Assessment of Pollution Levels in the Jangsungcheon Watershed Using Load Duration Curves and Analysis of the Causes

  • Cho, Sohyun (Yeongsan River Environment Research Center, National Institute of Environmental Research) ;
  • Bak, Jonghun (Yeongsan River Environment Research Center, National Institute of Environmental Research) ;
  • Lee, Yeong Jae (Yeongsan River Environment Research Center, National Institute of Environmental Research) ;
  • Kim, Kyunghyun (Yeongsan River Environment Research Center, National Institute of Environmental Research) ;
  • Jung, Kang Young (Yeongsan River Environment Research Center, National Institute of Environmental Research)
  • Received : 2019.10.02
  • Accepted : 2019.10.29
  • Published : 2019.10.31


In this study, a load duration curve was applied to the Jangseongcheon, one of the tributaries of the Yeongsan River, to assess whether the target water quality was achieved. In addition, pollution of the water body was investigated to develop and suggest the optimal management time with respect to polluted flow sections and monthly conditions. The average flow rates of sections JS1 and JS2 were $0.25m^3/s$ and $1.08m^3/s$, respectively. The BOD and T-P for water-quality standards at JS1 were rated at II, whereas the COD and TOC were rated at III, thus indicating a fair level of water quality. By contrast, the BOD at JS2 was rated at III, the T-P at IV, and the TOC at V, indicating poor water quality in this section. The load duration curve was plotted using the actual flow data measured in eight-day intervals for eight years from 2011 to 2018 at locations JS1 and JS2 in the Jangsungcheon Basin. In an assessment using the load duration curve on whether the target water quality was met at location JS1, all of the water quality parameters (BOD, COD, TOC, T-N, T-P, and SS) satisfied the target water quality. By contrast, at location JS2, parameters COD, TOC, T-N, and T-P exceeded target values by more than 50%, indicating the target water quality was not met. The discharge loads of locations JS1 and JS2 were analyzed to identify the reasons the target water quality was exceeded. Results revealed that the land system contributed considerably. Furthermore, the discharge load of JS2 accounted for more than 80% of the load on the entire basin, excluding that of JS1. Therefore, the best method for restraining the inflow of pollutants into the stream near location JS2 must be applied to manage the water quality of the Jangsungcheon.


Supported by : National Institute of Environment Research (NIER)


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