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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korea Water Resources Association
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Journal DOI :
Korea Water Resources Association
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Volume & Issues
Volume 41, Issue 12 - Dec 2008
Volume 41, Issue 11 - Nov 2008
Volume 41, Issue 10 - Oct 2008
Volume 41, Issue 9 - Sep 2008
Volume 41, Issue 8 - Aug 2008
Volume 41, Issue 7 - Jul 2008
Volume 41, Issue 6 - Jun 2008
Volume 41, Issue 5 - May 2008
Volume 41, Issue 4 - Apr 2008
Volume 41, Issue 3 - Mar 2008
Volume 41, Issue 2 - Feb 2008
Volume 41, Issue 1 - Jan 2008
Selecting the target year
Development of a Decision Making Model for Efficient Rehabilitation of Sewer System
Lee, Jung-Ho ; Jun, Hwan-Don ; Joo, Jin-Gul ; Kim, Joong-Hoon ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 127~135
DOI : 10.3741/JKWRA.2008.41.2.127
The objective of sewer rehabilitation is to improve its function while eliminating inflow/infiltration (I/I) and insufficient carrying capacity (ICC). Such rehabilitation efforts, however, have not been particularly successful due to a lack of sewer data and unsystematic field practices. The present study aimed to solve these problems by developing a decision making model consisting of two models: the rehabilitation weighting model (RWM) and the rehabilitation priority model (RPM). In RWM, the I/I of each pipe in a drainage district is estimated according to various defects, with each defect given an individual weighting factor using an analytic hierarchy process (AHP). RPM determines the optimal rehabilitation priority (ORP) using a genetic algorithm (GA). The developed models can be used to overcome the problems associated with unsystematic practices and, in practice, as a decision making tool for urban sewer system rehabilitation.
Study on Critical_Allowable Shear Stress of Filling Rocks With Mattress Revetment
Bae, Sang-Soo ; Lee, Seung-Yoon ; Jee, Hong-Kee ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 137~147
DOI : 10.3741/JKWRA.2008.41.2.137
Critical and allowable shear stress acting on the mattress revetment, is presented in this study. First of all, shear stress at each spot is computed when the hydraulic power act on the waterway. Secondly, median diameter of the filling rocks is computed using shear stress and Shields coefficient which are used to decide the critical motion of the particle. Finally, the range of critical and allowable shear stress is estimated which meet the particle stability and indicated that the mattress is a stable hydraulic structure in comparison with the riprap. Therefore the required median diameter of riprap is three times higher than that of mattress. Contrarily, this study also analyzed that resisting power of mattress to shear stress is three times higher than that of riprap on the same size.
Application of SWAT for the Estimation of Soil Loss in the Daecheong Dam Basin
Ye, Lyeong ; Yoon, Sung-Wan ; Chung, Se-Woong ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 149~162
DOI : 10.3741/JKWRA.2008.41.2.149
The Soil and Water Assessment Tool (SWAT) developed by the USDA-Agricultural Research Service for the prediction of land management impact on water, sediment, and agricultural chemical yields in a large-scale basin was applied to Daecheong Reservoir basin to estimate the amount of soil losses from different land uses. The research outcomes provide important indications for reservoir managers and policy makers to search alternative watershed management practices for the mitigation of reservoir turbidity flow problems. After calibrations of key model parameters, SWAT showed fairly good performance by adequately simulating observed annual runoff components and replicating the monthly flow regimes in the basin. The specific soil losses from agricultural farm field, forest, urban area, and paddy field were 33.1,
depending on the tree types, 1.0, and 0.1 tons/ha/yr, respectively in 2004. It was noticed that about 55.3% of the total annual soil loss is caused by agricultural activities although agricultural land occupies only 10% in the basin. Although the soil erosion assessment approach adopted in this study has some extent of uncertainties due to the lack of detailed information on crop types and management activities, the results at least imply that soil erosion control practices for the vulnerable agricultural farm lands can be one of the most effective alternatives to reduce the impact of turbidity flow in the river basin system.
