Modelling of Water Pollution Propagation in the Sevastopol Bay

Abstract

Introduction. Tracking of spread of various contaminations and elaboration of the operational systems to control wrecking discharges are among the important tasks of marine environment monitoring. The processes of transport of the contaminating impurity inflowing from different sewers were modeled based on the diagnostic calculations of water circulation in the Sevastopol Bay. Data and Methods. The currents field was calculated using the sigma-coordinate version of the Princeton Ocean Model adapted for the regional conditions in the Sevastopol Bay. To calculate the polluting impurity transport, the model of the matter transfer and diffusion was incorporated into the circulation model. The data on the wind speed and direction obtained at the Sevastopol met office, the temperature, salinity and density climatic fields calculated using the information of 2.7 thousands hydrological stations in the Sevastopol Bay, average seasonal variations of the River Chernaya water discharge and the digital bottom relief with spatial resolution 68 m were used in the model. Analysis of Results. Numerical experiments on the contaminant propagation from the point of possible discharge in the Gollandiya Bay reveal that dependence of the pollutant movement trajectory (direction) upon the pattern of water circulation is most evident in the Yuzhnaya Bay and less manifested in the central part of the Sevastopol Bay. In case of a wrecking discharge in the River Chernaya mouth, a contaminant spot, regardless of wind conditions, moves to the northwest and reaches the Gollandiya Bay. Further evolution of the polluted water volume is similar to the process developing after a sewage discharge directly within the Gollandiya Bay. Discussion and Conclusions. The carried out numerical calculations confirm operatioinal capability of the model and its adequate reproduction of the physical processes under study. It permits both to model the circulation seasonal variation and the thermohaline structure of the Sevastopol Bay waters, and to describe more accurately trajectories of the contaminants’ spread.