• Journal of the Korean Society of Groundwater Environment
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• v.7 no.2
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• pp.73-88
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• 2000

The geochemistry of the $CO_2$-rich waters ($Pco_2\leq$about 1 atm) in NE part of the Kangwon province was investigated. The $CO_2$-rich waters can be divided to three types based on chemical compositions: Na-$HCO_3$, Ca-Na-$HCO_3$and Ca-$HCO_3$types. The water chemistry indicates that these type waters were evolved through reaction with host rocks by supply of deep-seated $CO_2$during deep circulation, and their geochemical environments in depth might have been different each other. The dissolution process of plagioclase is important in water/granite interactions and its solubility change according to reaction temperature played an important role in the determination of chemical compositions. The higher reaction temperature coincides with the lower different in solubility between albite and anorthite. It means that calcium is mainly released to the water in the lower temperature, whereas sodium in the higher temperature due to high Na/Ca ratio in plagioclase. The application of various chemical geothermometries on the $CO_2$-rich waters shows that the calculated reservoir temperature of Na-$HCO_3$type (about 15$0^{\circ}C$) is higher than those of Ca-$HCO_3$type. Therefore, we now interpret the recognized chemical difference was mainly due to the difference of reaction temperature. Considering normal thermal gradient, we can understand that the Na-$HCO_3$type was evolved from deeper crustal depth than the Ca-$HCO_3$type.

• Geophysics and Geophysical Exploration
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• v.6 no.3
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• pp.143-152
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• 2003

Among the various geophysical approaches to identify the leakage of leachate with conductivity variation, conventional electrical resistivity survey has been mainly used at waste landfill. We adopted small-loop electromagnetic (EM) survey using multi-frequencies in parallel with electrical resistivity survey to delineate the leakage of leachate through the shallow soil layer at a waste landfill in Jeju Island, and also with self-potential monitoring to detect the streaming potential produced by the movement of leachate. There were no evidences of leakage from waste landfill according to the results of the electrical resistivity survey and SP monitoring, and it was also true from the results of water quality analysis at stream around waste landfill periodically. On the other hand, the results of one-dimensional inversion of spatially-filtered small-loop EM survey data showed the anomalous zone of low resistivity with depth both around and inner waste landfill.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.292-303
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• 2016

This study described the spatial distributions of marine environmental factors such as water temperature, salinity, chlorophyll a concentration and turbidity, and characteristics of phytoplankton community such as species composition, standing crops and dominant species at 19 fishing ports around Jeju Island during the early summer of 2016. I analyzed bio-oceanographical characteristics using principal component analysis (PCA) of the environmental factors and biological parameters. Water temperature, salinity, chlorophyll a and turbidity ranged from 17.6 to $20.7^{\circ}C$, from 26.19 to 32.33 psu, from 0.76 to $7.13{\mu}g\;L^{-1}$, and from 0.51 to 14.49 FTU, respectively. A total of 51 species of phytoplankton belonging to 35 genera were identified. In particular, diatoms and dinoflagellates accounted for more than 56.8% and 27.4% of all the species, respectively. Moreover, the number of phytoplankton species was controlled by salinity. Phytoplankton cell density ranged from $2.9cells\;mL^{-1}$ to $185.9cells\;mL^{-1}$. The dominant species were Navicula spp. Stephanopyxis turris, Eutreptiella gymnastica and Mesodinium rubrum. Environmental factors and the phytoplankton community varied greatly between sampling sites. According to PCA, the biological oceanographic characteristics of the around Jeju Island were characterized by meteorological factors such as air temperature, precipitation and discharge of ground water during early summer.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.4
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• pp.192-202
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• 2010

Submarine groundwater discharge (SGD) has been recognized as a provider for freshwater, nutrients, and dissolved constituents from continents to the oceans and paid more attention with regard to the mass balance of water or dissolved constituents on local and global scales. The submarine discharge of fresh groundwater (fresh SGD) through seepage or springs in coastal ocean may be especially important in aspects of water resource and marine environment managements in the future. Based on the worldwide compilations of observed fresh SGD, our review reveals that fresh SGD occurs in various marine environments along most shoreline of the world and the global estimates of fresh SGD were approximately 0.01-17% of surface runoff. In addition, the input of fresh SGD calculated and investigated in this study were about 50%, 57%, 89%, and 420% of total river discharge in Jeju Island, Yeongil Bay, Masan Bay, and Yeoja Bay, respectively. These inputs from fresh SGD along the shoreline of Korea Peninsula are much higher than those of the whole world, greatly vary with the region. However, since these estimates are based on the water balance method mainly used in coastal ocean, we have to perform continuous monitoring of various parameters, such as precipitation, tide, evapotanspiration and water residence time, which have an impact on the water balance in a lot of areas for evaluating the precise input of fresh SGD. In addition, since the method estimating the input of fresh SGD has brought up many problems, it is required to make an intercomparison between various methods such as hydrogeological assumption, numerical modeling, and seepage meter.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.67-72
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• 2005

