• Journal of Environmental Impact Assessment
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• v.11 no.4
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• pp.271-280
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• 2002

The purpose of this study is to explore the hydrological impacts and soil loss variation due to the land use change of Namak New Town development area. The analysis of hydrological effects and soil loss variation has been carried out using GIS in this study. In order to estimate the peak runoff volume, the Rational Method which is the most popular technique to predict runoff amounts is used. To estimate the soil loss in the study area, Universal Soil Loss Equation(USLE), which is one of the most comprehensive and useful technique to predict soil erosion is adopted. The result of this study has shown that the peak runoff volume and the total soil loss increase according to the land use change. The peak runoff volume and the total soil loss have been increased about 2 times and about 48 times more than that of pre development. The increasing of the peak runoff volume can be effective erosion, flooding and so on. A careful city planning is the first essential step to minimize the environmental impacts and to construct the ecological city.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.208-213
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• 2007

When overland flow water is small and slow, it moves down a stream slowly and we use it as available resource. However, it could not only be good for nothing but arouse an inundation if a lot of runoff pour down to stream at a torrential rain. So it is important to know how much water to flow out and be stored in soil and on land in order to predict a flood and conserve soil and water quality. We intended to develop the prediction model of runoff in upland at a torrential rain and conducted lysimeter study in soybean cultivation and bare soil with 3 slopeness, 3 slope length and 5 soil texture from 1985 to 1991. The data of rainfall and runoff were used when daily rainfall was over 80 mm, the level of torrential rain warning. Minimum rainfall occurring runoff (MROR) was dependent on surface coverage and slope length. However soil texture and slopeness had a little influence on MROR. Runoff after MROR increased in proportion to precipitation which depended on surface coverage, soil texture and slope. Runoff ratio was larger in fine texture and bare soil than coarse soil and soybean coverage. Runoff ratio was in proportion to a square root of slope angle(radian) and reduced with slope length to converge a certain value. From these basis, we developed the prediction model following as $$Runoff(mm)=a(s^{0.5}+l^b)(Rainfall(mm)-80(1-e^{-bl}))$$ where a is a coefficient relevant soil hydraulic properties, b is a surface coverage coefficient, s is a slope angle and l is a slope length. The coefficient a was 0.5 in sandy loam and 0.6 in clay, and b was 0.06 in bare soil and 0.5 in soybean cultivation.

• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.231-235
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• 2004

To investigate removal effects of nutrients in stormwater runoff by soil of riparian protection zone, soil column experiment was conducted for 20 months. Artificial stormwater runoff containing phosphate and nitrate was applied on the surface of soil column twice a week, and phosphate and nitrate concentrations were measured from the leached water. Soil of riparian protection zone reduced the released amount of infiltrated water to the surrounding water. After infiltration of 1m depth of soil column, average removal rates of phosphate and nitrate were 97.7 % and 74.7 %, respectively. As main mechanisms of phosphate are adsorption to soil particle and utilization by plants, periodical replacement of soil and harvesting of plant at the end of growing season are required. For the removal of nutrients in stormwater runoff by the soil layer, soil of riparian protection zone has higher hydraulic conductivity to infiltrate stormwater. Sandy soil having hydraulic conductivity of about $1{\times}10^{-2}cm/s$ range might be appropriate for this purpose.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4B
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• pp.393-403
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• 2008

While characteristics of topography, soil, and vegetation coverage were surveyed, also surface runoff and soil erosion for each rainfall event were measured to analyze effect of change of land cover conditions in mountain areas, Yangyang, directly after wildfire. Fifteen rainfall events were taken in total during the survey period. The result of this survey appeared that the amount of surface runoff and soil erosion are a great difference between plots with rapidly recovered vegetation and bare plots after wildfire. The burned plots where vegetation recovered rapidly generated two times or more of surface runoff and soil erosion than control plots, as burned plots with bare soil showed about ten times of surface runoff and sediment than control plots. The result of correlation analysis between main parameters of the surface runoff and soil erosion presented that rainfall factors and vegetation factors had significant effects on runoff and soil erosion. The sensitivity of runoff and soil erosion showed specially high correlation with vegetation indices. If the land surface disturbed by wildfire are recovered by natural vegetation as time passes, runoff and soil erosion may be decreased gradually. Because runoff and soil erosion in the areas with rare vegetation or bare soil are generated continuously, the discriminated mediation strategies would be established as condition of each region.

• Journal of The Geomorphological Association of Korea
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• v.23 no.1
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• pp.77-85
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• 2016

To understand the difference of runoff discharge processes between Gwangneung deciduous and coniferous forest catchments, we collected hydrological data (e.g., precipitation, soil moisture, runoff discharge) and conducted hydrochemical analyses in the deciduous and coniferous forest catchments in Gwangneung National Arboretum in the northwest part of South Korea. Based on the end-member mixing analysis of the three storm events during the summer monsoon in 2005, the hillslope runoff in the deciduous forest catchment was higher 20% than the coniferousforest catchment during the firststorm event. Howerver, hillslope runoff increased from the second storm event in the coniferous catchment. We conclude that low soil water contents and topographical gradient characteristics highly influence runoff in the coniferous forest catchment during the first storm events. In general, coniferous forests are shown high interception loss and low soil moisture compared to the deciduous forests. It may also be more likely to be a reduction in soil porosity development when artificial coniferous forests reduced soil biodiversity. The forest soil porosity is an important indicator to determine the water recharge of the forest. Therefore, in order to secure the water resources, it should be managed coniferous forests for improving soil biodiversity and porosity.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.4
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• pp.85-93
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• 1998

