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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 42, Issue 12 - Dec 2009
Volume 42, Issue 11 - Nov 2009
Volume 42, Issue 10 - Oct 2009
Volume 42, Issue 9 - Sep 2009
Volume 42, Issue 8 - Aug 2009
Volume 42, Issue 7 - Jul 2009
Volume 42, Issue 6 - Jun 2009
Volume 42, Issue 5 - May 2009
Volume 42, Issue 4 - Apr 2009
Volume 42, Issue 3 - Mar 2009
Volume 42, Issue 2 - Feb 2009
Volume 42, Issue 1 - Jan 2009
Selecting the target year
The assessment of the relative contribution of the shape of instantaneous unit hydrograph with heterogeneity of drainage path
Choi, Yong-Joon ; Kim, Joo-Cheol ; Kim, Jae-Han ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 897~909
DOI : 10.3741/JKWRA.2009.42.11.897
The relative contribution of between hillslope-flow and stream-flow by heterogeneity of drainage path are quantitatively assessed in the present study with GIUH model based on grid of GIS. Application watersheds are selected Pyeongchang, Bocheong and Wi river basin of IHP in Korea. The mean and variance of hillslope and stream length are estimated and analyzed in each watershed. And coupling with observation storm events, estimate hillslope and stream characteristic velocity which dynamic parameters of GIUH model. The mean and variance of distribution of travel time (i.e. IUH) calculate using estimated pass lengths and characteristic velocities. And the relative contributions are assessed by heterogeneity of drainage path. As a result, the effect of the variance that determine shape of IUH dominate with hillslope's effect in the small watershed area (within 500
). Thus, GIUH in the small watershed area must consider hillslope-flow.
Estimation of Crop Virtual Water in Korea
Yoo, Seung-Hwan ; Choi, Jin-Yong ; Kim, Tae-Gon ; Im, Jeong-Bin ; Chun, Chang-Hoo ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 911~920
DOI : 10.3741/JKWRA.2009.42.11.911
Virtual water is defined as the volume of water required to produce a commodity or service. The degree of food self-sufficiency is currently about 27 % in South Korea, so that Korea is one of the largest net virtual water import countries for agricultural product, thus it is necessary to estimate suitable virtual water for South Korea. The objective of this paper is to quantify the agricultural virtual water use (AWU) and virtual water content (VWC) using the method suggested by Chapagain and Hoekstra during the period 1991-2007. To calculate the virtual water content, 44 different crop production quantity and harvested area data were collected for 17 years and FAO Penman-Monteith equation was adapted for computing crop consumptive use of water. As the results, AWU has been estimated at 15.1 billion
in average showing a tendency to decrease. Rice has the largest share in the AWU, consuming about 10.1 billion
/yr which is about 75 % of gross AWU, and the VWC is 1600.1
/ton for paddy rice. The largest VWCs of crops are oilseed and tuber crop, and the smallest are leaf and root vegetables. The primary crop production VWC can be used for calculating the VWC of various secondary products using the contribution ratio, therefore the results of this study are expected to be used as basic data for national agricultural water footprint.
An Analysis of the Effect of Climate Change on Byeongseong Stream's Hydrologic and Water Quality Responses Using CGCM's Future Climate Information
Choi, Dae-Gyu ; Kim, Mun-Sung ; Kim, Nam-Won ; Kim, Sang-Dan ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 921~931
DOI : 10.3741/JKWRA.2009.42.11.921
For the assessment of climate change impacts for the Byeongseong stream, CGCM 3.1 T63 is selected as future climate information. The projections come from CGCM used to simulate the GHG emission scenario known as A2. Air temperature and precipitation information from the GCM simulations are converted to regional scale data using the statistical downscaling method known as MSPG. Downscaled climate data from GCM are then used as the input data for the SWAT model to generate regional runoff and water quality estimates in the Byeongseong stream. As a result of simple sensitivity analysis, the increase of CO2 concentration leads to increase water yield through reduction of evapotranspiration and increase of soil water. Hydrologic responses to climate change are in phase with precipitation change. Climate change is expected to reduce water yields in the period of 2021-2030. In the period of 2051-2060, stream flow is expected to be reduced in spring season and increased in summer season. While soil losses are also in phase with water yields, nutrient discharges (i.e., total nitrogen) are not always in phase with precipitation change. However, it should be noted that there are a lot of uncertainties in such multiple-step analysis used to convert climate information from GCM-based future climate projections into hydrologic information.
Characteristic Change Analysis of Rainfall Events using Daily Rainfall Data
Oh, Tae-Suk ; Moon, Young-Il ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 933~951
DOI : 10.3741/JKWRA.2009.42.11.933
Climate change of global warming may affect the water circulation in Korea. Rainfall is occurred with complex of multiple climatic indices. Therefore, the rainfall is one of the most significant index due to climate change in the process of water circulation. In this research, multiple time series data of rainfall events were extracted to represent the rainfall characteristics. In addition, the occurrence of rainfall time series analyzed by annual, seasonal and monthly data. Analysis method used change analysis of mean and standard deviation and trend analysis. Also, changes in rainfall characteristics and the relative error was calculated during the last 10 years for comparison with past data. At the results, significant statistical results weren't showed by randomness of rainfall data. However, amount of rainfall generally increased last 10 years, and number of raining days had trend of decrease. In addition, seasonal and monthly changes in the rainfall characteristics can be found to appear differently.
