• Journal of the Speleological Society of Korea
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• no.89
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• pp.46-58
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• 2008

동굴 퇴적물의 형성과정은 1단계 기권 (Atmosphere): 빗방울 (H2O) 이 대기중에서 CO2의 혼합으로 산성비 (H2CO2)가 되어 석회암 (CaCO3)에 떨어져서 최초의 용식작용이 시작된다. 2단계 토양권 (Pedosphere): 산성비와 석회암성분이 합쳐 형성된 가용성 화합물 (Ca(HCO3)2)은 식생부식(植生腐植)에 의한 토양 (Humic acidic soils) 에 의해 기반암의 용식이 촉진 되어 지표에는 Karren과 석문 (석문(石門) Natural Bridge), 와지 (Dolines, Sinkholes) 지형을 형성시키고, 암석의 분순물은 지표에 남겨져서 결국 적색풍화토 (Residuum, Risidual Redish Soils) 를 만든다. 3단계 암권 (Lithosphere): 용식작용에 의해 지상에서 지하 로 확대되어진 모암의 균열을 타고, 지하의 공간이 지하수의 유입과 유출에 의해 점차 확대되어 동공형의 Conduites; Voids; Shaft 이라는 특수지형을 형성시키고,동굴의 천정으로부터 나온 Ca(HCO3)2 는 탄산염의 지속적인 분해 공급에 의해 동굴내에는 종류석, 석순, 유착석 (Speleothem)등의 새로운 동굴지형 (Speleoscape)을 조성하게 된다. 4단계 수권 (Hydrosphere): 동굴의 형성작용을 거친 물은 동굴지하수로 잔여 Calcite를 함유한 채로 유출 (Spring) 된다. 동굴을 떠난 잔여 Calcite는 또다시 하천유역에 침전시켜서 석회화 단구형의 집적지형 (Tufa Formation: Tufa Dam, Tufa Flowstone)을 최종적으로 동굴을 나와 외벽 이나 하천의 바닦에 형성하는 과정을 거치면서 카르스트 지형의 발달과정이 1차적인 순환을 마치게 된다.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.963-969
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• 2011

The river-bed sediments from the major river basins were analysed for the chemical and physical properties to evaluate environmental safety for the agricultural uses. The samples were taken from 16 sites of Han river, 36 of Geumgang river, 27 of Yeongsan river, and 140 of Nakdong river. The total of 219 samples from the 28 counties were taken from the surface of the sediments at the depth of 50 cm. The particle density of the sediments was greater than $2.63Mg\;m^{-3}$ and the whole range of the density was $2.60{\sim}2.69Mg\;m^{-3}$, the average particle size was 0.7 mm whereas the size range was 0.075~0.85 mm. The analyses of the particle sizes by basins showed that Han and Geumgang river had particle sizes of 0.075~0.85 mm, while Geumgang and Yeongsan river had particle sizes of 0.25~0.85 mm. Geumgang and Yeongsan river tended to have greater particle sizes. The average values of the chemical properties were 6.3 for pH, $0.16dS\;m^{-1}$ for EC, $8g\;kg^{-1}$ for organic matter, $101mg\;kg^{-1}$ for available phosphate, 0.39, 3.47, and $0.93cmol_c\;kg^{-1}$ for exchangeable potassium, calcium, and magnesium respectively. The greatest property at each basin was pH for Han river, Ec, available phosphate and exchangeable sodium for Geumgang river, organic matter, exchangeable calcium and magnesium for Yeongsan river, and exchangeable potassium for Nakdong river.

• Analytical Science and Technology
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• v.29 no.6
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• pp.293-299
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• 2016

$^{137}Cs$ was investigated in river bottom sediments located in South-Han River basin and it was compared with international case studies to estimate the concentration level of $^{137}Cs$ in river sediment of Korea. The obtained values of $^{137}Cs$ which was analyzed by gamma-ray spectrometry were in the range of <$MDA{\sim}3.80{\pm}0.14Bq/kg{\cdot}dry$ and similar to the $^{137}Cs$ activities in soil of Korea. According to international case studies, $^{137}Cs$ activities were between 3.7 to $15,396Bq/kg{\cdot}dry$, when pollutants such as nuclear power plant accidents and radiation leaks were present near the rivers. The $^{137}Cs$ activities showed a variety of distribution depending on the country, when pollution occurs and survey time. Also, $^{137}Cs$ activities of river sediments without pollution sources were mostly less than $10Bq/kg{\cdot}dry$ in other countries. It was comparable with the obtained $^{137}Cs$ activities in this study. The obtained values provide useful information on the background concentration of $^{137}Cs$ in river sediment and will be able to use a basis for determining contamination of $^{137}Cs$ in the river.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.271-281
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• 2001

