낙동강 조류발생 특성분석 및 관리정책 방안

Abstract

Analysis and management of algal bloom in the Nakdong River Concerns about water quality in the Nakdong River have been raised because the Nakdong River will change from a lotic environment to a lentic environment due to the installation of eight weirs to be constructed as part of the Four Major Rivers Restoration Project. Accordingly, this study suggests comprehensive policy directions for management and control of algal blooms in the Nakdong River through review of current trends in domestic and overseas algal management, collection and analysis of water quality data from the river, and confirmation of limiting factors for algal blooms in the river. To this end, the following systems were considered and reviewed: the Algal Prediction System of Korea; the Harmful Algae Blooms Observing System (HABSOS), Mississippi River Watershed Conservation system, and Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) system of the U.S.; the New South Wales Algal Alert System, the Victoria Algal Management System, and the National Eutrophication Management Program (NEMP) of Australia; and the Standards for Blue-Green Algae of the World Health Organization (WHO). As a result, suggestions were proposed to improve standards for Korea's Algal Prediction System. According to the results of analysis of the water quality data measured at the Mulgeum water intake station over the last 15 years, the current downstream of the Nakdong River has been classified as in a eutrophic state based on the eutrophication criteria applied to lakes and reservoirs. In addition, waste loads in the Nakdong River were estimated before and after the 4 Major Rivers Restoration Project, in order to determine how much phosphorus load, which is one of the limiting factors to algal growth, can be controlled in the watershed. This study evaluated available technologies to control algal blooms, but found that few can be applied to the Nakdong River because of their low field applicability. The conclusions of the study propose use of the “Algal Alarm System” and the “Algal Forecasting System” in lieu of the current “Algae Prediction System” as the river’s algal management system. In addition effluent standards need to be strengthened and treatment facilities must be constructed in order to reduce phosphorus load in the watershed. Integrated watershed management is also necessary in the Nakdong River, including non-point source management, if a healthy water environment is to be achieved over the long term. Finally, this study indicates the significance of long-term fundamental research programs to resolve algal issues and eutrophication in the Nakdong River.