• 기술사
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• 제18권2호
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• pp.1-5
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• 1985

In the flood prediction research, it is pointed out that the difficulty of flood prediction is the frequently experienced overestimation of flood peak. That is caused by the rainfall prediction difficulty and the nonlinearity of hydrological phenomena. Even though the former reason will remain still unsolved, but the latter one can be possibly resolved the method of the AMRA (Auto Regressive Moving Average) model for each runoff component as developed by Dr. Hino and Dr. Hasebe. The principle of the method consists of separating though the numerical filters the total runoff time series into long-term, intermediate and short-term components, or ground water flow, interflow, and surface flow components. As a total system, a hydrological system is a non-linear one. However, once it is separated into two or three subsystems, each subsystem may be treated as a linear system. Also the rainfall components into each subsystem a estimated inversely from the runoff component which is separated from the observed flood. That is why flood prediction can be done without rainfall data. In the prediction of surface flow, the Kalman filter will be applicable but this paper shows only impulse function method.

• 한국수자원학회논문집
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• 제31권6호
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• pp.833-844
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• 1998

본 연구의 목적은 융설모형을 국내에 도입하고 이를 강우-유출모형과 결합하여 우리나라 북부 산간지방의 장기 유출해석을 위한 융설의 영향을 고찰하는데 있다. 선택된 모형은 미국 국립기상청의 온도지수 융설모형이며, 이를 유연면적이 1,059.6$\textrm{km}^2$ 인 내린천 유역에 적용.검토하였다. 모형에 의해서 계산된 강설의 지역적 분포에 대한 시간적 변동성은 인제 측후소에서 관측된 강설량의 변동성과 잘 일치하는 것으로 나타났다. 또한 모형에 의해서 계산된 토양수분 및 하천유량은 융설모형의 존재 유무에 따라 매우 다른 거동을 나타냄을 알 수 있었다. 따라서 본 연구의 융설모형은 국내의 상황에 적합한 것으로 생각되며, 본 연구 대상지역의 장기 유출해석시 융설의 영향은 중요한 것으로 판단된다.

• 한국농림기상학회지
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• 제13권4호
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• pp.157-164
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• 2011

침엽수인공림에서 임분 성장 및 간벌이 장기 물수지에 미치는 영향을 파악하기 위하여 광릉 침엽수인공림유역 및 활엽수천연림유역에서 1982년부터 2009년까지 28년에 걸쳐 관측한 연강수량 및 연유출량의 변화를 분석하였다. 광릉 침엽수인공림유역은 1976년에 유역 전반에 걸쳐 잣나무와 전나무, 리기다소나무가 3,000본/ha의 밀도로 식재되었으며, 1996년에 잔존 본수의 약 45%를 간벌하였다. 1982년부터 2009년까지의 기간을 광릉 침엽수인공림유역 내 침엽수림의 영급을 기준으로 4개 기간으로 구분하여 연평균 강수량 및 유출량을 비교한 결과, 활엽수천연림유역의 기간별 연평균 유출량은 강수량이 증가함에 따라 동일하게 증가하는 추세를 보였으나, 침엽수인공림유역에서는 임령증가 및 간벌 실시에 따라 증감을 반복하는 것으로 나타났다. 간벌을 실시하지 않은 침엽수인공림은 임령이 증가할수록 높은 식재밀도로 인해 수관울폐도가 과도하게 높아지고 이로 인해 수관차단 및 증산량 증가 등 물손실이 커진다. 본 연구에서도 간벌 실시전 침엽수인공림유역의 연평균 유출량이 감소하였으나 간벌 실시 후에는 간벌 전에 비해 연평균 유출량이 약 1.7배 증가하는 등 유출량 증가 경향이 뚜렷하였다. 이러한 경향은 연강수량 및 연유출량의 이중 누가곡선 비교분석에서도 동일하게 나타났다. 본 연구에서는 간벌 후 약 10년 경과시 연강수량의 뚜렷한 증가 경향에도 불구하고 침엽수인공림유역의 유출량이 다시 감소하였는데, 이는 임분이 성장함에 따라 수관차단 등 물손실량이 다시 증가하기 때문이다. 따라서, 침엽수인공림유역에서 지속적인 수자원 확보를 위해서는 10년 이내의 간격으로 적정한 밀도의 간벌을 반복해서 실시하는 것이 바람직할 것으로 판단된다.