The characteristics of the heavy metal contamination in the soils affected by the tailings of the Palbong mine have been studied. The soils in the studied area consist mostly of loam by the particle size analysis, but a little of it, located near the stream, consist of loamy sand to sandy loam, finally to loam downward. The organic contents of soils are significantly low aoom 2 percent and the pH is in acidic ranging 6.0 $\pm$ 0.1. The samples of the parent rocks, the normal soils, the tailings and the channel deposits from the studied area were chemically analysed. From the result, the heavy metal concenlration of the soils is a little Jow compared with that of the parent rocks, shows the hydrologic process of the surface and the groundwater. The contamination of the tailings from the ore mining are high in lead, copper and arsenic. In the channel deposits the concenlrations of lead and copper are abnormally high but that of arsenic is uniquely low. And most of heavy metal contamination are decreased with the distance from the mine. It is caused by the properties of the surface and the ground water during the process of the heavy metal migration. The correlation-coefficient between sand and silt contents and the concentrations of Cd, Cu and Pb are significant but the amounts of As and Hg are increased with the clay contents. The dispersion of the heavy metals with the distance shows that the concentrations of them in the soils sampled at distance of 100 m to 200 m along the stream started near the Palbong mine are extremely high compared with those from other distances. These discrepancies are significant in Cd, Cu, Pb and Hg, but low in As. All the samples contain below detection limit of Cr+6 In the present stream water the concentrations of the heavy metals are not detected. So, it is interpreted that the concentrations in the soils are caused by the activities of the mining during the operation and have been continued by the dispersion from the tailings since after the closure of the mining, especially by the surface and ground water. The concentrations are diminished with the distance from the mining site, but in the interval of 800-2000 m increases abruptly. In the soil samples counted on the dispersion direction by wind, the lowering of the concentration is relatively uniform with the distance from the mining site. So, the rapid increase of the heavy metal concentrations is presumed to have been caused by the ground-water movement. In the migration of the heavy metals, the groundwater conditions, such as pH, Eh, the contents of colloidal particles, and Mn and Fe oxides are closely involveo. Integrating with these factors, it is interpreted that the groundwater conditions which have caused the heavy metal contamination of the studied area are those that the pH is about 3 in oxidized conditions, the contents of the colloidal particles are low, and Mn and Fe oxides are not involved in the migration of the heavy metals. Meanwhile, the vegetables growing on the soils in the studied area are not affected by the contamination of the heavy metals.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.1
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• pp.10-20
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• 1998

Heavy metal contamination in subsurface soils and stream sediments at the Suggok mine area were investigated on the basis of major, trace and rare earth elements geochemistry and mineralogy. The Sanggok mine area is mainly composed of Cambro-Ordovician carbonate rocks. The mine had been mined for Pb-Zn-Fe and Au- Ag, but already closed in past. For major elements, especially Fe (mean value=18.58 wt.%) and Mn (mean value=4. 18 wt.%) are enriched in soils, and the average enrichment indices of soils and sediments are 6.84 and 1.54, respectively. The average enrichment index of rare earth elements are 0.92 of mining drainage sediments and 0.52 of subsurface soils on the tailing dam. Concentrations of minor and/or environmental toxic elements in those samples range from 29 to 3400 for As,1 to 11 for Cd, 35 to 292 for Cu, 50 to 1827 for Pb, 1 to 22 for Sb and 112 to 2644 for Zn. Extremely high concentrations (mean values) are found in subsurface soils on the tailing dam (As=2278, Cd=7, Cu=206, Pb=1372, Sb=14 and Zn=2231 ppm, respectively). Average enrichment index normalized by composition of non-mining drainage sediments is 2.42 in mining drainage sediments and 25.47 in subsurface soils on the tailing dam. Based on EPA value, enrichment index of toxic elements is 0.53 in non-mining drainage sediments, 1.84 in mining drainage sediments and 23.71 in subsurface soils on the tailing dam. As a results from X-ray powder diffraction method, mineral composition of soils and sediments near the mine area varied in part, and are calcite, dolomite, magnesite, quartz, mica, chlorite and clay minerals. With the separation of heavy minerals, soils and sediments of highly concentrated toxic elements included some pyrite, arsenopyrite, sphalerite, galena, goethite and hydroxide minerals on the polished sections.