To investigate the feasibility of a new concept of storing Liquefied Natural Gas (LNG) in a lined hard rock cavern, and to develop essential technologies for constructing underground LNG storage facilities, a small pilot plant storing liquid nitrogen (LN2) has been constructed at the Korea Institute of Geoscience and Mineral Resources (KIGAM). The LN2 stored in the cavern will subject the host rock around the cavern to very low temperatures, which is expected to cause the development of an ice ring and the change of ground condition around the storage cavern. To investigate and monitor changes in ground conditions at this pilot plant site, geophysical, hydrogeological, and rock mechanical investigations were carried out. In particular, geophysical methods including borehole radar and three-dimensional (3D) resistivity surveys were used to identify and monitor the development of an ice ring, and other possible changes in ground conditions resulting from the very low temperature of LN2 in the storage tank. We acquired 3D resistivity data before and after storing the LN2, and the results were compared. From the 3D images obtained during the three phases of the resistivity monitoring survey, we delineated zones of distinct resistivity changes that are closely related to the storage of LN2. In these results, we observed a decrease in resistivity at the eastern part of the storage cavern. Comparing the hydrogeological data and Joint patterns around the storage cavern, we interpret this change in resistivity to result from changes in the groundwater flow pattern. Freezing of the host rock by the very low temperature of LN2 causes a drastic change in the hydrogeological conditions and groundwater flow patterns in this pilot plant.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.294-300
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• 1996

We performed an experiment to confirm the possibility of wasabi culture using the wat­er of the Soyang River Dam in Chunchon and the ground water in Suwon. Water mineral content of Soyang River except for P was less than that of ground water of Suwon. Dis­solved oxgen and E C of Chunchon was proper to culture wasabi but E C and dissolved oxgen of Suwon was not suitable for that. Water temp. of Soyang river was very changable by month while that of the ground water in Suwon was kept constantly. In Soyang river of Chunchon the month that water temp. show $8{\sim}18^{\circ}C$, optimal growth temp., was May to Nov. and the month that water temp. show less than $6^{\circ}C$, growth limit temp., was $Jan.\;{\sim}\;Feb.$ of Chunchon. Rhizome weight of main stem in Chunchon and Suwon was 63g and 22g per plant and rate of maketable rhizome was each 80%, 0% by culture of 32 months to include raising see­dling period of 13 months. Dry matter partitioning ratio of petiole in Soyang river of Chunchon was the highest of all others but it was lowest of all others in ground water of Suwon. Rhizome weight of main stem in Chunchon was showed possitive correlation with plant height and fresh top weight and in Suwon it was showed possitive correlation with root weight and high possitive correlation with No. of total leaves and No. of tillers.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.395-406
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• 2002

The sixty natural springs and community wells used as a drinking water in the Daejeon area are mainly located at the parks and the natural green districts. The purpose of this study is to investigate the characteristics of water quality and the contamination of the springs and the wells, and to suggest the management strategy for the springs and wells. For this study, we undertook water quality data from Daejeon City. According to the statistic analysis of water quality data, unacceptable rate as a drinking water was about 28 percent in 1999 and 24.5 percent in 2000, respectively. Major unacceptable factor is coliform, and others are bacteria, yersinia, color, turbidity, Fe and F. The unacceptable rate shows a roughly positive relationship with precipitation, that is, it shows highest rate during a rainy season between June and September. The major contamination source is likely to be the excrement of wild animals around natural springs and wells. Most of springs are vulnerable to the contamination of coliform and bacteria because of short residence time and shallow circulation in subsurface environment. The water samples collected from 31 springs or wells show weak acidic pHs, the electrical conductivity ranging from 63 to 357 $\mu\textrm{S}$/cm, and the hydrochemical types of Na(Ca)-HC0$_3$ and Ca-HC0$_3$. The groundwater samples of low total dissolved solid(TDS) belong to Na(Ca)-HC0$_3$. type, and the groundwater of high total dissolved solid is shifted towards Ca-HC0$_3$ type in the chemical composition. These hydrochemical characteristics indicate that most natural springs is in the early stage of geochemical evolution. The natural springs should be closed during a rainy season, which shows a high contamination rate. We suggest that a protection barrier around the springs should be built to keep wild animals away from the springs.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.129-134
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• 2005

