active particles were 48.2% (8,188 kg) with the largest contribution from Jakarta. While the stranded boundary conditions show lost particles of 1.6% (271 kg), active particles 3.35% (562 kg), and trapped particles 95.05% (15,594 kg) with the largest contribution for lost particles is sourced from Cirebon, active particles and trapped sourced from Jakarta. This is due to the dynamics of ocean currents have an important role in the spread of plastic waste in the Java Sea which is dominated by tidal currents and the influence of monsoon winds coupled with the many small islands and the shape of the coastline that curves inward, so that it can trap macroplastic particles in the Java Sea.