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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korea Water Resources Association
Journal Basic Information
Journal DOI :
Korea Water Resources Association
Editor in Chief :
Volume & Issues
Volume 34, Issue 6 - Dec 2001
Volume 34, Issue 5 - Oct 2001
Volume 34, Issue 4 - Aug 2001
Volume 34, Issue 3 - Jun 2001
Volume 34, Issue 2 - Apr 2001
Volume 34, Issue 1 - Feb 2001
Selecting the target year
Dispersion of Nonconservative Contaminants Accidentally Released into Natural Streams
Jo, Seong-U ; Jeon, Gyeong-Su ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 289~301
A fractional step finite difference model for the longitudinal dispersion of nonconservative pollutants is applied to the Nakdong River to simulate the phenol spill accident which occurred on March, 1971. Prior to the dispersion calculation, the flow conditions are simulated to provide inputs to the dispersion model. An unsteady flow model based on Preissmann's four-point scheme is used for this purpose. Sensitivities of the dispersion calculation to empirical equations for dispersion coefficient and to the first-order decay coefficient are analyzed. The time to peak concentration at a downstream location is significantly different depending on the formula for the dispersion coefficient. Although the decay coefficient does not affect the shape of the temporal concentration distribution, the concentration values depend on the decay coefficient verb significantly. An optimization technique is used to calibrate the dispersion model as well as the flow model. The time to the peak concentration is simulated for major positions of water intake along the Nakdong River.
Hydrological Forecasting Based on Hybrid Neural Networks in a Small Watershed
Kim, Seong-Won ; Lee, Sun-Tak ; Jo, Jeong-Sik ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 303~316
In this study, Radial Basis Function(RBF) Neural Networks Model, a kind of Hybrid Neural Networks was applied to hydrological forecasting in a small watershed. RBF Neural Networks Model has four kinds of parameters in it and consists of unsupervised and supervised training patterns. And Gaussian Kernel Function(GKF) was used among many kinds of Radial Basis Functions(RBFs). K-Means clustering algorithm was applied to optimize centers and widths which ate the parameters of GKF. The parameters of RBF Neural Networks Model such as centers, widths weights and biases were determined by the training procedures of RBF Neural Networks Model. And, with these parameters the validation procedures of RBF Neural Networks Model were carried out. RBF Neural Networks Model was applied to Wi-Stream basin which is one of the IHP Representative basins in South Korea. 10 rainfall events were selected for training and validation of RBF Neural Networks Model. The results of RBF Neural Networks Model were compared with those of Elman Neural Networks(ENN) Model. ENN Model is composed of One Step Secant BackPropagation(OSSBP) and Resilient BackPropagation(RBP) algorithms. RBF Neural Networks shows better results than ENN Model. RBF Neural Networks Model spent less time for the training of model and can be easily used by the hydrologists with little background knowledge of RBF Neural Networks Model.
Estimation of Area Average Rainfall Amount and Its Error
Yu, Cheol-Sang ; Jeong, Gwang-Sik ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 317~326
This study evaluates the errors involved in the area average rainfall amounts estimated by the arithmetic mean method, the Thiessen's weighting method, and the optimal weighting method from the estimation theory. This study was applied to the upstream part of Nam-Han river basin (upper part of Youngwal) and the following results could be obtained. First, in case the raingauges are located evenly over the basin, no obvious difference can be found in the area average rainfall amounts from the arithmetic mean method or from the Thiessen's weighting method. However, as these two methods cannot consider the spatial variability of rainfall, the estimation error could be higher when the spatial variability of rainfall is high. In our application the estimation error from the arithmetic mean method or the Thiessen's weighting method was also found to be higher than that from the method from the information theory, which considers the spatial variability of rainfall. Thus, we could conclude that for the rainy season of Korea or for the mountain area when and where the spatial variability of rainfall is high, a proper method of considering the spatial variability of rainfall should be used regardless of the basin size. The isohyetal method generally used for the large basins or the optimal weighting method from the estimation theory used in this study could be good alternatives for this case.
Fall-Velocity Measurement Using Image Analysis Technique
Yun, Byeong-Man ; Yu, Gwon-Gyu ; No, Yeong-Sin ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 327~333
Particle tracking velocimetry (PTV) is introduced and applied to the fall-velocity measurement. The fall velocities of sediment particles were measured using PTV in the still water and compared with the values presented in the existing literature. Comparison shows that PTV measures the fall velocities accurately. This result enables the measurement of fall velocity in the turbulent flows, which was not possible with conventional methods.
An Analysis of Hydrologic Changes in Daechung Dam Basin using GCM Simulation Results due to Global Warming
An, Jae-Hyeon ; Yu, Cheol-Sang ; Yun, Yong-Nam ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 335~345
The objective of this research is to analyze the hydrological environment changes in Daechung Dam Basin due to the global warming. GCM simulation results are used to predict the possible changes in precipitation and temperature. The changes of potential evapotranspiration, soil moisture and runoff due to the changes of precipitation and temperature are analyzed using a conceptual water balance model. From the simulation results using the water balance model for lx
situations, it has been found that the runoff would decrease in Winter, but increase in Summer and Fall due to the global warming. Therefore, it is predicted that the frequency of drought and flood occurrences in Daechung Dam Basin would be increased in 2x
On the Change of Hydrologic Conditions due to Global Warming : 1. An Analysis on the Change of Temperature in Korea Peninsula using Regional Scale Model
An, Jae-Hyeon ; Yun, Yong-Nam ; Lee, Jae-Su ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 347~356
Even though the increase of greenhouse gases such as
is thought to be the main cause for global warming, its impact on global climate has not been revealed clearly in rather quantitative manners. However, researches using Genral Circulation Model(GCM) has shown that the accumulation of greenhouse gases increases the global mean temperature, which in turn impacts on the global water circulation pattern. A climate predictive capability is limited by lack of understanding of the different process governing the climate and hydrologic systems. The prediction of the complex responses of the fully coupled climate and hydrologic systems can be achieved only through development of models that adequately describe the relevant process at a wide range of spatial and temporal scales. These models must ultimately couple the atmospheres, oceans, and lad and will involve many submodels that properly represent the individual processes at work within the coupled components of systems. So far, there are no climate and related hydrologic models except local rainfall-runoff models in Korea. The purpose of this research is to predict the change of temperature in Korean Peninsula using regional scale model(IRSHAM96 model) and GCM data obtained from the increasing scenarios of
Korean Peninsula increased by
and the duration of Winter in
condition would be shorter the
condition due to global warming.
