• 한국지형학회지
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• 제28권2호
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• pp.31-44
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• 2021

Due to recent climate change, continuous soil loss is occurring in the mountainous watershed. The development of geographic information systems allows the spatial simulation of soil loss through hydrological models, but more researches applied to the mountain watershed areas in Korea are needed. In this study, prior to simulating the soil loss characteristics of the mountainous watershed, the field monitoring and the SWAT and GeoWEPP models were used to simulate and analyze the rainfall and runoff characteristics in the mountainous watershed area of Jirisan National Park. As a result of monitoring, runoff showed a characteristic of a rapid response as rainfall increased and decreased. In the simulation runoff results of calibrated SWAT models, R², RMSE and NSE was 0.95, 0.03, and 0.95, respectively. The runoff simulation results of the GeoWEPP model were evaluated as 0.89, 0.30, and 0.83 for R², RMSE, and NSE, respectively. These results, therefore, imply that the runoff simulated through SWAT and GeoWEPP models can be used to simulate soil loss. However, the results of the two models differ from the parameters and base flow of actual main channel, and further consideration is required to increase the model's accuracy.

• 한국제4기학회:학술대회논문집
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• 한국제4기학회 2005년도 하계학술대회
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• pp.7-11
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• 2005

The soil erosion processes have estimated using spatial distribution of 137Cs radionuclide in Granite and Sedimentary Hillslopes in South Korea. The local variability of 137Cs inventory indicates that was related positively to organic matter content, clay content and water content and negatively to hydraulic permeability and slope gradient for bulk samples in different landforms within Granite and Sedimentary rock basins. The vertical variability of 137Cs inventory shows that most of 137Cs concentration and organic matter were accumulated between 0 and 2cms and gradually decrease with soil depth in incremental samples in both basins. The vertical variability of 137Cs inventories shows that 137Csinventories increase as we go to toward downslope in both basins. Finally, the soil loss values indicate that hillslope erosion processes are more intensive in Granite rock basin than those in Sedimentary rock basin.

• Coupled systems mechanics
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• 제3권2호
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• pp.213-232
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• 2014

Pounding is a major cause of bridge damage during earthquakes. In an extreme situation, it can even contribute to the unseating of bridge girders. Long-span bridges will inevitably experience spatially varying ground motions. Soil-structure interaction (SSI) may play a significant role in the structural response of these structures. The objective of this research is to experimentally investigate the effect of spatially varying ground motions on the response of a three-segment bridge considering SSI and pounding. To incorporate SSI, the model was placed on sand contained in sandboxes. The sandboxes were fabricated using soft rubber in order to minimise the rigid wall effect. The spatially varying ground motion inputs were simulated based on the New Zealand design spectra for soft soil, shallow soil and strong rock conditions, using an empirical coherency loss function. The results show that with pounding, SSI can amplify the pier bending moments and the relative opening displacements.

• Earthquakes and Structures
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• 제2권3호
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• pp.207-232
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• 2011

The development of reliable earthquake mitigation plans and seismic risk management procedures can only be based on the establishment of comprehensive earthquake hazard and loss scenarios. Two cities, Grevena (Greece) and D$\ddot{u}$zce (Turkey), were used as case studies in order to apply a comprehensive methodology for the vulnerability and loss assessment of lifelines. The methodology has the following distinctive phases: detailed inventory, identification of the typology of each component and system, evaluation of the probabilistic seismic hazard, geotechnical zonation, ground response analysis and estimation of the spatial distribution of seismic motion for different seismic scenarios, vulnerability analysis of the exposed elements at risk. Estimating adequate earthquake scenarios for different mean return periods, and selecting appropriate vulnerability functions, expected damages of the water and waste water systems in D$\ddot{u}$zce and of the roadway network and waste water system of Grevena are estimated and discussed; comparisons with observed earthquake damages are also made in the case of D$\ddot{u}$zce, proving the reliability and the efficiency of the proposed methodology. The results of the present study constitute a sound basis for the development of efficient loss scenarios for lifelines and infrastructure facilities in seismic prone areas. The first part of this paper, concerning the estimation of the seismic ground motions, has been utilized in the companion paper by Kappos et al. (2010) in the same journal.

