• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.78-88
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• 2006

This paper is to apply Geographical Information System (GIS) supported Geomorphoclimatic Instantaneous Unit Hydrograph (GCIUH) approach for the calculated flash flood trigger rainfall of the mountainous area. GIS techniques was applied in geography data construction such as average slope, drainage area, channel characteristics. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. We compared the GCIUH peak discharge with the existing report using the design storm at Chundong basin($14.58km^2$). The results showed that derived the GCIUH was a very proper method in the calculation of mountaunous discharge. At the Chundong basin, flash flood trigger rainfall was 12.57mm in the first 20 minutes when the threshold discharge was $11.42m^3/sec$.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.15-27
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• 2006

This paper is about the threshold discharge computation using GIUH(Geomorphoclimatic Instantaneous Unit Hydrograph) on ungauged small basin. GIUH is one of the possible approaches to predicting the hydrograph characteristics. This study is calculated the various ways which are hydrologic characteristics, bankfull flows, unit peak flows(the Clark, the Nakayasu and the S.C.S) as well as threshold runoffs on about $5km^2$ scale at Kyungbuk gampo in subbasin. We are estimated propriety that peak discharge calculated the GIUH from acquiring data by GIS(Geographic Information System) compared to observed peak discharge. And, the threshold discharge was calculated by NRCS(Natural Resources Conservation Service) for a flash flood standard rainfall.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.317-327
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• 2005

The flood is the most general and frequently occurs among natural disasters. Generally flood by the rainfall which extends superexcellently for the occurrence but flash flood from severe rain storm gets up an absurd drowsiness at grade hour. This paper aims to 1 hour real-time flash flood and predict possibility at the area where is the possible flood will occur from the rainfall hour mountain after acquiring data in GIS(Geographic Information System) base by GcIUH(Geomorphoclimatic Instantaneous Unit Hydrograph). The flash flood occurrence is set up at 0.5m, 0.7m and 1.0m in standard depth. And this study suggests standard flood alarm which designed by probable flood according to duration time. The research result shows real-time flash flood evaluation has the suitable standard in the basin when comparing with the existing official warning announcement system considering topographical information.

• 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 KSRS Conference
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• v.2
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• pp.884-887
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• 2006

This paper focuses on minimizing flood damage in the Yeongdeok basin of South Korea by establishing a flood prediction model based on a geographic information system (GIS), remote sensing, and geomorphoclimatic instantaneous unit hydrograph (GcIUH) techniques. The GIS database for flash flood prediction was created using data from digital elevation models (DEMs), soil maps, and Landsat satellite imagery. Flood prediction was based on the peak discharge calculated at the sub-basin scale using hydrogeomorphologic techniques and the threshold runoff value. Using the developed flash flood prediction model, rainfall conditions with the potential to cause flooding were determined based on the cumulative rainfall for 20 minutes, considering rainfall duration, peak discharge, and flooding in the Yeongdeok basin.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.2 s.36
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• pp.15-22
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• 2006

Runoff Characteristics has been Analysis Using geomorphologic Instantaneous Unit Hydrograph(GIUH) and geomorphoclimatic unit hydrograph(GCUH) on an ungaged vary small basin about $5km^2$ scale in Kyungbuk gampo area. First, we estimated hydrology Factor using Geographic Information System(GIS) tool and then, calculated the characteristic velocity using the real rainfall-runoff data. It is compared with several velocities derived from GCUH theory and several other concentration time formulae. Kerby and Braby-Williams seems to be more applicable as characteristic velocity formula. Second, We compared the GCUH peak discharge with the probable flood, also compared the unit hydrograph as like the Clark, the Nakayasu and the S.C.S and GCUH with the observed discharge using the real rainfall events. The comparison results showed that GCUH could be applicable on an ungaged vary small basin. We expected that the result can be used as for estimation of a flash flood standard rainfall as well as emergency management plan.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.319-319
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• 2012

