• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.281-288
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• 2004

The objective of this study is to propose a methodology of the flood runoff analysis in steep mountainous basins and the analysis basin is the Jasa valley basin in Chungju city Analyzing the spatial pattern of the rainfall in 1994. 6 30~7.1, the seasonal rainy front was tied up in the whole central district, and the rainfall center was moving from the northern Chungbuk province to the northern Kyongbuk province and caused heavy storm. Analyzing the temporal pattern with the Huff method, the 52.5% of the rainfall was concentrated on the 3rd quartile. Rainfall frequency analysis is accomplished by five distribution types; 2-parameter Lognomal, 3-parameter Lognomal, Pearson Type III, Log-Pearson Type III and Extremal Type I distribution Rainfall-runoff analysis in Jasa valley basin was made using HEC-HMS model. Jasa valley basin was divided into 3 sub-basins and the analysis point was 3 points{A, B and C point) With the rainfall data measured by the 10 minutes, the flood runoff also was calculated by as many minutes. SCS CN model, Clark UH model and Muskingum routing model in HEC-HMS model were used to simulate the runoff volume using selected rainfall event.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1216-1220
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• 2006

최근 들어 기상이변으로 인해 집중호우가 빈번히 발생하여 막대한 홍수피해를 야기하고 있으며, 이에 자연재해에 대한 방재대책의 중요성 및 수공구조물들의 설계빈도를 상향조정하는 등의 대책마련이 절실히 요구되고 있는 실정이다. 특히 2002년 여름 강릉지역에 발생한 태풍 '루사'로 인한 집중호우는 기존 PMP(가능 최대강수량) 규모를 초과하는 사상 초유의 24시간 최대 강수량(880mm)을 기록하여 기존 댐 등과 같은 수공구조물의 설계기준에 대한 재고가 불가피 하게 되었다. 이에 본 연구에서는 미계측 유역인 상관저수지 유역을 대상으로 지속시간별 PMP를 산정한 후 임계지속시간을 고려한 PMF(가능최대홍수량)를 산정하여 유역내 대표적인 수공구조물인 저수지의 수문학적 치수안정성 여부를 검토하였다. 분석 대상유역인 상관저수지 유역의 PMP는 전국 전계절별 PMP도로부터 호우중심의 PMP와 유역중심의 PMP를 동일하게 하여 지속시간별 PMP를 산정하였다. 산정된 PMP로부터 Huff의 4분위법을 이용하여 강우를 시간분포 시킨 후 상관저수지 유역의 PMF를 산정하였으며, 이 때 이용된 유역의 홍수량추정 기법으로는 Clark 단위도법이다. 또한 본 연구에서는 수공구조물의 치수안정성을 검토하기 위하여 HEC-5모형을 이용한 저수지 홍수추적을 실시하였으며, 검토 결과 상관저수지의 수문학적 안정성은 확보된 것으로 분석되었다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.1-7
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• 2003

In the study, aeroelastic behaviors and aerodynamic performances of flexible airfoil in low Reynolds number environment are evaluated. To facilitate the present study, flexible airfoil in modeled through attaching massless membrane in portion of the upper CLARK-Y airfoil surface, which is often proposed low Reynolds number airfoil. The behavior of membrane in governed by aerodynamic forces and membrane equilibrium equation. Nondimensional parameter deducted by nondimensionalizing the membrane equilibrium equation, which represents the interaction between fluid and membrane has a great influence on membrane aeroelastic behavior. Changing the starting point of the membrane is conducted on aerodynamic performances. As a result, the value of nondimensional parameter should almost linearly increase according to moving the starting point of the membrane surface toward the trailing edge.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.358-364
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• 1993

Low foaming scouring agents(SLFS) were prepared by blending of 2-ethylhexylaminoethyl sulfate, Na-dioctyl sulfosuccinate, Newpol PP-2000, MJU-100, ethylene glycol and organic solvent. As the results of several tests, SLFS-2 showed good scouring effect, penetrating ability, emulsifiability and anti-alkaline property, and showed not much water pollution. The foaming power of SLFS-2 measured by Ross & Mites method was 8mm foam height immediately after foaming. And the foaming power of SLFS-2 measured by Ross & Clark method were less than 300mm foam height at $30^{\circ}C$, and 15mm at $80^{\circ}C$. As a result, SLFS-2 was proved as a good low foaming scouring agent.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1849-1853
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• 2007

