• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.321-330
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• 2002

This study aims at the analysis of the geomorphological instantaneous unit hydrograph model (GIS-GIUH) with geographic information system for the rainfall-runoff analysis of watershed which is ungaged or doesn't have sufficient hydrologic data. The rainfall-runoff analysis was performed in Wi stream(Dongkok, Koro, Miseung, Byeungchun, Hyoreung, Museung) which is a representative experimental river basin of IHP. In the process of analysis of the GIUH model, developed GIS-GIUH model and Rosso-GIUH model were applied the study basin and computed hydrographs by these models were compared with observed hydrograph. The GiS-GIUH model shows more closely to the observed hydrograph than Rosso-GIUH model in the peak discharge of the hydrograph. For the development of the GIS-GIUH model, Gamma function factor N was given by N=3.25( $R_{B}$/ $R_{A}$)$^{0.126}$ $R_{L}$$^{-0.055}$, which is the relation of the watershed geomorphological factor, K was also obtained as K=1.50( $R_{A}$/( $R_{B}$. $R_{L}$))/$^{0.10}$.(( $L_{{\Omega}}$+ $L_{{\Omega}-1}$)/V)$^{0.37}$. As the results of analysis, it was found that GIS-GIUH model can be applied to an ungaged watersheds.eds.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.85-91
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• 2011

RV-GIUH must be applied at an outlet or a junction of highest order stream of a subbasin because the model was derived for basins following Horton's ordering system. However hydrograph is calculated at various locations which does not fit to the desirable points. Therefore, some guideline is required for RV-GIUH application in practice. This study would like to suggest the outlet location criteria for appling RV-GIUH at un-gauged basin. Locations were selected by moving to upstream from outlet of Sanganmi basin and unit hydrograph using derived and simple RV-GIUH were estimated at each location. As the results, the peaks of RV-GIUH in upstream were exaggerated because of distortion of length ratio and total stream length. To avoid this error, the location must be selected at 60% downstream of highest stream length. To apply RV-GIUH at various places, equations correcting distortion of total stream length were suggested. With the correcting equations, it can be possible that RV-GIUH is applied at 20% downstream of highest stream length. Application and precision of RV-GIUH will be improved through this research.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.705-709
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• 2005

수공분야에 매우 중요한 강우-유출 해석을 위해 미계측 유역이나 자료가 결핍된 유역에서 효과적으로 사용하는 GIUH모형을 이용하기 위해서는 지형$\cdot$지질특성, 토지피복상태, 유역의 하천 분기특성 등이 필요하다. 본 연구에서는 지형학적 인자를 추출하여 지형형태학적 특징과 Clark 단위도법을 이용하여 GIUH 모형을 보청천 유역의 산성지점에 비교하였다 그 결과 GIUH 모형을 이용한 수문곡선이 Clark 단위도법을 이용하여 작성한 수문곡선 보다 실측치와 유사한 결과가 나오는 것을 알 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.13-17
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• 2010

Rodriguez-Iturbe and Valdes(1979)가 제안한 지형형태학적 순간단위도(Geomorphologic Instantaneous Unit Hydrograph, GIUH)는 미계측유역에서 지형인자만으로 단위도를 구할 수 있는 장점이 있으나 최고차 하천길이에 따라 단위도의 첨두가 민감하게 영향을 받는다. 그렇기 때문에 적절한 유역출구의 선정이 중요하다. 본 연구에서는 미계측 유역에서 GIUH를 사용하여 단위도를 산정하는 경우, 유역출구를 결정할 수 있는 기준을 제시하고자 한다. IHP 대표유역인 평창강의 상안미 유역에 대하여 유역출구에서부터 최고차 하천길이를 줄여가며 12개 지점을 선정하였으며 GIUH식과 간략식을 사용하여 각 지점에서의 단위도를 산정하였다. 그 결과 최고차 하천의 길이가 11.02km, 총 유하길이의 67%이상인 지점의 단위도는 일정한 첨두값을 주었다. 그러나 최고차 하천의 길이가 이보다 짧은 지점에서는 단위도의 첨두가 150%-3,000% 크게 산정되었다. 본 연구를 통해 미계측유역에서 GIUH를 적용할 때 적절한 유역출구를 결정할 수 있는 기준이 제시될 것이며, 이를 통해 GIUH 모형의 정확성이 향상될 수 있을 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.533-545
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• 2003

