• Journal of the Korean Society of Groundwater Environment
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• v.1 no.1
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• pp.1-5
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• 1994

The contaminant migration through the subsurface of Nanjido landfill is studied using a 2-D finite element model of contaminant transport. The leachate mounding caused by the installation of partial slurry wall around the pheriperal area of the Landfill is analysed using the finite difference model of groundwater flow. Model parameters were validated using in-situ concentration data and the behavior of the transport next 30 years is predicted. The sensitivities of chloride concentration by the change of model parameters, e.g. leachate mounding in the Landfill and the dispersivity are analysed. The results of the analyses show that the maximum chloride concentration level near Han River caused by the leachate of Nanjido Landfill would be 1488mg/1 and comes 17 years after the landfill closure. Increase of the leachate concentration is caused by the increase of both the leachate mounding and the dispersivity. However, the rate of concentration increase becomes higher with the rise of leachate mounding level, while it tends to converge a certain concentration with the increase of the dispersivity.

• Economic and Environmental Geology
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• v.51 no.1
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• pp.39-48
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• 2018

We carried out the standoff compensation data from 2007 to 2011 into four different density borehole models to find out the most effectiveness of standoff compensation charts. First, we investigated the irregular collapse characteristics of gamma ray and cut the non-ideal gamma response to improve the effectiveness of the standoff compensation error data. Effectiveness of detector combinations, density of borehole, and spine and ribs techniques from the modified standoff compensation data was analyzed. As the result of comparison, LSD-MSD combination has been suitable for standoff compensation more than LSD-SSD combination and it is possible to do standoff compensation for soil or weathered zone under groundwater level without fatal errors. Even though error scales of density transformed spine and ribs techniques were generally large compared to the conventional standoff compensation, standoff compensation for soil and weathered zone under groundwater level were sufficiently effective.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.437-448
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• 2022

This work aims to assess the threat to human health of hazardous materials in groundwater that is used domestically and for drinking. Two distinct sub-assessments are considered: cancer and non-cancer risk. The studied groundwater is in an agricultural area of Gyeongnam Province, Korea, and is contaminated by arsenic at a mean level of 16.27 ㎍/L, far greater than the WHO guideline (10 ㎍/L for drinking water). We collected groundwater data from the National Groundwater Information Center (gims.go.kr) and assessed the risk to human health following the methodology of the United States Environmental Protection Agency. We considered three exposure scenarios: domestic use (scenario 1) and drinking use with different doses (scenarios 2 and 3). Scenario 1 had a median hazard quotient (HQ) of 0.77 and a cancer risk (CR) of 0.013. Scenario 2 had a median HQ of 0.08 and a CR of 3.69 × 10^-5, and the values for scenario 3 were 0.11 and 4.82 × 10^-5, respectively. Scenario 1 is likely the most hazardous to human health. Further study of the origin of arsenic in groundwater in the study area is required, as are remedial measures to mitigate its health effects.

• Journal of the Korean earth science society
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• v.44 no.6
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• pp.629-642
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• 2023

Currently, low and intermediate level radioactive waste is being disposed of at the Gyeongju disposal site for permanent isolation. Since 2006, the Korea Radioactive Waste Agency has been conducting site characteristics surveys continuously verifying changes in the site based on the site monitoring and investigation plan. The hydrogeochemical environment of the disposal site is considered for the evaluation of natural barriers. However, the seawater must be considered because of the regional characteristics of Gyeongju, which is near the East Sea. Therefore, this study, collected 30 samples for deriving the groundwater quality data from seven wells and compared with two seawater samples collected from October 2017 to June 2022. Additionally, the study explores the groundwater monitoring method using statistical tools such as clustering and background concentration analysis. The groundwater samples in the study area were classified into two to four clusters depending on their chemical constituents-especially, EC, HCO₃, Na, and Cl-using statistical analysis, molar ratio, and K-means clustering.

• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.192-203
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• 2016

A field investigation was conducted on an aquifer contaminated with trichloroethylene (TCE) for application of in situ reactive zone treatment using nanosized zero-valent iron (NZVI). The aquifer was an unconfined aquifer with a mean hydraulic conductivity of $5.14{\times}10^{-4}cm/sec$, which would be favorable for NZVI injection. Seasonal monitoring of TCE concentration revealed a presence of non-aqueous phase liquid form of TCE near IW (injection well). The hydrochemical data characterized the site groundwater to be a $Ca-HCO_3$ type. The average value of Langelier Saturation Index of the groundwater was -1.33, which implied that the site was favorable for corrosion of NZVI. Dissolved oxygen (DO) concentration varied between 2.5~11.5 mg/L, which indicated that DO would greatly compete with TCE as an electron acceptor. The hydrogeological and hydrochemical characterization reveals that the time around November would be appropriate for NZVI injection when water level and temperature are relatively high and DO concentration is low.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.3
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• pp.133-139
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• 1999

