• Spatial Information Research
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• v.11 no.3
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• pp.241-249
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• 2003

The purpose of this paper is to provide the basic data to select the most proper site, which is essential for the economic activation of North Korea by means of the GIS tool. In this purpose, firstly, Nampo area is sampled as model case, classifying the factors into the natural environmental one and socio- cultural one. Secondly, to analyze the land use status and topographic status which is essential for natural environment factor. Besides USLE(Universal Soil Loss Equation), which is one of the disaster effect assessments, is being applied to suggest the selection method for minimizing the environment change by way of assuming the land effluence amount. The started could advance to prove the ideal model in selecting the most suitable site while minimizing the environmental change by means of the composite tool of GIS and USLE.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.5
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• pp.109-126
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• 2017

Universal soil loss equation (USLE) is used to estimate soil loss solely or employed in any hydrologic models. Since soil erosion has been an issue in South Korea for decades, the Ministry of Environment enacted a law to regulate soil erosion in 2012, which is the Notification of topsoil erosion status. The notification is composed of preliminary and field investigations, the preliminary investigation suggests to use USLE and provides USLE factors. However, the USLE factors provided in the notification was prepared at least 10 years ago, therefore it is limited to reflect recent climate changes. Moreover the current yearly USLE approach does not provide an opportunity to consider seasonal variation of soil erosion in South Korea. A GIS-based model was therefore applied to evaluate the yearly USLE approach in the notification. The GIS-based model employs USLE to estimate soil loss, providing an opportunity to estimate monthly soil loss with monthly USLE factor databases. Soil loss was compared in five watersheds, which were Geumgang, Hangang, Nakdonggang, Seomjingang, and Yeongsangang watersheds. The minimum difference was found at Seomjingang watershed, the yearly potential soil loss were 40.15 Mg/ha/yr by the notification approach and 34.42 Mg/ha/yr by the GIS-based model using monthly approach. And, the maximum difference was found at Nakdonggang watershed, the yearly potential soil loss were 27.01 Mg/ha/yr by the notification approach and 10.67 Mg/ha/yr by the GIS-based model using monthly approach. As a part of the study result, it was found that the potential soil loss can be overestimated in the notification approach.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.112-117
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• 2012

The Revised Universal Soil Loss Equation (RUSLE) is a revision of the Universal Soil Loss Equation (USLE). However, changes for each factor of the USLE have been made in RUSLE which can be used to compute soil loss on areas only where significant overland flow occurs. RUSLE which requires standardized methods to satisfy new data requirements estimates soil movement at a particular site by utilizing the same factorial approach employed by the USLE. The rainfall erosivity in the RUSLE expressed through the R-factor to quantify the effect of raindrop impact and to reflect the amount and rate of runoff likely is associated with the rain. Calculating the R-factor value in the RUSLE equation to predict the related soil loss may be possible to analyse the variability of rainfall erosivity with long time-series of concerned rainfall data. However, daily time step models cannot return proper estimates when run on other specific rainfall patters such as storm and daily cumulative precipitation. Therefore, it is desirable that cross-checking is carried out amongst different time-aggregations typical rainfall event may cause error in estimating the potential soil loss in definite conditions.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.37-44
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• 2018

Universal soil loss equation (USLE) had been employed to estimate potential soil loss since it was developed from the statewide data measured and collected in the United States. The equation had an origin in average annual soil loss estimation though, it was modified or improved to provide better opportunities of soil loss estimation outside the United States. The equation has five factors, most studies modifying them to adapt regional status were focused on rainfall erosivity factor and cover management factor. While the conservation practice factor (USLE P factor) is to represent distinct features in agricultural fields, it is challenging to find studies regarding the factor improvements. Moreover, the factor is typically defined using slopes. The factor defining approach was suggested in the study, the approach is a step-by-step method allowing USLE P factor definition with given condition. The minimum condition is slope and field location to provide an opportunity for using in any GIS software and to reflect regionally distinct features. If watershed location, slope, crop type, and mulching type on furrows are given, detailed definition of the factors are possible. The approach was developed from field survey in South-Korea, it is expected to be used for potential soil loss using USLE in South-Korea.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.101-112
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• 2006

A Geographic Information System (GIS) was developed to estimate basin-wide soil losses using the Universal Soil Loss Equation (USLE). It was applied to estimate the annual average soil losses from the Saemangeum watershed. The USLE factors for each subarea of uniform land use and treatments were estimated from the GIS routines from digital topographic maps, land cover and detailed soil maps. A routine was developed to estimate the averaged cropping management factors (C) of USLE for multi-cropping farmlands, based on cropping system records from the district offices. The resulting C factors ranged from 0.28 to 0.35 for multi-cropping areas. The estimated annual average soil loss was approximately 2.9 million tonnes. Typical soil losses from different land uses were 0.8 t/ha at paddies, 33.7 t/ha at uplands and 1.1 t/ha from forested mountains. It was also found that 6.0% of the arable land of the watershed possessed high risks of soil losses, and conservation measures were needed to reduce soil losses.

