Author(s): Alexander Breugem; Kai Chu; Theofano Koutrouveli; Li Wang; Boudewijn Decrop
Linked Author(s): Li Wang
Keywords: Macroplastic；TELEMAC-3D; Particle tracking; Plastic cleaner
Abstract: Plastics pollution impose threats on both water quality and aquatic environment. Therefore, appropriate management of past and future plastic debris that enters into the aquatic environment has become a necessity. Process-based numerical models have been recognized as useful comprehensive tools to fulfill such purpose. In this study a three-dimensional hydrodynamic model developed in TELEMAC-3D is online coupled to a particle-tracking module to simulate the dispersion of macroplastics in a tidal river estuaries and shelf seas. In order to accurately capture the physical mechanisms of plastic transportation, some new functionalities have been developed in this study. A particle tracking module is extended to determine the transport patterns of macro-plastics using a Lagrangian approach. The different types/classes of marcoplastics are released in the model and tracked individually. Different plastics are distinguished by different types of particles with different properties of buoyancy, size and settling velocity etc. Random walking and dragging force exerted directly on plastics by winds are considered as important processes in determining plastic dispersion patterns, and thus are properly parameterized in the model. The input plastics to the model is determined based on both field data and literatures, based on which, different classes of representative plastics will be selected and parametrized as different particles in the model. The release location of plastics are modelled based on probability in space. Large cities such as Antwerp is often the main contributor to the input of plastics to the river. The output of this study will be spatial distribution maps and particle tracking lines of different plastics over time, from which areas can be selected in which most particles and litter objects will pass by. This will serve as a guidance to determine the most optimal positions for installation of plastic cleaner. It also helps to track the sources and understand pathways of plastics flowing to sea and ocean.