반폐쇄성 해역의 빈산소층 관리를 위한 수직 확산계수 산정

Abstract

Abstract

There are rapid development and population centralization in our coastal today, and various pollutants and domestic sewage occur coastal contamination. Also, aquaculture industry increases to secure the food resource at coastal zone and has great importance. Especially, in the case of contaminants input from a Semi-enclosed Bay and a little nutrient circulation with the open sea, Hypoxia are formed and destroy the marine ecosystem by killing the living things in marine farm and benthic organisms. Hypoxia means that dissolved oxygen is less than 2.0 mg/L and it has been studied throughout the world. Physical and biological factor are a cause of Hypoxia formation. First of all, physical factor means that stratification is formed by changes of the water temperature and salinity. Once stratification is formed, vertical diffusion coefficients is reduced and it blocks the oxygen supply from the surface to the bottom. Secondly, biological factor means that once organic matter is accumulated at the bottom, it makes Hypoxia. Therefore, to manage the Hypoxia at a semi-closed bay, there are needs to calculate the physical and biological factors and estimate vertical diffusion coefficient. In this paper, Masan Bay was selected to the study area because pollutant input has been exceeded to the capacity of the environment and has sufficient condition to form the stratification. The study period is from 2008 to 2009. The vertical diffusion coefficient by the density difference and box model which considered biological factor are calculated to form Hypoxia. Density and the physical factor of the box model are calculated by the EFDC model. Box model is constructed by STELLA program. Vertical diffusion coefficient depends on the difference of the density. Density difference, stratification and rainfall patterns in the study area are similar. Dissolved oxygen couldn’t match with the box model but the patterns are similar with observed data and calculated data. In addition, there are needs to study with many box model and the diffusion coefficients by each floor. The diffusion coefficient in this study should be used to other regions.