• Economic and Environmental Geology
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• v.53 no.2
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• pp.133-145
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• 2020

Soil in mine waste-rock fields, and at the pithead, sediments and farmlands around an abandoned mine in the Chungcheong Province of South Korea were investigated to assess the distribution of metallic elements and to understand the scope of the pollution. Reddening was observed from the mine up to a distance of 61 m. Losses of waste rock around the mine were assessed over a section of 1800 ㎥. Yellowish precipitates on the bottom of a stream were identified as ferrihydrite and goethite. For anions, a mean sulfate ion level over 773.6 mg/L was found during August in the river water samples. Mine drainage at the site was shown to have a pH of 4.9 and a sulfate concentration of 1557.8 mg/L during the August rainy season. A possible cause of the metallic element contamination in the mine is waste-rock loss, because mine waste-rock is located on the slope in this area. In conclusion, the total soil area to be treated, based on the amount that exceeded the recommended Korean soil pollution levels, was assessed to be 10,297 ㎡.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.207-211
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• 2011

하천공사의 매립 및 준설 시 뿐만 아니라 최근에는 호우 시에도 발생하는 고농도 오탁수의 유출 확산으로 인하여 주변 수역의 수산자원 및 자연환경에 심각한 영향을 미치고 있다. 특히 유사는 하천과 호소에 유입되어 탁도를 증가시켜 수자원의 이용가치를 저하시키며, 박테리아나 각종 미생물의 이동 매개체가 되고 있다. 또한 퇴적된 유사는 유량이 증가하면 다시 침식되어 부유상태가 되며 이때에 영양염류나 독성물질이 재용출 되기도 하는 등 하천의 물리 및 토양환경의 장 단기적인 변화를 유발하는 원인이 된다. 결국 유사는 다양한 방식으로 하천과 호소의 생태환경에 큰 변화를 초래한다. 부유토사의 발생 가능한 피해의 범위와 정도는 유역의 부유토사 발생율과 하천, 호소 퇴적물의 성분종류와 입도분포, 그리고 유속에 따라 결정된다. 따라서 탁수의 영향범위를 예측하고, 악영향이 예측될 경우에는 탁도를 저하시킬 수 있는 오탁물질의 저하기법을 적용하여 그 대책을 수립하여야 한다. 현재 정부가 역점을 두고 있는 4대강 살리기 사업 중 하나인 하천 준설 사업 시 발생되는 고농도 오탁수는 주변 수역의 수자원 및 자연환경에 심각한 영향을 미치므로 자연환경의 보존, 해양자원을 보호하기 위하여 오탁물질의 제어가 반드시 필요한 실정이다. 기존의 오탁 저감시설이나 방법의 경우 오탁물질의 확산을 제어하는데 한계가 있고 오탁물질의 종류와 관계없이 일률적으로 시공함으로서 오탁제어 효과가 의문 시 되고 있다. 이러한 문제점을 개선하기 위하여 오탁물질의 확산 범위를 줄이고 침강효율을 높이는 방법을 찾아 오탁확산 제어 효율을 개선할 필요가 있다. 본 연구에서는 오탁물질 제어 시 2차 응집물로 인한 오염이 발생하는 않는 천연광물 제올라이트를 이용한 실내실험을 통하여 고농도 탁수의 탁도 저감효율을 파악하여 고농도 탁수의 탁도 저감에 대한 제올라이트의 적용 가능성을 살펴보았다. 4대강 살리기 사업 중인 OO강 OO공구의 OO보 현장에서 하천 준설 시 발생하는 고농도 탁수를 이온을 첨가한 제올라이트를 이용하여 확산제어에 관한 효과를 검토한 결과 2,000NTU 정도의 고농도로 유하하는 탁수에 대하여 제올라이트 혼합 후 20분이 경과한 시점에 제거효율이 90%이상으로 제올라이트의 탁수저감 효과가 대단히 크다는 것을 알 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.34-34
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• 2019

