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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
Application of Continuous Stirred Tank Reactor Model for Water Quality Control and Management in Wetland Treatment
Kim, Kyung-Sub ; Ahn, Tae-Jin ; Kim, Min-Su ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 243~249
DOI : 10.3741/JKWRA.2008.41.3.243
Continuous stirred tank reactor(CSTR) model which can be applied to control and management of the surface flow wetland is developed to simulate the water quality in this research. The model solution is obtained from the optimization model using the least-squares and 4th-order Runge-Kutta methods. The model is applied to simulate BOD and TSS in the wetland database of U.S. EPA, in which the hydraulic and water quality data are enough and the number of pond is just one for simple analysis of running results. The model is tested in two different cases, one constant volume case and another constant volume and flow rate case considering only reaction term, mass flux term and both reaction and mass flux terms respectively. It is found that the model simulates the real water quality very well with both reaction and mass flux terms rather than only reaction term and the settling velocity of TSS becomes
. The model can be applied in wetlands treatment efficiently.
Derivation of Intensity-Duration-Frequency and Flood Frequency Curve by Simulation of Hourly Precipitation using Nonhomogeneous Markov Chain Model
Choi, Byung-Kyu ; Oh, Tae-Suk ; Park, Rae-Gun ; Moon, Young-Il ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 251~264
DOI : 10.3741/JKWRA.2008.41.3.251
In this study, a nonhomogeneous markov model which is able to simulate hourly rainfall series is developed for estimating reliable hydrologic variables. The proposed approach is applied to simulate hourly rainfall series in Korea. The simulated rainfall is used to estimate the design rainfall and flood in the watershed, and compared to observations in terms of reproducing underlying distributions of the data to assure model`s validation. The model shows that the simulated rainfall series reproduce a similar statistical attribute with observations, and expecially maximum value is gradually increased as number of simulation increase. Therefore, with the proposed approach, the non-homogeneous markov model can be used to estimate variables for the purpose of design of hydraulic structures and analyze uncertainties associated with rainfall input in the hydrologic models.
Simulation of Hourly Precipitation using Nonhomogeneous Markov Chain Model and Derivation of Rainfall Mass Curve using Transition Probability
Choi, Byung-Kyu ; Oh, Tae-Suk ; Park, Rae-Gun ; Moon, Young-Il ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 265~276
DOI : 10.3741/JKWRA.2008.41.3.265
The observed data of enough period need for design of hydrological works. But, most hydrological data aren`t enough. Therefore in this paper, hourly precipitation generated by nonhomogeneous Markov chain model using variable Kernel density function. First, the Kernel estimator is used to estimate the transition probabilities. Second, wet hours are decided by transition probabilities and random numbers. Third, the amount of precipitation of each hours is calculated by the Kernel density function that estimated from observed data. At the results, observed precipitation data and generated precipitation data have similar statistic. Also, rainfall mass curve is derived by calculated transition probabilities for generation of hourly precipitation.
Development of a Integrated Indicator System for Evaluating the State of Watershed Management in the Context of River Basin Management Using Factor Analysis
Kang, Min-Goo ; Lee, Kwang-Man ; Ko, Ick-Hwan ; Jeong, Chan-Yong ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 277~291
DOI : 10.3741/JKWRA.2008.41.3.277
In order to carry out river basin management, it is necessary to evaluate the state of the river basin and make site-specific measures on the basis of management goals and objectives. A river basin is divided into several watersheds, which are composed of several components: water resources, social and economic systems, law and institution, user, land, ecosystems, etc. They are connected among them and form network holistically. In this study, a methodology for evaluating watershed management was developed by consideration of the various features of a watershed system. This methodology employed factor analysis to develop sub-indexes for evaluating water use management, environment and ecosystem management, and flood management in a watershed. To do this, first, the related data were gathered and classified into six groups that are the components of watershed systems. Second, in all sub-indexes, preliminary tests such as KMO (Kaiser-Meyer-Olkin) measure of sampling adequacy and Bartlett`s test of sphericity were conducted to check the data`s acceptability to factor analysis, respectively. Third, variables related to each sub-index were grouped into three factors by consideration of statistic characteristics, respectively. These factors became indicators and were named, taking into account the relationship and the characteristics of included variables. In order to check the study results, the computed factor loadings of each variable were reviewed, and correlation analysis among factor scores was fulfilled. It was revealed that each factor score of factors in a sub-index was not correlated, and grouping variables by factor analysis was appropriate. And, it was thought that this indicator system would be applied effectively to evaluating the states of watershed management.
Development and Validation of A Decision Support System for the Real-time Monitoring and Management of Reservoir Turbidity Flows: A Case Study for Daecheong Dam
Chung, Se-Woong ; Jung, Yong-Rak ; Ko, Ick-Hwan ; Kim, Nam-Il ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 293~303
DOI : 10.3741/JKWRA.2008.41.3.293
Reservoir turbidity flows degrade the efficiency and sustainability of water supply system in many countries located in monsoon climate region. A decision support system called RTMMS aimed to assist reservoir operations was developed for the real time monitoring, modeling, and management of turbidity flows induced by flood runoffs in Daecheong reservoir. RTMMS consists of a real time data acquisition module that collects and stores field monitoring data, a data assimilation module that assists pre-processing of model input data, a two dimensional numerical model for the simulation of reservoir hydrodynamics and turbidity, and a post-processor that aids the analysis of simulation results and alternative management scenarios. RTMMS was calibrated using field data obtained during the flood season of 2004, and applied to real-time simulations of flood events occurred on July of 2006 for assessing its predictive capability. The system showed fairly satisfactory performance in reproducing the density flow regimes and fate of turbidity plumes in the reservoir with efficient computation time that is a vital requirement for a real time application. The configurations of RTMMS suggested in this study can be adopted in many reservoirs that have similar turbidity issues for better management of water supply utilities and downstream aquatic ecosystem.
