• 한국농공학회지
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• 제32권E호
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• pp.47-58
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• 1990

Abstract A regionalized daily streamflow model using a modified retention parameter in the SCS method was developed to predict the daily streamflow of a natural series for Korean watersheds. Model verification showed that it is possible to use the model for extending short period records in a gaged watershed or for predicting daily streamflow in any ungaged watershed, with reasonable accuracy by simply inputing the name of the watershed boundary, the watershed size, the latitude and longitude of the watershed, and the daily areal rainfall.

• 물과 미래
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• 제14권1호
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• pp.51-58
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• 1981

본 연구는 하천일류량을 추계학적으로 분석하여 그 특성을 구명하고 이에 적합한 모의발생 모델을 설정하여 검토하는데 목적을 두고 있다. 한강, 낙동강 및 금강유역의 주요관측지점의 일류량으로부터 통계학적 특성인 Correlogram 및 Spectrum 분석에 의한 시계별 특성을 구하였으며 모의발생모델의 결정에 위해 Markov 모델의 Correlogram을 원자료의 그것과 비교한 결과에 따라 모의 발생 모델의 적합도를 예측할 수 있었으며, 또한 다차수모델의 결정계수 R$$에 대한 해석으로부터 다차수 모델의 차수를 결정했으며, 모의발생에 있어서는 수정 Markov 모델과 다차수 모델을 적용한 결과 대체적으로 2차 수정 Markov 모델과 2차 다차수모델이 최적의 결과를 보여주었다.

• 한국관개배수논문집
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• 제13권2호
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• pp.274-282
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• 2006

The objective of this study was to develop a hydrologic simulation model to predict daily streamflow from a small agricultural watershed considering irrigation return flow. The proposed IREFLOW(Irrigation REturn FLOW) model consists of hillslope runoff model, irrigation scheme drainage model, and irrigation return flow model, and simulates daily streamflow from an irrigated watershed. Two small watersheds were selected for monitoring of hydrological components and evaluating the model application. The relative error (RE) between observed and simulated daily streamflow were 2.9% and 6.4%, respectively, on two small agricultural watersheds (Baran and Gicheon) for the calibration period. The values of RE in daliy streamflow for the validation period were 6.0% for the Baran watershed, and 2.8% for the Gicheon watershed.

• 한국농공학회지
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• 제33권4호
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• pp.61-72
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• 1991

A lumped deterministic model(DAWAST model) was developed to predict the daily streamflow. Since the streamflow is dominantly determined by the soil water storage in the watershed, the model takes the soil water accounting procedures which are based on three linear reservoirs representing the surface, unsaturated, and saturated soil layers. The variation of soil water storage in the unsaturated zone is traced from the soil water balance on a daily basis. DAWAST model consists of 5 parameters for water balance and 3 parameters for routing. A optimization technique of unconstrained nonlinear Simplex method was applied for the determination of the optimal parameters for water balance. Model verification was carried out to the 7 hydrologic watersheds with areas of 5.89-7,126km$^2$ and the results were generally satisfactory. The daily streamflow can be arbitrarily simulated with the input data of daily rainfall and pan evaporation by the DAWAST model at the station where the observed streamflow data of short periods are available to calibrate the model parameters.

• 한국농공학회논문집
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• 제48권5호
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• pp.29-38
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• 2006

Geographic Information System has extended to higher assessment of water resources. GIS linking with hydrological model becomes a trend in water resource assessment modeling. One of the most popular models is SWAT2000 which have effectiveness in multi-purpose processes for predicting the impact of land management practices on water, sediments and chemicals yields in large complex watershed with varying soils, land uses, and management conditions over long period of time. In this study, SWAT2000 model was applied to Gap stream watershed in Daejeon city where TMDL (Total Maximum Daily Load) Regulation would be implanted. The Gap Stream watershed was partitioned into 8 subbasins, however, only 3 out of 8 subbaisns were observed for having practical gauged data on the basis of streamflow from the year of 2002 to 2005. Gauged streamflow data of Indong, Boksu and Hoeduck stations were used for calibration and validation of the SWAT Streamflow simulation. Estimation Efficiency Analysis (COE), Regression Analysis ($R^{2}$), Relative Error (R.E.) were used for comparing observed streamflow data of the 3 subbasins on the daily and monthly basis with estimated streamflow data in order to fix optimized parameters for the best fitted results. COE value for the daily and monthly streamflow was ranged from 0.45 to 0.96. $R^{2}$ values for daily and monthly streamflow ranged from 0.51 to 0.97. R.E. values for total streamflow volume ranged from 3 % to 22.5 %. The accuracy of the model results shows that the SWAT2000 model can be applicable to Korean watersheds like the Gap Stream watershed that needs to be partitioned into a number of subbasins for TMDL regulation.