In this study, flow-sediment discharge characteristics and relationships are estimated for the Cheonggyecheon basin, newly restored in 2005. Flow and sediment discharge measurement is performed on Ogansugyo, Majanggyo 2 and Yongdugyo during the rainy seasons in 2005-2006. The parameters of Clark UH are estimated using measured data, and sediment rating curves are derived by using grading and concentration analysis. Concentration time and storage coefficient of Clark UH are estimated 0.5 hr and 0.63 hr for Majanggyo 2, and 0.4 hr and 0.45 hr for Yongdugyo, respectively. Grain size of sediments are composed of fine silt to fine sand (0.008-0.25mm) based on the sediment grain size classification (Lane, 1947). Flow-sediment relationships derived by using concentration analysis shows that sediment discharge has no obvious relationship with flow discharge.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.103-111
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• 2014

This study was to develop the flood analysis module (FAM) for implementation of a web-based real-time agricultural flood management system. The FAM was developed to apply for an individual watershed, including agricultural reservoir. This module calculates the flood inflow hydrograph to the reservoir using effective rainfall by NRCS-CN method and unit hydrograph calculated by Clark, SCS, and Nakayasu synthetic unit hydrograph methods, and then perform the reservoir routing by modified Puls method. It was programmed to consider the automatic reservoir operation method (AutoROM) based on flood control water level of reservoir. For a $15.7km^2$ Gyeryong watershed including $472{\times}10^4m^3$ agricultural reservoir, rainfall loss, rainfall excess, peak inflow, total inflow, maximum discharge, and maximum water level for each duration time were compared between the FAM and HEC-HMS (applied SCS and Clark unit hydrograph methods). The FAM results showed entirely consistent for all components with simulated results by HEC-HMS. It means that the applied methods to the FAM were implemented properly.

• 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.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.57-66
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• 2007

The purpose of this study is both the variation of hydrologic topographical informations extracted by using WMS and the quantitative effect of rainfalll-runoff simulation due to dividing watershed. Miho stream basin in Geum river was selected by this study. Watershed dividing method are determined by area, channel slope and channel length. Hydrological response of divided watershed using Clark method, SCS method and Snyder method was compared with actual measured flood hydrograph. As a results, area-based watershed dividing method are particularly suitable the hydrologic applications using SCS method. This study can be used as basic data for the phase of the runoff variation in Miho stream basin.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.65-74
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• 2012

In this study, three different unit hydrograph methods (NRCS, Snyder and Clark) in the HEC-HMS were compared to find better fit with the observed data in the Namgang-Dam watershed. The Sancheong, Shinan, and Changchon in Namgang-Dam watershed were selected as the study watersheds. The input data for HEC-HMS were calculated land use, digital elevation map, stream, and watershed map provided by WAter Management Information System (WAMIS). Sixty six storms from 2004 to 2011 were selected for model calibration and validation. Three unit hydrograph methods were compared with the observed data in terms of simulated runoff volume, and peak runoff for the selected storms. The results showed that the coefficient of determination ($R^2$) for the peak runoff was 0.8295~0.9999 and root mean square error (RMSE) was 0.029~0.086 mm/day for calibration stages. In the model validation, $R^2$ for the peak runoff was 0.9061~0.9916 and RMSE was 0.030~0.088 mm/day which were more accurate than calibrated data. Analysis of variance showed that there was no significant difference among the three unit hydrograph methods.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.265-270
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• 1993

The symbiotic dynamics of Bradyrhiwbium japonicum YCK strains indigenous to Korean soils were investigated accordingly to their competitive conditions for nodulation. For this experiment the single strain inoculants of YCK strains and the mixed inoculants of one YCK strain and one USDA strain were applied to Korean Jangbaekkong and American Clark soybeans at mollisol soils(Torroxic Haplustoll, pH 6.8). The results were summarized as follows : 1. The symbiotic effectiveness of B. japonicum YCK strains was increased on the average of nitrogen accumulation by mixing with USDA strains, especially with strain USDA 110. 2. The effectiveness of each mixed inoculant was affected by soybean cultivar. 3. YCK strains occupied on the average of 83 and 86 % of the nodules against strain USDA 110 on Jangbaekkong and Clark soybeans, respectitvely. 4. The most effective strain among three YCK strains was strain YCK 213 as a single inoculant and was strain YCK 141 as a mixed inoculant with USDA strains. 5. The mixed inoculants of YCK strains and strain USDA 123 showed antagonism for nodulation.