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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 45, Issue 12 - Dec 2012
Volume 45, Issue 11 - Nov 2012
Volume 45, Issue 10 - Oct 2012
Volume 45, Issue 9 - Sep 2012
Volume 45, Issue 8 - Aug 2012
Volume 45, Issue 7 - Jul 2012
Volume 45, Issue 6 - Jun 2012
Volume 45, Issue 5 - May 2012
Volume 45, Issue 4 - Apr 2012
Volume 45, Issue 3 - Mar 2012
Volume 45, Issue 2 - Feb 2012
Volume 45, Issue 1 - Jan 2012
Selecting the target year
Analysis of Loop-Rating Curve in a Gravel and Rock-bed Mountain Stream
Kim, Dong-Su ; Yang, Sung-Kee ; Yu, Kwon-Kyu ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 853~860
DOI : 10.3741/JKWRA.2012.45.9.853
It is well-known that loop effect of the stage-discharge relationship is formulated based on many field observations especially for the sand rivers. Theoretical understandings of the loop effect for the sand rivers have been widely provided, based on the facts that it is driven by the flood wave propagation and bed form changes over the given flood period. However, very few theoretical studies or field observations associated with loop-rating curves in the gravel or rock-bed mountain streams have been attempted so far, due particularly to the difficulties in the accurate discharge measurement during the flood in such field conditions. The present paper aims to report a unique loop-rating curve measured at a gravel and rock-bed mountain stream based on the flood discharge observation acquired during the typhoon, Muifa that passed nearby Jeju Island in summer of 2011. As velocity instrumentation, a non-intrusive Surface Velocity Doppler Radar to be suitable for the flood discharge measurement was utilized, and discharges were consecutively measured for every hour. Interestingly, the authors found that the hysteresis of the loop-rating curve was adverse compared to the typical trend of the sand bed streams, which means that the discharge of the rising limb is smaller than the falling limb at the same stage. We carefully speculate that the adverse trend of the loop-rating curve in the gravel bed was caused by the bed resistance change that works differently from the sand bed case.
Comparing Prediction Uncertainty Analysis Techniques of SWAT Simulated Streamflow Applied to Chungju Dam Watershed
Joh, Hyung-Kyung ; Park, Jong-Yoon ; Jang, Cheol-Hee ; Kim, Seong-Joon ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 861~874
DOI : 10.3741/JKWRA.2012.45.9.861
To fulfill applicability of Soil and Water Assessment Tool (SWAT) model, it is important that this model passes through a careful calibration and uncertainty analysis. In recent years, many researchers have come up with various uncertainty analysis techniques for SWAT model. To determine the differences and similarities of typical techniques, we applied three uncertainty analysis procedures to Chungju Dam watershed (6,581.1
) of South Korea included in SWAT-Calibration Uncertainty Program (SWAT-CUP): Sequential Uncertainty FItting algorithm ver.2 (SUFI2), Generalized Likelihood Uncertainty Estimation (GLUE), Parameter Solution (ParaSol). As a result, there was no significant difference in the objective function values between SUFI2 and GLUE algorithms. However, ParaSol algorithm shows the worst objective functions, and considerable divergence was also showed in 95PPU bands with each other. The p-factor and r-factor appeared from 0.02 to 0.79 and 0.03 to 0.52 differences in streamflow respectively. In general, the ParaSol algorithm showed the lowest p-factor and r-factor, SUFI2 algorithm was the highest in the p-factor and r-factor. Therefore, in the SWAT model calibration and uncertainty analysis of the automatic methods, we suggest the calibration methods considering p-factor and r-factor. The p-factor means the percentage of observations covered by 95PPU (95 Percent Prediction Uncertainty) band, and r-factor is the average thickness of the 95PPU band.