In the 2nd year study of a 5 year project to evaluate the soil quality and develop the best management practices for mountaineous soils, 11 runoff plots were treated and monitored with respect to physical property of the soil, runoff and sediment discharge, and the following results were obtained. 1. Bulk density and porosity did not show any siginificant difference between experimental treatments. 2. Runoff was basically dependent on the soil's physical property and tillage. Up-and-down plots showed the highest runoff while contour plots the lowest runoff. 3. Sediment yield in the mountaineous soils was directly related to tillage and residue cover. Residue covered plots showed the lowest sediment yield and up-and-down plots the highest sediment yield. And it is recommended that the best management practices using till_age and residue cover for the mountaineous soils must be developed to protect soil quality and maintain agricultural productivity.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.260-267
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• 2010

As sloped farmland is subject to runoff and soil erosion and consequently require appropriate vegetative coverage to conserve soil and water, a field study was carried out to evaluate the impact of crop canopy coverage on soil loss and runoff from the experimental plot with three different textural types (clay loam, loam, and sandy loam). The runoff and soil loss were examined at lysimeters with 15% slope, 5 m in length, and 2 m in width for five months from May to September 2009 in Suwon ($37^{\circ}$ 16' 42.67" N, $126^{\circ}$ 59' 0.11" E). Red pepper (Capsicum annum L. cv. Daechon) seedlings were transplanted on three different dates, May 4 (RP1), 15 (RP2), and 25 (RP3) to check vegetation coverage. During the experimental period, the vegetation coverage and plant height were measured at 7 day-intervals and then the 'canopy cover subfactor' (an inverse of vegetation cover) was subsequently calculated. After each rainfall ceased, the amounts of soil loss and runoff were measured from each plot. Under rainfall events >100 mm, both soil loss and runoff ratio increased with increasing canopy cover subfactor ($R^2$=0.35, p<0.01, $R^2$=0.09, p<0.1), indicating that as vegetation cover increases, the amount of soil loss and runoff reduces. However, the soil loss and runoff were depending on the soil texture and rainfall intensity (i. e., $EI_{30}$). The red pepper canopy cover subfactor was more highly correlated with soil loss in clay loam ($R^2$=0.83, p<0.001) than in sandy loam ($R^2$=0.48, p<0.05) and loam ($R^2$=0.43, p<0.1) plots. However, the runoff ratio was effectively mitigated by the canopy coverage under the rainfall only with $EI_{30}$<1000 MJ mm $ha^{-1}hr^{-1}$ ($R^2$=0.34, p<0.05). Therefore, this result suggested that soil loss from the red pepper field could be reduced by adjusting seedling transplanting dates, but it was also affected by the various soil textures and $EI_{30}$.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.35-51
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• 1997

To clarify the effect of forest environmental changes (forest type difference and clearcut) on water storage capacity in soil and stream flow, watershed had been investigated in Pyungchang, Kangwon-Do during 1983∼1993. Hydrological datas such as runoff, monthly ratio of runoff to precipitation, runoff-duration, monthly runoff(by plenty, ordinary, low and scanty duration), total runoff, direct runoff by runoff components, bulk density, porosity, coarse pore, fine pore, permeability and effective water storage were obtained from Backokpo and Yimokjong watersheds. The monthly ratio of runoff to precipitation, runoff and runoff-duration were higher in Yimokiong than in Backokpo due to forest type difference. On compararing pre-treatment with trement period in two experimental watersheds, pre-treatment period was lower than treatment period. Physical properties of soil such as bulk density, porosity, permeability, and effective water storage capacity conditions were better during the pre-trement period than treatment period in the two experiment plots.

• KIEAE Journal
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• v.13 no.1
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• pp.9-15
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• 2013

This study aims to analyze, by forming an experimental area of artificial soil green area that is of equal scale and analyzing the characteristics of runoff water in accordance with the cross-section configuration, applied the benefits in an actual multi-housing case study complex. In examining the measurement test results of the runoff water infiltration amount and surface runoff amount of a low-profile type green area(Dish type) and a general type green area(Mound type), Dish type was seen to have 1.5-times higher runoff water infiltration amount than Mound type during heavy rainfalls and showed about a 50% reduction with respect to the surface runoff amount. In other words, artificial soil green area offers the benefit of reduction of surface runoff amount and suggests, in actuality even with a change to the cross-sectional configuration of artificial soil green area alone at the time of construction of multi-housings, the possibility of benefits and reduction of costs spent on existing rainwater management facilities.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.3
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• pp.29-40
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• 2003

The objective of the paper is to compute the half-month rainfall-runoff erosivity factor for revised universal soil loss equation (RUSLE). RUSLE is being used to develop soil conservation programs and identify optimum management practices. Rainfall-runoff erosivity factor (R) is a key input parameter to RUSLE. Rainfall-runoff erosivity factor has been calculated for twenty six stations from the nationwide rainfall data from 1973 to 2002 in south Korea. The average annual Rainfall-runoff erosivity factor at the analyzed stations Is between 3,130 and 10,476 (MJ/ha)ㆍ(mm/h). According to the computation of the half-month Rainfall-runoff erosivity factor for locations, 66-85% of the average annual R value has occurred during the summer months, June-August. The half-month R values from this study can be used for RUSLE.