This study analyzed several storm events observed in the Seolma-chun basin to derive the characteristic velocity of GIUH (Geomophological Instantaneous Unit Hydrograph) as well as its variability. Especially, this study focused on the variation of characteristic velocity due to the change of rainfall characteristics. The IUH of the Seolma-chun basin was derived using the HEC-1, whose peak discharge and time were then compared with those of the GIUH to derive the characteristic velocities. The characteristics velocities were analyzed by comparing with the GcIUH (Geomorphoclimatic IUH) as well as the characteristics of rainfall. Results are summarized as follows. (1) The characteristic velocity of GIUH was estimated higher with higher variability than the GcIUH, but their trends were found similar (2) Total amount of effective rainfall (or, mean effective rainfall) well explains the characteristic velocity of GIUH. This could be assured by the regression analysis, whose coefficient of determination was estimated about 0.6. (3) The duration and the maximum intensity of rainfall were found not to affect significantly on the characteristic velocity of GIUH. The coefficients of determination were estimated less than 0.3 for all cases considered. (4) For the rainfall events used in this study, the characteristic velocities of GIUH were found to follow the Gaussian distribution with its mean and the standard deviation 0.402 m/s and 0.173 m/s, respectively. Most of the values are within the range of 0.4∼0.5 m/s, and its coefficient of variation was estimated to be 0.43, much less than that of the runoff itself (about 1.0).

• Water for future
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• v.28 no.5
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• pp.117-127
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• 1995

The application and analysis for the scale considering GIUH model proposed by the authors in this issue have been performed for the leemokjung sub-basin in the Pyungchang basin one of IHP representative basin in Korea. Scales of topographic maps for model application and fractal analysis are 1:25,000, 1:50,000 and 1:100,000. The ratio between successive scales is therefore constant. Link lengths were measured using a curvimeter with the resolution of 1 mm. Richardson's method was employed to have fractal dimension of streams. Apparent alternations of parameters were found in accordance with variations of map scale. And this tendency could mislead physical meanings of parameters because model parameters had to preserve their own value in spite of map scale change. It was found that uses of fractal transform and Melton's law could help to control the scale problem effectively. This methodlogy also could emphasize the relationship between network and basin to the model. To verify the applicability of GIUH proposed in this research, the model was compared with the exponential GIUH model. It is proven that proposed 2-parameter gamma GIUH model can better simulate the corresponding runoff from any given flood events than exponential GIUH model. The result showed that 2-parameter gamma GIUH model and fractal theory could be used for deriving scale considered IUH of the basin.

• Water for future
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• v.20 no.4
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• pp.267-278
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• 1987

This study aims at the decision of geomorphologic instantaneous unit hydrograph(GIUH) model parameter fore the ungaged or the data deficiented Basin, to analyze rainfall runoff relation in river basin by applying queueing theory with geomorphologic factors.The concept of GIUH model is based upon the principle of queueing theory of rain drops which may follow many possible routes during rainfall period within watershed system to ist outlet. Overland flow and stream flow can be simulated, respectively, by linear reservoir and linear channel conceptual models. Basically, the model is a mon-lineal and time variant hydrologic system model. The techniques of applying are adopted subarea method and mean-value method, the watershed is divided according to its stream number and order. To prove it to be applicable, the GIUH model is applied to the Wi-Stream basin of Nak-Dong River(Basin area; 475.53$\textrm{km}^2$), southen part of Korea. The simulated and the observed direct runoff hydrographs are compared with the peak discharge, times to peak and coefficients of efficiency, respectively, and the results show quite satisfactory.Therefore, th GIUH model can be extensively applied for the runoff analysis in the ungaged and the data deficiented basin.

