• 한국농공학회논문집
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• 제49권2호
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• pp.49-60
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• 2007

The alpine agricultural activities are usually performed at higher and steep areas in nature. Thus, significant amounts of soil erosion are occurring compared with those from other areas. Thus, the soil erosion induced environmental impacts in these areas are getting greater. The Doam watershed is located at alpine areas and it has been well known that the agricultural activities in the watershed are causing accelerated soil erosion and water quality degradations. Many modeling approaches were employed to solve soil erosion and water quality issues. In this study, the Soil and Water Assessment Tool (SWAT) model was utilized to simulate the hydrologic and sediment behaviors in the Doam watershed. In many previous modeling studies, the digital soil map and its corresponding soil properties were used without modification to reflect soil conditioning at many agricultural fields of the Doam watershed. Thus, the soil sample was taken at the agricultural field within the Doam watershed and analyzed for its physical properties. In this study, the digital topsoil properties in the agricultural fields within the Doam watershed were replaced with the soil properties for reconditioned soil analyzed in this study to simulate the impacts of using soil properties for reconditioned soil in hydrologic and sediment modeling at the Doam watershed using the SWAT model. The hydrologic component of the SWAT model was calibrated and validated for measured flow data from 2002 to 2003. The $R^2$ value was 0.79 and the EI value was 0.53 for weekly simulated data. The calibrated model parameters were used for hydrologic component validation and the $R^2$ value was 0.86 and the EI value was 0.74 for weekly data. For sediment comparison, the $R^2$ value was 0.67 and the EI value was 0.59. These statistics improved with the use of soil properties of the reconditioned soil in the field compared with the results obtained without considering soil reconditioning. The simulated sediment amounts with and without considering the soil properties of the reconditioned soil were 284,813 ton and 158,369 ton, respectively. This result indicates that there could be approximately 79% of errors in estimated sediment yield at the Doam watershed, although the model comparison with the measured data gave similar satisfactory statistics with and without considering soil properties from the reconditioned soil.

• 미생물학회지
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• 제34권3호
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• pp.132-136
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• 1998

자연환경의 미생물군집을 분자생태학적 방법으로 분석하기 위해서는 오염되지 않은 순수한 핵산의 분리가 필요하다. 해양퇴적물에서 핵산을 추출할 때 같이 추출되는 부식물질(humic substances)은 핵산중폭반응을 저해하기 때문에, 이를 제거하기 위한 네 가지의 방법, 아가로즈젤 전기영동후 용출, Sephadex G-75 젤, Hydroxyapatite 젤, 그리고 PVPP(poluvinylpolypyrrolidone) microspin column 방법에 대해 그 효율성을 비교하였다. 조산된 방법 중에서 PVPP microspin column을 이용하면 건조 퇴적물 1g당 $4.8{\mu}g$의 순수한 DNA를 신속하고 간편하게 얻을 수 있었고, 이 방법으로 분리된 DNA를 PCR의 주형으로 사용한 결과 16S rRNA 유전자의 거의 전 범위에 해당하는 1.5 kb 크기의 PCR 산물을 얻을 수 있었다.

• Water Engineering Research
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• 제5권2호
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• pp.55-68
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• 2004

The GLEAMS (Groundwater Loading Effects of Agricultural Management System, version 3.0) water quality model was used to predict hydrology and water quality and to evaluate the effects of soil types from a cattle-grazed pasture field of Bermuda-Rye grass rotation with poultry litter application as a fertilizer in North Alabama. The model was applied and evaluated by using four years (1999-2002) of field-measured data to compare the simulated results for the 2.71- ha Summerford watershed. $R^2$ values between observed and simulated runoff, sediment yields, TN, and TP were 0.91, 0.86, 0.95, and 0.69, respectively. EI (Efficiency Index) of these parameters were 0.86, 0.67, 0.70, and 0.48, respectively. The statistical parameters indicated that GLEAMS provided a reasonable estimation of the runoff, sediment yield, and nutrient losses at the studied watershed. The soil infiltration rates were compared with the rainfall events. Only high intensity rainfall events generated runoff from the watershed. The measured and predicted infiltration rates were higher during dry soil conditions than wet soil conditions. The ratio of runoff to precipitation was ranging from 2.2% to 8.8% with average of 4.3%. This shows that the project site had high infiltration and evapotranspiration which generated the low runoff. The ratio of runoff to precipitation according to soil types by the GLEAMS model appeared that Sa (Sequatchie fine sandy loam) soil type was higher and Wc (Waynesboro fine sandy loam, severely eroded rolling phase) soil type relatively lower than the weighted average of the soil types in the watershed. The model under-predicted runoff, sediment yields, TN, and TP in Wb (Waynesboro fine sandy loam, eroded undulating phase) and Wc soil types. General tendency of the predicted data was similar for all soil types. The model predicted the highest runoff in Sa soil type by 105% of the weighted average and the lowest runoff in Wc soil type by 87% of the weighted average