• 물과 미래
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• 제10권1호
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• pp.79-94
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• 1977

본 연구는 Run-Length와 Run-Sum에 의한 강우량과 하천유량을 분석하여 그 특성을 구명하고, 이로부터 모의발생 모델(Simulation Model)을 설정하여 검토하는데 목적을 두고 있다. 분석에 있어서는 우리나라의 주요도시(서울, 대구 및 부산)의 일강우량과 주요하천(한강, 낙동강 및 금강)의 일류량 자료들을 사용하였다. 또한 해석에 있어서는 Run-Length와 Run-Sum에 대한 각각의 분포형 분석으로부터 Weibull 분포 및 1-변수지수 분포를 하고 있음을 알았으며, 이로부터 Monte Carlo 기법(Monte Carlo technique)을 기초로 하는 Weibull모델(Weibull model)과 1-변수지수 모델(One-Parameter Exponential Model)에 의해서 Run-Length와 Run-Sum을 모의발생 시켰다. 그 결과 기록치(Historical Data)에 근사한 모의발생 자료(Simulation Data)를 얻었다.

• 물과 미래
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• 제26권3호
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• pp.47-61
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• 1993

수정 tank 모형의 입력, 구동, 출력 및 매개변수의 보정을 실시할 수 있는 쉘 프로그램 DSFS를 개발하고, 중소 유역의 일 유출량의 추정에 적용하도록 하였다. 수정 tank 모형은 유역의 일별 증발산 손실을 추정함으로써 유출량을 정의하도록 하였으며, 증발손실량은 배재 증발산량에 토양수분계수 및 토지 이용상태에 따른 월별 작물피복계수를 써서 조정하도록 하였다. 모형의 매개변수를 보정하고, 매개변수와 유역 특성인자와의 관계를 얻었다. 개발된 쉘 프로그램을 미계측유역에 적용하였으며, 일유출량 추정에서 최적화 결과와 유사한 값은 보였으나, 년 유출량은 10% 정도 큰 값은 보였다.

• 한국농공학회지
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• 제28권1호
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• pp.33-40
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• 1986

Unit-graph model to estimate the daily streamfiow was developed on the basis of distribution graph method. The results of evaluating the application of the model to Nakdong watersheds were generally satisfactory and this model would be the groundwork of the "Unit-graph model for daily streamflow in Korean watersheds".eds".uot;.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.944-944
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• 2012

Urbanization leads to a change of hydrologic responses because impervious area is increased by urbanization. Decrease of groundwater recharge and increase of overland flow are general hydrologic characteristics caused by urbanization. This can be a source of damages such as increased flooding and reduced groundwater levels. Daily streamflow in Gabcheon watershed, South Korea is simulated by ARCSWAT model, an extension of SWAT2005. After calibration and validation of model, the simulated daily streamflow from 1997 to 2001 are statistically analyzed. The phenomenon that $T_{Qmean}$ is inversly proportional to coefficient of variation for the simulated daily streamflow is demonstrated. Also, hydrologic response was more influenced by weather than land use for high flow. This study also examines the effect of land use change on daily streamflow with spatially and quantitatively different land use maps. The simulated stream flow is tested by Mann-Whitney method. The median between stream flows simulated for 1990 and 2000 land use maps is significantly different, but the simulated streamflow for spatially different land use maps is almost unchanged.

• 한국물환경학회지
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• 제27권6호
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• pp.914-925
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• 2011

The variation of streamflow is regarded as one of the most influential factors on the fluctuation of water quality in the stream. The characteristics of the variation should be taken into account in the plans for the management of Total Maximum Daily Loads (TMDLs). This study analysed and characterized spatial distribution and temporal variation of streamflow at each unit watershed in Guem-river basin. For the analysis of the distribution of streamflow, the type and the extent of the distribution were investigated for the unit watershed. For the analysis of the variation, short and long term changes of streamflow were examined. The result showed that most of the distributions were not log-normalized and the extent of variation tends to be greater at the unit watershed placed on the tributaries in the basin. A kind of margin could be granted to the unit watershed involving high variations so as to establish the water quality goal and load allotment more reasonably and effectively in view of whole waterbody.