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.603-610
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• 2000

Climate factors such as rainfall, temperature, wind, humidity, and solar radiant heat affect soil erosion. Among those factors, rainfall influences soil erosion to the most extent. The kinetic energy of rainfall breaks away soil particles and the water flow caused by the rainfall entrains and transport them downstream. In order to estimate soil erosion, therefore, it is important to determine the rainfall erosivity. In this study, the annual average Rainfall Erosivity(R) in Korea, an important factor of the Universal Soil Loss Equation(USLE) and Revised Equation(RUSLE), has been estimated using the nationwide rainfall data from 1973 to 1996. For this estimation, hourly rainfall data at 53 meterological stations managed by the Meterological Agency was used. It has been found from this study that the newly computed values for R are slightly larger than the existing ones. It would be because this study is based on the range of rainfall data that is longer in period and denser in the number of gauging stations than what the existing result used. The final result of this study is shown in the form the isoerodent map of Korea.

• Journal of Wetlands Research
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• v.14 no.3
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• pp.317-328
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• 2012

The objects of this study are to perform appropriateness analysis of USLE(universal soil loss equation) model and to accumulate the data measured in field. The basin area of Bongdong station is $342.27km^2$. This study simulated sediment outflows in the basin and performed a comparative analysis of simulated outputs with actual measurement values. Also annual rainfall was used to calculate rainfall-runoff erosivity factor which can influence soil erosion. The calculation of annual average soil erosion was made by soil erosion maps. The maps with a resolution of ($30m{\times}30m$) were created by multiplication of factors(R, LS, K, C, P) from ArcView Map Calculator. In this paper, it was shown that soil erosion was not occur in the most of basin.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.162-177
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• 1998

Conentionally, LS factor for the USLE suggested by Wischmeier has been computed manually on topographic maps based on one dimensional approach. But outcomes of the equation could be severely affected by the convergence and divergence of surface runoff at complex terrains. Thus the objective of this research are to develop a method to automatically compute LS factor based on the multiple flow algorithm, and to test the accuracy of this method by comparing outcomes of this method to previous measurements or estimations of soil erosion. The program for the automatic calculation of LS factor was developed by utilizing Fox Pro 4.5, and outcomes of the program is designed to input to IDRISI. The accuracy test of LS factor was carried out by comparing the actual measurements of soil loss at two test sites in and around of Suwon. The calculated volume of soil erosion at Buju mountain, Mokpo, was also compared to the outcome of a previous research based on the LS factor calculated by the conventional onedimensional approach. The outcomes of this research are as follows. First, the computed L based on the multiple flow algorithm for concae slopes are greater than those of convex slopes,. Second, the estimated soil loss based on this method at the test site in Mokpo is much greater than the outcomes based on the conventional one-dimensional approach. It can e concluded that the application of this automatic calculation method of LS factor can improve the accuracy of USLE and facilitate soil erosion prevention methods.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.29-36
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• 2017

Universal soil loss equation (USLE) has been frequently employed to estimate potential soil loss in land since it was developed based on the statewide data measured and collected in the United States. The equation is an empirical model mainly used for U.S. soil, thus it has been recently modified to reflect Korean soil conditions and named as Korean Soil Loss Equation (KORSLE). The modified equation was implemented in ArcGIS software, and used for estimation of potential soil loss from 2003 to 2016 in the thirty-eight Water Protection Districts. Five out of the thirty-eight districts were identified as the area of potential soil erosion most severly. In those five districts, potential soil erosion were estimated to be more than 50 Mg/ha/year that requires site investigation under supervision of the Korean Ministry of Environment. Distinctive site characteristics were found in the potential soil loss estimation such that the districts of low potential soil loss had low five factors in the aggregate. However, if one of more factors are dominantly large, the potential soil loss significantly increased. This study provides a useful tool to identify the potential areas for soil erosion and the important factors that play an important role in the estimation process.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1586-1590
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• 2006

In order to calculate the actual erosion according to the universal soil loss equation (USLE) and to estimate the impact of land use on soil erosion in Saemangeum, it is important to know the C-factor. Based on the USLE crop-growth stages, the cover-management C-factors were calculated for the main crop and crop rotation systems by National Institute of Agricultural Science and Technology. Combining this result with statistical data about crop cultivation area and crop rotation systems, C-factors of each administrative district in Saemangeum watershed were calculated. The range of C-factors were between 0.28 and 0.35. High C-factor value was obtained with Gimje (C = 0.35) and small C-factor values were found in Wanju (C = 0.28) and Jeongeup (C = 0.29). With this result, calculated annual soil loss was 2,804,483 ton per year. Because of the lack of sufficient statistical data about crop rotation systems, further studies are required on collecting field survey data.