• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.439-449
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• 2016

The methodology of synthetic unit hydrograph using geomorphic characteristics was suggested. Six geomorphic components over 19 watersheds were used to estimate synthetic unit hydrograph and the test watersheds were classified into two groups on the basis of the area of $200km^2$. The regression formulas between standardized geomorphic characteristics for each group and peak quantities of specific streamflow and time of representative unit hydrograph were suggested and the Nash and the Clark unit hydrographs were derived. For verifying the derived unit hydrographs, the resulting hydrographs were compared with the ones using the existing Clark unit hydrographs based on the empirical parameter estimation for the 145 storm events during 2010 to 2011 for the additional six watersheds. The results showed the relatively higher performance over the existing synthetic unit hydrograph methods, which could be a contribution to the hydrologic estimation in ungauged watersheds.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.380-380
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• 2011

본 연구는 경인 아라뱃길의 운영을 위한 기초자료로써 굴포천 유역에서 분포형 강우 모형을 적용하기 위한 것으로 HEC-HMS의 ModClark 방법을 사용하였다. HEC-HMS에서 사용가능한 강우유출모형 중 ModClark 방법은 격자기반의 공간적 강우 분포 모형으로 본 연구에서는 그 기초 지형격자 자료를 10m DEM을 이용해 ArcGIS에서의 작업을 통해 추출하였다. HEC-HMS에 입력 가능한 격자기반 지형자료를 얻기 위해서 미 공병단에서 배포하는 GIS tool 인 HEC-GeoHMS를 이용하였다. 또한 강우자료는 한국수자원공사의 3km*3km 격자기반의 K-PPM 자료를 사용하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1822-1829
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• 2006

본 연구에서는 계산된 유량과 실측 유량을 비교하여 Clark 단위도 방법의 매개변수를 추정하고자 하였다. 오산천과 진위천 상류유역에 대하여 Arcview와 WMS로 지형자료에 대한 전 처리를 한후, HEC-HMS 프로그램을 이용하여 유출량을 산정하였다. 2001년부터 2005년까지 4개의 사상에 대하여 강우량, 기흥저수지와 이동저수지의 실제 방류량을 이용하여 유출량을 산정하였으며, Clark 모형의 매개변수를 Russel 공식, Sabol 공식 및 HEC-HMS 프로그램에 내장된 Nelder-Mead 최적화 방법을 이용하여 매개변수를 각각 산정하여 회화 지점의 실측 유출량과 비교.평가하였다. 빈도가 큰 유출사상의 경우에는 Sabol 식을 적용한 결과가 Russel 식을 적용한 모의결과보다 첨두유량의 재현성이 우수하게 나타났으며, 유출량이 작은 경우에는 Russel 식을 적용한 모의결과가 우수하였다. 첨두가 중제곱평균제곱근오차, 잔차자승의 합, 절대잔차의 합 등 3가지의 서로다른 목적함수를 적용하여 매개변수를 자동 보정하였을 때, 목적함수에 따른 첨두유량의 오차는 거의 동일하였으며, 첨두시간에 대한 오차는 첨두가중제곱평균제곱근오차를 적용했을 때 가장 작은 것으로 분석되었다. 그리고 Clark 유역 추적모형의 자동보정을 통하여 추정한 매개변수인 도달시간과 저류상수는 강우사상에 따라서 변동하는 특성을 나타내기 때문에 최적의 도달시간 및 저류상수는 홍수사상별로 추정되어야 하며 이 결과는 홍수량 산정을 위한 매개변수 추정과정의 비유일성 및 복잡성을 암시하고 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2255-2265
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• 2013

This study presents the width function-based Clark model. To this end, rescaled width function with distinction between hillslope and channel velocity is used as time-area curve and then it is routed through linear storage within the framework of not finite difference scheme used in original Clark model but analytical expression of linear storage routing. There are three parameters focused in this study: storage coefficient, hillslope velocity and channel velocity. SCE-UA, one of the popular global optimization methods, is applied to estimate them. The shapes of resulting IUHs from this study are evaluated in terms of the three statistical moments of hydrologic response functions: mean, variance and the third moment about the center of IUH. The correlation coefficients to the three statistical moments simulated in this study against these of observed hydrographs were estimated at 0.995 for the mean, 0.993 for the variance and 0.983 for the third moment about the center of IUH. The shape of resulting IUHs from this study give rise to satisfactory simulation results in terms of the mean and variance. But the third moment about the center of IUH tend to be overestimated. Clark model proposed in this study is superior to the one only taking into account mean and variance of IUH with respect to skewness, peak discharge and peak time of runoff hydrograph. From this result it is confirmed that the method suggested in this study is useful tool to reflect the heterogeneity of drainage path and hydrodynamic parameters. The variation of statistical moments of IUH are mainly influenced by storage coefficient and in turn the effect of channel velocity is greater than the one of hillslope velocity. Therefore storage coefficient and channel velocity are the crucial factors in shaping the form of IUH and should be considered carefully to apply Clark model proposed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.29-39
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• 2012

Climate change has been obtained researchers' interest, especially in water resources engineering to adjust current conditions to the new circumstance influenced by climate change. In this study, WRF-ARW will be evaluated the capability to estimate distributed precipitation using global weather information instead of the data from rainfall observatory or radar. Cheongmi watershed is selected and adopted to generate a distributed rainfall-runoff model using ModClark. The results from the distributed model with precipitation data from WRF-ARW and the lumped model using observed precipitation data were compared to the observed discharge values. The final results showed that the distributed model, ModClark generated similar pattern of hydrograph to the observations in terms of the time and amount of peak discharge. In addition, the trend of hydrograph from the distributed model presented similar pattern to the observations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.157-170
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• 2013

