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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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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
A Derivation of a Hydrograph by Using Smoothed Dimensionless Unit Kernel Function
Seong, Kee-Won ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 559~564
DOI : 10.3741/JKWRA.2008.41.6.559
A practical method is derived for determining the unit hydrograph and S-curve from complex storm events by using a smoothed unit kernel approach. The using a unit kernel yields more convenient way of constructing a unit hydrograph and its S-curve than a conventional method. However, with use of real data, the unit kernel oscillates and is unstable so that a unit hydrograph and S-curve cannot easily obtained. The use of non-parametric ridge regression with a Laplacian matrix is suggested for deriving an event averaged unit kernel which reduces the computational efforts when dealing with the Nash instantaneous unit hydrograph as a basis of the kernel. A method changing the unit hydrograph duration is also presented. The procedure shown in this work will play an efficient role when any unit hydrograph works is involved.
Estimation of WEPP's Parameters in Burnt Mountains
Park, Sang-Deog ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 565~574
DOI : 10.3741/JKWRA.2008.41.6.565
Fire-enhanced soil hydrophobicity often increases runoff and erosion in the mountain hillslope following severe wildfires. Estimation techniques for WEPP's parameters were studied in burnt mountain slopes. In burnt mountain slopes, the model over-predicted runoff in the small runoff and under-predicted runoff in the great runoff, and in the lower sediment runoff it had a tendency to over-predict soil loss. The effective hydraulic conductivity was most sensitive in the WEPP's runoff and its sediment runoff was mainly effected by the effective hydraulic conductivity, initial saturation, rill erodibility, and interrill erodibility. To improve the applicability of the WEPP, the adjustment coefficient of effective hydraulic conductivity was defined for runoff and the adjustment coefficient of rill erodibility and interrill erodibility was presented for sediment runoff. The adjustment coefficient of effective hydraulic conductivity in wildfire mountain slopes increased with maximum rainfall intensity of single storm and the vegetation height index. The adjustment coefficients of rill erodibility depended on soil components of size distribution curve and total rainfall depths in single storm. The adjustment coefficients of interrill erodibility decreased with increases of maximum rainfall intensity and vegetation height index. These results may be used in the application of WEPP model for wildfire mountain slopes.
Discharge Computation in Natural Rivers Using Chiu's Velocity Distribution and Estimation of Maximum Velocity
Kim, Chang-Wan ; Lee, Min-Ho ; Yoo, Dong-Hoon ; Jung, Sung-Won ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 575~585
DOI : 10.3741/JKWRA.2008.41.6.575
It is essential to obtain accurate and highly reliable streamflow data for water resources planning, evaluation and management as well as design of hydraulic structures. A new discharge computation method proposed in this research uses Chiu's velocity distribution and estimation of maximum velocity. This method shows acceptable channel discharges comparing these by the exiting velocity-area method. When velocity-area method is used, it is required to observe velocities at every specified point and vertical line using a velocity meter like Price-AA. If the method proposed in this research, is used, however it is not necessary to observe all point velocities needed in the velocity-area method. But this method can not be applied for the cases of very complex and strongly asymmetric channel cross-sections because Chiu's velocity distribution using entropy concept may be quite biased from that of natural rivers.
A Practical Approach Determining an IDF formula with Limited Rainfall-Duration Data Availability
Seong, Kee-Won ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 587~595
DOI : 10.3741/JKWRA.2008.41.6.587
In order to aid the derivation of the IDF relationship for a station with insufficient duration-rainfall data, an approach to derive a simple and practical IDF formula is presented. The IDF formula is described simply by the term of the two parameters and a design frequency. The model parameters were estimated from a statistical technique based on the normal distribution of transformed rainfall intensities. In order to give the transformed data, both the Kruskal-Wallis statistic and the Manly transformation of duration-rainfall data were adopted. With the methods, the proposed IDF formula becomes a simpler model that compares well with conventional form. In addition, it allows avoiding an exceptional condition of the higher rainfall intensity for longer duration. The performance of the proposed formula was evaluated by using the limited rainfall data for short duration from two gauge stations. The result showed that the IDF formula developed in this work was an effective tool, providing a reliable relationship between the intensity and duration even though insufficient data are only available.
