Lee Hyeonju, Koo Min-Ho, Kim Kisu, Kim Yongcheol
Department of Geoenvironmental Sciences, Kongju National University, Kongju, Republic of Korea.
Korean Institute of Geoscience and Mineral Resources, Daejeon, Republic of Korea.
Ground Water. 2016 May;54(3):448-458. doi: 10.1111/gwat.12373. Epub 2015 Sep 16.
The "Four Major Rivers Restoration Project" was conducted to secure sufficient water resources, introduce comprehensive flood control measures, improve water quality, and restore river ecosystems in Korea. As a part of the project, 16 sites were dredged and weirs were installed in the Han, Geum, Yeongsan, and Nakdong Rivers from late 2010 to early 2012. Groundwater data were obtained from 213 groundwater monitoring wells near the four major rivers to analyze the impacts of weir construction on the nearby groundwater flow system. The groundwater level and chemical characteristics were analyzed to investigate how the groundwater flow system and water quality changed following weir construction. Our results show that the groundwater level immediately increased with increased river levels following weir construction. In addition, the hydrologic condition of some rivers upstream of the weirs was changed from gaining to losing streams. Consequently, the direction of groundwater flow changed from perpendicular to parallel to the river, and groundwater downstream of the weir became recharged from the area upstream of the weir. This should affect groundwater quality, which should become similar to the river water; however, this change has not yet been observed. Therefore, both further monitoring of the groundwater quality and further hydrogeochemical analysis are required for quantitative evaluation of the effects of weir construction in the study area.
“四大江恢复工程”旨在确保韩国有充足的水资源，引入全面的防洪措施，改善水质，并恢复河流生态系统。作为该项目的一部分，2010年末至2012年初，在汉江、锦江、荣山江和洛东江疏浚了16个地点并安装了堰。从四大江附近的213个地下水监测井获取了地下水数据，以分析堰建设对附近地下水流系统的影响。分析了地下水位和化学特征，以研究堰建设后地下水流系统和水质如何变化。我们的结果表明，堰建设后，随着河流水位上升，地下水位立即升高。此外，堰上游一些河流的水文状况从补给型河流变为排泄型河流。因此，地下水流方向从垂直于河流变为平行于河流，堰下游的地下水由堰上游区域补给。这应该会影响地下水水质，使其与河水相似；然而，尚未观察到这种变化。因此，需要进一步监测地下水水质并进行进一步的水文地球化学分析，以便对研究区域内堰建设的影响进行定量评估。
