• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.04a
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• pp.91-98
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• 2000

Derivation of stage-discharge relationship and characteristics for Yangsan river is presented in this paper. This research has been conducted as the second one after the first trial of 1997. The determination of discharge at a Yangsan river gauging was best made by measuring the flow velocities with a current meter and rod float. The rating curve obtained through 52 stage-discharge measurements on Yangsan river basin in 1999 is represented by Q=15.3540-140.6076H+182.44372$H^2$, which is discovered to be most excellent among other curves in reliability analysis. The capability of the observed stage-discharge data for Yangsan river was tested by HEC-RAS program, and its capability to reproduce discharge was investigated and compared with the computational results. Rating curve stability is determined on the basis of deviations in the stage-discharge relationship, utilization of specific gauge, and absolute differences between sequential stream flow measurements and an analysis residuals. Therefore it seems necessary to research method to obtain rating curve in a rigorous and accurate manner.

• Journal of Korean Port Research
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• v.14 no.1
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• pp.107-114
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• 2000

Derivation of stage-discharge relationship and characteristics for Yangsan river is presented in this paper. This research has been conducted as the second one after the first trial in 1997. The determination of discharge at a Yangsan river gauging was best made by measuring the flow velocities with a current meter and rod float. The rating curve obtained through 52 stage-discharge measurements on Yangsan river basin in 1999 is represented by Q=15.3540-140.6076H+182.44372H$^2$, which is discovered to be most excellent among other curves in reliability analysis. The observed stage-discharge data for Yangsan river was tested by HEC-RAS program, and reproduction of discharge by the induced curve was investigated and compared with the computational results. The rating curve of Yangsan river shows characteristics of Yangsan river more accurately compared with those separated in terms of water levels.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.109-114
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• 2012

Stage-discharge relationship is applied to convert water level into discharge at the auto-measuring station in many irrigation canals. The stage-discharge curve is very important for reliable application for the agricultural water management system. We made results of discharge measurement at 18 stations in the irrigation canal nearby the Idong reservoir from 2010 to 2011. Stage-discharge relationships for each 18 stations were drawn considering of different hydraulic and geometrical characteristics at each stations. R-squared over 0.91 at each stations show high reliability for application of these relationships.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.177-184
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• 2013

This study analyzed the hydraulic characteristics of a venturi flume with a circular cone using a 3-D numerical model which uses RANS(Reynolds-Averaged Navier-Stokes Equation) as the governing equation. The venturi flume with the circular cone efficiently measures the discharge in the low-flow to high-flow range and offers the advantage of accurate discharge measurements in the case of a low flow. With no influence of the tail-water depth, the stage-discharge relationship and the flow behaviors were analyzed to verify the numerical simulation results. Additionally, this study reviewed the effect of the tail-water depth on the flow. The stage-discharge relationship resulting from a numerical simulation in the absence of an effect by the tail-water depth showed a maximum margin of error of 4 % in comparison to the result of a hydraulic experiment. The simulation results reproduced the overall flow behaviors observed in the hydraulic experiment well. The flow starts to become influenced by the tail-water depth when the ratio of the tail-water depth to the total head exceeds approximately 0.7. As the ratio increases, the effect on the flow tends to grow dramatically. As shown in this study, a numerical simulation is effective for identifying the stage-discharge relationship of a venturi flume with various types of venturi bodies, including a venturi flume with a circular cone.

• Journal of Environmental Science International
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• v.21 no.6
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• pp.739-747
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• 2012

