This page has only limited features, please log in for full access.

Unclaimed
Yongcheol Kim
Groundwater Research Center, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon 34132, South Korea

Basic Info

Basic Info is private.

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 13 August 2021 in Science of The Total Environment
Reads 0
Downloads 0

Nitrate–nitrogen (NO3–N) contamination in groundwater is a major problem of drinking and domestic waters in rural areas. This study revealed the influence of land use type on shallow alluvial groundwaters in a typical rural area in South Korea by applying a self-organizing map (SOM), principal component analysis (PCA), and hierarchical cluster analysis (HCA). The uncertainty of spatial information on land use was improved by using a buffer zone of the average influence radius of 32.65 m surrounding wells. Two major land-use types, forests (44.9%) and rice fields (28.8%), occupied a total of 73.7% of the rural area. The higher concentrations of NO3–N in public facilities and livestock areas were demonstrated to directly recharge groundwater pollutants. NO3–N contamination in rice paddies, which also contained chlorine (Cl) and sulfate (SO4), was assessed according to the nutrients and residual salt in the soil. In addition, different NO3–N concentrations for the same land use indicate various biochemical reactions and NO3–N recharge types into the groundwater system. The shallow groundwaters in the study area were classified into three clusters according to their chemical constituents and land–use properties, especially NO3–N concentration, including pH, Cl, and SO4, using a SOM, PCA, and HCA. Unlike existing studies, we applied a buffer zone based on the Cooper–Jacob equation to obtain an improved SOM model prediction accuracy approximately 10% greater than that using the original dataset.

ACS Style

Chung-Mo Lee; Hanna Choi; Yongcheol Kim; Moonsu Kim; Hyunkoo Kim; Se-Yeong Hamm. Characterizing land use effect on shallow groundwater contamination by using self-organizing map and buffer zone. Science of The Total Environment 2021, 800, 149632 .

AMA Style

Chung-Mo Lee, Hanna Choi, Yongcheol Kim, Moonsu Kim, Hyunkoo Kim, Se-Yeong Hamm. Characterizing land use effect on shallow groundwater contamination by using self-organizing map and buffer zone. Science of The Total Environment. 2021; 800 ():149632.

Chicago/Turabian Style

Chung-Mo Lee; Hanna Choi; Yongcheol Kim; Moonsu Kim; Hyunkoo Kim; Se-Yeong Hamm. 2021. "Characterizing land use effect on shallow groundwater contamination by using self-organizing map and buffer zone." Science of The Total Environment 800, no. : 149632.

Journal article
Published: 24 October 2020 in Water
Reads 0
Downloads 0

Hydraulic structures have a significant impact on riverine environment, leading to changes in stream–aquifer interactions. In South Korea, 16 weirs were constructed in four major rivers, in 2012, to secure sufficient water resources, and some weirs operated periodically for natural ecosystem recovery from 2017. The changed groundwater flow system due to weir operation affected the groundwater level and quality, which also affected groundwater use. In this study, we analyzed the changes in the groundwater flow system near the Geum River during the Baekje weir operation using Visual MODFLOW Classic. Groundwater data from 34 observational wells were evaluated to analyze the impact of weir operation on stream–aquifer interactions. Accordingly, the groundwater discharge rates increased from 0.23 to 0.45 cm/day following the decrease in river levels owing to weir opening, while the hydrological condition changed from gaining to losing streams following weir closure. The variation in groundwater flow affected the groundwater quality during weir operation, changing the groundwater temperature and electrical conductivity (EC). Our results suggest that stream–aquifer interactions are significantly affected by weir operation, consequently, these repeated phenomena could influence the groundwater quality and groundwater use.

ACS Style

Hyeonju Lee; Min-Ho Koo; Byong Wook Cho; Yong Hwa Oh; Yongje Kim; Soo Young Cho; Jung-Yun Lee; Yongcheol Kim; Dong-Hun Kim. Effects of Baekje Weir Operation on the Stream–Aquifer Interaction in the Geum River Basin, South Korea. Water 2020, 12, 2984 .

AMA Style

Hyeonju Lee, Min-Ho Koo, Byong Wook Cho, Yong Hwa Oh, Yongje Kim, Soo Young Cho, Jung-Yun Lee, Yongcheol Kim, Dong-Hun Kim. Effects of Baekje Weir Operation on the Stream–Aquifer Interaction in the Geum River Basin, South Korea. Water. 2020; 12 (11):2984.