The Study on the Technical Efficiency of Industrial Water in Manufacturing
Min, Dong-Ki ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 597~603
DOI : 10.3741/JKWRA.2008.41.6.597
This paper estimates technical efficiency of industrial water in order to afford some information for improving the efficiency of government water management policy. To estimate technical efficiency, this paper uses data envelopment analysis. The result shows that the average pure technical efficiency of industrial water is 0.407. This estimate is less than the estimates when all inputs are considered as variables in the previous researches. This result means that the managers may have not tried to improve the efficiency of industrial water usage since the cost for industrial water is trivial compared to other inputs. In addition, this result shows that the previous researches which assume that all inputs are used in efficient way may give a biased results.
Development of a Comprehensive Flood Index through Standardizing Distributions of Runoff Characteristics
Wi, Sung-Wook ; Chung, Gun-Hui ; Kim, Tae-Woong ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 605~617
DOI : 10.3741/JKWRA.2008.41.6.605
This study developed a flood index which evaluates runoff characteristics. Runoff characteristics expressed in a hydrograph were reflected in the flood index in the form of characteristic factors such as a rising curve gradient, a peak discharge, a flood response time, and a flood discharge volume prior to peak. This study applied the standardization method to estimate the relative severity of the characteristic factors by transforming the distribution of characteristic factors into the standard normal distribution. The flood index developed in this study is a comprehensive flood index (CFI) which makes up for the weak points of a flash flood index (FFI) in determining relative severities. The CFI was applied to Han River basin and Selma River basin, and was compared with the FFI based on the correlation analysis and the regression analysis. The CFI could comprehensively evaluate flood runoff characteristics because the CFI is not dominated by a specific characteristic factor, and the CFI could explain more efficiently the relationship between rainfall and runoff than the FFI.
Optimal Design of Bank Protection Work Using Analytic Hierarchy Process
Lee, Jae-Mun ; Lee, Sang-Il ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 619~628
DOI : 10.3741/JKWRA.2008.41.6.619
Bank protection is a structure constructed to protect directly embankment breakage and erosion by river flow. Traditionally, the type of bank protection has been decided by practitioner's subjective and empirical judgement, which often causes problems after construction. Recently, however, it becomes important to consider not only physical protection but also environment. Various types of bank protection for environment-friendly river are now available. Thus, there is a need for more objective and quantitative decision method for bank protection work. This study adopts the analytic hierarchy process (AHP) to improve the objectiveness in the decision of bank protection work. Criteria for stability, economy, construction, environment are identified and a standardized process is presented for field application. With the proposed method, one can prioritize various bank protection works and make the optimal decision. We believe that the method can serve as a useful tool for river engineers in practice.
Hydrologic Scenarios for Sustained Drought in Han River
Lee, Gwang-Man ; Cha, Hyung-Sun ; Lee, Seung-Yoon ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 629~641
DOI : 10.3741/JKWRA.2008.41.6.629
Many studies on sustained droughts have often been limited to the analysis of historic flow series. A major disadvantage in this approach can be described as the lack of long historic flow records needed to obtain a significant number of drought events for the analysis. To overcome this difficulty, one of the present study idea is to use synthetically generated hydrologic series. A methodology is presented to develop flow series based on the probabilistic analysis of the stochastic properties of the observed flows. The method can be utilized to generate a flow series of desired length so as to include many multiyear drought events within the process. In this paper, a concept of creating multiyear drought scenarios is introduced, and its development procedure is illustrated by a case study of the water supply system in Han River Basin. Also, it was found that the generated flow series can be reliably used to predict the long drought duration and sustained drought hydrologic scenarios within a given return period.
Analysis of Characteristics for Runoff Variation Considering Irrigation Area of Each Irrigation Facilities
Ryoo, Kyong-Sik ; Lee, Sang-Jin ;
Journal of Korea Water Resources Association, volume 41, issue 6, 2008, Pages 643~651
DOI : 10.3741/JKWRA.2008.41.6.643
This study was conducted to promote reliability of the simulated result for the long-term streamflow in Daecheong watershed. This system was constructed by the SSARR model that considered the effect of small scale irrigation facilities. We investigated the present condition of small scale irrigation facilities and analyzed the relation between irrigation facilities and river discharge. According to the analysis result about the effect of irrigation facilities, the error occurrence frequency was increased at the sub-basin that has many reservoirs and during the second quarter except for the 2003 year. Therefore, we created the relative equation between small irrigation facilities and river water and estimated the simulated streamflow for the main stations. Consequently, error of the runoff simulated with considering small scale irrigation facilities was decreased than that without considering small scale irrigation facilities at all.