Due to the difficulties for measuring flood discharge in the dangerous field conditions, conventional instruments with relatively low accuracy such as float still have been widely utilized for the field survey. It is also limited to use simple stage-discharge relationship for assessment of the flood discharge, since the stage-discharge relationship during the flood becomes complicated loop shape. In recent years, various non-intrusive velocity measurement techniques such as electromagnetic wave or surface images have been developed, which is quite adequate for the flood discharge measurements. However, these new non-intrusive techniques have little tested in the flood condition, though they promised efficiency and accuracy. Throughout the field observations, we evaluated the validity of these techniques by comparing discharge and velocity measurements acquired concurrently during the flood in a mountain stream. As a result, the flood discharge measurements between electromagnetic wave and surface image processing techniques showed high positive relationship, but velocities did not matched very well particularly for the high current speed more 3 m/s. Therefore, it should be noted here that special cares are required when the velocity measurements by those two different techniques are used, for instance, for the validation of the numerical models. In addition, authors assured that, for the more accurate flood discharge measurements, velocity observation as well as stage height is strongly necessary owing that the unsteady flow occurs during the flood.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.831-838
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• 2018

This paper presents a method to estimate the flow discharge in a backwater affected river junction. First, unsteady HEC-RAS model was simulated and calibrated using 2 recent real flood and then HPG (Hydraulic Performance Graph) was created by plotting the relationship between upstream and downstream stages and discharge in the reach and performing kriging interpolation. During a flood, the discharge through the reach can be estimated based on the stages at its ends and the developed HPG. These discharge data were in good agreement with the automatic discharge measurements such as ADVM. This study could provide an economical and practical method for estimating discharge in a junction with a high hysteresis of stage-discharge relationships.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.1-9
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• 2009

This study is focused on the analysis of loop characteristics of stage-discharge relation which is widely used for the production of discharge data and the simulation of loop stage-discharge relation using the numerical model. Analysis of consecutive stage and discharge data at 3 points revealed that loop of stage-discharge relationship is very strong. This means that the existing single stage-discharge relation may include large amount of error. Various flood events are simulated in mainstream of Han river with one-dimensional numerical model. The calculated stage data are compared with measured data. Especially continuous field-flow measurements concurrently collected with an Acoustic Doppler Velocity Meter (ADVM) on Hangang bridge in the case of 2007 flood event are used to verify the model applicability of estimating flows in open channels. This comparison shows that numerical model is an accurate and reliable alternative for making the real stage-discharge relation. Simulation of stage-discharge relation by a numerical model at Paldang and Hangang bridge showed good agreements with measured one, so it may be possible to generate real loop stage-discharge relation with properly calibrated and verified numerical model. It can be concluded that results of this study can contribute to error analysis of conventional single stage-discharge relation and development of loop stage-discharge relation with numerical model.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.807-816
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• 2015

In general, the water stage-discharge relationship curve is established based on the assumptions of linearity and homoscedasticity. However, the relationship between the water stage and discharge is affected from geomorphological factors, which violates the basic assumptions of the water stage-discharge relationship curve. In order to reduce the error due to the violations, the curve is divided into several sections based on the manager's judgement considering change of cross-sectional shape. In this research, the objective-splitting criteria of the curve is proposed based on the measured data without the subjective decision. First, it is assumed that the coefficient of variation follows the normal distribution. Then, if the newly calculated coefficient of variation is outside of the 95% confidential interval, the curve is divided. Namely, the groups is divided by the characteristics of the coefficient of variation and the reasonable criteria is provided for establishing a multi-segmented rating curve. To validate the proposed method, it was applied to the data generated by three artificial power functions. In addition, to confirm the applicability of the proposed method, it is applied to the water stage and discharge data of the Muju water stage gauging station and Sangegyo water stage gauging station. As a result, it is found that the automatically divided rating curve improves the accuracy and extrapolation accuracy of the rating curve. Finally, through the residual analysis using Shapiro-Wilk normality test, it is confirmed that the residual of water stage-discharge relationship curve tends to follow the normal distribution.

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.535-540
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• 2000

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.393-403
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• 2019

The water-storage performance of an intake weir can be evaluated by stage-discharge ratings. The stage-discharge rating of a gabion weir depends on the physical characteristics of the filling materials. This study reviewed existing discharge formulae for the evaluation of the water-storage performance of gabion weirs. A previously published relationship between the characteristics of filling materials and experimental constants was adapted for stage-discharge rating. The mean size of the filling material is the most influential factor for the water intake and water-storage performance of gabion weirs.