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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 48, Issue 12 - Dec 2015
Volume 48, Issue 11 - Nov 2015
Volume 48, Issue 10 - Oct 2015
Volume 48, Issue 9 - Sep 2015
Volume 48, Issue 8 - Aug 2015
Volume 48, Issue 7 - Jul 2015
Volume 48, Issue 6 - Jun 2015
Volume 48, Issue 5 - May 2015
Volume 48, Issue 4 - Apr 2015
Volume 48, Issue 3 - Mar 2015
Volume 48, Issue 2 - Feb 2015
Volume 48, Issue 1 - Jan 2015
Selecting the target year
Simulation of Agricultural Water Supply Considering Yearly Variation of Irrigation Efficiency
Song, Jung Hun ; Song, Inhong ; Kim, Jin Taek ; Kang, Moon Seong ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 425~438
DOI : 10.3741/JKWRA.2015.48.6.425
The objective of this study was to evaluate simulation of agricultural water supply considering yearly variation of irrigation efficiency. The water supply data of the Idong reservoir from 2001 through 2009 was collected and used for this study. Total 6 parameters including irrigation efficiency (Es), drainage outlet height, and infiltration, were used for sensitivity analysis, calibration, and validation. Among the parameters, the Es appeared to be the most sensitivity parameter. The Es was calibrated on a yearly basis considering sensitivity and time-varying characteristic, while other parameters were set to fixed values. The statistics of percent bias (PBLAS), Nash-Sutcliffe efficiency (NSE), and root means square error to the standard deviation of measured data (RSR) for a monthly step were 2.7%, 0.93, and 0.26 for the calibration, and 3.9%, 0.89, and 0.32 for the validation, correspondently. The results showed a good agreement with the observations. This implies that the modeling only with appropriate parameter values, apart from modeling approaches, can simulate the real supply operation reasonably well. However, the simulations with uncalibrated parameters from previous studies produced poor results. Thus, it is important to use calibrated values, and especially, we suggest the Es's yearly calibration for simulating agricultural water supply.
A Comparison Study of Runoff Projections for Yongdam Dam Watershed Using SWAT
Jung, Cha Mi ; Shin, Mun-Ju ; Kim, Young-Oh ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 439~449
DOI : 10.3741/JKWRA.2015.48.6.439
In this study, reliable future runoff projections based on RCPs for Yongdam dam watershed was performed using SWAT model, which was validated by k-fold cross validation method, and investigated the factors that cause the differences with respect to runoff projections between this study and previous studies. As a result, annual average runoff compared to baseline runoff would increase 17.7% and 26.1% in 2040s and 2080s respectively under RCP8.5 scenario, and 21.9% and 44.6% in 2040s and 2080s respectively under RCP4.5 scenario. Comparing the results to previous studies, minimum and maximum differences between runoff projections over different studies were 10.3% and 53.2%, even though runoff was projected by the same rainfall-runoff model. SWAT model has 27 parameters and physically based complex structure, so it tends to make different results by the model users' setting. In the future, it is necessary to reduce the cause of difference to generate standard runoff scenarios.
Estimation and Assessment of Future Design Rainfall from Non-stationary Rainfall Frequency Analysis using Separation Method
Son, Chan-Young ; Lee, Bo-Ram ; Choi, Ji-Hyeok ; Moon, Young-Il ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 451~461
DOI : 10.3741/JKWRA.2015.48.6.451
This study aimed to estimate the future design rainfall through a non-stationary frequency analysis using the rainfall separation technique. First, we classified rainfall in the Korean Peninsula into local downpour and TC-induced rainfall through rainfall separation technique based on the path and size of a typhoon. Furthermore, we performed the analysis of regional rainfall characteristics and trends. In addition, we estimated the future design rainfall through a non-stationary frequency analysis using Gumbel distribution and carried out its quantitative comparison and evaluation. The results of the analysis suggest that the increase and decrease rate of rainfall in the Korean Peninsula were different and the increasing and decreasing tendencies were mutually contradictory at some points. In addition, a non-stationary frequency analysis was carried out by using the rainfall separation technique. The outcome of this analysis suggests that a relatively reasonable future design rainfall can be estimated. Comparing total rainfall with the future design rainfall, differences were found in the southern and eastern regions of the Korean peninsula. This means that climate change may have a different effect on the typhoon and local downpour. Thus, in the future, individual assessment of climate change impacts needs to be done through moisture separation. The results presented here are applicable in future hydraulic structures design, flood control measures related to climate change, and policy establishment.
Assessment of Precipitation Characteristics and Synoptic Pattern Associated with Typhoon Affecting the South Korea
Kim, Tae-Jeong ; Park, Kun-Chul ; Kwon, Hyun-Han ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 463~477
DOI : 10.3741/JKWRA.2015.48.6.463
The recent unusual climate and extreme weather events have frequently given unexpected disaster and damages, facing difficulties in the management of water resources. In particular, climate change could result in intensified typhoons, and this would be the worst case scenario that can happen. The primary objective of this study is to identify the patterns of typhoon-induced precipitation and the associated synoptic pattern. This study focused on analyzing precipitation patterns over the South Korea using historic records as opposed to a specified season or duration, and further investigates the potential connection with heavy rainfall to synoptic patterns. In this study, we used the best track data provided by the Regional Specialized Meteorological Center of Japan for 40 years from 1973 to 2012. The patterns of the typhoon-induced precipitation were categorized into four groups according to a given typhoon track information, and then the associated synoptic climatology patterns were further investigated. The results demonstrate that the typhoon-induced precipitation patterns could be grouped and potentially simulated according to the identified synoptic patterns. Our future work will focus on developing a short-term forecasting model of typhoon-induced precipitation considering the identified climate patterns as inputs.
