• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.125-136
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• 2020

In this study, we identified the major pollution-zones of the mainstream and its tributaries of Gongneung stream and investigated their pollution sources based on water quality, flowrate and pollution-load data of the stream having the characteristics of the urban-rural complex to examine the effect of the tributaries on the water quality changes in the mainstream. The water quality and flowrate data were collected for 10 months (2018 ~ 2019) at 3 points of mainstream and ten tributaries. Water quality index (WQI), load duration curve (LDC), discharge load density (DLD)and delivery ratios for each tributary were obtained so as to investigate the pollution characteristics and some of the information visualized on GIS. The main pollution-zone in the Gongneung stream was in the middle and lower streams, and the tributaries that may affect the pollution of the area were JS, JY, SL and SM. JS and SL had low WQI levels (34.7/37.5) and DLD (kg/d/㎢) of BOD and T-P were relatively high in JY (99.2/6.00) and SL (60.0/2.07). BOD and T-P delivery ratios in JS were high (0.94/0.83), suggesting that JS had significant influence on the water quality of the main pollution-zone in the Gongneung stream. Meanwhile, SM having a high T-P delivery ratio (0.97) was found to be more affected by the non-point source due to the higher LDC excess rate (%) in the low flow compared to high flow. This study provides basic data on the water quality and pollution characteristics of the Gongneung stream, and the analysis results are expected to be used as examples for identifying the main pollution-zone and tributaries of stream and their pollution sources.

• Journal of Korea Water Resources Association
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• v.42 no.5
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• pp.425-432
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• 2009

Gongneung Weir 2 was built in 1970s to supply water for irrigation. For a long time, the weir was left uncared because of the land use change of the nearby area. The weir is 1.5 m high, and the stream in which the weir was installed has bed materials of fine sands to fine gravels. In 2006, the local government and residents agreed on uninstalling the weir, and the weir was removed completely on April 14. This paper reports the results of three field investigations for the study of the stream morphology change after the weir removal. Changes in grain size distribution, bed elevation, and cross section before and after the weir removal are provided and discussed. Net amount of sediment deposits within 1 km reach of the stream is estimated, and the results illustrates that the sediment process, leading to an equilibrium of the bed, progressed very swiftly, namely within 45 days.