• 한국물환경학회지
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• 제26권5호
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• pp.841-849
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• 2010

Soil erosion is an natural phenomenon. However accelerated soil erosion has caused many environmental problems. To reduce soil loss from a watershed, many management practices have been proposed worldwide. To develop proper and efficient soil erosion best management practices, soil erosion rates should be estimated spatially and temporarily. The Universal Soil Loss Equation (USLE) and USLE-based soil erosion and sediment modelling systems have been developed and tested in many countries. The Sediment Assessment Tool for Effective Erosion Control (SATEEC) system has been developed and enhanced to provide ease-of-use interface to the USLE users. However many researchers and decision makers have requested to enhance the SATEEC system for simulation of soil erosion and sediment reflecting effects of single storm event. Thus, the SATEEC R factors were estimated based on 5 day antecedent rainfall data. The SATEEC 2.1 daily R factor was applied to the study watershed and it was found that the R2 and EI values (0.776 and 0.776 for calibration and 0.927 and 0.911 for validation) with the daily R were greater than those (0.721 and 0.720 for calibration and 0.906 and 0.881 for validation) with monthly R, which was available in the SATEEC 2.0 system. As shown in this study, the SATEEC with daily R can be used to estimate soil erosion and sediment yield at a watershed scale with higher accuracy. Thus the SATEEC with daily R can be efficiently used to develop site-specific soil erosion best management practices based on spatial and temporal analysis of soil erosion and sediment yield at a daily-time step, which was not possible with USLE-based soil erosion modeling system.

• 한국지리정보학회지
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• 제19권4호
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• pp.130-145
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• 2016

본 연구에서는 1분 상세강우자료를 이용하여 개정범용토양유실공식(RUSLE)의 강우침식도 R의 추정을 위해 2002년부터 2015년까지 14년간 전국 기상청 관측소의 강우 자료를 수집하여 지점별로 새롭게 계산한 연 강우침식도 및 경험식을 산정하였으며 남한전체($99,720km^2$)를 대상으로 연강우침식인자의 공간분포도를 작성하였다. 1분 강우자료로 계산된 강우침식도와 연평균 강우량의 상관관계로부터 도출된 경험식과의 결정계수($R^2$, determination coefficient)는 0.70~0.98로 높은 상관관계를 나타냈으며 이는, 기존의 국내에서 적용된 경험식과 비교하여 실측값과의 정확성이 높게 개선됨을 알 수 있다. 또한, 물리적인 지리요소가 고려된 공간 강우침식인자(R) 분포도를 산정하기 위해 고도가 고려된 공간보간기법(IDW)을 이용하여 연강우량 분포도를 산정하였다. 최종적으로 본 연구에서의 1분 강우자료부터의 R 산정 및 1시간 강우자료와의 회귀산정 과정의 방법 및 절차를 일반 사용자가 간단하게 사용 할 수 있도록 Python GUI 프로그램을 이용하여 R 산정 프로그램을 개발하였다.

• 대한원격탐사학회지
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• 제35권6_4호
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• pp.1351-1361
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• 2019