In this study, flood runoff characteristics is analyzed according to subbasin divisions by physically based rainfall-runoff model and appropriate number of subbasin divisions is suggested for midsize test basins. The Clark method, a lumped model in HEC-HMS, and the ModClark method, a semi-distributed model are used to simulate rainfall-runoff processes on Andong-reservoir basin, Imha-reservoir basin, and Pyeongchang river basin. The test basins were divided into nine subdivision cases by equal-area subdivision method such as single basin, 3, 5, 6, 7, 9, 10, 12, and 15 subbasins, and compared the simulated and observed values in terms of the peak flow and the peak time. The simulation results indicated that the peak flows tended to increase and the peak time shifted earlier as the number of subdivisions increased and this tendency weakened after the certain number of subdivisions. In this research, the specific number of subdivision was defined as the minimum number of subdivision considering both peak flow and peak time. Consequently, the minimum number of subdivisions is determined as 5 for Andong and Imha reservoir basins and 7 for Pyeongchang river basin.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.537-543
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• 1999

While there are to estimating design discharge , we are in trouble with how to separate area, Because discharges will be different depending on the shape of area even though there are same size of area . This study is for a reasonable presentation of design discharge method where there are changing characteristcs of area with SCS and Clark theory by sung HEC-1 Model. While we were Estimating desgin discharge with separating area in a relation to Time of Concentration(Tc) with SCS , Clark method, we found that if there are no variation of Tc the value of a discharge is not changed where shapes of area are different though. And from the result of analysis with SCS and Clark method, we ascertained that discharge by the SCS method was more bigger than that of the Clark where Area is less than 100ha. On the other hand, Clark method is more bigger in the more 1000ha.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.332-332
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• 2020

본 연구에서는 유역 출구에서의 첨두유속과 Clark 모형 매개변수 간의 관계를 검토하였다. 첨두유속과 집중시간의 관계가 먼저 검토되었으며, 이후 집중시간과 저류상수의 관계가 검토되었다. 이를 위해, 다년간의 수위 관측 및 유속 및 유량 측정 성과가 있는 지점들이 선정되었다. 분석을 위해 관측 수위 및 수위-유량 곡선이 존재하는 호우사상들이 고려되었으며, 이 중 첨두유속 자료가 존재하는 사상들이 첨두유속과 집중시간 관계 검토를 위해 고려되었다. 본 연구의 결과를 요약하면 다음과 같다. (1) 호우사상 규모가 커짐에 따라 첨두유속은 크게, 집중시간은 작게 나타나며, 이 둘은 선형적인 관계를 가진다. (2) 집중시간과 저류상수는 호우사상 규모에 관계없이 유역별로 어느 정도 일정하게 나타나며, 이는 유역의 상사성과 높은 상관을 가진다.

• Journal of Korea Water Resources Association
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• v.37 no.11
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• pp.929-938
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• 2004

In this study, Miho stream basin(Seokhwa water level gauging station) In Geum river, Flood control main station of Geum River Flood Control Office, is selected. Hydrologic topographical informations are calculated using WMS which is hydrologic analysis software coupled with GIS Method, and flood analysis is accomplished by HEC-1 included In WMS. To calculate the effective rainfall CN values of SCS are used. Clark, Snyder and SCS methods are selected respectively to derive unit hydrograph. This study shows the applicability of GIS techniques to runoff simulation in ungauged basin by comparing with actual measured flood hydrograph. As a results, Snyder(Tulsa) method and Clark (Herby) method is suitable to Miho stream basin. But Snyder(Tulsa) method is suitable more than Clark(Herby) method. And according to the degree of urbanization, the peak discharge has increased and the peak time has tended to decrease.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.428-428
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• 2015

최근 제주도는 극한사상의 기상발생빈도가 점차 증가하여 집중호우, 태풍 등에 의한 홍수피해가 점자 증가하고 있는 실정이다. 따라서 지역특성에 적합한 단위유랴도 산정은 실제 하천설계 및 치수방재를 위해 필수적이다. 따라서 본 연구에서는 외도천유역의 유역특성을 반영한 최적 단위유량도를 산정하기 위해 강우-유출모형은 HEC-HMS모형을 이용하였으며 적용한 단위도는 Clark, Sndyer, SCS 합성단위유량도법으로 각 사상마다 실측 유량자료와 비교 분석하였다. 일원분산분석 결과는 각 단위도의 첨두유량과 첨두시간에 대한 p-value가 유의수준 0.05보다 크기 때문에 귀무가설이 성립이 되며 각 단위유량도의 방법별 첨두유량 및 첨두 시간의 유의적 차이는 없다고 분석되었다. 오차율로 비교하면 Clark 합성단위도가 대상유역인 외도천의 유역특성을 가장 잘 반영하는 것으로 판단되며 Clark 단위유량도의 오차율은 0.02 ~ 1.93%로 타나났으며 첨두시간에 대한 오차율은 0 ~ 2.74%으로 나타났다. 향후 홍수유출량 산정하기 위해 장기간 지속적으로 유량관측자료 확보 및 구축이 필요하며, 이러한 제주형 유도식 개발 및 최적의 매개변수와 단위도를 적용한다면 신뢰도 높은 유출 특성 결과를 도출 할 수 있을 것으로 판단된다.