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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 46, Issue 12 - Dec 2013
Volume 46, Issue 11 - Nov 2013
Volume 46, Issue 10 - Oct 2013
Volume 46, Issue 9 - Sep 2013
Volume 46, Issue 8 - Aug 2013
Volume 46, Issue 7 - Jul 2013
Volume 46, Issue 6 - Jun 2013
Volume 46, Issue 5 - May 2013
Volume 46, Issue 4 - Apr 2013
Volume 46, Issue 3 - Mar 2013
Volume 46, Issue 2 - Feb 2013
Volume 46, Issue 1 - Jan 2013
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Parameter Estimation of a Distributed Hydrologic Model using Parallel PEST: Comparison of Impacts by Radar and Ground Rainfall Estimates
Noh, Seong Jin ; Choi, Yun-Seok ; Choi, Cheon-Kyu ; Kim, Kyung-Tak ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1041~1052
DOI : 10.3741/JKWRA.2013.46.11.1041
In this study, we estimate parameters of a distributed hydrologic model, GRM (grid based rainfall-runoff model), using a model-independent parameter estimation tool, PEST. We implement auto calibration of model parameters such as initial soil moisture, multipliers of overland roughness and soil hydraulic conductivity in the Geumho River Catchment and the Gamcheon Catchment using radar rainfall estimates and ground-observed rainfall represented by Thiessen interpolation. Automatic calibration is performed by GRM-MP (multiple projects), a modified version of GRM without GUI (graphic user interface) implementation, and "Parallel PEST" to improve estimation efficiency. Although ground rainfall shows similar or higher cumulative amount compared to radar rainfall in the areal average, high spatial variation is found only in radar rainfall. In terms of accuracy of hydrologic simulations, radar rainfall is equivalent or superior to ground rainfall. In the case of radar rainfall, the estimated multiplier of soil hydraulic conductivity is lower than 1, which may be affected by high rainfall intensity of radar rainfall. Other parameters such as initial soil moisture and the multiplier of overland roughness do not show consistent trends in the calibration results. Overall, calibrated parameters show different patterns in radar and ground rainfall, which should be carefully considered in the rainfall-runoff modelling applications using radar rainfall.
Development of Distributed Ecohydrologic Model and Its Application to the Naeseong Creek Basin
Choi, Daegyu ; Kim, In-Hwan ; Kim, Jeongsook ; Kim, Sangdan ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1053~1067
DOI : 10.3741/JKWRA.2013.46.11.1053
Distributed ecohydrological model which can simulate hydrological components, vegetation and landsurface temperature using practically available input and observed data with minimum parameters is introduced. This model is designed to properly simulate in area with lack of observed data. Parameter estimation and calibration of the model can be carried out with indirectly estimated data (monthly surface runoff by NRCS-CN method and annual actual vaporization by empirical equation) and remote sensing data (NDVI, LST) instead of observed data. We applied this model in the Naeseong creek basin to evaluate the model validity. Firstly, we found the sensitive parameters which largely influence the simulation results by sensitivity analysis, and then hydrological components, vegetation, land-surface temperature, routed streamflow and water temperature were simulated over 10 years (2001 to 2010) using calibrated parameters. Parameters are estimated by optimization method. It is shown that most of grids are well simulated. In the case of streamflow and water temperature, we checked two observed points in the outlet of watershed and it is shown that streamflow and water temperature are properly simulated as well. Hence, it can be shown that this model properly simulate the hydrological components, vegetation, land-surface temperature, routed streamflow and water temperature as well, even though in despite of using limited input data and minimum parameters.
Analysis of the Water Quality Change Due to Water Level Control of Sayeon Dam
Lee, Sang Hyeon ; Cho, Hong Je ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1069~1078
DOI : 10.3741/JKWRA.2013.46.11.1069
The Bangudae Petroglyphs, national treasure No. 285 is located within submerged upper districts of Sayeon dam supplying the main residential water in Ulsan. Of the many ways for the reservation of Petroglyphs located the altitude at 53~57 m, the plan that we take it out of the water lowering the water level from 60 m to 52 m has been examined mainly in case of controlling artificially the water level of the dam. In this paper, we examined expected problems from the loss of dam function and the change of water quality from water deterioration caused by the water level control of the Sayeon dam. Using the model of Vollenweider and CSTR (Continuous Stirred Tank Reactor), we analyzed the density change of BOD and COD, representative water quality index and the TP and TN, the main reason of algae growth. The result showed that the density of COD lowered a little but the density of TP and TN went up over 130% when controlling the water level from 60 m to 52 m. These changes cause a serious algae problem and if doing the water quality management as the density of TN and TP, the water quality would become worse. Water storage and supply residential water decreases, and the water quality becomes worse because of eutrophic state.
Assessment of Streamflow Depletion Due to Groundwater Pumping from a Well
Lee, Jeongwoo ; Kim, Nam Won ; Chung, Il Moon ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1079~1088
DOI : 10.3741/JKWRA.2013.46.11.1079
Groundwater pumping from a well has different impacts on streamflow depletion because hydraulic properties of the aquifer and the stream bed differ depending on its location. Therefore, quantitative assessment of streamflow depletion due to each groundwater pumping with different well locations is needed for the effective groundwater development and streamflow management. In this study, a watershed-based surface water and groundwater integrated model, SWAT-MODFLOW was used to assess the streamflow depletion near stream reach due to groundwater pumping from a well located within the Sinduncheon watershed. The arbitrary 50 wells among the currently used groundwater pumping wells were selected within the study area and the streamflow responses to each groundwater pumping were simulated at nearby and downstream reaches. In particular, the applicability of the Stream Depletion Factor (SDF) and Stream Bed Factor (SBF), which are widely used for evaluating the degree of streamflow depletion due to groundwater pumping, was evaluated. The simulated results demonstrated that the streamflow depletion rate divided by the pumping rate significantly differ depending on well locations and distance between well and stream, showing a wide range of values from below 20% to above 90%. From the simulated results, it was found out that the SDF or the SBF can be a partial referred value but not an absolute criterion in determining whether a pumping well has a great impact on streamflow depletion or not.