본 연구에서는 금강 유역(대청댐~금강하구둑)을 대상으로 RUSLE (Revised Universal Soil Loss Equation)를 활용하여 하천정비사업 전(2007년)과 후(2015년)의 연간 표토 침식량을 계산하였고, 이를 5단계의 class를 구분하여 해당 구간 별 표토침식면적을 산출하고 그 결과를 환경부의 토지피복 변화와 비교·분석하였다. RUSLE을 구성하는 각 인자를 생성하기 위하여 2007년과 2015년의 토지피복도, 국가기본 공간정보, 정밀 토양도, 연평균 강수량 자료 등의 다양한 공간정보자료를 활용하였다. 연구 결과, 연구지역에서의 연간 표토 침식량은 2007년과 대비하여 2015년에 class 1의 면적은 증가하였고, class 2, 3, 5의 면적은 감소하였으며, class 4의 면적은 증가하였다. 이러한 원인으로는 연구지역의 연평균 강수량의 감소, 생태공원조성과 이로 인한 인공시설물 확대, 농경지 감소 등으로 인하여 대부분의 지역에서 연평균 표토 침식량이 감소된 것으로 사료된다.

• 농촌계획
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• 제10권1호
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• pp.19-26
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• 2004

In this paper, forestry area change effect on the soil erosion in Asan lake watershed was estimated. Temporal variations of land use in the study watershed were analyzed from Landsat-5 TM remote sensing images. Geographic Information System (GIS) combined with Universal Soil Loss Equation (USLE) was used to estimate the soil erosion of Asan lake watershed. Spatial data for each USLE factors was obtained from the Landsat-5 TM remote sensing images and 1/25,000 scale digital contour maps. Sediment yield to Asan lake was estimated by sediment delivery ratio and sediment accumulation in lake was estimated by trap efficiency. The estimation methods were validated for sediment accumulation in Asan lake. From the hydrographic survey from 1974 to 2003 for Asan lake, sediment accumulation was measured. The estimated accumulation sediment of 303,569ton/yr showed similar value with observed of 295,888ton/yr. From the validated estimation methods, the increasing amount of soil erosion when 1% of forest area in Asan lake watershed decreases was calculated from 12.91 to 1482.05ton/yr.

• 한국지반환경공학회 논문집
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• 제20권12호
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• pp.33-39
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• 2019

The upsurge of population, internal migration, economic activities and developmental works has brought significant land use and land cover (LULC) change over the period of 1990 and 2010 in the Bagmati basin of Nepal. Along with alteration on various other ecosystem services like water yield, water quality, soil loss etc. carbon sequestration is also altered. This study thus primary deals with evaluation of LULC change and its impact on the soil carbon storage for the period 1990 to 2010. For the evaluation, InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) Carbon model is used. Residential and several other infrastructural development activities were prevalent on the study period and as a result in 2010 major soil carbon reserve like forest area is decreased by 7.17% of its original coverage in 1990. This decrement has brought about a subsequent decrement of 1.39 million tons of carbon in the basin. Conversion from barren land, water bodies and built up areas to higher carbon reserve like forest and agriculture land has slightly increased soil carbon storage but still, net reduction is higher. Thus, the spatial output of the model in the form of maps is expected to help in decision making for future land use planning and for restoration policies.

• 대한토목학회논문집
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• 제35권1호
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• pp.111-117
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• 2015

본 연구에서는 강우의 공간분포에 따른 토사유출의 특성을 토조 실험을 통해 탐구하였다. 강우의 공간분포는 강우 집중위치를 사면의 중앙부와 상류부로 각각 설정함으로 조정하였다. 토사유출의 시간적 변동성을 충분히 포착하기 위해 장시간(8 시간)의 실험시간 동안 높은 시간해상도(10 분)로 직접유출량, 지하수유출량, 토사유출량을 측정하였다. 그 결과, 강우를 토조의 상류부에 위치시킬수록 토사유출량곡선의 첨둣값은 감소하고 누적토사유출량은 증가하였다. 누적토사유출량은 시간에 따라 선형적으로 증가하였으나, 그 증가율이 2 시간을 기준으로 급격히 감소하였다. 이러한 점은 현재 총량 위주로 기록되어있는 토사유출 실측자료를 사용함에 있어 고려해야 할 사항이라고 결론지을 수 있다. 본 연구 결과는 또한, 향후의 토사유출량 실측은 높은 시간해상도로 측정될 필요가 있음을 시사한다.