An Experimental Study for Estimation of Head Loss Coefficients at Surcharged Circular Manhole
Kim, Jung-Soo ; Song, Ju-Il ; Jang, Suk-Jin ; Yoon, Sei-Eui ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 305~314
DOI : 10.3741/JKWRA.2008.41.3.305
Urban sewer systems are designed to operate in open-channel flow regime and energy loss at circular manholes are usually not significant. However, the energy loss at manholes, often exceeding the friction loss of pipes under surcharge flow, is considered as one of the major causes of inundation in urban area. Therefore, it is necessary to analyze the head loss associated with manholes, especially in surcharge flow. Hydraulic experimental apparatus which can be changed the invert type(CASE A, B, C) and step height(CASE I, II, III) was installed for this study. The range of the experimental discharges were from
. As the manhole diameter ratio(
) increases, head loss coefficient increases due to strong horizontal swirl motion. Head loss coefficient was maximum because of strong oscillation of water surface when the range of manhole depth ratios(
) were from 1.0 to 1.5. The average head loss coefficients for CASE A, B, and C were 0.45, 0.37, and 0.30, respectively. Accordingly, U-invert is most effective for energy loss reduction at circular manhole. This head loss coefficients could be available to design the urban sewer system with surcharge flow.
Estimating of Social Preference of the Watershed Resident about the Anyangcheon Watershed Water Quality Improvement
Kong, Ki-Seo ; Kong, Doo-Ho ; Yoo, Jin-Chae ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 315~324
DOI : 10.3741/JKWRA.2008.41.3.315
This paper double-bound dichotomous choice method as a contingent valuation methods is used to derive willingness to pay for the water quality at the Anyangcheon watershed. The linear random utility model show that value of improvement of the Anyangcheon watershed water quality is 4,930 won per house and month of the Seoul and Gyeong-gi area residents. There is no difference between Seoul and Gyeong-gi area residents. Respondents overall accepted the contingent market and were willing to contribute a significant amount (3,860 to 5,101 won), on average, per household per month. The aggregate value of the water quality improvement in the Anyangcheon watershed amounts to approximately 83.0 to 109.7 billion won per year. This study is expected to contribute to the decision-making process for policy-makers by providing useful methodological framework and quantitative information related to watershed improvement projects.
Regional Low Flow Frequency Analysis Using Bayesian Multiple Regression
Kim, Sang-Ug ; Lee, Kil-Seong ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 325~340
DOI : 10.3741/JKWRA.2008.41.3.325
This study employs Bayesian multiple regression analysis using the ordinary least squares method for regional low flow frequency analysis. The parameter estimates using the Bayesian multiple regression analysis were compared to conventional analysis using the t-distribution. In these comparisons, the mean values from the t-distribution and the Bayesian analysis at each return period are not significantly different. However, the difference between upper and lower limits is remarkably reduced using the Bayesian multiple regression. Therefore, from the point of view of uncertainty analysis, Bayesian multiple regression analysis is more attractive than the conventional method based on a t-distribution because the low flow sample size at the site of interest is typically insufficient to perform low flow frequency analysis. Also, we performed low flow prediction, including confidence interval, at two ungauged catchments in the Nakdong River basin using the developed Bayesian multiple regression model. The Bayesian prediction proves effective to infer the low flow characteristic at the ungauged catchment.
Flood Forecasting and Warning Using Neuro-Fuzzy Inference Technique
Yi, Jae-Eung ; Choi, Chang-Won ;
Journal of Korea Water Resources Association, volume 41, issue 3, 2008, Pages 341~351
DOI : 10.3741/JKWRA.2008.41.3.341
Since the damage from the torrential rain increases recently due to climate change and global warming, the significance of flood forecasting and warning becomes important in medium and small streams as well as large river. Through the preprocess and main processes for estimating runoff, diverse errors occur and are accumulated, so that the outcome contains the errors in the existing flood forecasting and warning method. And estimating the parameters needed for runoff models requires a lot of data and the processes contain various uncertainty. In order to overcome the difficulties of the existing flood forecasting and warning system and the uncertainty problem, ANFIS(Adaptive Neuro-Fuzzy Inference System) technique has been presented in this study. ANFIS, a data driven model using the fuzzy inference theory with neural network, can forecast stream level only by using the precipitation and stream level data in catchment without using a lot of physical data that are necessary in existing physical model. Time series data for precipitation and stream level are used as input, and stream levels for t+1, t+2, and t+3 are forecasted with this model. The applicability and the appropriateness of the model is examined by actual rainfall and stream level data from 2003 to 2005 in the Tancheon catchment area. The results of applying ANFIS to the Tancheon catchment area for the actual data show that the stream level can be simulated without large error.