• 한국물환경학회지
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• 제22권6호
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• pp.1068-1074
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• 2006

For receiving water quality protection a control systems of urban drainage for CSOs reduction is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as storm-water detention storage is highly dependant on the temporal variability of storage capacity available as well as the infiltration capacity of soil and recovery of depression storage. For the continuous long-term analysis of urban drainage system this study used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model has evolved that offers much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. Runoff characteristics manifested the unique characteristics of the subject area with the infiltration capacity of soil and recovery of depression storage and was examined appropriately by sensitivity analysis. This study presented the average annual CSOs, number of CSOs and event mean CSOs for the decision of storage volume.

• 농업과학연구
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• 제48권3호
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• pp.433-446
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• 2021

In this study, the future flood inundation changes under a climate change were simulated in the Tonle Sap basin in Cambodia, one of the countries with high vulnerability to climate change. For the flood inundation simulation using the rainfall-runoff-inundation (RRI) model, globally available geological data (digital elevation model [DEM]; hydrological data and maps based on Shuttle elevation derivatives [HydroSHED]; land cover: Global land cover facility-moderate resolution imaging spectroradiometer [GLCF-MODIS]), rainfall data (Asian precipitation-highly-resolved observational data integration towards evaluation [APHRODITE]), climate change scenario (HadGEM3-RA), and observational water level (Kratie, Koh Khel, Neak Luong st.) were constructed. The future runoff from the Kratie station, the upper boundary condition of the RRI model, was constructed to be predicted using the long short-term memory (LSTM) model. Based on the results predicted by the LSTM model, a total of 4 cases were selected (representative concentration pathway [RCP] 4.5: 2035, 2075; RCP 8.5: 2051, 2072) with the largest annual average runoff by period and scenario. The results of the analysis of the future flood inundation in the Tonle Sap basin were compared with the results of previous studies. Unlike in the past, when the change in the depth of inundation changed to a range of about 1 to 10 meters during the 1997 - 2005 period, it occurred in a range of about 5 to 9 meters during the future period. The results show that in the future RCP 4.5 and 8.5 scenarios, the variability of discharge is reduced compared to the past and that climate change could change the runoff patterns of the Tonle Sap basin.

• 한국물환경학회지
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• 제29권1호
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• pp.88-96
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• 2013

Much attention has been needed in water resource management at the watershed due to drought and flooding issues caused by climate change in recent years. Increase in air temperature and changes in precipitation patterns due to climate change are affecting hydrologic cycles, such as evaporation and soil moisture. Thus, these phenomena result in increased runoff at the watershed. The Soil and Water Assessment Tool (SWAT) model has been used to evaluate rainfall-runoff at the watershed reflecting effects on hydrology of various weather data such as rainfall, temperature, humidity, solar radiation, wind speed. For bias-correction of RCP data, at least 30 year data are needed. However, for most gaging stations, only precipitation data have been recorded and very little stations have recorded other weather data. In addition, the RCP scenario does not provide all weather data for the SWAT model. In this study, two scenarios were made to evaluate whether it would be possible to estimate streamflow using measured precipitation and long-term average values of other weather data required for running the SWAT. With measured long-term weather data (scenario 1) and with long-term average values of weather data except precipitation (scenario 2), the estimate streamflow values were almost the same with NSE value of 0.99. Increase/decrease by ${\pm}2%$, ${\pm}4%$ in temperature and humidity data did not affect streamflow. Thus, the RCP precipitation data for Hongcheon watershed were bias-corrected with measured long-term precipitation data to evaluate effects of climate change on streamflow. The results revealed that estimated streamflow for 2055s was the greatest among data for 2025s, 2055s, and 2085s. However, estimated streamflow for 2085s decreased by 9%. In addition, streamflow for Spring would be expected to increase compared with current data and streamflow for Summer will be decreased with RCP data. The results obtained in this study indicate that the streamflow could be estimated with long-term precipitation data only and effects of climate change could be evaluated using precipitation data as shown in this study.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.610-614
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• 2004

