• 한국토양비료학회지
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• 제44권3호
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• pp.337-343
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• 2011

A particular empirical equation for rainfall kinetic energy is needed to compute rainfall erosivity, calculated by the annual sum of the product of total rainfall energy and maximum 30-min rainfall intensity. If rainfall kinetic energy equation was different, rainfall erosivity will be produced differently. However, the previous studies in Korea had little concern about rainfall kinetic energy equation and it was not clear which rainfall kinetic energy is suitable for Korea. The purpose of this study is to analyze and evaluate the difference of the rainfall erosivity based on different rainfall kinetic energy equations obtained from previous studies. This study introduced new rainfall erosivity factors based on rainfall kinetic energy equation of Noe and Kwon (1984) that is only regression model developed in Korea. Data of annual rainfall erosivity for 21 weather stations in 1980~1999 were used in this study. The result showed that rainfall erosivity factors by the previous equations had been about 10~20% overestimated than rainfall erosivity by Noe and Kwon (1984)'s equation in Korea.

• 한국지반환경공학회 논문집
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• 제19권12호
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• pp.15-23
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• 2018

우리나라에서 발생하는 대부분의 토양침식은 물에 의한 토양침식이며 강우와 밀접한 관계를 가진다. 강우로부터 발생하는 토양침식은 토지자원의 손실을 발생시키고 이후 하천에 유입되고 퇴적되어 하천수자원의 관리 및 이용에 많은 어려움을 주고 있다. 최근 기후변화의 영향으로 우리나라에서는 30mm/hr 이상의 집중호우의 발생횟수가 증가하고 있어 단기간에 토양침식이 발생할 가능성이 높아지고 있다. 본 연구에서는 강우의 물리적인 특성을 고려하기 위하여 누적분포함수를 이용하여 강우강도별 강우입자의 분포를 추정하고 단일 호우사상이 가지는 강우에너지를 계산하는 방법을 제안하고자 하였다. 강우에너지 산정공식을 개발하기 위하여 강우강도 0.254~152.4mm/hr에서 측정된 강우입자 자료를 이용하였다. 누적분포함수를 적용하여 산정된 강우에너지는 강우강도의 관계에서 멱함수형태로 증가하는 경향으로 나타났으며, 이 관계로 얻어진 식을 바탕으로 1~80mm/hr 강우강도의 강우 운동에너지를 산정한 결과 $0.03{\sim}48.26Jm^{-2}mm^{-1}$로 나타났다. 강우강도와 강우에너지의 관계를 바탕으로 강우에너지 식을 멱함수로 제시하였다. 본 연구에서 제안된 공식은 한시적으로 설치하는 침사지와 같은 시설물의 규모를 결정하는 계획의 토양침식량을 예측에 활용될 수 있을 것으로 판단된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.234-238
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• 2008

The energy conservation theory is introduced for investigating processes of runoff and soil erosion on the hillslope system changed vegetation condition by wildfire The rainfall energy, input energy consisted of kinetic and potential energy, is influenced by vegetation coverage and height. Output energy at the outlet of hillslope is decided as the kinetic energy of runoff and erosion soil, and mechanical work according to moving water and soil is influenced dominantly by the work rather than the kinetic energy. Relationship between output and input energy is possible to calculate the energy loss in the runoff and erosion process. The absolute value of the energy loss is controlled by the input energy size of rainfall because energy losses of runoff increase as many rainfall pass through the hillslope system. The energy coefficient which is dimensionless is defined as the ratio of input energy of rainfall to output energy of runoff water and erosion soil such as runoff coefficient. The energy coefficient and runoff coefficient showed the highest correlation coefficient with the vegetation coverage. Maximum energy coefficient is about 0.5 in the hillslope system. The energy theory for output energy of runoff and soil erosion is presented by the energy coefficient theory associated with vegetation factor. Also runoff and erosion soil resulting output energy have the relation of power function and the rates of these increase with rainfall.

