• 환경영향평가
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• 제21권3호
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• pp.339-352
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• 2012

Total maximum daily load have been implemented and indicated that nonpoint discharge coeffients in flow duration curve were 0.50 of Normal flow duration ($Q_{185}$) and 0.15 of low flow duration($Q_{275}$). By using SWAT, nonpoint discharge coefficients are studied with the conditions of the instream flow and the rainfall in two study areas. The nonpoint discharge coefficient average of BOD and TP for normal flows duration in 3 years are 0.32~0.36 and 0.28~0.31. For the low flow duration, the nonpoint discharge coefficient avergae of BOD and TP were 0.10~0.12 and 0.10~0.11. These are lower than the coefficients of total maximum load regulation. There are big differences between one of regulation and one of SWAT for the normal flow duration. With the consideration of rainfall condition, the nonpoint discharge coefficient of flood flow duration are influenced on the amount of rainfalls. However, the nonpoint discharge coefficients of normal flow duration and low flow duration are not effected by the rainfall condition. Since the spatial distribution and geomorphological characteristics could be considered with SWAT, the estimation of nonpoint discharge coefficient in watershed model is better method than the use of the recommended number in the regulation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.890-897
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• 2005

Stability of embankment is influenced on landfill condition, permeability, shear strength and soil engineering propensity and so on, and need examination in reply because is different according to change of soil property of foundation ground and permeability condition. Analyzed seepage behaviour by finite element method for embankment, and change permeability of base to analyze effect that permeability of ground water table formation before embankment and analyze seepage behaviour to typical embankment in this research. In the case of permeability of foundation ground is 10 more than landfill permeability, rise of groundwater table was changed slightly. Pore water pressure was decreased slowly in landfill after rainfall. The effect of permeability of foundation ground was effected in change of pore water pressure. For permeability of foundation ground is 10 more than landfill, stability of road landfill was small changed during rainfall. But in the case of permeability of base soil similar to landfill permeability, road landfill stability was large decreased during rainfall.

• 한국농공학회지
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• 제36권2호
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• pp.123-131
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• 1994

Experimental studies were conducted to make clear the soil moisture environment under the condition of paddy-upland rotational fields by investigating water-table depths and soil moisture contents during growing season of crops in two kinds of soil. The following results were obtained. 1.Although water-table depths fluctuated with the amount of rainfall in the experimental field, it seemed that the variation of vater4able depths in the paddy-upland rotational, field was strongly affected by the condition of locations on paddy fields. 2.It is recognized that the concept of sum of excess water depth(SEWxx) and sum of excess water day(SEDxx) can be used to represent the soil moisture stress index due to the fluctuation of water-table depths. 3.The results of this study clearly indicate that drainage in paddy-upland rotational field to maintain an optimum soil moisture content must be made by introducing the concept of block drainage which needs both subsurface drainage and intercept drainage around a field. 4.Soil moisture contents were affected by both the amount of rainfall and water-table depths, however, the moisture content for top soil showed higher correlation with the amount of rainfall while that for subsoil with water-table depths.

• 한국지반공학회논문집
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• 제27권2호
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• pp.27-34
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• 2011

본 연구에서는 강우 시 지반정수 변화에 따른 사면붕괴 모델결정에 관한 기초연구로서 강우재현장치를 활용한 모형실험을 실시하여 불포화 상태의 사면에 침투하는 강우에 대하여 지속강우특성과 투수특성을 고려하여 간극수압, 토압, 함수비의 변화에 따른 사면 거동에 대해 분석하였다. 연구결과 강우(50mm/h)가 지속적으로 발생됨에 따라 화강 풍화토의 간극수압은 상부에서 먼저 상승하기 시작하며, 이어서 중간부와 하부에서 간극수압이 상승하기 시작하였다. 표준사의 간극수압은 역으로 하부에서 상부로 간극수압이 상승하는 것을 확인할 수 있었으며 이 같은 원인은 표준사 와 화강풍화토의 투수계수의 차이로 판단된다. 실험결과 지반조건 별로 다른 차이가 있으나 약 60~75% 정도 포화될 경우와 누적강우량 120mm이상 지속 시 사면붕괴의 발생 위험성이 있는 것을 알 수 있었다.

• 한국농공학회논문집
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• 제59권2호
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• pp.69-79
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• 2017

In this study, we developed real-time urban stream discharge forecasting model using short-term rainfall forecasts data simulated by a regional climate model (RCM). The National Centers for Environmental Prediction (NCEP) Climate Forecasting System (CFS) data was used as a boundary condition for the RCM, namely the Global/Regional Integrated Model System(GRIMs)-Regional Model Program (RMP). In addition, we make ensemble (ESB) forecast with different lead time from 1-day to 3-day and its accuracy was validated through temporal correlation coefficient (TCC). The simulated rainfall is compared to observed data, which are automatic weather stations (AWS) data and Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA 3B43; 3 hourly rainfall with $0.25^{\circ}{\times}0.25^{\circ}$ resolution) data over midland of Korea in July 26-29, 2011. Moreover, we evaluated urban rainfall-runoff relationship using Storm Water Management Model (SWMM). Several statistical measures (e.g., percent error of peak, precent error of volume, and time of peak) are used to validate the rainfall-runoff model's performance. The correlation coefficient (CC) and the Nash-Sutcliffe efficiency (NSE) are evaluated. The result shows that the high correlation was lead time (LT) 33-hour, LT 27-hour, and ESB forecasts, and the NSE shows positive values in LT 33-hour, and ESB forecasts. Through this study, it can be expected to utilizing the real-time urban flood alert using short-term weather forecast.