Chicago/Turabian Style

Hyeonju Lee; Min-Ho Koo; Byong Wook Cho; Yong Hwa Oh; Yongje Kim; Soo Young Cho; Jung-Yun Lee; Yongcheol Kim; Dong-Hun Kim. 2020. "Effects of Baekje Weir Operation on the Stream–Aquifer Interaction in the Geum River Basin, South Korea." Water 12, no. 11: 2984.

Journal article
Published: 23 June 2018 in Water
Reads 0
Downloads 0

This study showed the hydrogeological characteristics of an alluvial aquifer that is composed of sand, silt, and clay layers in a small domain. It can be classified into a lower high-salinity layer and an upper freshwater layer and contains shells and remnant paleo-seawater (average 5000 μS/cm) due to sea level fluctuation. Geological and electrical conductivity logging, a long-term pumping test, and multi-depth water quality measurements were conducted at pumping, injection, and observational wells to evaluate the hydrogeologic properties, identify the optimal recharge rate, and assess artificial recharge. Using a hydraulic test, a large difference in drawdown and salinity appeared at the radially located observational wells because of the difference in hydraulic connectivity between the wells in the small study area. It was concluded that the hydraulic anisotropy and heterogeneity of the alluvial aquifer should be carefully examined when locating an injection well and considering the efficient design of artificial recharge.

ACS Style

Soo-Hyoung Lee; Se-Yeong Hamm; Kyoochul Ha; Yongcheol Kim; Dong-Chan Koh; Heesung Yoon; Sung-Wook Kim. Hydrogeologic and Paleo-Geographic Characteristics of Riverside Alluvium at an Artificial Recharge Site in Korea. Water 2018, 10, 835 .

AMA Style

Soo-Hyoung Lee, Se-Yeong Hamm, Kyoochul Ha, Yongcheol Kim, Dong-Chan Koh, Heesung Yoon, Sung-Wook Kim. Hydrogeologic and Paleo-Geographic Characteristics of Riverside Alluvium at an Artificial Recharge Site in Korea. Water. 2018; 10 (7):835.

Chicago/Turabian Style

Soo-Hyoung Lee; Se-Yeong Hamm; Kyoochul Ha; Yongcheol Kim; Dong-Chan Koh; Heesung Yoon; Sung-Wook Kim. 2018. "Hydrogeologic and Paleo-Geographic Characteristics of Riverside Alluvium at an Artificial Recharge Site in Korea." Water 10, no. 7: 835.

Journal article
Published: 04 May 2017 in Water
Reads 0
Downloads 0

Time series models based on an artificial neural network (ANN) and support vector machine (SVM) were designed to predict the temporal variation of the upper and lower freshwater-saltwater interface level (FSL) at a groundwater observatory on Jeju Island, South Korea. Input variables included past measurement data of tide level (T), rainfall (R), groundwater level (G) and interface level (F). The T-R-G-F type ANN and SVM models were selected as the best performance model for the direct prediction of the upper and lower FSL, respectively. The recursive prediction ability of the T-R-G type SVM model was best for both upper and lower FSL. The average values of the performance criteria and the analysis of error ratio of recursive prediction to direct prediction (RP-DP ratio) show that the SVM-based time series model of the FSL prediction is more accurate and stable than the ANN at the study site.

ACS Style

Heesung Yoon; Yongcheol Kim; Kyoochul Ha; Soo-Hyoung Lee; Gee-Pyo Kim. Comparative Evaluation of ANN- and SVM-Time Series Models for Predicting Freshwater-Saltwater Interface Fluctuations. Water 2017, 9, 323 .

AMA Style

Heesung Yoon, Yongcheol Kim, Kyoochul Ha, Soo-Hyoung Lee, Gee-Pyo Kim. Comparative Evaluation of ANN- and SVM-Time Series Models for Predicting Freshwater-Saltwater Interface Fluctuations. Water. 2017; 9 (5):323.

Chicago/Turabian Style

Heesung Yoon; Yongcheol Kim; Kyoochul Ha; Soo-Hyoung Lee; Gee-Pyo Kim. 2017. "Comparative Evaluation of ANN- and SVM-Time Series Models for Predicting Freshwater-Saltwater Interface Fluctuations." Water 9, no. 5: 323.