Estimating the Total Precipitation Amount with Simulated Precipitation for Ungauged Stations in Jeju Island
Kim, Nam-Won ; Um, Myoung-Jin ; Chung, Il-Moon ; Heo, Jun-Haeng ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 875~885
DOI : 10.3741/JKWRA.2012.45.9.875
In this study, the total precipitation amount in Jeju Island was estimated with the simulated precipitation for ungauged stations missing precipitation data using the spatial precipitation analysis. The missing data were generated through the modified multiple linear regression in this study, and the analysis of spatial precipitation was conducted with the PRISM(Parameter-elevation Regression on Independent Slope Model). The generated data with modified multiple linear regression model have similar pattern with original data. Thus, the model in this study shows good applicability to estimate the missing data. The difference of annual average precipitation between Case 1 (original data) and Case 2 (modified data) appears very small ratio which is about 1.5%. However, the difference of annual average precipitation according to elevation shows the large ratio up to 37.4%. As the results, the method of estimating missing data in this study would be useful to calculate the total precipitation amount at the low station density area and the places with the high spatial variation of precipitation.
Assessment of Drought Severity over South Korea using Standardized Precipitation Evapo-transpiration Index (SPEI)
Kim, Byung-Sik ; Sung, Jang-Hyun ; Kang, Hyun-Suk ; Cho, Chun-Ho ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 887~900
DOI : 10.3741/JKWRA.2012.45.9.887
Drought is a non-negligible disaster of nature and it is mainly caused by rainfall shortage for a long time though there are many definitions of drought. `Standard Precipitation Index` (SPI) that is widely used to express the level of meteorological drought intensity has a limit of not being able to consider the hydrological changes such as rainfall and evapotranspiration caused by climate change, because it does not consider the temperature-related variables other than the precipitation. Recently, however, `Standardized Precipitation Evapotranspiration Index` (SPEI), a drought index of new concept which is similar to SPI but can reflect the effect of temperature variability as well as the rainfall change caused by climate variation, was developed. In this study, the changes of drought occurrence in South Korea were analyzed by applying SPEI for meteorological data (1973~2011) of 60 climate observatories under Korea Meteorological Administration (KMA). As the result of application, both of SPI and SPEI showed the trend of deepening drought in spring and winter and mitigating drought in summer for the entire nation, with SPI showing greater drought intensity than SPI. Also, SPI and SPEI with 12 months of duration showed that severe droughts with low frequency of around 6 years are generally being repeated.
Fuzzy TOPSIS Approach to Flood Vulnerability Assessment in Korea
Kim, Yeong-Kyu ; Chung, Eun-Sung ; Lee, Kil-Seong ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 901~913
DOI : 10.3741/JKWRA.2012.45.9.901
This study will be a new attempt to quantify flood vulnerability taking into account uncertainty. Information obtained from the real world has lots of uncertainties. Therefore, this study developed an approach to quantify spatial flood vulnerability of Korea using Fuzzy TOPSIS approach. Also, Fuzzy TOPSIS were compared with TOPSIS and weighted sum method. As a result, rankings of some areas were changed dramatically due to the uncertainty. Spearman rank correlation analysis indicated that the rankings of TOPSIS and weighted sum method were almost similar, but quite different from ranking of Fuzzy TOPSIS. In other words, because applying Fuzzy concept in regional vulnerability assessment may cause a significant change in priorities, the model presented in this study may be a method of vulnerability assessment.