• 한국지리정보학회지
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• 제6권3호
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• pp.1-10
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• 2003

최근 수정범용토양유실공식을 활용한 토양침식 연구가 활발히 진행중에 있으나, 실측자료와의 비교가 어렵기 때문에 계산된 결과를 정량적으로 검증하지는 못하였다. 본 연구에서는 RUSLE 모형을 구성하고 있는 인자들을 GIS 격자분석기법으로 분석하였으며, 특히 1:250,000 개략토양도를 주로 활용하였던 기존의 연구와 달리 1:25,000 정밀토양도를 활용한 토양침식인자를 제시하였다. 그리고 RUSLE 모형으로 계산한 토양침식량의 검증을 위해 보성강 유역의 비퇴사량 실측자료를 이용하였으며, 토양도의 축척을 고려한 결과 1:25,000 개략토양도의 경우는 120m의 해상도가 적합한 것으로 평가되었고 1:25,000 정밀토양도를 고려한 경우는 150m 해상도가 적합한 것으로 평가되었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.41-46
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• 1998

The purpose of the study was changed of Flood Characteristics in Down stream of Keum River by the Keum River Estuary Dam Construction. The water surface slope of Kuem river after the Keum River Estuary Dam construction was steeper then before. The flood control capacity increase after construction. But, Increasing sediment in Kuem river will be decreased flesh reservoir volume for yield irrigation.

• 환경영향평가
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• 제25권6호
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• pp.525-531
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• 2016

본 연구는 2007년과 2014년 국가토지피복지도에 따른 토양유실량을 평가하기 위해 GIS와 토양유실공식(USLE)을 활용하였다. 토양유실량의 공간분포를 추정하기 위해 USLE 모델의 토지피복변화와 식생인자를 적용하였다. 하지만, 토양유실량은 토지피복지도의 적용방법과 연산과정에 따라 서로 다른 결과가 나타났다. 본 연구에서는 USLE 모델을 적용하기 위해서 환경부의 식생인자와 토지피복지도를 적용하여 2014년 강원도 내린천 유역의 인제스터디움 개발지역 토양유실량 발생을 비교하였다. 연구지역의 토양유실량 산정을 위해 토지피복도, 지형도, 토양도 그리고 강수량 등의 자료들을 사용하였다. 토지피복의 변화는 중분류와 세분류 지도에 의해 평가되었고, 토양유실량은 최대 두 배의 차이가 나타났다.

• 한국방재학회 논문집
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• 제9권6호
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• pp.119-124
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• 2009

본 연구에서는 토양침식성 인자, 사면경사길이 인자, 피복관리 인자 등 RUSLE 모형의 각종 인자들의 산정방법의 특성을 검토하고 산정방법간의 오차를 분석하고자 하였다. 또한, 42개의 강우사상에 대해 RUSLE모형을 강원 토사유출 시험유역에 적용하여 토사유출량을 산정하고 그 결과를 관측 토사유출량과 비교함으로써 모형의 적용성을 검토하였다. RUSLE모형의 각종 인자들에 대한 분석결과 피복관리 인자가 가장 민감한 것으로 나타났으며, 산지유역에 RUSLE를 적용하는 경우 식생의 영향을 반드시 고려할 필요가 있다. 또한 국립농업과학원 토양정보시스템의 토양통 자료를 이용하는 경우 현장토양 특성을 반영하지 못해 큰 오차가 발생하는 것으로 나타났다. 강우에너지 산정방법에 따라서는 최대 22.7%의 오차가 발생하는 것으로 나타났으며, 향후 보다 많은 자료를 이용하여 각 인자들을 검증할 필요가 있다.

