Verification of water environment monitoring network representativeness under estuary backwater effects
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The multi-functional weirs constructed as part of the Four Major River Restoration Project in Korea are operated for water level management and may have a backwater effect in estuaries. If the main channel of the Nakdong River flows backward and affects the estuary water, the water quality in the estuaries may not be representative of the tributary water quality. In this study, we confirmed the representativeness of the existing water quality monitoring networks using spatiotemporally disperse electrical conductivity observations, self-organizing maps (SOMs) for monthly pattern analysis, and the LOcally WEighted Scatter plot Smoother (LOWESS) technique for trend analysis. The results show that the Namgang 4-1 site, which is located in the Nam River estuary, is not affected by the Nakdong River, while the Baekcheon (Sunwongyo) site in the Baekcheon estuary is always affected by the Nakdong River. Therefore, it is necessary to relocate the existing monitoring network or establish a new monitoring network for locations affected by mainstream backflow, as is seen in Baekcheon (Sunwongyo). The methods proposed in this study, including spatiotemporally diverse electrical conductivity measurement, dimensionless fluctuation values, SOMs, and LOWESS, can be used to verify the representativeness of water quality measurement networks in other regions.
KeywordsTributary drainage Water quality Backwater effect SOM LOWESS
This research was supported by a grant (NIER-2017-01-01-081) from the National Institute of Environmental Research (NIER), which is funded by the Ministry of Environment (MOE) of the Republic of Korea.
- Davie, T. (2002). Fundamentals of hydrology (2nd ed.). London and New York: Routledge.Google Scholar
- Helsel, D. R., & Hirsch, R. M. (2002). Statistical methods in water resources techniques of water-resources investigations. Book 4, chapter A3, U.S. Geological Survey, 226–230, 329–335.Google Scholar
- Kadlec, R. H., & Wallace, S. (2009). Treatment wetlands (2nd ed.). USA: CRC Press.Google Scholar
- Kim, J., Kim W., & Kim S. H. (2015a). Discharge estimation at monitoring station affected by backwater effects in a junction. 2015 Proceedings of the Korea Water Resource Association, 393.Google Scholar
- Kohonen, T. (2002). Self-organizing maps. Berlin: Springer.Google Scholar
- Lu, H., Bryant, R. B., Buda, A. R., Collick, A. S., Folmar, G. J., & Kleinman, P. J. A. (2015). Long-term trends in climate and hydrology in an agricultural, headwater watershed of central Pennsylvania. Journal of Hydrology: Regional Studies, 4, 713–731.Google Scholar
- Ministry of Environment. (2017). Water environmental monitoring network operation plan. Sejong, Korea: Ministry of Environment.Google Scholar
- Ministry of Land, Infrastructure, and Transport. (2009). Nakdonggang river maintenance basic plan. Sejong, Korea: Ministry of Land, Infrastructure, and Transport.Google Scholar
- Paik, B. C., Kim, C. K., & Kim, T. R. (2011). A study on the pattern analysis of correlation between the river flow and water quality using a SOM technique. Journal of Korea Society for the Urban Environment, 11(2), 153–160.Google Scholar
- SOM Toolbox Team. (2000). SOM toolbox for Matlab 5. Helsinki: Helsinki University.Google Scholar
- Water Environment Information System. (2017). Available online at: http://water.nier.go.kr (accessed on 12. 2017).