낙동강 하류 유역 농업용 양배수지와 배수지의 수질특성 및 오염부하량 산정

Abstract

Agricultural detention basin refers to river facilities which temporarily retain runoff from agricultural area and then rushes the polluted runoff into nearby streams or reuse it for irrigation as needed, and should be monitored to efficiently protect river water quality. The objective of this study is to provide optimal management strategies for agricultural pumping and drainage facilities as well as drainage facilities operated along the lower Nakdong River by assessing their water quality profiles as well as pollution loads. A short-term monitoring campaign extending over three months was conducted in the period from September 2018 to November 2018 to measure water quality and flow rate in a total of 68 facilities and the pollution loads in the river mainstream were compared with those estimated from both monitoring and modeling results. Results showed that 8 facilities out of 68 ones needed intensive management plans according to the criteria of TP above 0.03 mg/L and TN above 10 mg/L and there was no significant difference in water quality among inlet, outlet, and storage stations, including all stations, for individual facilities. However, the pollution loads estimated from agricultural pumping and drainage facilities as well as drainage facilities were significantly lower thant those in the mainstream, which was mainly attributed to the limited monitoring survey and modeling results. We expect that reinforced survey of pollutant source information on the upstream watershed and advanced input data to the model enable not only a more precise estimation of pollutant loads, but also good management practices of existing and future agricultural pumping and drainage facilities as well as drainage facilities.