• 한국수자원학회논문집
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• 제47권6호
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• pp.513-522
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• 2014

최근 도시화 및 기후변화에 의한 홍수피해의 증가로 인하여 이에 대응하는 방안으로 저영향개발(LID) 요소기술에 관하여 다양하게 개발이 되고 있다. 하지만 이러한 요소기술에 대한 효율을 검증할 수 있는 표준화된 검증방법 및 기기는 부재한 실정이다. 본 연구에서는 LID 기법에 대한 물순환의 효율성 검증이 가능한 강우-유출 모의장치를 개발하였다. 소유역 내 강우가 균등하게 분사될 수 있도록 강우공간분포실험 및 유입유량-유효우량 관계 실험을 통하여 강우를 검증하고 유입되는 강우와 이로 인해 발생되는 침투 및 지표유출 관계 실험을 실시하였다. 그 결과 노즐의 종류에 따른 적정유량범위와 RPM의 관계를 정리하였으며 강우-유출 모의장치를 이용한 실험을 통해 투수면과 불투수면에서의 강우 시의 수문학적 물순환(지표유출, 중간유출, 침투량)의 관계를 정량적으로 검증하였다.

• 한국지반공학회논문집
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• 제34권5호
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• pp.37-51
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• 2018

우리나라의 산지사면은 풍화잔류토 층의 깊이가 얕아 강우의 침투로 인한 사면파괴가 많이 발생한다. 이때 파괴면의 깊이는 얕고 토사층과 기반암의 경계면 근처를 통과하는 특징을 가지고 있다. 강우의 침투로 인한 불포화 토사사면의 불안정성에 중요한 영향을 미치는 지반 정수들은 큰 불확실성을 포함한다. 따라서 본 연구에서는 강우로 인한 사면파괴를 예측하기 위하여 지반의 수리학적 특성과 강도특성을 랜덤변수로 고려하는 몬테카를로 시뮬레이션에 의한 확률론적 해석 절차를 제안하였다. 일정한 강우강도에 대한 기반암이 얕게 존재하는 불포화 토사사면의 안정성 예측을 위하여 강우강도에 따른 사면 표면에서의 경계조건을 반영하여 Green-Ampt 모델을 수정하고 얕은 기반암의 경계조건을 도입하였다. 침투해석의 결과를 무한사면 해석에 적용하여 안전율을 계산하였다. 제안된 확률론적 해석법은 강우의 침투에 따른 사면의 시간 의존적 파괴확률을 계산할 수 있다.

• 대기
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• 제29권4호
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• pp.463-480
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• 2019

This study classified heavy rain types from K-means clustering for the hourly relationship between rainfall intensity and cloud top height over the Korean peninsula, and then examined their statistical characteristics for the period of June~August 2013~2018. Total rainfall amount of warm-type events was 2.65 times larger than that of the cold-type, whereas the lightning frequency divided by total rainfall for the warm-type was only 46% of the cold-type. Typical cold-type cases exhibited high cloud top height around 16 km, large reflectivity in the upper layer, and frequent lightning flashes under convectively unstable condition. Phenomenally, the cold-type cases corresponded to cloud cluster or multi-cell thunderstorms. However, two warm-type cases related to Changma and typhoon were characterized by heavy rainfall due to long duration, relatively low cloud top height and upper-level reflectivity, and the absence of lightning under the convectively neutral and extremely humid conditions. This study further confirmed that the forecast skill of rainfall could be improved by applying correction factor with the overestimation for cold-type and underestimation for warm-type cases in the Local Data Assimilation and Prediction System (LDAPS) operational model (e.g., BIAS score was improved by 5%).

• 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.

• 한국지반공학회논문집
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• 제31권5호
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• pp.47-58
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• 2015

본 연구에서는 2011년에서 2014년까지 최근 4년간 국내에서 발생한 사면재해에 대한 현장조사를 수행하고 재해발생지의 지질 및 강우자료를 수집하여 국내 사면재해 현황 및 유발강우와 지질특성을 분석하였다. 분석 결과, 변성암 지역에서 가장 많은 사면재해가 발생하였으며, 사면재해 중에서는 토석류가 가장 많이 발생한 것으로 나타났다. 월평균 강우량이 높을 때 사면재해도 증가하는 것으로 나타났으나, 대부분의 사면재해는 최대시간강우량이 내린 이 후 일정한 시간이 지나고 발생한 것으로 나타났다. 또한, 전반적인 사면재해 발생횟수는 1개월 이상의 장기강우와 관련이 있는 것으로 분석되었다.