H112-0014
Hydrogeological and Geochemical Characterization of Groundwater and Surface Water in a Small Lake System through Analyses of Water Quantity and Quality

Friday, 11 December 2020
Poster
Jeonga Kim1, Sung-Wook Jeen2, Jeonghoon Lee3, Wonbin Kim1,4, Ho Jeong Jo1,4, Dong-Chan Koh4 and Kyung-Seok Ko5, (1)Jeonbuk National University, Department of Earth and Environmental Sciences & The Earth and Environmental Science System Research Center, Jeonju, South Korea, (2)Jeonbuk National University, Department of Earth and Environmental Sciences, Jeonju, South Korea, (3)Ewha Womans University, Department of Science Education, Seoul, Korea, Republic of (South), (4)Korea Institute of Geoscience and Mineral Resources, Daejeon, South Korea, (5)KIGAM Korea Institute of Geoscience and Mineral Resources, Daejeon, South Korea
Abstract:
Groundwater can greatly affect surface water in terms of water quantity and quality, and its impact may vary depending on the season. Thus, it is important to evaluate groundwater-surface water interaction and to quantify the hydrogeological and geochemical characteristics of groundwater and surface water for sustainable management of water resources. In this study, both water quantity and quality analyses were conducted to evaluate the temporal contribution of groundwater to surface water at Osongji, a small lake located in Jeonju-si, Jeollabuk-do, Korea, from October 2018 to August 2019. Groundwater fluxes and levels of groundwater and surface water were measured using seepage meters and piezometers, respectively. Hydraulic conductivity for the lakebed sediment was calculated with the measured groundwater flux and hydraulic gradient using the Darcy equation. For the analysis of water quality, on-site water quality parameters, cations, and anions for groundwater and surface water were analyzed. Hydrogen and oxygen isotopes for groundwater, surface water and rain water were also analyzed, and monthly contribution of groundwater to surface water was calculated using two-component isotopic hydrograph separation. Groundwater fluxes were in the range of + 2.2â…¹10-10 m/s ~ + 4.9â…¹10-8 m/s, and they were not directly correlated to precipitation. Aqueous chemistry indicated that groundwater composition was differentiated with that of surface water, and showed that hydrogeochemical characteristics of surface water were largely affected by groundwater. The results of the isotope analysis indicated that the contribution of groundwater to surface water was high in dry season while low in rainy season. As precipitation increases between April and August, the absolute groundwater influx gradually increased, however, the relative contribution of groundwater to surface water decreased to 49.9% ~ 69.3%. This study suggests that water quantity and quality data can be complementarily used to evaluate temporal changes in groundwater-surface water interaction. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (NRF-2019R1A2C1086667) and by the Polar Academic Program (PE20900) of the Korea Polar Research Institute.
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