• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.35-37
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• 2001

This study has investigated the chemical characteristics and the contamination of groundwater in relation to land use in Daejeon Metropolitan City. An attempt was made to distinguish anthrophogenic inputs from the influence of natural chemical weathering on the chemical composition of groundwater at Taejon. Groundwater samples collected at 170 locations in the Taejon area show very variable chemical composition of groundwater, e.9. electrical conductance ranges from 65 to 1,290 S/cm. Most groundwater is weakly acidic and the groundwater chemistry is more influenced by land use and urbanization than by aquifer rock type. Most of groundwater from green areas and new town residential districts has low electrical conductance, and is of Ca-HC $O_3$ type, whereas the chemical composition of groundwater from the old downtown and industrial district is shifted towards a Ca-Cl (N $O_3$+S $O_4$) type with high electrical conductance. A number of groundwater samples in the urbanized area are contaminated by high nitrate and chlorine, and exhibit high hardness. The Ep$CO_2$, that is the $CO_2$ content of a water sample relative to pure water, was computed to obtain more insight into the origin of $CO_2$ and bicarbonate in the groundwater. Factor analysis of the chemical data shows that the HC $O_3$ and N $O_3$ concentrations have the highest factor loadings on factor 1 and factor 2, respectively. Factors 1 and 2 represent major contributions from natural processes and human activities, respectively. The results of the factor analysis indicate that the levels of $Ca^{2+}$, $Mg^{2+}$, N $a^{+}$, Cl and SO4$^2$ derive from both pollution sources and natural weathering reactions.ons.

• Economic and Environmental Geology
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• v.28 no.2
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• pp.165-176
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• 1995

Dongrae is one of the most famous hot spring resort area in the Republic of Korea. The water temperature ranges $50^{\circ}C{\sim}66$. The chemical composition of the thermal water is quite different from normal groundwater. $Na^+$ and $Cl^-$ are the main components, measured more than 75%, $Ca^{+{+}}$ is contained about 22% and the other ions such as $SO_4$ or $HCO_3$ are the minor components. The heat source is uprising along the fracture zone of granite which is indicated as a subsurface high temperature belt. During the research period of 1991~1992, the groundwater table was lowered down to the depth of about 100 m according to continuous increase of daily use of thermal water. The groundwater table was fluctuated with an amplitude of day, weak or seasion. The groundwater table was the lowest at 18:00 h in a day and also lowest at the weekend for the week period. There was a relavent relationship between drawdown and the amount of thermal water use on a long term base. To protect such a rapid drawdown of groundwater table, Dongrae resort area is now asked to take strong municipal control for the daily use of thermal water.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.191-193
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• 2001

This paper presents the result of groundwater analysis in Changwon area and the characteristics of the groundwater properties. Changwon city conducted groundwater analysis at 551 sites in 1996 and 1997. The water quality is suitable as groundwater use at 466 sites (84.6 %) and exceeds maximum contaminant levels (MCLs) at 85 sites (15.4 %). Major contaminants are total bacteria, coliform and nitrate-N. DNAPLs, e.g. TCE and PCE are detected in the areas of industrial complex and residence. The detection of TCE and PCE is due to organic solvents from manufacturing companies. They are also derived from laundries, Photographer's studios, septic tanks, etc. In addition, fifty groundwater samples were analyzed. Iron, manganese, zinc, copper, lead, aluminum and fluorine are detected in nearly all the groundwater samples. The groundwaters shown on the Piper diagram mostly belong to Ca-HCO$_3$ type.

• The Journal of Engineering Geology
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• v.4 no.3
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• pp.297-309
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• 1994

For a total of 210 city and Kun areas in Korea, a model was developed to predict the amount of groundwater use at each area. At first, the total areas were classified into 3 groups by the characteristics of groundwater use: residential(87), industrial(27) and agricultural (96) areas. Among them, type areas, represented by the dominant groundwater usage for typical purposes, were selected: residential(22), industrial(8) and agricultural(32) areas. Data for the various factors possibly related to the groundwater use were statistically analyzed. The factors include, 1) agricultural area, 2) industrial area, 3) adininistrative unit area(city or Kun), 4) population, 5) groundwater capadty for community water supply, 6) average water supply for a person per day, 7) agricultural water-use, 8) industrial water-use, 9) residential wateruse, 10) rates of community water supply. The data were correlated to the total amount of groundwater use, and the correlations tested at the 95% and 99% significance levels. Influential, significantly related, factors were identified from the tests. Using the multiple regression method with the influential factors, predictive equations were drawn to calculate the amount of groundwater use for residential-industrial and agricultural areas, respectively. The equations were calibrated to minimize the RMS(root mean square) of the differences between predicted and observed groundwater use. After the validation with future data, the model can be utilized in the regional development plans to predict the maximum groundwater demand at each area.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.167-172
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• 2002

Seoul subway system has been constructed to solve traffic difficulties of Seoul metropolitan, and now is the major public transportation. However, the more line has added in the system the deeper the bottom of the tunnel base. And a huge amount of groundwater along the line has seeping into the tunnel. Several subway stations has pumping system to extract the groundwater to the outside and consequently, groundwater table along the line has declined gradually. Groundwater table has dropped about 40 meters at some areas, There was some study for the proper usage of the abstracted groundwater and the project to use the groundwater has launched already by the local government. However. more serious problem is expected on quality degradation of soil and groundwater as the decline of groundwater table along the subway line. This study suggests that the detailed groundwater environmental study should be made as soon as possible for this. If there is any pollution leaking at the surface area of the groundwater depression, the pollution will be seep into the subway tunnel in some day even though the time will be different with the soil material and hydraulic characteristics of the aquifer. And the polluted area of the soil and groundwater would be enlarged along the pathway The study on possibility of the soil subsidence and reducing surface water flow in small creek were also needed. This study suggest one of the counter measurement that restoring the declined groundwater table after groundwater environmental study

