• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.110-110
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• 2019

유역 강우-유출 과정의 물리적 특성과 비선형성을 반영하여 유출을 예측할 수 있는 새로운 방법을 제시한다. Dynamic wave 이론 기반의 강우-유출 모형과 유역의 지형적, 수문학적 특성을 이용하여 유역의 순간단위도를 S-수문곡선 방법을 통해 유도하였으며, 비선형성을 고려한 유출수문곡선 산정을 위해 순간단위도의 회선적분 시 강우강도별로 달라지는 순간단위도를 반영하였다. 기존 선형 가정에 근거한 단위도 방법이나, kinematic wave 이론 기반의 순간단위도 방법들에 비해 유역 반응의 물리적 특성과 비선형성을 잘 반영할 수 있었으며, 수치 시뮬레이션을 통한 강우유출 예측 방법에 비해 예측에 소요되는 시간이 짧다는 이점을 가졌다. 본 연구에서 제시한 방법에 대한 이상적 유역, 실제 유역에 대한 검증을 진행하였으며 실제 관측결과와 비교해 본 결과 유역의 강우-유출 관계를 정확히 예측하였다는 결론을 얻을 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.313-313
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• 2020

여름철 발생하는 집중호우는 해안지역 및 하천유역의 저지대에 상습적인 침수를 유발하며, 도시지역은 높은 불투수율로 인해 추가적인 침수 피해가 발생하는 경우가 많다. 본 연구에서는 폭함수를 통해 하천망의 공간적인 특성을 함수형태로 나타내어 유역의 수문분석에 이용하는 폭함수 단위도법(WFIUH, Width Function Instantaneous Unit Hydrograph)을 소개하고, 적용성을 검토하기 위하여 실제 유역 및 강우 사상에 적용해보았다. WFIUH는 기존의 집중형 수문모형과 다르게 매개변수를 물리적으로 결정할 수 있으며, 유역특성과 시공간적 변동성을 수문곡선 산정에 반영할 수 있는 장점이 있다. WFIUH의 적용성을 검토하기 위하여 2003년 한반도에 심각한 침수피해를 입힌 태풍 매미로 인해 발생한 강우사상과 그로인해 큰 피해가 있었던 마산 지역의 남천, 삼호천 일부 유역을 대상으로 강우-유출 분석을 실시하였다. 분석결과 범용 수문모형인 HEC-HMS와 비교 시 유사한 결과를 보이며, 실제 관측치와도 유사한 결과를 보이는 것으로 나타났다. 또한 강우의 이동을 반영하여 강우의 이동이 수문곡선과 첨두유량에 미치는 영향을 비교분석 하였다.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.799-810
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• 2003

Hydrologic models generally require land surface analysis to different topographic parameters defined as direct or indirect input variables to the model. Specially GIS supply the these parameters from digital data set of land surface The sensitivity analysis to DEM(Digital Elevation Model) resolution and the threshold area are of GIS extracted digital data set applied GIUH(Geomorphological Instantaneous Unit Hydrograph)model is investigated. Also it is compared the responses of GIUH model as input data of stream networks from digital data set(blue line) of NGIS and those extracted from DEM of various grid sizes. The results shows that the GIUH model is significantly affected by the DEM resolution and threshold area. According to the results, DEM grid size is suitable from 25m to 50m. Also threshold area is in the range of 30%∼50% for exceedance probability.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.1
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• pp.55-64
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• 1987

The schemes synthesizing the instantaneous unit hydrograph(IUH) are presented by using the geomorphologic parameters of a basin. To this end, the channels in the network are numbered according to the Strahler scheme, and the mathematical formulation corresponding to a dynamic probability theory for deriving the geomorphologic IUH(GUH) is refered to the existing techniques adopted by Rodriguez-Iturbe and Valdes. Also, the mean runoff velocity is applied for expressing a dynamic state of flow. The applicability of the GUH to the real drainage basins is tested by using the data observed in a few basins with areas of the order of 9.2, 20, 33.63, and $109.73km^2$ in Korea. The test is carried out by checking the discrepancies between the observed and simulated values for the peak discharge and its time of occurrence which are the most important parameters of an IUH by varing the mean runoff velocity and the inputs. As a result, good agreement is found between them, and it is shown that the variability in peak discharge of hydrograph depends on the mean runoff velocity more than the constant loss rate.

• Water for future
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• v.19 no.2
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• pp.139-148
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• 1986

The hydrologic response function in a small basin is expressed by the distribution function of slope length. The characteristics of topographical factors is represented to the concentration time, and the instantaneous unit hydrograph is derived as a hydrologic rsponse function by application of probobility density function. The averaging process of runoff characteristics within watershed was analyzed for a few small watershed where was split up the small basin itself. The method of calculation of the effective rainfall should play important roles in the transformation process from hydrologic response function to runoff hydrograph. In this paper, the Horton's infiltration quation is used as a method of calculation of effective rainfall, a new response function of runoff process is derived. The $\Phi$-index method and the infiltration method are tested by comparing the observed and estimated values.