Hydrologic Regimes Analyses on Down Stream Effects of the Young Chun Dam by Indicators of Hydrologic Alterations
Park, Bong-Jin ; Kim, Joon-Tae ; Jang, Chang-Lae ; Jung, Kwan-Sue ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 163~172
DOI : 10.3741/JKWRA.2008.41.2.163
Hydrologic regimes play a major role in determining the biotic composition, structure, and function of river ecosystem. In this study, hydrologic regimes were analyzed on down stream effects of the Young-Chun dam construction using the Indicators of Hydrologic Alterations(IHA). The analysis results were as follows ; (1) Monthly mean flows were decreased during drought and flood season on the pre and post dam, (2) Magnitude and Duration of Annual Exterm Conditions, annual minima 1-day means was
and annual maxima 1-day mean was
on the pre and post dam (3) Timing of Annual Exterm conditions, Julian date of the annual minima 1-day means was 180th(June) in the pre dam, 257th(September) in the post dam, Julian date of the annual maxima 1-day means was 209th(July) in the pre dam, 217th(August) in the post dam, (4) Frequency and Duration of High and Low Pulse, Low Puls counts and duration were 3 times and 23 days in the pre dam, High Pulse counts and duration were 4 times and 2 days in the pre dam. (5) Rate and Frequency of Water Condition Changes, rise rates was 39.27 %, 19.36 % and fall rates -15.85 %, -8.16 % in the pre and post dam, respectively (6) Coefficient of Variation, annual exteram water conditions were decreased from 0.9054 to 0.6314 and from 1.0440 to 0.9617, Timing of Annual Exterm conditions were incereased for minima flow from 0.269 to 0.282, for maxima form 0.069 to 0.153.
Development of a Monitoring Technique of Dryness and Wetness in Watershed using Climatic Water Budget
Shin, Sha-Chul ; Hwang, Man-Ha ; Ko, Ick-Hwan ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 173~184
DOI : 10.3741/JKWRA.2008.41.2.173
Climatic water balance has been applied to obtain quantity of various hydrologic components. Hydrologic information is estimated by comparison between rainfall and evapotranspiration under complex terrain condition. Water deficit is defined as that subtraction of actual supply from climatic demand. The water deficit will occur, when monthly evapotranspiration exceed monthly rainfall. Contrary water surplus is defined as that surplus water after meeting the demand by plants. The water surplus will be occurred when monthly rainfall exceeds monthly evapotranspiration. Finally, the discrete moisture indices were calculated and mapped for the whole watershed to estimate dryness and wetness status using the climatic water balance approach. The result of this study can properly interpret the real drought and non drought. Based upon the results, it can be concluded that the climatic water balance model is useful to monitor water conditions for the watershed.
Estimation of the Flash Flood Severity using Runoff hydrograph and Flash flood index
Kim, Byung-Sik ; Kim, Hung-Soo ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 185~196
DOI : 10.3741/JKWRA.2008.41.2.185
The flash flood has been studied in the climatological aspect which considers temporal and spatial characteristics of rainfall. However, we have not interested in runoff hydrograph for flash flood study. Therefore, our objectives of this study are to apply a work of Bhaskar et. al (2000) which studied runoff hydrograph to represent the flash flood to Korea and also to distinguish flash flood event from general flood event. That is, we quantified the severity of flash flood by estimation of flash flood index using runoff hydrograph. This study estimated the flash flood index for investigating the relative severity of flash flood in Han river basin with 101 flood events. Also we quantified the flash flood severity for flood event by heavy rainfall occurred in July of 2006. As a result, Kangwon-do province showed more severe flash flood than other areas in Han river basin and urban area such as Jungrang cheon stream also showed severe flash flood. We analyzed a flash flood of July of 2006 by dividing July into 1st to 3rd terms. From the analysis we knew that the 1st term of July showed the severe flash flood was occurred in Seoul area and the 2nd term showed it was occurred in Kangwon-do province.
