• 한국농공학회논문집
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• 제53권3호
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• pp.53-58
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• 2011

This study is analyzed the characteristics of the soil erosion with the geotechnical conditions and rainfall conditions, such as the ground slope, the compaction ratio, rainfall intensity and duration of rainfall etc. To this ends, a series of model test are conducted on clayey sands. From the results, the variation of soil loss is analyzed with the geotechnical and the rainfall conditions. The amount of soil loss is decreased as the increase of compaction ratio and is increased as the ground slope, rainfall intensity and the duration of rainfall.

• 한국농공학회지
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• 제20권1호
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• pp.4599-4613
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• 1978

This study was intended to investigate the effects of bituminous material content of soil-cement mixtures on their durability. For the purpose, unconfined compressive strength test, Freeze-thaw test, and wet-dry test were performed with three types of soil. Each type of soil was mixed with three levels of cement content and each soil-cement mixture was mixed with four levels of bituminous material content. For the unconfined compressive strength test, Freeze-thaw test and wet-dry test, 324, 108, and 108-specimens were prepared respectively. Unconfined compressive strength was measured at age of 7-days, 14-days and 28-days using 108-specimens in each age. The soil-cement loss rate due to freeze-thaw and wet-dry were calculated after 12 cycles of test using 108-specimens in each test. The results are summarized as follows : 1. Optimum moisture content was increased with increase of cement content, but maximum dry density was changed irregulary with increase of the cement content. 2. The unconfined compressive strength was increased with increase of cement content, bituminous material content and curing age. Cement is more effective factor than bituminous material on unconfined compressive strength of soil-cement Mixture. 3. It is estimated as the most economical cement content that the recommended cement content of A.S.T.M. because increasing rate of unconfined compressive strength at age of 28-days was low when cement content is above the recommanded cement content of A.S.T.M. among all types of soil. 4. Although a portion of cement content is substituted for bituminous material, the necessary unconfined compressive strength can be obtained. 5. The soil-cement loss was more influenced by wet-dry than Freeze-thaw 6. The bituminous material is more effective on the decrease of soil-cement loss than increase of unconfined compressive strength 7. The void ratio of soil-cement mixture was changet irregularly with increase of cement content, but that was decreased in proportion to the increase of bituminous material content. 8. The regression equation between the unconfined compressive strength and soil-cement loss rate were obtained as table 7.

• 한국농공학회논문집
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• 제48권6호
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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.

• 한국토양비료학회지
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• 제18권4호
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• pp.373-377
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• 1985

토양유실(土壤流失)을 지배(支配)하는 토양특성(土壤特性)을 구명(究明)하기 위하여 사양토(砂壤土)와 미사질양토(微砂質壤土)에 친수성(親水性)인 Uresol과 소수성(疎水性)인 Bitumen을 처리(處理)하여 토양입단(土壤粒團)의 특성(特性)을 달리한 후, 인공강우하(人工降雨下)에서 토양유실량(土壤流失量)을 조사(調査)하였다. 강우시작후(降雨始作後) 초기(初期) 유거(流去)가 일어나는 시간(時間)은 소수성(疎水性)인 Bitumen처리(處理)에 의하여 빨라졌으며 친수성(親水性)인 Uresol처리(處理)에 의하여는 현저히 늦어졌다. Bitumen처리(處理)에 의(依)하여 유출량(流出量)은 증가되고 유출비(流出比)는 감소(減少)되었으나 Uresol처리(處理)는 유출량(流出量)과 유출비(流出比) 모두 감소(減少)시켰다. 토양유실(土壤流失)은 Uresol처리(處理)에 의(依)하여 1.7~23.6%로 크게 감소(減少)되었으며, Bitumen처리(處理)는 미사질양토(微砂質壤土)에서는 55.5%로 낮아졌으나 사양토(砂壤土)에서는 무처리(無處理) 보다 오히려 증가되었다. 토양구조(土壤構造)가 안정(安定)할수록 토양유실(土壤流失)이 크게 억제(抑制)되어 낮은 유실량(流失量)/유출양비(流出量比)를 나타내었으며 습윤각(濕潤角)-안정지수(安定指數)는 토양유실(土壤流失)과 대수함수적(對數函數的)인 상관(相關) ($r=-0.935^{**}$)이 있었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.85-88
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• 2002

This paper presents the result of the Water Erosion Prediction Project(WEPP) watershed scale model's application for prediction of sediment yield from a watershed which is comprised of hillslopes and channels and analyses of the soil loss from hillslopes and channels with crop practice and shape. To evaluate the model's application, the model is applied to a watershed that comprised of six hillslope and one channel, and the result was a good agreement with the observed values. The soil loss from hillslope was increased as the hills lope was under fallow conditions and slope length was longer. The soil loss from the channel was increased at the downstream for the concentration of flow.