• 한국지형학회지
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• 제26권3호
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• pp.69-85
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• 2019

Humans have been important driver to reconfigure the terrestrial surface of the Earth by altering its morphology and processes. The effect of human activities on the physical landscape, however, shows substantially uneven geographical patterns. Most of anthrogemorphoogical studies regarding human-induced denudation have focused on areas with a long history of human modifications such as humid landscapes, so the hypothesis is naturally a great human impact on landscapes. The effect of human activities on dryland Earth surfaces are far less commonly studied, although erosion is one of major concerns in arid and semi-arid region regarding land and water quality degradation. The urban metropolis of Phoenix, Arizona, USA provides an opportunity to explore the impact of the Anthropocene. The Phoenix metropolitan area rests on classic desert landforms, such as extensive pediments, alluvial fans and sand sheets. Human activities including cattle crazing, wildfire resulting from introduced grass species by human, and recent urbanization processes have impacted these classic desert landforms and altered geomorphic processes. The purpose of this paper, therefore, rests in examining Anthropocene in the geomorphology of the north-central Sonoran Desert. The objectives of this paper are: i) to understand the impact of the Anthropocene on the geomorphological processes and forms through field observations; ii) to quantify the magnitude of human impacts on landscape using a published two-decade long record of erosion dataset and natural background erosion dataset in submitted manuscript at the sprawling edge of the Phoenix metropolitan region; iii) to examine how geomorphic outcome can affect the sustainability of cities through the estimation of sediment yield under the condition of urban sprawl.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.148-148
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• 2019

The 2006 Millennium Ecosystem Assessment (MA) defines ecosystem services (ES) as "the benefits people obtain from ecosystems". Identifying where ES originates, whom it benefits and how it is changing over a period of time is critical in rapidly developing country like Nepal, where the risk of ES loss is high. In the context of various ecosystem services provided by watershed, this study, particularly deals with water yield, Soil loss and Carbon sequestration computation and evaluation in Bagmati Basin of Nepal. As Bagmati Basin incorporates capital city Kathmandu of nepal, land use change is significant over decades and mapping of ES is crucial for sustainable development of Basin in future. In this regard, the objectives of this study are 1) To compute the total and sub-watershed scale water yield of the basin, 2) Computation of soil loss and sediment retention in the basin, and 3) Computation of carbon sequestration in the basin. Integrated Valuation of Environmental Services and Tradeoffs (InVEST), a popular model for ecosystem service assessment based on Budyko hydrological method is used to compute Ecosystem services. The scenario of ES in two periods of time can be referenced for various approaches of prioritization and incorporation of their value into local and regional decision making for management of basin.

• 한국지반환경공학회 논문집
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• 제11권2호
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• pp.33-42
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• 2010

본 연구는 부산시에 위치한 하천퇴적물에 대한 현재의 오염상태와 혐기성 상태에서의 잠재메탄발생량을 평가하기 위해 실시하였다. 먼저 부산시 하천중 총 5곳을 선정하였고 대상하천의 퇴적물을 채집하였다. 그리고 퇴적물특성을 알아보기 위해 퇴적물의 화학적산소요구량, 강열감량, 총 유기탄소에 대해서 분석을 실시하였고 그 결과 각각 15.20~75.07mg $15.20{\sim}75.07mg\;g^{-1}$, 2.34~11.54%, 1.28~34.21%로 나타났다. 또한 실험실규모의 BMP Test를 실시하였고 그 결과 pH가 약간 증가하다가 약 7.11~7.35에서 평형을 이루었으며, C/N, 최종메탄 및 이산화탄소수율 그리고 생분해도는 각각 1.05~10.27, 10.1~179.4, 10.3~34.4, 4.0~30.1을 나타내었다. 그리고 최종메탄수율과 C/N비, 최종이산화탄소수율, COD, 강열감량, 총유기탄소와의 상관관계를 알아보기 위해 선형모델에 최소자승법을 적용해 평가하였고 그 결과, COD($r^2=0.7586$)와 강열감량($r^2=0.7876$)을 제외한 나머지 모든 항목에서 최종메탄수율과 높은 상관관계를 띔을 알 수 있었다($r^2=0.9795{\sim}0.9858$). 따라서 C/N 또는 TOC 분석결과를 통해 메탄발생수율을 예측 가능할 것으로 판단된다.