• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.191-200
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• 2015

This study was carried out to investigate coefficient and exponent of runoff energy in MUSLE for small forest watershed, Hwachoen watershed in Gangwon-do. For 15 rainfall events, runoff volume, peak discharge and sediment yield were measured and these data were used to calculate coefficient and exponent of runoff energy. The results of this study showed that $LS{\bullet}K{\bullet}C{\bullet}P$ factors of MUSLE were affected by slope steepness. The coefficient and exponent of runoff energy were validated with coefficient of efficiency of 0.92 and these values were suggested to 0.002 and 0.81 respectively. The comparison of the coefficients and exponents between Hwacheon and other forest watersheds showed that these values would reflect the effect of forest management within watershed.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2009.04a
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• pp.269-270
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• 2009

This study builds a sediment rating curve using the measured sediment yield and the simulated soil erosion by a GIS-embedded empirical model. Then the structured sediment rating curve is used to determine the SDR on a basin scale in southern Korea. The whole data(year of 2002-2008) are divided into two groups and the first group(year of 2002-2005) is used for calibration, while the other is used for validation. Two cases(rainfall amount and rainfall intensity) are analyzed to consider the rainfall runoff erosivity factor in simulating soil erosion. The results show the derived SDR provides reasonable accuracy and rainfall intensity gives better performance in calculating soil erosion than rainfall amount.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.124-128
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• 2011

토양유실 모델링의 중요한 입력자료인 강우침식인자는 분석자료, 호우사상의 분류, 강우 운동에너지식의 적용, 30분 최대 강우강도의 산정방법 등에 따라 연구자별로 결과값이 달라질 수 있다. 본 연구의 목적은 다양한 강우 운동에너지식에 따른 (R)USLE의 강우침식인자(R factor) 값의 차이와 정도를 비교 분석하기 위한 것이다. 이를 위해서 기상청으로부터 서울 지점에 대한 1960∼1999년 기간의 1분 단위 강우자료를 이용하여 5가지 강우 운동에너지식에 따른 강우침식인자를 각각 계산하였으며, 그 값을 비교 분석하였다. 연구결과 Wischmeier와 Smith(1978)의 강우 운동에너지식을 적용한 강우침식인자 값이 가장 크게 나타났고, Brown과 Foster(1987)의 식을 적용한 값이 이에 비해 약 10%, 노재경과 권순국(1984)의 식을 적용한 값이 약 20% 작게 평가되는 것으로 나타났다. 국내에서 개발된 유일한 강우 운동에너 지식인 노재경과 권순국(1984)의 강우 운동에너지식을 적용한 서울 지점의 강우침식인자는 6988.9MJmm/ha/hr/yr이었다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.102-114
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• 2003

The objectives of the paper are to evaluate cell based pollutant loadings for different storm events, to monitor the hydrology and water quality of the Baran HP#6 watershed, and to validate AGNPS with the field data. Simplification was made to AGNPS in estimating storm erosivity factors from a triangular rainfall distribution. GIS-AGNPS interface model consists of three subsystems; the input data processor based on a geographic information system. the models. and the post processor Land use patten at the tested watershed was classified from the Landsat TM data using the artificial neural network model that adopts an error back propagation algorithm. AGNPS model parameters were obtained from the GIS databases, and additional parameters calibrated with field data. It was then tested with ungauged conditions. The simulated runoff was reasonably in good agreement as compared with the observed data. And simulated water quality parameters appear to be reasonably comparable to the field data.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.294-294
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• 2016

세계 각국에서는 국가별, 지역별 전역적인 강우침식인자에 대한 연구를 지속하고 있다. 우리나라에서도 몇 차례에 걸쳐 남한 전역에 대한 강우침식인자를 규명하기 위한 연구가 이루어졌고, 그 결과물로서 등강우침식도가 제작된 바 있다. 그러나 현재까지 우리나라의 강우침식인자가 세계 각국에 비해서 어느 정도의 토양침식에 대한 잠재 위험성을 가지고 있는지에 대한 연구는 이루어지지 않았다. 본 연구는 국제 및 국내 학계에 보고된 자료를 토대로, 세계 각국의 강우침식인자를 수집하고, 우리나라의 강우침식인자와 비교하여 우리나라의 강우에 의한 토양침식 잠재위험성을 분석하기 위한 것이다. 이를 통해 현재 실무에 활용중인 강우침식인자 값에 대한 개선방안을 검토하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.430-430
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• 2022

20년 이상의 분단위 강우자료가 없는 지역에서는 연강수량, 월강수량, 일강수량 등을 이용하여 강우가식성지표를 추정하는 연구가 이루어지고 있다. 이중에서 월강수량을 이용한 연평균 강우가식성지표 추정방법은 Fouriner Index, Modified Index, IAS index, Modified IAS index 등 학계에서 다양한 모델이 제시된 바 있다. 국내에서는 1971 ~ 1999년 기간의 기상청 관측지점에 대한 평가가 일부 이루어진 바 있으나, 월강수량을 이용한 추정모델에 대한 후속 연구는 이루어지지 않았다. 본 연구에서는 1981 ~ 2020년 기간의 기상청 강우자료를 이용하여 월강수량 기반 강우가식성지표 추정모델의 적용성을 평가하기 위한 것으로, 선행 연구에서 기산정된 지점별 연평균 강우가식성지표 값을 바탕으로, 월강수량 기반의 기존 추정모델로 산정한 값을 비교 분석하였다. 이를 바탕으로 실무에서 활용할 수 있도록 월강수량을 이용하여 연평균 강우가식성지표를 추정할 수 있는 경험식을 업데이트 하여 제안하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.260-260
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• 2016