급격한 기후변화의 영향으로 강우의 발생패턴과 높은 강우강도를 갖는 호우의 발생빈도가 높아지고 있어, 짧은 시간동안 다량의 표토가 손실될 가능성이 증가하고 있다. 강우에 의한 표토손실은 다양한 영역에서 발생하는데, 특히 산지유역과 농경지에서 발생할 경우 산림자원의 손실과 작물을 재배할 수 있는 영역이 감소하는 문제를 가져오게 된다. 또한 침식된 표토가 하천으로 유입되면 퇴적으로 인한 통수능력 저하, 하천생태 교란 등의 다양한 문제가 나타나고 있다. 우리나라는 표토침식량을 추정하기 위하여 연평균 토양침식모델을 적용하고 있다. 이모형은 기본적으로 연평균 토양침식을 예측하기 위해 개발되어온 모형으로, 적용하고 있는 매개변수도 연평균 개념의 값을 가지고 있다. 따라서 이모형은 짧은 시간동안에 발생하는 호우사상으로 발생하는 표토침식을 예측하는데 한계를 가진다. 본 연구에서는 기후변화의 영향으로 나타나는 단기호우사상에 의한 표토침식을 예측하기 위해 외부에서 작용하는 침식요인인 강우강도를 고려하기 위하여, 강우입자의 물리적인 특성을 반영한 강우에너지 산정공식을 제시하였다. 또한 기 개발된 분포형 단기표토침식모형에 제안된 식을 적용하여 타당성을 검토하였다.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.221-233
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• 2014

Soil erosion, transportation, and sedimentation by water flow often occur in a stream. This excessive occurrence threatens the safety of hydraulic structures, and aggravates natural disasters like flood. To prevent soil disaster according to the soil erosion, it is necessary to predict accurate sediment outflow primarily. Besides, it is very important to choose appropriate models by basin characteristics, to estimate accurate quantity of related factors, and to acquire available hydrological data. Therefore, the purpose of this study is to estimate soil erosion amount and sediment amount according to rainfall-runoff by using rainfall, discharge, and sediment in the Seolmacheon experimental catchment. And, it proposed sediment delivery ratio of the Seolmacheon catchment by result of studying sediment delivery ratio. Hereafter, this study will estimate sediment delivery ratio by basin characteristics, and formulate the method of estimating soil erosion and sediment outflow in various conditions by applying the results in other catchments.

• Journal of Korea Water Resources Association
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• v.43 no.11
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• pp.995-1009
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• 2010

Accelerated soil erosion due to extreme climate change, such as increased rainfall intensity, and human-induced environmental changes, is a widely recognized problem. Existing soil erosion models are generally based on the gross erosion concept to compute annual upland soil loss in tons per acre per year. However, such models are not suitable for event-based simulations of erosion and deposition in time and space. Recent advances in computer geographic information system (GIS) technologies have allowed hydrologists to develop physically based models, and the trend in erosion prediction is towards process-based models, instead of conceptually lumped models. This study aims to propose an effective and robust distributed rainfall-sediment yield-runoff model consisting of basic element modules: a rainfall-runoff module based on the kinematic wave method for subsurface and surface flow, and a runoff-sediment yield-runoff model based on the unit stream power method. The model was tested on the Cheoncheon catchment, upstream of the Yongdam dam using hydrological data for three extreme flood events due to typhoons. The model provided acceptable simulation results with respect to both discharge and sediment discharge even though the simulated sedigraphs were underestimated, compared to observations. The spatial distribution of erosion and deposition demonstrated that eroded sediment loads were deposited in the cells along the channel network, which have a short overland flow length and a gentle local slope while the erosion rate increased as rainfall became larger. Additionally, spatially heterogeneous rainfall intensity, dependant on Thiessen polygons, led to spatially-distinct erosion and deposition patterns.