최근 GIS의 발달로 지리정보를 정확하게 분석한 후 각종 수리 해석에 활발히 적용되고 있다. 수문지형학(Hydrogeomorphology)은 Rodriguez-Iturbe(1971)가 유역의 지형학적 인자를 기초로 하여 순간단위도를 유도하는 방법을 제시하는 것을 시작으로 Rodriguez-Iturbe와 Gonzalez-Sanabria(1982)가 지형학적 순간단위유량도(GIUH, Geomorphologic Instantaneous Unit Hydrograph) 매개변수와 유효우량만으로 함수를 표시하는 지형기후학적 순간단위유량도(GcIUH, Geomorphoclimatic Instantaneous Unit Hydrograph)를 유도하여 오늘날까지 발전해 오고 있다. GIS를 활용한 돌발홍수 및 지형학적 지형 기후학적 순간단위도 유도 및 한계유출량에 관한 연구에서 Sweeney(1992)는 돌발홍수능의 표준적인 산정 알고리즘을 제시하였고, Carpenter 등(1999)은 GIS와 연계하여 돌발홍수능을 산정하는데 중요한 한계유출량 산정방법에 관해 연구하였으며, 국내에서는 김운태 등(2002)은 GIS를 이용한 미소유역 규모의 한계유출량 산정 시스템을 개발한 바 있으며, 황보종구(2007)는 국내 유역에 적합한 GcIUH 산정방안에 관한 연구를 수행한 바 있다. 본 연구에서는 한국건설기술연구원에서 1995년부터 운영해 온 설마천 유역에 대하여 GIS 기법을 활용하여 강우-유출 해석시 GcIUH의 매개변수를 산정하여 유역에 적합한 돌발홍수 기준우량을 산정하는 것을 목적으로 하였다. GIS 기법의 적용결과를 통해 산정된 설마천 유역의 지형학적 특성은 <표 1>과 다음과 같다. 한편, 돌발홍수의 개념에서 한계유출량( )은 소하천의 제방을 월류하기 시작하여 홍수를 일으키기 시작할 때의 유효우량으로 정의되며, 유역전반에 걸쳐 균등하게 내리는 단위유효우량으로 인해 발생하는 직접유출 수문곡선이므로 제방이 가득 찬 상태의 유량 즉, 제방이 월류하기 시작할 때의 유량은 등류상태의 흐름을 해석하는 Manning의 공식으로부터 산정할 수 있으며(Chow et al., 1988), 설마천 유역의 경우 50년 빈도 홍수량에 해당하는 수위와 한계유량을 산정하였다. 향후 2011년 홍수 분석을 통해 한계유량 및 기준우량의 적합성을 평가하고 이를 바탕으로 설마천 유역의 돌발홍수예측을 위한 기준우량의 산정 등을 통해 산지 특성을 고려한 돌발홍수예측시스템 프로토타입을 개발하고자 한다.

• 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 $14.54m^3/sec$.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.571-580
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• 2012

This study is on the purpose of leading Geomorphoclimatic Instantaneous Unit Hydrograph(GcIUH) by using GIS Techniques, and estimating trigger rainfall for predicting flash flood in Seolmacheon catchment, mountain river watershed. This study leads GcIUH by using GIS techniques, calculates NRCS-CN values for effective rainfall rate, and analyzes 2011 main rainfall events using estimated GcIUH. According to the results, the case of Memorial bridge does not exceed the amount of threshold runoff, however, the case of Sabang bridge shows that simulated peak flow, approximately $149.4m^3/s$, exceeds the threshold runoff. To estimate trigger rainfall, this study determines the depth of 50 year-frequency designed flood amount as a threshold water depth, and estimates trigger rainfall of flash flood in consideration of duration. Hereafter, this study will analyze various flood events, estimate the appropriateness of trigger rainfall as well as threshold runoff through this analysis, and develop prototype of Flash Flood Prediction System which is considered the characteristics of mountain river watershed on the basis of this estimation.