• Membrane and Water Treatment
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• 제10권1호
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• pp.45-55
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• 2019

Climate change has significantly affected the rainfall characteristics which can influence the pollutant build-up and wash-off patterns from the catchment. Therefore, this study explored the influence of varying rainfall characteristics on urban and agricultural runoff pollutant export using statistical approaches. For this purpose, Mann-Kendall and Pettitt's test were applied to detect the trend and breakpoint in rainfall characteristics time series. In addition, double mass curve and correlation analysis were used to drive the relationship between rainfall-runoff and pollutant exports from both catchments. The results indicate a significant decreased in total rainfall and average rainfall intensity, while a significant increased trend for antecedents dry days and total storm duration over the study periods. The breakpoint was determined to be 2013 which shows remarkable trend shifts for total rainfall, average rainfall intensity and antecedents dry days except total duration. Double mass curve exhibited a straight line with significant rainfall-runoff relationship indicates a climate change effect on both sites. Overall, higher pollutant exports were observed at both sites during the baseline period as compared to change periods. In agricultural site, most of the pollutants exhibited significant (p< 0.05) association with total rainfall, average rainfall intensity and total storm duration. In contrast, pollutants from urban site significantly correlated with antecedent dry days and average rainfall intensity. Thus, total rainfall, average rainfall intensity and total duration were the significant factors for the agricultural catchment while, antecedents dry days and average rainfall intensity were key factors in build-up and wash-off from the urban catchment.

• 대한토목학회논문집
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• 제40권1호
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• pp.111-118
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• 2020

한국은 강우로 인해 발생되는 토양침식량을 정량적으로 예측하기 위해서 미국에서 유도된 강우운동에너지식을 지난 40년 동안 사용해왔다. 강우의 특성은 기후, 지역 및 시간에 의존하기 때문에 연구 지역에서 측정된 호우사상으로부터, 토양 침식을 일으키는 강우운동에너지의 특성을 분석해서 연구에 활용하는 것이 필요하다. 본 연구의 목적은 서울 지역의 강우운동에너지의 특성을 분석하기 위한 것으로서 서울에서 3년 동안 측정 한 파시벨 강우자료를 사용하였다. 본 연구는 파시벨로 측정한 자료 중 강우강도에 따른 강우운동에너지의 관계를 규명하는데 중점을 두었으며, 새로운 강우운동에너지식을 제안하였다. 또한, 기존에 국내 및 국외에서 개발된 강우운동에너지식과 본 연구에서 도출한 서울 지점에서의 강우운동에너지의 특성을 비교 분석하였다.

• 물과 미래
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• 제9권1호
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• pp.47-54
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• 1976

The research are intend to establish the design criteria for slopy upland reclamation, with protecting the loss of top-soil, Recently undertaken reclamation works for developing the slopy upland of 310,000 ha. have faced to the vagueness of their deign criteria. One of the most influencing factors to cause the soil erosion depends basically upon the kinematic energy of rainfall, which is developed by the rainfall intensity. Their relationship between the rainfall and its kinematic energy is expressed as EK=916+ 331 log I. Consequently, the study was carried out through analyzing each intensity of the independant rainfall through out the 14 rainfall stations. About 10,000 single storms self recording chart of more than 10mm of rainfall amout were collected and analyzed by computer. The results of research show their kinematic energy for the 14 stations, and will be available for the establishment of the design oriteria.

• 한국수자원학회논문집
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• 제48권7호
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• pp.595-604
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• 2015

강우에 의한 세류간 토양침식은 운동에너지를 갖는 빗방울이 지표면을 타격하여 발생하는 빗물튀김의 박리현상과 지표유출수의 면상흐름에 의한 토사입자의 운반으로 구분할 수 있다. 강우운동에너지는 토양입자를 토양체로부터 분리시키기 위한 강우의 잠재적인 능력의 지표로 널리 사용되고 있다. 본 연구에서는 강우운동에너지가 세류간 토양침식에 미치는 영향을 파악하기 위해 강우의 충돌을 제어하는 스트립 커버를 이용한 토양침식 강우모의 실험을 수행하였다. 강우모의에 의한 강우운동에너지는 자연강우에 비해 0.58배 규모로 재현되었다. 강우강도가 증가함에 따라 지표유출량은 증가하고 지표하유출량은 상대적으로 감소하였다. 지표커버가 없는 사면으로부터 발생한 지표유출량이 지표커버가 있는 경우에 비해 평균 1.82배 증가하였다. 강우운동에너지는 지표유출 및 지표하유출 발생시간에도 영향을 끼쳤다. 빗물튀김과 면상흐름의 상호작용으로 토사유출량이 3.6~5.9배 증가하였으며 그 증가폭은 강우강도의 증가에 따라 감소하였다. 단위수류력과 토사유출량의 관계분석 결과 강우운동에너지는 빗물튀김에 의한 토양입자의 분리침식을 증가시킬 뿐만 아니라 지표유출수 증가에 따른 토사이송능력을 가중시켜 토사유출량을 크게 증가시키는 것으로 확인되었다.