Soil erosion is a very serious problem from agricultural as well as environmental point of view. Various computer models have been used to estimate soil erosion and assess erosion control practice. Universal Soil loss equation (USLE) is a popular model which has been used in many countries around the world. Erosivity (USLE R-factor) is one of the USLE input parameters to reflect impacts of rainfall in computing soil loss. Value of R factor depends upon Energy (E) and maximum rainfall intensity of specific period ($I30_{max}$) of that rainfall event and thus can be calculated using higher temporal resolution rainfall data such as 10 minute interval. But 10 minute interval rainfall data may not be available in every part of the world. In that case we can use hourly rainfall data to compute this R factor. Maximum 60 minute rainfall ($I60_{max}$) can be used instead of maximum 30 minute rainfall ($I30_{max}$) as suggested by USLE manual. But the value of Average annual R factor computed using hourly rainfall data needs some correction factor so that it can be used in USLE model. The objective of our study are to derive relation between averages annual R factor values using 10 minute interval and hourly rainfall data and to determine correction coefficient for R factor using hourly Rainfall data.75 weather stations of Korea were selected for our study. Ten minute interval rainfall data for these stations were obtained from Korea Meteorological Administration (KMA) and these data were changed to hourly rainfall data. R factor and $I60_{max}$ obtained from hourly rainfall data were compared with R factor and $I30_{max}$ obtained from 10 minute interval data. Linear relation between Average annual R factor obtained from 10 minute interval rainfall and from hourly data was derived with $R^2=0.69$. Correction coefficient was developed for the R factor calculated using hourly rainfall data.. Similarly, the relation was obtained between event wise $I30_{max}$ and $I60_{max}$ with higher $R^2$ value of 0.91. Thus $I30_{max}$ can be estimated from I60max with higher accuracy and thus the hourly rainfall data can be used to determine R factor more precisely by multiplying Energy of each rainfall event with this corrected $I60_{max}$.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.357-360
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• 2005

Soil loss is widely recognized as a threat to farm livelihoods and ecosystem integrity worldwide. Soil loss prediction models can help address long-range land management planning under natural and agricultural conditions. Even though it is hard to find a model that considers all forms of erosion, some models were developed specifically to aid conservation planners in identifying areas where introducing soil conservation measures will have the most impact on reducing soil loss. Revised Universal Soil Loss Equation (RUSLE) computes the average annual erosion expected on hillslopes by multiplying several factors together: rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C), and support practice (P). The value of these factors is determined from field and laboratory experiments. This study calculated soil erosion using GIS-based RUSLE model in Imha basin and examined soil erosion source area using SPOT 5 high-resolution satellite image and land cover map. As a result of analysis, dry field showed high-density soil erosion area and we could easily investigate source area using satellite image. Also we could examine the suitability of soil erosion area applying field survey method in common areas (dry field & orchard area) that are difficult to confirm soil erosion source area using satellite image.

• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.1
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• pp.73-82
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• 1994

This paper presents the experimental results of runoff and soil losses from sloping runoff plots under three cropping practices. Twenty-nine runoff plots having slopes of 10, 20, and 30 percent in gradient, and lengths of 10, 20 and 30 meter, respectively, were cultivated with soybean, alfalfa, and fallow conditions during 1989~1990 seasons. Crop stages were grouped based on crop canopy conditions and the cropping management factors of the Univer- sal Soil Loss Equation were derived as ratios of the soil losses to fallow conditions. The results from this study are summarized as follows : 1. Annual rainfall erosivity factor at Ichun station varied from 127 to 1336, averaging 472 and 200 in 1989. The month variations reach the peak in July, being 19& 2. Canopy cover percent for soybean that was taken by a photographic method increased sharply during 30 to 80 days after seeding and the results were used to identify periods for the six crop stages. 3. Annual average runoff rates from soybean and alfalfa plots were 35 and 16 percent of those from fallow ones, respectively. The runoff rates decreased as the crops grew. 4. Soil losses from soybean and alfalfa plots were 14 and 16 percent of those from fallow plots. And the crop coefficients were proposed for different crop stages.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.169-173
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• 2010

토양침식은 농경지 면적의 감소 및 사태 유발, 토사의 하천 유입으로 인한 생태계 교란 및 오염물질 확산 등의 피해를 야기시킨다. 토양침식을 유발하는 가장 큰 인자는 일반적으로 강우로 알려져 있으며, 연구대상 지역의 토양침식량을 산정하기 위해서는 강우침식인자를 추정하는 과정을 거치게 된다. 이와 관련하여 정필균(1983), 박정환 등(2000)은 각각 1980년, 1996년 이전의 강우자료를 이용하여 우리나라 강우침식인자를 제시한 바 있으나, 기상청에서 제공하는 1시간 단위 강우량으로 30분 최대 강우강도를 추정하는 것이 제한되어, 근래에 들어서는 연강수량을 이용하여 강우침식인자를 산정할 수 있는 국외 추정식을 적용하는 연구사례가 늘고 있다. 본 연구는 기상청에서 제공하는 1시간 단위 강우자료를 바탕으로 각 호우사상별 30분 최대 강우강도를 추정하여 보다 정확한 연강우침식인자를 산출하기 위한 것으로서 강우의 스케일 성질을 이용하였다. 속초 지점의 2007년 강우자료를 바탕으로 각 호우사상의 1시간 최대 강우량을 하향스케일링 하여 30분 최대 강우강도를 산출하여 강우침식인자를 산정한 결과, 기존의 $EI_{30}$와 $EI_{60}$의 상관관계식 및 연강수량을 이용한 추정방법보다 더 합리적임을 알 수 있었다.