• Journal of Korea Water Resources Association
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• v.41 no.11
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• pp.1107-1121
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• 2008

The simple equation of GIUH are frequently used in many researches instead of the derived equation of GIUH. However it is still unknown whether the simple equation of GIUH is adaptable for estimating IUHs for basins with various geomorphologic conditions. To verify the applicability of the simple equation of GIUH, in this research, four basins which were Bangrim, Sanganmi, Museong, and Byeongcheon were selected and each basin was assumed as the third and fourth stream order basin according to variable resolutions. After than, IUHs were estimated using the derived and simple equations of GIUH. Eight to sixteen hydrographs were estimated from the each IUH, compared with observed graphs. In case of that the basin is assumed as a third order stream, the derived equation underestimated the peak flows while the simple equation overestimated them. When the basin is assumed as a fourth order stream, the simple equation generally overestimated the peak flows whereas the derived equation produced peak flows good agreement with the observed peak flow. Moreover, the simple equation showed various deviations in accuracy whereas the derived equation produced stable results. Based on the fact found from this research, it can be concluded that the derived equation of GIUH brings better results than the simple equation of GIUH to estimate IUHs for ungauged basins.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.1 s.20
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• pp.49-58
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• 2006

Rainfall-runoff characteristics are analysed based on the geomorphological instantaneous unit hydrograph(GIUH) derived by geomorphological parameters using geographical information system in watershed ungaged or deficient of field data. Observed data of Seom river experiment watershed at upstream of Hoengseong dam and variable slope method for hydrograph separating of direct non are used. The 4th stream order of Seom river experimental watershed is developed with a regular correlation referred to the Horton-Strahler's law of stream order. The characteristic velocity to determine shape parameter of GIUH is 1.0m/s and its equation is modified for accurate results. Hydrograph at the outlet of 4th stream order of Maeil gage station and at the outlets of 3rd stream order of Sogun and Nonggeori gage stations show a little differences in falling limb of hydrograph but agree well to the observed data in general. The results by hydrological routing with HEC-HMS to the outlet of 4th stream order of Maeil gage station which the hydrograph by GIUH obtained at Sogun and Nonggeori gage stations of 3rd stream oder are applied as upstream inputs give better agreement with observed data than those by hydrograph by GIUH obtained at Maeil gage station of 4th stream order. In general, the rainfall-runoff by GIUH has applicability to the watershed routing of ungaged project regions.

• Proceedings of the Korea Water Resources Association Conference
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• 1987.07a
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• pp.31-42
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• 1987

본 연구는 유역의 지형인자를 대기행렬이론(Queueing theory)에 적용하여 하천유역의 강우-유출 관계를 해석하고, 미 계측 유역이나 자료가 결핍된 유역에 적용할 수 있는 GIUH(Geomorphologic Instantaneous Unit Hydrograph)모델의 매개변수를 결정하는데 그 목적을 두었다. GIUH모델의 개념은 유역 시스템내의 강우의 지속기간동안 유역의 출구에서 가능한 많은 경로를 추적 할 수 있을것이라는 강우 대기행렬이론의 원리에 기초를 두었으며, 적용기법은 분할법(Sub-area method)과 평균치법(Mean-value method)을 적용하였다. GIUH모델의 적용성을 증명하기 위해서, 낙동강 위천유역(유역면적 472.53km)에 적용하였으며, 분할법과 평균치법은 유역의 분할을 위해서 채택하였다. 계산된 직접 유출 수문곡선과 관측 직접 유출 수문곡선을 비교한 결과는 첨두 유출량, 도달시간, 효률계수가 매우 근접한 결과를 나타내고 있었다. 따라서, GIUH모델은 미 계측 유역이나 자료가 결핍된 유역의 유출량 산정에 광범위하게 적용할 수 있음을 알 수 있었다.