• Water for future
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• v.18 no.2
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• pp.143-152
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• 1985

A method is suggested for the reappearance of a surface runoff hudorgraph of a river basin by linking the hydrologic response of a catchment represented by the instantaneous unit hydrograph(IUH) with the Horton's empirical gemorphologic laws. The geomorphologic theory of the IUH developed by G. Itrube et al. and the geomorphoclimatic theory of the IUH developed by Bras et al. are used to derive the new hydrologic response function in consideration of geomorphologic parameters and climatic characteristics by applying to Sukekawa's rainfall-runoff model. The derived response function was tested for on some observed hydrographs in a natural watershed and showed promising, and by considering a drainage basin as m(1∼4) identical linear reservoir in series, it was founded that the model(m=2) is most applicable to predict hydrologic response regardless of the size of basins. A modelization algorithm of a basin using Sthahler's ordering scheme of drainage network will give good result in analysis of the surface runoff huydrograph by the method of this study.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.389-392
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• 2004

A recent unusual change in the weather is formed as a localized heavy rain in a short time. This phenomenon has caused a flash flood, and flash floods extensively have damaged human lives many times. In large river's case, the extent of loss of lives and properties has been decreased through the flood warning system by flood control stations of each stream. However, the extent of damage in other small rivers has increased reversely. Therefore, it is necessary to establish a new flood warning system against flash floods instead of the existing flood warning system. It is a specific character that the damage from flash floods in mountain streams brings much more loss of lives than large river's flood. The purpose of this study is calculating the characteristic of flash floods in streams, analyzing topographical characteristics of water basin through applying GIS techniques with the calculation as mentioned above and researching what topographical conditions have influence on hydrological flash floods in water basin. The flash flood prediction model we used is made by GIUH (geomorphoclimatic instantaneous unit hydrograph) with hydrologic-topographical technology. As applying the flash flood prediction model, this is a procedure for calculating topographical information in basin: we made a topological data up out of database with utilizing GIS, and we also produced a DEM (digital elevation model) and used it as a topographical data for determining amount of flash floods.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.89-94
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• 2009

The purpose of this study is to estimate the critical flood discharge and flash flood trigger rainfall for alarm system providing for a flash flood in mountainous area. The flash flood need non-linear approaching method, because rainfall-runoff is nonlinear and it is difficult to explain the existing linear rainfall-runoff. Hydrological characteristics would be utilized to apply such as hydrologic modelling or basin management. This study was effectively estimated a topographic characteristic factor of basin using the GIS. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. A flash floods defined as a flood which follows shortly after a heavy or excessive rainfall event, with a few hours. In this study, we gave a definition that a critical flood for alarm is the flood when valley depth judging dangerous depth is over 0.5m depth from the bottom of channel. Result that calculate threshold discharge to use GCIUH, at the Mureung valley basin, flash flood trigger rainfall was 16.34mm in the first 20minutes when the threshold discharge was $14.54m^3/sec$.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.946-946
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• 2012

현재 국내 하천의 설계홍수량은 하천정비 기본계획이나 유역종합 치수계획 등을 통하여 고시 되고 있다. 이러한 설계홍수량은 홍수량 산정 지침에 따라 산정되며, 최종적으로 결정된 설계홍수량을 기준으로 하도계획이나 교량, 암거 등의 설계를 실시하였다. 현재 많은 수의 홍수조절용 다목적 댐과 강변저류지 등 각종 수리조작 구조물들이 축조되면서부터 홍수량을 시간별로 조절할 수 있게 되었지만, 미계측 유역에서는 유역의 유출량을 예측하기가 쉽지 않기 때문에 수리조작 구조물들의 효과를 예상하고 조작 및 운영방법을 결정하기 어려운 실정이다. 이러한 이유로, 본 연구에서는 미계측 유역 내 축조하는 수공 구조물의 최적 설계 및 운영방법 결정을 위하여 설계홍수량과 함께 합성단위도법을 적용한 수문곡선을 적용할 수 있도록 Nash 모형을 이용하였다. 유역의 유출특성이 반영된 대표단위도를 산정하기 위해 여러 유역의 다양한 형상계수를 이용하여, 도달시간과 첨두유량에 관한 회귀식을 산정하였다. 이렇게 산정된 회귀식을 여러 형태의 유역과 강우-유출 사상에 적용하여, 미계측 유역의 특정지점에서 발생의 개연성이 충분하고 수공구조물의 설계와 효과에 가장 중요하게 영향을 미칠 수 있는 설계홍수수문곡선을 도출하는 것을 목적으로 하였다. 본 연구의 결과로 나타나는 대표홍수수문곡선을 미계측 유역에 적용한다면 미지의 설계홍수량을 추정함과 동시에 설계홍수량에 상응하는 수문곡선을 도출하여 수공구조물 설계에 이용할 수 있을 것이라 기대한다.