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.106-112
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• 2011

This study developed preliminary assessment methodology for priority listing of soil and groundwater contamination sources, considering source characteristics, local environments and risk receptors. Source characteristics were evaluated by scoring relative risk of contamination sources. Local environments were evaluated by scoring annual rainfall, hydraulic conductivity of aquifer, and annual groundwater use. Risk receptors were evaluated by scoring local population, direct distance to surface water, direct distance to drinking-water wells. Scores of each parameter were allocated by analysing distribution of parameter values obtained from government databases. Distributed scores of source characteristics local environments: risk receptors were 12 : 12 : 12. The preliminary assessment scored 0 to 36 for each soil and groundwater sources. Inventory of soil and groundwater sources consisted of 7 categories. This study applied the preliminary assessment methodology to Manan-Gu, Anyang City, Korea. The number of car repair and washing facility was the largest in the contamination source inventory. Petroleum storage facilities showed the highest assessment score. The preliminary assessment methodology also indicated that Anyang-Dong was the priority section among Anyang-Dong, Suksu-Dong, Bakdal-Dong. This study is the first trial for relative ranking soil and groundwater contamination sources by considering source and local characteristics. Therefore, further researches and revision of the preliminary assessment methodology need to be pursued for various applications.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.28-32
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• 2000

There are many different chemical pollutants that originate from atmospheric deposition and transportational activities along roads. This paper review the characteristics of heavy metal pollution, relationships between land use and pollutant load in urban area. Four land use areas in Seoul were selected for sampling and study with different characteristics during the period from April 1998 and February 2000. A series of studies have been carried out concerning the physicochemical characteristics of the sediments settling down in a gully pot to evaluate the contamination for heavy metals. The sediment samples from gully pots were characterized by the chemical extraction experiments. Sediments are characterized by very high concentrations of heavy metals, probably because of a long-term accumulation of vehicle- and industrial-related pollutants. The characteristics of heavy metal pollution show that each land use has different sources of contaminations. Mean Zn concentration in Yeouido and Junggu areas is 2-3 times higher than those in Dobonggu area. This suggests that Zn may be derived from the source of automobile traffic. The mean concentrations of Cu and Cr are very significantly high in Junggu and Gurogu areas and indicate that the industrial activities may contribute to the accumulation of Cu and Cr in sediments. The low Pb levels throughout the whole study areas in Seoul can be accounted for the use of unleaded gasoline since 1987.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.78-91
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• 2007

The groundwater chemistry is heavily influenced by land use. This study has investigated the groundwater quality and contamination characteristic associated with land use. Contamination index ($C_d$) was estimated for evaluating and areal distribution of groundwater contamination degree. Groundwater samples collected from 216 locations in the study area show great variability in chemical composition. Electrical conductance ranges from 100 to $31,360\;{\mu}S/cm$. The pH values are between 4.6 (acidic) and 8.57 (weak alkaline). The water types predominantly represent the $Ca-HCO_3$ and $Ca-Na-HCO_3$ types, whereas, in the residential and business areas, the water type is shifted to (Na, Ca)-Cl type with rich concentration of Cl. The $C_d$ values of the study area range from 1.1 to 117.6 with a mean of 9.56.

• Journal of Environmental Impact Assessment
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• v.13 no.3
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• pp.115-124
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• 2004

To utilize a closed municipal solid waste landfill site in environmentally secure conditions, it is necessary to verify the stabilization level of landfill leachate. To assess leachate stabilization of an open-dumping municipal solid waste landfill (Noeun Landfill) which is located at the upper drainage basin of Namhan River which flows into Lake Paldang utilized for Seoul Metropolitan water supplies, the surrounding characteristics of the landfill site was surveyed. After then, leachate, groundwater and soil samples from this landfill were chemically analyzed, and the analysis results were evaluated by "The Criteria of Landfill Waste Stabilization(CLWS)", "Discharge Criteria of Landfill Leachate", "The Criteria of Domestic Use in Groundwater Quality", and "Soil Contamination Criteria" promulgated by Korean Ministry of Environment. The closed open-dumping landfill was equipped with the final soil cover, 3 groundwater monitoring wells and poor landfill gas extraction devices for the post-closure management of the landfill. BOD/CODcr ratios in leachate were less than or slightly higher than 1/10. This results seemed to imply that the leachate stabilization level of this landfill based on the CLWS was almost completed. Qualities of groundwater sampled from monitoring wells located at outside of landfill were adequate for "The Criteria of Domestic Use in Groundwater Quality". Finally, concentrations of soil contaminants that were likely to be influenced by this landfill site were adequate to "Soil Contamination Criteria".

• Journal of the Korean earth science society
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• v.43 no.4
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• pp.481-489
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• 2022

Various types of karst topographies are found worldwide. Owing to their global distribution, karst areas have been extensively studied by scientists who investigate new discoveries by linking the characteristics of karst topographies with their own research fields. However, there have been only a few studies on karsts in the Republic of Korea, and little research exists on their hydrogeology. Fragmentary studies have been conducted on the hydrochemical characteristics of groundwater in limestone areas, the causes of high arsenic concentrations in groundwater, and the hydraulic conductivity of limestone areas. Research on hydrogeological characterization and flow mechanisms in these areas has only began recently. Identification and the proper management of available groundwater resources in karst (limestone) areas is essential as their unique geological characteristics render it difficult to construct reservoirs or dams at appropriate scales. We have reviewed prior work on karsts in the Republic of Korea to provide information that supports water resource security in the karst areas, to improve the understanding of the equitable use of water resources, and to identify the best management practices for groundwater resource resilience improvement.