The geostatistical method Kriging is used to estimate the areal distributions of the depth to the water table and the altitude of the water table measured from the sea level. A northern part of the city of Pohang, Kyeong-Buk, Korea has been chosen and the digital map of the area with 1:5,000 scale from the National Geographic Information System (NGIS) project by National Geographic Institute has bun used to reproduce the ground surface distribution. The water table depth appears to be in the range between 7 m and 9.5 m except a few localities where mountain tops exist and the use of groundwater for agicultural purposes is believed to be heavy. The overall distribution of the water table altitude shows a monotonic gradual decrease from the west to the east (seaward direction from the inland) and to the south with maximum rate approximately at 90 m over 6 km in horizontal distance and indicates that the groundwater is moving several meters per day there.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.499-508
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• 2004

Changwon City first constructed riverbank filtration plants in Book-Myeon and Daesan-Myeon in Korea in the year 2001. This study evaluated hydrogeological characteristics and groundwater flow simulation between the Nakdong River and the fluvial aquifers adjacent to the river in Book-Myeon, Changwon City. The groundwater simulation calculated the influx rate from the Nakdong River and the fluvial aquifers to pumping wells through the riverbank filtration system. The groundwater flow model utilized drilling, grain size analysis, pumping test, groundwater level measurements, river water discharge and rainfall data. Hydraulic heads calculated by the steady-state model closely matched measured heads in pumping and observation wells. According to the transient flow model, using a total pumping amount of 14,000 $m^3$/day, the flux into the pumping wells from the Nakdong River accounts for 8,390 $m^3$/day (60%), 590 $m^3$/day (4%) is from the aquifer in the rectilinea. direction to the Nakdong River, and 5,020 $m^3$/day (36%) is from the aquifer in the parallel direction to the Nakdong River. The particle tracking analysis shows that a particle from the Nakdong River moves toward the pumping wells at a rate of about 1.85 m/day and a particle from the aquifer moves toward the pumping wells at a rate of about 0.75 m/day. This study contributes to surface water/groundwater management modeling, and helps in understanding, how seasonal change affects pumping rates, water quality, and natural recharge.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.277-282
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• 2018

BACKGROUND: At these days, the human health and environmental concerns of pesticide used for turf grass management at golf courses in Korea have increased. The objectives of the study were to determine the pesticide residues for golf course and neighboring area and evaluate the impact moved into neighboring area of pesticides treated at golf courses. METHODS AND RESULTS: Three golf courses and neighboring areas in Korea were monitored from July to October, 2017. The soil sample collection was divided the golf course into its logical parts (such as a greens, fairways, and rough) and neighboring area soil samples were collected at three different points. The water samples of the golf course and neighboring area were collected at three different points, respectively. The pesticide residues for soil and water sample were monitored by the multi-residue screening method of 98 pesticide with HPLC-MS-MS. The concentrations of detected pesticide in soil and water samples of the golf course were in the range of 0.01~1.26 mg/kg and 0.0001~0.0089 mg/kg, respectively. The residue levels for detected pesticides in neighboring area were at 0.01~0.04 mg/kg and 0.0001~0.0029 mg/kg, respectively, well below those level in golf course. CONCLUSION: This study indicate that the pesticide residue levels of golf course and neighboring area in Korea may not a possible risk of exposure on soil and aquatic environment. For future work, more monitoring should be performed so that the evaluation data becomes more valid.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.315-315
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• 2017

In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.

• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.57-67
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• 2010

Specific yield is an essential parameter of the water table fluctuation method for recharge calculation. Specific yield is not easily estimated because of limited availability of aquifer test data and soil samples at National Groundwater Monitoring Stations in South Korea. The linear relationship between rainfall and water level rise was used to estimate the specific yields of aquifer for 34 shallow monitoring wells which were grouped into three clusters. In the case of Cluster-1 and Cluster-2, this method was not applicable because of low cross correlation between rainfall and water level rise and also a long lag time of water level rise to rainfall. However, the specific yields for 19 monitoring wells belonging to Cluster-3, which have relatively high cross correlation and short lag time, within 2 days after rainfall, range from 0.06 to 0.27 with mean value of 0.17. These values are within the general range for sand and gravel sediments and similar to those from aquifer test data. A detailed field survey is required to identify monitoring sites that are not greatly affected by pumping, stream flow, evapotranspiration, or delayed response of water levels to rainfall, because these factors may cause overestimation of specific yield estimates.