Change Projection of Extreme Indices using RCP Climate Change Scenario
Jeung, Se-Jin ; Sung, Jang Hyun ; Kim, Byung-Sik ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1089~1101
DOI : 10.3741/JKWRA.2013.46.11.1089
The study uses a regional climate model to check future changes in extreme climate, to calculate extreme indexes presented by STARDEX, and to analyze the trends to predict the continuity and changes in the spatial distribution of extreme climate in the future. An analysis of extreme climate indices showed that they are likely to increase in the Seoul metropolitan area, in Gyeonggi-do, in Yongdong in Gangwon-do, and in the southern shore region of Korea. It is, however, forecasted to diminish in the central inland region. The analysis also showed that the average temperature in Korea will increase because of climate change. On the other hand, an analysis of extreme rainfall indexes showed that the trend of heavy rainfall threshold is 0.229 in Seogwipo, the greatest five-day rainfall is 5.692 in Seogwipo, and the longest dry period is 0.099 in Sokcho. Of extreme temperature indexes, the trend of Hotdays threshold is 0.777 in Incheon and the longest heat wave is 0.162 in Uljin. The Coldnight threshold is 0.075 in Inje and -0.193 in Tongyeong, according to the analysis.
Determination Methods of Pressure Monitoring Location in Water Distribution System
Kwon, Hyuk Jae ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1103~1113
DOI : 10.3741/JKWRA.2013.46.11.1103
In this study, determination methods of the pressure monitoring location in water distribution system were introduced and applied to sample pipe network. The best determination method of the pressure monitoring location was suggested and applied to the real city pipe network. Three kinds of determination methods of pressure monitoring locations are categorized such as the sensitivity analysis according to changing roughness coefficient, pressure contribution analysis, and sensitivity analysis according to changing demand. Further-more, pressure contribution analysis and sensitivity analysis from the results of unsteady analysis were conducted and compared each other. From the results, the most accurate and simplest method was selected in this study. Therefore, the best method can be applied for the pressure management or leakage detection as a determination method of pressure monitoring location in water distribution system.
Evaluation of Suspended Solids and Eutrophication in Chungju Lake Using CE-QUAL-W2
Ahn, So Ra ; Kim, Sang Ho ; Yoon, Sung Wan ; Kim, Seong Joon ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1115~1128
DOI : 10.3741/JKWRA.2013.46.11.1115
The purpose of this study is to evaluate the suspended solids and eutrophication processes relationships in Chungju lake using CE-QUAL-W2, two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model. For water quality modeling, the lake segmentation was configured as 7 branches system according to their shape and tributary distribution. The model was calibrated (2010) and validated (2008) using 2 years of field data of water temperature, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and algae (Chl-a). The water temperature began to increase in depth from April and the stratification occurred at about 10 m early July heavy rain. The high SS concentration of the interflow density currents entering from the watershed was well simulated especially for July 2008 heavy rainfall event. The simulated concentration range of TN and TP was acceptable, but the errors might occur form the poor reflection for sedimentation velocity of nitrogen component and adsorption-sediment of phosphorus in model. The concentration of Chl-a was simulated well with the algal growth patterns in summer of 2010 and 2008, but the error of under estimation may come from the use of width-averaged velocity and concentration, not considering the actual to one side inclination by wind effect.
Analysis of Spatial Precipitation Field Using Downscaling on the Korean Peninsula
Cho, Herin ; Hwang, Seokhwan ; Cho, Yongsik ; Choi, Minha ;
Journal of Korea Water Resources Association, volume 46, issue 11, 2013, Pages 1129~1140
DOI : 10.3741/JKWRA.2013.46.11.1129
Precipitation is one of the important factors in the hydrological cycle. It needs to understand accurate of spatial precipitation field because it has large spatio-temporal variability. Precipitation data obtained through the Tropical Rainfall Monitoring Mission (TRMM) 3B43 product is inaccurate because it has 25 km space scale. Downscaling of TRMM 3B43 product can increase the accuracy of spatial precipitation field from 25 km to 1 km scale. The relationship between precipitation and the normalized difference vegetation index(NDVI) (1 km space scale) which is obtained from the Moderate Resolution Imaging Spectroradiometers (MODIS) sensor loaded in Terra satellite is variable at different scales. Therefore regression equations were established and these equations apply to downscaling. Two renormalization strategies, Geographical Difference Analysis (GDA) and Geographical Ratio Analysis (GRA) are implemented for correcting the differences between remote sensing-derived and rain gauge data. As for considering the GDA method results, biases, the root mean-squared error (RMSE), MAE and Index of agreement (IOA) is equal to 4.26 mm, 172.16 mm, 141.95 mm, 0.64 in 2009 and 17.21 mm, 253.43 mm, 310.56 mm, 0.62 in 2011. In this study, we can see the 1km spatial precipitation field map over Korea. It will be possible to get more accurate spatial analysis of the precipitation field through using the additional rain gauges or radar data.