Estimation of Mean and Variance for
data of Puyeo Intake
Kim, Hyeong-Su ; Jeong, Geon-Hui ; Kim, Eung-Seok ; Kim, Jung-Hun ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 357~364
Sometimes the observed data is too small to discriminate it from noise of the instrument. Say, the data can be recorded as below DL(Detection Level) value. Even though the data below Detection Level(BDL) is small vague, it can be resulted in wrong estimates for mean and variance. However, in practice, the BDL data is generally eliminated as N.D. (Not Detected) and do not record it in Korea. This study investigates the distributions according to the data values of ammonia concentration (NH
-N) in Puyeo intake. Also we try to find out DL value and an appropriate method for the estimations of mean and variance of BDL values that can be discriminate the distributions. The DL is estimated by trial and error method. The appropriate method for the estimations of mean and variance of above the detection level(ADL)and BDL dada sets is selected, and the mean and variance are estimated. As a result, it is found that the Bias Corrected Maximum Likelihood Estimator is the most accurate method for NH
-N in Puyeo intake.
Assessment of Ascending Capacity of Migratory Fish in Fishways by Eco-hydraulic Experiments (I) - Baffled Fishways -
Park, Sang-Deok ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 365~379
This paper presents an echo-hydraulic experimental approach to assessment of ascending capacity of migratory fish in a baffled fishway. Sweetfish, Plecoglossus altivelis, trout, Oncorhynchus mykiss, are used in these experiments. Ascending environment of the migratory fish in rivers is analyzed through the results of taco-hydraulic experiments. Important factors affecting the ascending capacity of migratory fish in baffled fishways are the discharge and slope of fishways and the fall height between the fishway entrance and the river bed. In these fishways the migratory capacity of sweetfish for a given fishway discharge is mainly affected by fishway slope, whereas the ascending capacity of trout for a given fishway slope was influenced by the change of fishway discharge. Loss of ascending properties of landlocked salmon, Oncorhynchus masou var ishikawai, was confirmed by these experiments. An ascending hydraulic criteria of the baffled fishway is defined by means of dimensionless factor F
and falling head H
. Ascending capacity of migratory fish in existing baffled fishways in river of eastern coastal region is poor because the slope of fishways is verb steep.eep.
Assessment of Ascending Capacity of Migratory Fish in Fishways by Eco-hydraulic Experiments (II)
Park, Sang-Deok ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 381~390
This is to evaluate the ascending capacity of migratory fish in the pool and weir type fishways. Ascending environment of the migratory fish in rivers is analyzed through eco-hydraulic experiments using sweetfish, Plecoglossus altivelis, trout, Oncorhnchus mykiss, and surveying the fall height of existing pool and weir type fishways. When the fall height is less than 16.0cm, the ascending capacity of sweetfish in the pool and weir type fishways is greater than trout. On the other hand when the fall height is over 20.0 cm, the ascending capacity of trout is greater than sweetfish. A sweetfish may prefer to jump for upward moving than trout. And its endurance after upward jumping over wear is greater than that of sweetfish. Because of high fall height of existing pool and weir type fishways the migratory environment in rivers is so poor. When the pool and weir type fishways are designed and constructed in river the fall height of weir must be considered for the variety of migratory fish living in river and the fall height of weir less than 20.0cm is suggested.
Prediction of Soil Distribution Using Digital Terrain Indices
Lee, Hak-Su ; Kim, Gyeong-Hyeon ; Han, Ji-Yeong ; Kim, Sang-Hyeon ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 391~401
Several curvature parameters, solar radiation parameter and topographic flow generation parameters have been summarized and calculated to predict the spatial distribution of soil moisture content. The spatial distribution of soil moisture data can be obtained using Global Positioning System(GPS) and portable soil moisture monitoring equipment, Theta-Probe. Correlation analysis has been performed between the parameters of soil moisture prediction and measured data of soil moisture. Multiple regression analysis of soil moisture prediction shows the potential capability and limitations of existing methods of digital terrain analysis
Runoff Analysis of Modified TOPMODEL with Subsurface Storm Flow Generation Mechanism
Lee, Hak-Su ; Han, Ji-Yeong ; Kim, Gyeong-Hyeon ; Kim, Sang-Hyeon ;
Journal of Korea Water Resources Association, volume 34, issue 4, 2001, Pages 403~411
This paper investigates the applicability of a modified version of TOPMODEL considering shallow subsurface storm flow in a forested mountaneous catchment. The macroporous soil structure provides a hydrological pathway for rapid runoff generation. A modified version of TOPMODEL introduces the two-storage system to analyze the hydrograph recession including rapid subsurface storm flow component. The two-month continuous hydrologic simulations of sulmachun watershed suggest that a modified version of TOPMODEL represents comprehensive and realistic flow generation mechanism comparing to those of an original version of TOPMODEL. The results of parameter calibration with Monte-Carlo method indicate a modified version of TOPMODEL produces a set of physically meaningful parameters.