SOURCE AND MOVEMENT OF MARINE DEBRIS PARTICLES TRACKING IN THE NUSA PENIDA MARINE PROTECTED AREA, USING A 3D NUMERIC MODEL

• Main Author: Made Dharma Raharja, I
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67585
• Institution: Institut Teknologi Bandung

Nusa Penida is an area located in Bali Province, Klungkung Regency. The Nusa Penida area has a water area designated as a Marine Protected Area (MPA). One of the problems faced by the Nusa Penida MPA area is the presence of marine debris that inhabits or is stranded in these waters. The marine debris consists of several forms, including macro and micro forms, with the dominant type found in the form of plastic waste. Based on these problems, this study was conducted to determine the distribution of macroplastic and microplastic particles, simulated backward and forwards, focusing on the Nusa Penida MPA area. This study uses the Finite Volume Community Ocean Model (FVCOM). Validation was carried out on several data: tidal elevation, current velocity components, and particle movement. The comparison between model data and tidal observation data shows a pattern and an almost similar increase, with the correlation value reaching 0.9 and the coefficient of determination of 0.8. Furthermore, for error analysis, the RMSE value is 0.05 m, and the Willmott Index is 0.96. Based on the results of leveraging the current component, the correlation values for u and v components are 0.93 and 0.96, respectively. Then, the calculation of the coefficient of determination obtained 0.87 and 0.92. In the error analysis, the RMSE for the u-component and v-component are 0.21 m/s and 0.07 m/s, respectively, while in the calculation of the Willmott Index, the values for the u-component and v-component are 0.65. and 0.81. In the motion of the particle movement that has been carried out, the resulting pattern is almost similar between the data model and the data observation. However, the data model has a delay of almost 5 hours from the observation data. In general, tidal, current, and particle movement data models can represent data in the field. The macro-particles movement model are strongly influenced by seasonal wind and surface current conditions. As well as macro-particles, micro-particles are closely related to the seasonal wind and surface currents. In addition, micro-particles are also influenced by currents in the surface current and settling velocity, which causes particles to sink more easily than macro-particles, leading to micro-particles having a slightly different movement pattern from macro-particles. In backward particle analysis, it is investigated that macro-particles originate from the Provinces of South Kalimantan (22.48%), East Java (1.84%), and Bali (18.21%). Meanwhile, micro-particles are sourced from Central Java (9.86%), East Java 8.46%), and Bali (1.60%). In seasonal analysis, the highest particle density is in the west, north, and east areas of Nusa Penida. Meanwhile, the particles are consistently located southwest to the southeastern part of Nusa Penida during the seasonal particle residence time.