장기 유역 유출모형인 SWAT에 도시지역의 영향을 적절히 고려할 수 있도록 SWMM 모형을 포함시킨 SWAT-SWMM 결합모형을 테스트하기 위해 시험유역에 적용하였다. 이로부터 SWAT 모형과 SWAT-SWMM 결합모형에 의한 수문순환요소(지표수, 지하수, 하천유출, 증발산 등)를 비교${\cdot}$분석하였다. 또한 각 모형이 수문순환요소를 모식하는 방법을 비교${\cdot}$분석하여 SWAT-SWMM 결합모형을 개선하였다.

• 한국물환경학회지
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• 제27권4호
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• pp.425-432
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• 2011

To control non-point source pollution at a watershed scale, rainfall-runoff characteristics from forest watersheds should be investigated since the forest is the dominant land use in Korea. Long-term monitoring would be an ideal method. However, computer models have been utilized due to limitations in cost and labor in performing long-term monitoring at the watersheds. In this study, the Geo-spatial interface to the Water Erosion Prediction Project (GeoWEPP) model was evaluated for its runoff prediction from a coniferous forest dominant watersheds. The $R^2$ and the NSE for calibrated result comparisons were 0.77 and 0.63, validated result comparisons were 0.92, 0.89, respectively. These comparisons indicated that the GeoWEPP model can be used in evaluating rainfall-runoff characteristics. To estimate runoff changes from a coniferous forest watershed with various cover degree scenarios, ten cover degree scenarios (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%) were run using the calibrated GeoWEPP model. It was found that runoff increases with decrease in cover degree. Runoff volume was the highest ($206,218.66m^3$) at 10% cover degree, whereas the lowest ($134,074.58m^3$) at 100% cover degree due to changes in evapotranspiration under various cover degrees at the forest. As shown in this study, GeoWEPP model could be efficiently used to investigate runoff characteristics from the coniferous forest watershed and effects of various cover degree scenarios on runoff generation.

• 한국환경과학회지
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• 제24권12호
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• pp.1649-1656
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• 2015

Jeju Island is the highest rain-prone area in Korea that possesses affluent water resources, but future climate changes are predicted to further increase vulnerabilities as resultant of increasing of extreme events and creating spatial-temporal imbalance in water resources. Therefore, this study aimed to provide basic information to establish a proper water resources management plan by evaluating the effects of climate change on water resources using climate change scenario. Direct runoff ratio for 15 years (2000~2014) was analyzed to be 11~32% (average of 23%), and average direct runoff ratio for the next 86 years (2015~2100) was found as 28%, showing an increase of about 22% compared to the present average direct runoff ratio (23%). To assess the effects of climate change on long-term runoff, monthly runoff variation of future Gangjeong watershed was analyzed by dividing three time periods as follows: Present (2000~2030), Future 1 (2031~2070) and Future 2 (2071~2100). The estimated results showed that average monthly runoff increases in the future and the highest runoff is shown by Future 2. Extreme values has been expected to occur more frequently in the future as compared to the present.

• Water Engineering Research
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• 제5권2호
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• pp.81-99
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• 2004

Long term streamflow regime under virtual climate change scenario was examined. Rainfall forecast simulation of the Canadian Global Coupled Model (CGCM2) of the Canadian Climate Center for modeling and analysis for the IPCC SRES B2 scenario was used for analysis. The B2 scenario envisions slower population growth (10.4 billion by 2010) with a more rapidly evolving economy and more emphasis on environmental protection. The relatively large scale of GCM hinders the accurate computation of the important streamflow characteristics such as the peak flow rate and lag time, etc. The GCM rainfall with more than 100km scale was downscaled to 2km-scale using the space-time stochastic random cascade model. The HEC-HMS was used for distributed hydrologic model which can take the grid rainfall as input data. The result illustrates that the annual variation of the total runoff and the peak flow can be much greater than rainfall variation, which means actual impact of rainfall variation for the available water resources can be much greater than the extent of the rainfall variation.