Analysis of Hydraulic effects on Piers and Transverse Overflow Type Structures in Urban Stream
Yoon, Sun-Kwon ; Chun, Si-Young ; Kim, Jong-Suk ; Moon, Young-Il ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 197~212
DOI : 10.3741/JKWRA.2008.41.2.197
Recently, stream flow analysis has been accomplished by one or two dimensional equations and was applied by simple momentum equations and fixed energy conservations which contain many condition limits. In this study, FLOW-3D using CFD (Computational Fluid Dynamics) was applied to stream flow analysis which can solve three dimensional RANS (Reynolds Averaged Navier-Stokes Equation) control equation to find out physical behaviors and the effect of hydraulic structures. Numerical simulation accomplished those results was compared by using turbulence models such as
, RNG (Renormalized Group)
and LES (Large Eddy Simulation). Numerical analysis results have been illustrated by the turbulence energy effects, velocity of flow, water level pressure and eddy flows around the piers and transverse overflow type structures. These results will be able to used by basis data that catch hold of effects on long-term bed elevation changes, sediment accumulations, scours and water aggravations by removal of obsolete transverse over flow type structures in urban stream.
Comparison of Evapotranspiration Estimation Approaches Considering Grass Reference Crop
Rim, Chang-Soo ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 212~228
DOI : 10.3741/JKWRA.2008.41.2.212
Five representative reference evapotranspiration(RET) equations were selected, and these equations were compared with pan evaporation by correlation analysis. Pan coefficients were also estimated. Furthermore, five selected RET equations were compared to find the similarity among those at the 21 meteorological stations located in South Korea. Five RET equations selected from 4 different category were Penman(combination approach), FAO Penman-Monteith(FAO P-M) (single source approach), Makkink and Priestley-Taylor (radiation approach) and Hargreaves(temperature approach) equations. In this study, the geographical and topographical conditions were considered for the selection of study stations. The daily meteorological data measured from 1970 at an interval of 5 years were applied in this study. The evapotranspiration estimates obtained by applying evapotranspiration equations were evaluated with numerical and graphical methods. The correlation coefficients between pan evaporation and RET in study stations were above 0.9 indicating very high correlation; however, the slopes of the individual regression lines show the values greater or less than 1.0. Hargreaves equation(temperature approach) shows the most similar evapotranspiration estimates to those of FAO P-M equation from 12 study stations, which are located near to seashore except Daegu station. On the other hand, Priestley-Taylor equation(radiation approach) shows the most similar evapotranspiration estimates to those of FAO P-M equation from 8 study stations, which are located in inland.
Study on Derivation of Fourth-Order GIUH and Revision of Initial State Probability
Ham, Dae-Heon ; Joo, Jin-Gul ; Jun, Hwan-Don ; Kim, Joong-Hoon ;
Journal of Korea Water Resources Association, volume 41, issue 2, 2008, Pages 229~239
DOI : 10.3741/JKWRA.2008.41.2.229
This study is to derive the fourth-order Geomorphologic Instantaneous Unit Hydrograph (GIUH), driven for only third-order basin, for the application of GIUH to various types of basin. The second, third, and fourth order GIUHs were compared for various topographical conditions. The results showed lower peak runoff and later peak time in GIUH with higher stream order. Initial state probability was estimated from a function of geomorphologic parameters such as area ratio and bifurcation ratio for the application of GIUH. However, initial state probabilities and early parts of the GIUHs have negative values for many basins due to the inherent errors in the parameters. Initial state probability was calculated by area ratio of direct drainage using ArcView GIS 3.2 model to solve the problem. GIUHs were estimated for three basins, Sanganmi, Byeongcheon, and Sangye, using the above suggested method, and the results showed that the method is free of the problem.