• 한국지형학회지
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• 제23권3호
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• pp.105-122
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• 2016

To evaluate the changes in the physical characteristics of open rainfall related to canopy effects and rainfall intensity in Korea, the terminal velocity of raindrops and drop size distributions(DSD) were continuously measured by an optical-laser disdrometer in an open site(Op) and in two forest stands(Th1: Larix leptolepis, Th2: Pinus koraiensis) during five rainfall events in 2008. The terminal velocity, DSD and two forms of kinetic energy(KE, $Jm^{-2}$ $mm^{-1}$; KER, $Jm^{-2}$ $h^{-1}$) of open rainfall drops were determined and were compared with those of throughfall drops under two different canopy heights. The effects of the canopy and rainfall intensity, together with wind speed, on the changes in drop size and kinetic energy of throughfall were evaluated. Throughfall drops were larger than open rainfall drops. The distribution of terminal velocities for the drop sizes measured at Th2 was lower than that at Op; however, at Th1 the distribution was similar to that at Op. The total kinetic energy of throughfall at Th1 and Th2 was higher than the total kinetic energy of open rainfall, and the kinetic energy distribution for the drop sizes wassimilar to the drop size distribution. The observed throughfall-KER at Th1 was lower than an estimate previously produced using a model. The overestimation from the modeled value at Th1 was likely to be due to overestimated values of a square root transformation of fall height and its coefficient in the model because the distributions of terminal velocity for the drop size measured at Th1 were similar to those of open rainfall.

• Nuclear Engineering and Technology
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• 제34권5호
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• pp.415-420
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• 2002

The previous dynamic food chain model was improved for the consideration of the influence of radioactive contamination to agricultural products due to rain during the environmental releases of radionuclides in a nuclear accident Wet interception coefficients for the agricultural plants were derived as a function of radionuclide and rainfall amount, and mathematical formulations of the previous model were modified. As a result, rain during accidental releases was influential in agricultural contamination. The contamination level of agricultural products decreased dramatically according to increasing rainfall amount. It means that predictive concentrations in agricultural products using the previous model, in which dry interception to the agricultural plants is only considered, can be overestimated. The influence of rainfall in agricultural contamination was the most sensitive for $^{131}$ I, and the least sensitive for $^{90}$ Sr among the radionuclides considered in this study.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.151-151
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• 2022

The impact of raindrops on the soil surface causes soil detachment, which may be estimated by measuring the kinetic energy (KE) of the raindrops. Since direct measurements of rainfall force on ground surfaces are not generally available, empirical equations are an alternative option to estimate KE from rainfall intensity (I), which has the greatest influence over soil erosion and is easily accessible. Establishing the optimal formulation for the relationship between kinetic energy and rainfall intensity has proven to be difficult. Thus, this research considered thirty-seven rainfall events observed from June 2020 to December 2021 using a laster optical disdrometer erected in Kyungpook National University to examine the characteristics of KE-I relationships. We concentrated our discussion on the formation of two different expressions of the KE, including KE expenditure (KE_exp) and KE content (KE_con). The following conclusions were drawn: (1) We employed statistical analysis to demonstrate that the KE_exp is more suitable expression for establishing an empirical rule between KE and I than the KE_con. (2) A power-law model was used to find the best correlation between KE_exp-I relationship, whereas the best match between KE_con and I were found using an exponential equation.