Modelling Ballast Water Transport

Abstract

Ballast water discharges in the coastal environs have caused a great concern over the recent periods as they account for transporting marine organisms from one part of the world to the other. The movement of discharged ballast water as well as the species within it, largely depends on the prevailing hydrodynamics of the receiving water body. Modelling the hydrodynamics of marine environment will lead to reasonable and reliable prediction of the movement of the ballast water discharges. A case study has been carried out for the Gulf of Kachchh region on the west coast of India, where there are many minor ports and one major port are situated, using a two-dimensional hydrodynamic model - MIKE21. Tidal forcing and a constant wind field have been prescribed in the model to generate the general circulation pattern. The fate of discharged Ballast water plume at three locations in the study region has been modeled using the advection-diffusion processes. The model results show that the ballast water discharged near the shore tends to move alongshore and that discharged in the midgulf traverses back and forth in the channel and eventually spread towards the northern shore.