Development of Concentration Time and Storage Coefficient Considering Regional Trend in Urban Stream Watershed
Bae, Deg-Hyo ; Kim, Yong-Jae ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 479~489
DOI : 10.3741/JKWRA.2015.48.6.479
The objective of this study is to develop the equations for concentration time and storage coefficient considering regional trend in urban stream watershed for reliable hydrological analysis. The 13 basins located in Jungrang, Tan, Anyang, and Hongje stream are selected for the data collection and formula development in this study. The stepwise multiple-regression analysis is used for the development considering watershed, urban, and precipitation characteristic indices. The developed formulae are compared with the domestic and foreign empirical formulae and evaluated the accuracy in urban stream area. It shows the computed value from the equation developed in this study is more accurate than those from other empirical formulae. The error sum, average error and RMSE of computed values from the developed equations in this study are the lowest. The formulae considering the regional trend of urban stream watershed are worth in terms of showing better results than the domestic and foreign empirical formulae. It can be concluded the developed formulae can be useful in urban stream watershed.
Improving Initial Abstraction Method of NRCS-CN for Estimating Effective Rainfall
Park, Dong-Hyeok ; Ajmal, Muhammad ; Ahn, Jae-Hyun ; Kim, Tae-Woong ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 491~500
DOI : 10.3741/JKWRA.2015.48.6.491
In order to improve the runoff estimation accuracy of the Natural Resources Conservation Service (NRCS) curve number (CN) model, this study incorporated rainfall and maximum potential retention as contributors for initial abstraction. The modification was proposed based on 658 rank-order data of rainfall and subsequent runoff from 15 watersheds. The NRCS-CN model (M1), one of its inspired modified model (M2), and the proposed model (M3) were analyzed employing different CN approaches. Using tabulated, calculated and least squares fitted CNs (
, respectively), the models' performances were evaluated based on Root Mean Square Error (RMSE), Nash-Sutcliffe Efficiency (NSE), and Percent Bias (PBIAS). Applications of model M1, M2, and M3, respectively exhibited watershed cumulative mean [RMSE (23.60, 18.12, 16.04), NSE (0.54, 0.73, 0.79), and PBIAS (36.54, 20.25, 12.00)]. Similarly, using CNC (for M1 and M2 model) and
(for M3 model), the performance of three models respectively were assessed based on watershed cumulative mean [RMSE (17.17, 15.88, 13.82), NSE (0.76, 0.80, 0.85), and PBIAS (3.06, 4.47, 0.11)]. The proposed model (M3) that linked all of the NRCS-CN variants showed more statistically significant agreement between the observed and estimated data.
A Investigation and Analysis of Water Temperature by Juam Regulation Dam Outflow in Downstream and Suncheon Bay
Lee, Hyeon No ; Jung, Kwan Sue ; Cheon, Geun Ho ; Hur, Young Teck ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 501~509
DOI : 10.3741/JKWRA.2015.48.6.501
Lately multipurpose dam is required to consider various interests such as quality, ecological environment as well as flood control, water supply, hydropower generation, etc. The objective of this study is to investigation and analysis of water temperature in the areas where there are social conflicts due to cold water outflow. In this study, we monitored water temperature of Juam regulation dam, downstream river, Suncheon bay in a long term period and performed comparative analysis on a change of water temperature in downstream river and Suncheon bay by using three-dimensional numerical mode (EFDC) considering various external factors such as water outflow amount. The result of monitoring and numerical modelling indicates that effects of cold water outflow takes place from april to september. Also effects of the low temperature discharge of dam was complicatedly altered by various factors such as outflow time and amount, weather and tide level conditions etc. The result of this study can be utilized as a basic data for establishing improvement of dam operation plan to minimize negative effects of dam's cold temperature water outflow to downstream river and coastal area.
Effect of Observed Discharge Data on Regional Flood Frequency Analysis in the Han River Basin
Kim, Nam Won ; Lee, Jeong Eun ; Lee, Jeongwoo ; Jung, Yong ;
Journal of Korea Water Resources Association, volume 48, issue 6, 2015, Pages 511~522
DOI : 10.3741/JKWRA.2015.48.6.511
This study assessed the impact of uncertainties in flood data on the results of flood frequency analysis for Han river basin. To meet this aim, this study quantified assessment focused on the index flood and quantile by regional flood frequency analysis using the flood data from 17 water level gauges in Han river basin. We analysed the results categorized by three cases according to the characteristics of the measured data. Firstly, we analyzed the regional flood frequency for the water level gauge in the Pyungchang river basin to investigate the impact of water level data. The results has the error of 0.240 with respect to the mean flood. Secondly, we examined the impact of uncertainty in measurement data generated by the application of rating on the results of regional flood frequency analysis. We have compared the results by applying the rating estimated for each year to the one by the recently estimated rating. The results showed that the mean error has 0.246 in terms of the mean flood. Finally, we have inferred the regional flood frequency analysis results with the regulated flow in the downstream area of dams. The regulated specific discharge in the downstream area of dams controlled by dam operation showed a large difference to the estimated specific discharge in the downstream area of dams by extension of the natural specific discharge in the upstream area using the regionalization method.