Ths study was carried out to understand the geo-topographical characteristics of the landslide area (1.5 ha) in Maeri, Sangdong-myeon, Gimhaesi, Gyeongsangnam-do. The bedrock of the landslide area was diollites and the area in and around the upper slope with the scattered talus was composed of Masanam originated from Igneous rocks. The landslide occurred in 19th of April, 2004 and the amount of rainfall for 3 days before the landslide was 74mm. The landslide by land creeping in this area was mainly attributed to geo-topographical characteristics such as well developed colluvial and/or weathered soils, and land cutting in lower slope, although the landslide could be affected by the rainfall. The type of the landslide can be classified into the land creeping by concave colluvial soils.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.29-38
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• 1996

Among many geophysical prospecting methods, GPR(Ground Penetration Radar) and electrical resistivity method have been applied to a open waste dumping landfill for measuring of the site area and depth. The surveying was limited to a boarder of the site and inside area because of the field situation. The data of GPR were recorded by 50MHz antenna, and dipole array was used for electrical resistivity survey in the same survey line for the integrated interpretation. The result of GPR clearly indicated the horizontal boarder of site. However, the data of GPR did not have enough to measure the depth of site clearly. The electrical resistivity method may show the effective information by integrated interpreation. These results coincided with results of the boring test. Therefore, a combination of GPR and electrical resistivity is a good method for surveying of suspective open waste dumping landfill area and it's depth.

• Proceedings of the Korean Society of Rural Planning Conference
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• 1996.03a
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• pp.17-20
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• 1996

지난 20여년 동안 급격한 도시화, 산업화를 추진하는 과정에서 대기와 물의 오염, 쓰레기 공해 등 자연환경의 훼손과 피폐화가 심각한 상태에 이르렀다. 또한, 과다한 농약. 비료의 투입과 농사료에 의한 축산으로 높은 농업 생산성을 이룩하였으나, 이로 인하여 토양오염과 하천과 지하수 수질오염, 식생, 곤충 등 생태계 파괴 등의 문제가 대두되고 있다. 최근, 수자원 함양, 수질 정화 등의 순기능으로 농업의 환경 기여 효과가 큰 것으로 발표되었다. 논으로 부터의 오염부하는 생활 오수나 공장폐수 등에 비하여 정성적으로는 미미한 것이 사실이며, 실제로 관개수로 유입되는 영양물질이 작물에 의하여 흡수되므로 물질 수지적 측면에서 수질정화 효과를 나타낸다는 개념이다. 그러나, 오염된 관개수와 함께 유입되는 물질과 영농 목적으로 투입되는 다량의 비료와 농약, 제초제 등의 독성 물질 등에 의한 생태 환경의 변화 등에 대한 영향 등에 관한 종합적 관점에서의 효과는 불분명한 것이 현실이다. 특히, 폭우시 농경지로부터 유출에 의한 토사유실과 영양 물질이 손실 등에 대한 정량적 평가가 부족하며, 이로 인한 유역에서의 수문, 수질, 생태환경 등을 정량적 분석이 부족한 것이 현실이다. 따라서, 농업유역에서의 수문과 물질순환과정을 정량적으로 분석하고, 이를 통하여 주요 오염원을 파악하고, 효과적인 조절방법 등을 위한 유역수질관리 기술개발과 함께, 경지와 주변 생태계에 미치는 영향 등을 극소화할 수 있는 종합적인 연구가 필요하다. 특히, 관개시설 등 농업기반조성사업에 따른 인위적인 수문환경으로 인한 농경지내에서의 수문.물질순환 기작의 변화 등을 고려한 수질 및 생태환경에 판한 종합적인 모니터링, 모델링 등의 접근이 필요한 것이다. 본 논문에서는 $.$95 농림수산특정연구 중 첨단연구과제로 추진 중인 농업생태환경 및 종합적 환경관리 시스템 개발연구의 목표와 내용, 범위 등을 소개하고, 농촌지역에서의 건전한 환경관리를 위한 유역관리기술 개발의 방향 등을 정리하도록 한다.