Journal article
Published: 19 September 2014 in Journal of Radioanalytical and Nuclear Chemistry
Reads 0
Downloads 0

A continuous monitoring system (CMS) using an open loop equilibrator for assessment of Rn at the groundwater–surface water interface was developed and tested. For the characterization and validation of the system, three air loops (open loop, closed loop, and open bubble loop) were tested in relation to high and precise count rates, rapid response, and equilibration of radon. The water and air stream is fed to the equilibrator by an experimental setup with a commercial submersible water pump and the internal pump with built-in radon-in-air detector. Efficiency calibration of the CMS is done by simultaneous determination of a groundwater sample using liquid scintillation counting, and the RAD7 accessories RAD-HO, BigBottle RAD-HO. The higher count rates are provided by the closed loop. However, the open loop with bubbler (open bubble loop) provides the best precision count rates, rapid response, and equilibration time. The CMS allows radon determination in discrete water samples as well as continuous water streams.

ACS Style

Kil Yong Lee; Yoon Yeol Yoon; Soo Young Cho; Eunhee Lee; Sang-Ho Moon; Dong-Chan Koh; Kyoochul Ha; Yongcheol Kim; Kyung-Seok Ko. An open loop equilibrator for continuous monitoring of radon at the groundwater–surface water interface. Journal of Radioanalytical and Nuclear Chemistry 2014, 304, 33 -39.

AMA Style

Kil Yong Lee, Yoon Yeol Yoon, Soo Young Cho, Eunhee Lee, Sang-Ho Moon, Dong-Chan Koh, Kyoochul Ha, Yongcheol Kim, Kyung-Seok Ko. An open loop equilibrator for continuous monitoring of radon at the groundwater–surface water interface. Journal of Radioanalytical and Nuclear Chemistry. 2014; 304 (1):33-39.

Chicago/Turabian Style

Kil Yong Lee; Yoon Yeol Yoon; Soo Young Cho; Eunhee Lee; Sang-Ho Moon; Dong-Chan Koh; Kyoochul Ha; Yongcheol Kim; Kyung-Seok Ko. 2014. "An open loop equilibrator for continuous monitoring of radon at the groundwater–surface water interface." Journal of Radioanalytical and Nuclear Chemistry 304, no. 1: 33-39.

Journal article
Published: 19 September 2014 in Journal of Radioanalytical and Nuclear Chemistry
Reads 0
Downloads 0

Natural isotopes such as 222Rn, 3H, 18O and D were used to understand the groundwater–surface water interactions and these tracer showed surface water intrusion effect during the winter. The 222Rn concentrations of samples retrieved from the multi-depth well varied with sampling point and time, e.g. they decreased by about 80 % during the winter. The results of the analyses of stable isotopes show that the mean δ 18O value was −7.84 ‰ (−9.16 ‰ to −7.24 ‰), while the mean δD value was −54.13 ‰ (−57.86 ‰ to −50.98 ‰). The 3H groundwater concentrations ranged from 0.23 to 0.59 Bq/L, with an average value of 0.37 Bq/L.

ACS Style

Yoon Yeol Yoon; Yong Cheol Kim; Kil Yong Lee; Soo Young Cho; Youn Young Jung. The 222Rn, 3H and stable isotopes as tracers of groundwater–surface water interactions in a stream basin. Journal of Radioanalytical and Nuclear Chemistry 2014, 304, 107 -113.

AMA Style

Yoon Yeol Yoon, Yong Cheol Kim, Kil Yong Lee, Soo Young Cho, Youn Young Jung. The 222Rn, 3H and stable isotopes as tracers of groundwater–surface water interactions in a stream basin. Journal of Radioanalytical and Nuclear Chemistry. 2014; 304 (1):107-113.

Chicago/Turabian Style

Yoon Yeol Yoon; Yong Cheol Kim; Kil Yong Lee; Soo Young Cho; Youn Young Jung. 2014. "The 222Rn, 3H and stable isotopes as tracers of groundwater–surface water interactions in a stream basin." Journal of Radioanalytical and Nuclear Chemistry 304, no. 1: 107-113.