하천형 호소의 체류시간과 수질 = Residence Time and Water Quality in a Riverine-Type Reservoir

다국어 초록 (Multilingual Abstract)

Water quality in a reservoir is subject mainly to hydrodynamic structure. Paldang reservoir can be classified into a riverine-type, with small storage capacity and short residence time. Bukhan and Namhan rivers and Kyongan stream join at the Paldang reservoir. In particular, the confluence area with Kyongan strean and main channel of the reservoir has limited exchange rate of mass due to shallow depth and little discharge of inflow. It has been reported in recent 10 years that water quality was deteriorated, in the confluence area, with the reason believed due to high pollutant load and low exchange rate. Hence, investigation is required to understand the processes of pollutant transport along the region and provide solution to reduce pollutant levels. In this study, a particle tracking/random walk model is used to calculate residence time. The simulation results in residence time of 35, 22 and 8 days, respectively, for low, median and fruitful water levels. However, it was found that there was little difference between the cases with and without peak load from Chungpyung Dam upstream the Bukhan river. This result is not identical with the calculated using hydrological records. This is belived to be caused by that hydrological data cannot correctly give residence time when flow travels upward, yielding water mass increase and corresponding mixing effects.