Analysis of Tidal Asymmetry and Flood/Ebb Dominance around the Yeomha Channel in the Han River Estuary
Yoon, Byung-Il ; Woo, Seung-Buhm ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 915~928
DOI : 10.3741/JKWRA.2012.45.9.915
Han River estuary (HRE) is located at the middle of the western coast of Korea, and tidal currents were measured at 4 stations in this estuary during the winter season, and previously observed tide data was analyzed. The results of amplitude ratio of
showed that increasing upward to estuary in the HRE. Tide harmonic constants of relative phase
represent flood dominance, with under 180 degree. But this method has a limit of analysis that typically based on the non-linear distortion of the tidal current in tidal lagoon system where freshwater discharge is assumed to be relatively small. The results of statistically tidal current data indicated that ebb current velocity would be great unlike tide data. Ebb and flood duration time is calculated by slack time of tidal current showed that ebb duration time is longer than flood. The results of correlation of analysis show high value (0.9) between tidal current stations from Incheon harbor to north entrance of Yeomha channel. We reconstructed to find the reasons for the features of ebb dominance the results of harmonic analysis. As major component (
) in combination with shallow water component (
), the tidal curve was presented flood dominance that has a flood current is stronger. However, these curve were changed to ebb dominance add up the non-harmonic components that had ebb direction flow by calculated tidally averaged current. The characteristic of enhancement on ebb is showed around the Yeomha channel in the HRE, because averaged flow which acts seaward such as long-term tidal current components due to non-linear effect and freshwater which overcome the flood current.
Analysis of Water Quality Improvement in Downstream River of Heightening Irrigation Dam through the Reservoir Operation
Jee, Yong-Keun ; Lee, Mi-Seon ; Lee, Jin-Hee ; Jang, Jea-Ho ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 929~941
DOI : 10.3741/JKWRA.2012.45.9.929
In recent years, interest in river environment such as riparian landscape, water quality and ecological conservation has been growing with increasing recreation on agricultural river watershed. That caused the increase of necessity of water resources development, one of solutions for the diversification of agricultural water demand and shortages. In this respects, heightening irrigation dam, as a part of the 4-major river restoration project, is necessary to secure not only additional agricultural water but also instream flow for water quality improvement. However, operation plan of irrigation dam still not be clear. In this study, additional storage which secured through heightening irrigation dam was estimated using SWAT model. And instream flow effects on water quality of downstream were evaluated. The findings show that the additional water supply will contribute positively to water quantity and quality of downstream. The results show a 2~10% water quality improvement effect on nutrients, as well as an 1~8% water quantity increasing effect. In particular, additional storage can be effectively supplied from February to April by the reservoir operation. However, maintaining better water quality in irrigation reservoirs is important because the water quality of irrigation reservoirs can be negatively impacts the water quality in downstream of reservoirs.
Development of Erosion Fractal-based Interpolation Method of River Morphology
Hwang, Eui-Ho ; Jung, Kwan-Sue ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 943~957
DOI : 10.3741/JKWRA.2012.45.9.943
In this study, a technique based on Fractal Theory with Erosion Model was developed to interpolate the river morphology data at the border area between river bed and river side where both surface and under water surveyings can not be committed easily. Three dimensional river morphology data along the Ara River was generated by the developed technique. The Ara River is an artificially constructed waterway for vessels between the Han River and West Sea of Korea. The result was compared with the survey data by RMSE of 0.384, while the IDW interpolation result has RMSE of 0.802. Consequently, the developed river morphology data interpolation technique using Erosion Model based Fractal Theory is conceived to be superior to the IDW which has been generally used in generating the river morphology data.
Development of Flood Routing Model in the Navigation Waterway to Support Operations of Weir and Flood Gate
Noh, Joon-Woo ; Park, Myung-Ki ; Shim, Myung-Geun ; Lee, Sang-Jin ;
Journal of Korea Water Resources Association, volume 45, issue 9, 2012, Pages 959~968
DOI : 10.3741/JKWRA.2012.45.9.959
HEC-RAS has been applied to simulate water level variation in the Ara waterway during the flood season. To support decision making necessary for operation of the hydraulic structures especially during the flood season, it is important to consider various factors such as water level of the Han River, Gulpo River, and tidal level of the west sea in conjunction with operation of the hydraulic structures such as the Gyulhyun Weir, the West sea gate, and pumping stations. Especially for operation of the west sea gate, the Rule-script option was employed to determine the opening height considering the variation of the water level in the waterway and the west sea simultaneously. For model verification, comparison of water level computed at the upstream and downstream of the regulation weir shows a good agreement with observed data measured during the flood event in September 2010. The HEC-RAS model developed in this study will contribute to support operation of the waterway during the flood season.