• Journal of Korea Water Resources Association
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• v.36 no.1
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• pp.23-32
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• 2003

This study aims at the derivation of representative IUH considering geomorphological factors. Nash model has been combined with geomorphological IUH to estimate the parameters of representative IUH. For this purpose, total 18 storm events which have been recorded upstream parts of Sangye control point in Bocheong river watershed, one of the tributary of Keum river basin, have been analysed. The results show that n value is 3.17 and K value is 7.01. And the results also show that IUHs driven by the method of moments vary with each storm events significantly. As a result of this study the IUH could be median distribution which is representative IUH among each storm events. It is believed that this result considered geomorphological factors is more superior and physically meaningful comparing with the existing methods.

• Journal of Korea Water Resources Association
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• v.33 no.1
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• pp.123-132
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• 2000

In the study the instantaneous unit hydrographs (IUHs) based on the linear Nash (1957) and the nonlinear Diskin (1964) models are derived and compared for the Soyang river basin. Total 14 rainfall runoff events are used for the study and the model parameters are estimated by minimizing the sum of square error considering runoff hydrograph ordinates as relative weights. The representative IUHs for both models are decided to show an average shape of derived IUHs. In the application of the representative IUHs of Nash and Diskin, Diskin model shows better performances in reproducing the observed outflows, especially the peak flow. In the comparison of two Diskin models little difference could be found between the IUHs with the same or different number of two characteristic reservoirs.rvoirs.

• 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.

• 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.

• 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.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.559-569
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• 2010

This study proposes an empirical method for estimating the concentration time and storage coefficient of a basin using the Nash unit hydrograph. This method is based on the analytically derived concentration time and storage coefficient of the Nash model. More fundamentally, this method recursively searches convergent number of linear reservoirs and storage coefficient of linear reservoir representing the basin given. This method is to overcome the problem of HEC-HMS to use an optimization technique to estimate the basin concentration time and storage coefficient. The proposed method was applied to the Bangrim station of the Pyungchang river basin, also found to estimate physically reasonable values.

• Water for future
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• v.12 no.2
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• pp.56-62
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• 1979

Many methods of estimating design floods from rainfall data involve a trial and error procedure to determine the duration of the design rainfall, which is very complicated and time-consuming. In this study, an effort was given to derive an analytical expression for estimating the appropriate duration for use with a particular unit hydrograph. According to the so-derived analytical expression the coordinateds of hvdrograph curve and rainfall curve for the Musim Representative Basin were computed and then plotted on a same scal graph paper on which the critical durations of design rainfall excess of various recurrence intervals were determined by the point of intersection of the tow curves.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.99-109
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• 1999

In the case of domestic general waste landfills, cumulated leachate level is often formed in the landfill due to the waste of high moisture content and it becomes important to characterize the hydraulic properties of the disposed waste. Although many hydrologic studies have been peformed for leachate barriers and pheriperal subsurface environments, few studies have been done to investigate the hydraulic property of the disposed waste and cover soils and to analyse the leachate flow behavior within landfills. In this paper, the geotechnical properties of the waste and buried cover soils are identified through the field experiment including pumping and slug tests. The results of various tests show that the field density of the cover soils is somewhat higher than the maximum laboratory density of cover soils and the vertical flow of leachate and gas in the landfill is prevented by the buried cover soils. The hydraulic conductivities of field pumping test and slug tests are well matched and stayed in the range of hydraulic conductivities of well compacted wastes in the literature.

• Water for future
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• v.29 no.6
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• pp.189-201
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• 1996

The main objective of this study is to determine the time distribution models of rainfall in Korea for estimating design floods and to suggest new runoff model(Geomorphologic Instantaneous Unit Hydrograph; GIUH) in order to be easily use the rainfall-runoff model put rainfall models practice to be suitable for the regional characteristics of hydrologic situation by practicing engineers. As a result, the reappearance of triangular hyetograph and GIUH runoff model showed promising. The historical data from about 13,000 event-rainfalls and 73 rainfall-runoff measuring data during 12 years in International Hydrological Program (IHP) basins have been used to determine the statistical factors of the time distribution for rainfalls by the Yen-Chow, Huff, Pilgrim-Cordery and Mononobe models. The Rational, Kajiyama, Nakayasu and Clark model and GIUH model that this study runoff model were used for the purpose of application limit for basin area against design concept by the estimation of flood runoff and the derivation of empirical equations to estimate the parameters for ungaged basins.

• Journal of Science and Technology Studies
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• v.10 no.1
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• pp.27-71
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• 2010

Scientific creativity is defined as the production of novel scientific facts, methods, theories, explanations, and instruments, as well as the entire process by which these novel facts, theories, explanations and instruments are generated. There have been many studies on scientific creativity, but there were few studies on the scientific creativity of a research team collaborating in laboratory settings. This paper aims to find the elements that constitute the creativity of a laboratory through empirical participant observation and theoretical analysis of RNA Biology Lab in Seoul National University - a lab which is considered to be the most creative laboratory in Korea. Creative accomplishments demand not just a sudden inspiration but also a complicated and continuous evolutionary process which requires a systematic division of labor and a corporation between researchers who have diverse knowledges and capabilities. Also, this paper shows that laboratory culture and leadership are an important factor for vitalizing the corporative structure of the laboratory.