4대강 물환경 개선 중심의 수량 및 수질 통합관리 정책 연구 = A Study for Integrated Management of Water Quantity and Quality to Improve the Water Environment of 4 Rivers Restoration Project

다국어 초록 (Multilingual Abstract)

The four river restoration project is multipurpose project. After the completion of weir and major ancillary works including bicycle road and recreation site, many people visit there. We want to know the impact of this project to water environment and the perception and expectation of people from the survey (onsite / phone-visit / phone-no visit). We defined the components of water environment into five, such as water quantity, water quality, aquatic ecosystem, water related recreation, water culture. With the limited and incomplete data available for the analysis of impacts by this project, the purpose of flood control measure showed real decrease of the flood during last several years. The effect of water storage could be verified if there is severe droughts and the implementation of delivery methods from the storage place to the locations of water deficit. The comparison of water quality data between before and after of weir construction showed that the average water quality concentration slightly decreased after this project except the upper part of Nakdong river, especially near the weir location. The correlation coefficients between chlorophyll a and water quality constituents showed a little higher tendency after the project. This tendency showed significantly in case of the upper location of Nakdong river. There is not enough data to evaluate the difference of aquatic ecosystem. The number of people visiting project sites has been increasing but this is far behind the number of water front near Hangang public park. It`s impossible to compare the effect on water culture after this project. People who visited the project site are more interested in water environment and are most interested in water quality. More than 50% of people responded that the water environment was improved and visited people responded more positively. For the water quantity and flood control, people responded this project could make positive effect. For the water quality, peoples are positive but the negative response is higher in comparison with water quantity. People think the water should be clean and suitable for more than the recreational use. For aquatic ecosystem, people responded positively to see flora and fauna, but the negative response ratio was high. People responded negative for recreation opportunity and water culture restoration although the increase of the space for cultural experience. People think the most important factor to improve water environment is water quality and it should be high priority for the operation of weir. The weak points for water quality and aquatic ecosystem are the nutrient rich water quality, insufficient study about the relationship among water quality, weir and dam operation, and aquatic ecosystem, insufficient data for aquatic ecosystem because of relatively short history of systematic monitoring, fragmented horizontal- and vertical- institutional governance. The strong points are IT based system such as the water-TMS which could monitor more than 95% of effluents in flow base in real-time, the undergoing water quality forecasting system, the water information system. The change of magnitude and duration of temperature due to climate change is another threat to water environment. In conclusion, the water quality should be highest priority for the success of 4 river project in future. We have to find out the proper way to control and improve water quality and aquatic ecosystem through in-depth study for the relationship among weir and dam operation, water quality, and aquatic ecosystem to adapt the increased climate fluctuation. Strong political leadership and public awareness is very essential to make sustainable water environment