Stochastic Continuous Storage Function Model with Ensemble Kalman Filtering (I) : Model Development
Bae, Deg-Hyo ; Lee, Byong-Ju ; Georgakakos, Konstantine P. ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 953~961
DOI : 10.3741/JKWRA.2009.42.11.953
The objective of this study is to develop a stochastic continuous storage function model for enhancement of an event-oriented watershed and channel storage function models which have been used as an official flood forecast model in Korea. For this study, soil moisture accounting component is added to the original storage function model and each hydrologic component, such as surface flow, subsurface flow, groundwater flow and actual evaportranspiration, is simulated as a function of soil water content. And also, ensemble Kalman filtering technique is used for real-time assimilation of measured streamflow from various stream locations in the watershed. Therefore the enhanced model will be able to simulate hydrologic components for long-term period without additional estimation of model parameters and to give more accurate and reliable results than those from the existing deterministic model due to the assimilation of measured streamflow data.
Stochastic Continuous Storage Function Model with Ensemble Kalman Filtering (II) : Application and Verification
Lee, Byong-Ju ; Bae, Deg-Hyo ; Shamir, Eylon ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 963~972
DOI : 10.3741/JKWRA.2009.42.11.963
The objective of this study is to evaluate an application of stochastic continuous storage function model with ensemble Kalman filter technique. The case study is performed at the upstream basin of Jibo streamflow gauge including Andong and Imha dam. Test period is for the rainy season during 2006 and 2007. Long term runoff analysis is feasible in the case of using deterministic model. Ensemble members for input data and parameters are generated using Monte Carlo simulation for the purpose of applying ensemble Kalman filter technique. The cumulative absolute errors of stochastic model to the deterministic one are improved for the amount of 17.5 %, 18.3 % and more than 40.0 % for Andong dam, Imha dam and Jibo station, respectively. The results indicate that the stochastic model improves the accuracy of the simulated discharge considerably.
Development of Grid Reconstruction Method to Simulate Drying/Wetting in Natural Rivers (I): Model Development and Verification
Kim, Sang-Ho ; Choi, Seung-Yong ; Oh, Hyun-Wook ; Han, Kun-Yeun ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 973~988
DOI : 10.3741/JKWRA.2009.42.11.973
The objective of this study is to develop an accurate and robust two-dimensional finite element method to simulate drying and wetting in complex natural rivers. The Dry/Wet algorithm developed in this study is Grid Reconstruction Method which requires the definition of new meshes and renumbering of the nodes. Any drop of water level in the two-dimensional domain results in eliminating nodes and elements. Several numerical simulations were carried out to examine the performance of the Grid Reconstruction Method for the purpose of validation and verification of the model. The accuracy and application of the developed model are verified by comparing simulated results with observed values.
Development of Grid Reconstruction Method to Simulate Drying/Wetting in Natural Rivers (II): Model Application and Comparison
Choi, Seung-Yong ; Kim, Sang-Ho ; Hwang, Jae-Hong ; Han, Kun-Yeun ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 989~1004
DOI : 10.3741/JKWRA.2009.42.11.989
The objective of this study is to examine validation of Grid Reconstruction Method, which is developed to simulate drying/wetting in complex natural rivers with wetting and drying domain areas. To verify application of the developed model, the model was applied to natural rivers with wetting and drying domain areas such as Han river and Nakdong river. The simulation results have shown good agreements with observed data and the results for the developed model were more accurate and improved stability of numerical computation than those of RMA-2 model. If the analysis of contaminant advection-diffusion and sediment transport are performed with the study results, the results can be effectively applied to river flow analysis and ecological hydraulics.
Experimental Study to Parameterize Salt-Wedge Formations in Coastal Aquifer
Park, Hwa-Jun ; Kim, Won-Il ; Ho, Jung-Seok ; Ahn, Won-Sik ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 1005~1015
DOI : 10.3741/JKWRA.2009.42.11.1005
Saltwater intrusion in coastal aquifer was investigated using a laboratory model. Salt-wedge profiles were reproduced in a porous media tank 140 cm long, 70 cm high, and 10 cm wide. The experiments were performed with various conditions of porous media hydraulic conductivity, salinity, and ground surface slope to assess relationships on salt wedge location and inclination. Salt-wedge profiles induced by saltwater intrusion were observed in porous media equilibrium state, and compared with previously derived formulas of the Glover (1959), Henry (1959) and Strack (1976). It was found that salt-wedge shape and formations were affected by the water level ratio (
) due to high hydraulic conductivity, saltwater salinity and ground surface slope. High
of porous media having high hydraulic conductivity shifted the saltwater interface toward the saltwater reservoir. Increasing surface slope of the porous media caused the salt-wedge profile inclination to decrease. Saltwater salinity also contributed to the location of saltwater interface, yet the impact was not more significant than hydraulic conductivity.
Study of Direct Parameter Estimation for Neyman-Scott Rectangular Pulse Model
Jeong, Chang-Sam ;
Journal of Korea Water Resources Association, volume 42, issue 11, 2009, Pages 1017~1028
DOI : 10.3741/JKWRA.2009.42.11.1017
NSRPM (Neyman-Scott Rectangular Pulse Model) is one of the common model for generating future precipitation time series in stochastical hydrology. There are 5 parameters to compose the NSRPM model for generating precipitation time series. Generally parameter estimation using moment has some problems related with increased objective functions and shows different results in accordance with random variable generating models. In this study, direct parameter estimation method was proposed to cover with disadvantages of parameter estimation using moment. To apply the direct parameter estimation, generating stochastical data variance in accordance with numbers of precipitation events of NSRPM was done. Both kinds of methods were applied at the Cheongju gauge station data. Precipitation time series were generated using 4 different random variable generator, and compared with observed time series to check the accuracies. As a results, direct method showed more stable and better results.