• 한국환경과학회지
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• 제22권9호
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• pp.1079-1088
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• 2013

The objective of this paper is compare to landuse type for calculating peak flood and soil loss in rapidly expansion urban area. This study compares two landuse maps, including numerical landuse map and aerial photograph landuse map, for calculating the ratio of urban and agriculural area, curve number, time of concentration, peak flood discharge, and soil loss. It is found that flood discharge calculated using aerial photograph landuse map are larger than that calculated using numerical landuse map, and soil loss calculated using aerial photograph landuse map are smaller than that calculated using numerical landuse map. Results also indicate that landuse chage in rapidly expansion urban area significantly influences flood discharge and soil loss.

• 한국농공학회지
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• 제42권3호
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• pp.76-88
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• 2000

AGNPS model is applied in this study to analyze the changes of non-point source pollutant according to AMC condition using probable rainfall. Probable rainfall of H-dam area by Gumber's extreme value distribution is computed through frequency analysis for each return period. 35 coarse grids are subdivided into 134 find grids of finite differential network to analyze peak flow soil loss quantity and nutrients of study area and the modified CN estimation equation shows good result about rainfall events-peak flow relationship. And as the consequence of estimation of soil loss quantity for each rainfall event soil loss quantity shows 120%-170% of actual soil loss quantity Regression analysis for the observed and calculated values of flow T-P AMC has an important effect on nutrients concentration of outflow and it if found that the excessive fertilization under AMC III condition may cause eutrophication by nutrients because the range of increase of outflow concentration appears relatively high.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권3호
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• pp.52-64
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• 2020

The universal soil loss equation (USLE), a model for estimating the potential soil loss, has been used not only in research areas but also in establishing national policies in South Korea. Despite its wide applicability, USLE cannot adequately address the effect of seasonal variances. To overcome this limit, the ArcGIS-based Sediment Assessment Tool for Effective Erosion (ArcSATEEC) has been developed as an alternative model. Although the field-scale (< 100 ㎡) application of this model produced reliable estimation results, it is still challenging to validate accuracy of the model estimation because it only estimates potential soil losses, not the actual sediment yield. Therefore, in this study, a method for estimating actual soil loss based on the ArcSATEEC model was suggested. The model was applied to eight watersheds in South Korea to estimate sediment yields. Correction factor was introduced for each watershed, and the estimated sediment yield was compared with that of the estimated yield by LOAD ESTimator (LOADEST). Sediment yield estimation for all watersheds exhibited reliable results, and the validity of the proposed correction factor was confirmed, suggesting the correction factor needs to be considered in estimating actual soil loss.

• 한국환경복원기술학회지
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• 제3권4호
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• pp.52-59
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• 2000

This study was carried out to find out effect of by-product gypsum on reducing soil erosion at the sloping burned area at Sampo-ri, Gosung-gun in Kangwon-province during the period between June 28 and Sept. 30, 2000. Four experimental plots ($1.2m{\times}10m$) were prepared at the study area with slopes $15^{\circ}{\sim}18^{\circ}$ where forest fire took place twice during last 4 years. Phosphogypsum (PG) was applied to the soils of the 4 plots at the rates of 0 (control), 5, 7.5, and 10 ton/ha, respectively. Amount of rainfall, runoff, and soil loss were measured 7 times during the study. In the beginning, the amounts of runoff and soil loss from the PG treated plots were not different from those from the control plot due to steepness of the plots. However, the difference between the amount of runoff and soil loss from the PG treated plots and those from the control became apparent over time. The effect of PG treatment lasted until at least 870 mm of rainfall. Compared to the cumulative runoff from the control plot, the cumulative runoff from the plots treated with 5, 7.5, and 10 ton/ha PG decreased 7%, 31 %, and 35%, respectively. The cumulative soil loss from the plots treated with 5, 7.5, and 10 ton/ha PG decreased 44%, 53%, and 77% compared to that from the control plot. Strong acidity of PG (pH 2.0~2.5) did not affect the acidity of the soil and runoff.

• 한국토양비료학회지
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• 제44권6호
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• pp.1004-1009
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• 2011

Soil erosion in North Korea has been continued to accelerate by deterioration of topographical conditions. However, few studies have been conducted to predict the amount of soil loss in North Korea due to limited data so far. Rainfall erosivity is an important factor to predict the amount of long-term annual soil loss by USLE (universal soil loss equation). The purpose of this study is to investigate rainfall erosivity, which presented the potential risk of soil erosion by water, in North Korea. Annual rainfall erosivities for 27 stations in North Korea for 1983~2010 were calculated using regression models based on modified Institute of Agricultural Sciences (IAS) index in this study. The result showed that annual average rainfall erosivity in North Korea ranged from 2,249 to 7,526 and averaged value was $4,947MJmm\;ha^{-1}\;hr^{-1}\;yr^{-1}$, which corresponded to about 70% of annual average rainfall erosivity in South Korea. The finding was that the potential risk of soil erosion in North Korea has been accelerated by the increase of rainfall erosivity since the late 1990s.