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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 32, Issue 6 - Dec 1999
Volume 32, Issue 5 - Oct 1999
Volume 32, Issue 4 - Aug 1999
Volume 32, Issue 3 - Jun 1999
Volume 32, Issue 2 - Apr 1999
Volume 32, Issue 1 - Feb 1999
Selecting the target year
A Derivation of Rainfall Intensity-Duration-Frequency Relationship for the Design of Urban Drainage System in Korea
Lee, Jae-Jun ; Lee, Jeong-Sik ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 403~415
This study is to derive the rainfall intensity formula based on the representative probability distribution in Korea. The 11 probability distributions which has been widely used in hydrologic frequency analysis are applied to the annual maximum rainfall. The parameters of each probability distribution are estimated by method of moments, maximum likelihood method and method of probability weighted moments. Four tests such as
-test, Kolmogorv-Smirnov test, difference test and modified difference test are used to determine the goodness of fit of the distributions. The homogeneous tests (Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance of nonparametric test) are applied to find the stations with rainfall homogeneity. The results of homogeneous tests show that there is no representative appropriate distribution for the whole duration in Korea. The whole region could be divided into five zones for 12-durations. The representative probability distribution of each divided zone for 12-durations was determined. The GEV distribution for I,II,V zones and the 3-parameter Weibull distribution for III,IV zones were determined as the representative probability distribution. The rainfall were obtained from representative probability distribution for the selected return periods. Rainfall intensity formula was determined by linearization technique for the rainfall.
Comparison of Characteristics of Outflow Hydrograph Using the Linear and Nonlinear Muskingum-Cunge Methods
Kim, Jin-Su ; Kim, Jin-Hong ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 417~426
A series of numerical experiments is performed to compare the characteristics of outflow hydrograph using linear and nonlinear Muskingum-Cunge methods for two cases: (a) sinusoidal inflow hydrographs and (b) rainfall inputs. The nonlinear method shows the steepening of the rising limb, coupled with a corresponding flattening of the receding limb. The linear method conserves mass exactly. In contrast, the nonlinear method is subject to a gain and a loss of mass. The loss of mass and the subsidence of peak outflow increases with a mild slope, a small baseflow
and a large peak inflow to baseflow ratio
. A shock wave and associated numerical instability results in the increase of mass for a steep slope and a large
ratio. While the linear method depends on the reference flow per unit-width, the nonlinear method depends on a baseflow and the
ratio. It is found that, unlike for the sinusoidal inflow, the outflow for the rainfall inputs conserves mass fairly exactly in the nonlinear method.
Analysis of the Clark Model Using the Similarity Characteristics of the Basin
Seong, Gi-Won ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 427~435
The Clark unit hydrograph is a three parameter synthetic unit hydrograph procedure that can be used in flood hydrology. The present work is an attempt to estimate parameters of the Clark model in ungaged basin by means of relationships that provides for the hydrologic similarity. The time area concentration curve was determined by analytic method and the Clark model was generalized by being made dimensionless form. Calculation of the concentration time was made with the formula fractal concept used, and the storage coefficient was estimated by the empirical and regional equation. Evaluation on Dongok basin was performed to prove the validity of the proposed model. The derived hydrograph predicted the observed hydrograph fairly well.
Hydrologic Response Estimation Using Mallows'
Seong, Gi-Won ; Sim, Myeong-Pil ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 437~445
The present paper describes the problem of hydrologic response estimation using non-parametric ridge regression method. The method adapted in this work is based on the minimization of the
statistics, which is an estimate of the mean square prediction error. For this method, effects of using both the identity matrix and the Laplacian matrix were considered. In addition, we evaluated methods for estimating the error variance of the impulse response. As a result of analyzing synthetic and real data, a good estimation was made when the Laplacian matrix for the weighting matrix and the bias corrected estimate for the error variance were used. The method and procedure presented in present paper will play a robust and effective role on separating hydrologic response.
Bragg Reflection on a Sloping Beach
Lee, Jong-In ; Jo, Yong-Sik ; Lee, Jeong-Gyu ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 447~455
In this study, the Bragg resonant of cnoidal waves propagating over a sinusoidally varying topography lying on a uniformly sloping beach is investigated. The governing equations derived from the Boussinesq equations are numerically integrated. The effects of fast varying terms and nonlinearity in reflection coefficients are also examined. Variation of reflection coefficient for different sloping beaches is studied. It is found that reflection coefficients are not strongly dependent on slopes of beaches.
Estimation of Rainfall Erosivity in USLE
Kim, Chang-Wan ; U, Hyo-Seop ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 457~467
No complete methods for estimating soil loss, included by rain storms, from a small watershed are available yet, and the best recommended method is to use measured data from the watershed. When no measured data is available from the watershed, empirical models for estimating the soil loss, such as the Universal Soil Loss Equation(USLE), is well recommended in practice. For using this equation, it is necessary to estimated the rainfall erosivity, commonly expressed as R, of the watershed. In this study, first we collected data of the probable rainfalls with the return periods of 2, 5, 10, 20, 30, 50, 80, 100, 200, and 500-yr and with the duration hours of 0.5, 1, 2, 3, 6, 12, and 24-hr. Using this data, we calculated the design values for R for the return period of 24-hr at each major rainfall-measuring station nationwide. Then we constructed the iso-erodent map of Korea for each return period of the 24-hr design storm. This study shows that the 24-hr duration iso-erodent map of the 5-yr return period is very similar to the annual average iso-erodent map of Korea. This study also shows that the 24-hr duration R-values of a certain return period can be estimated by multiplying certain parameters, obtained from this study, to the 24-hr duration R-values for the 5-yr return period or the annual average R-values. Finally, the R-values of the design storm with the 24-hr return period obtained from this study can be used for designing the settling basins at small watersheds.
Minimum Velocity of Sewerage Pipes
Yu, Dong-Hun ; Lee, Jeong-Yeong ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 469~478
Explicit equations of minimum velocity, energy slope and pipe diameter are developed to ensure the cleaning of sewerage pipes. The equations of power form are employed for the estimation of critical shear stress of sediment particles and the friction factor of commercial pipes. They are all based on the existing laboratory data. Several cases are tested to check the values suggested in the manual, using the equations developed in the present study.
Runoff Analysis of Urban Area Using Urban Runoff Models
An, Sang-Jin ; Kim, Jin-Geuk ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 479~488
The flood damage has being increased because of urbanization due to the industrialization and the growth of population. Therefore, the hydrologic properties such as increasing the peak flow and decreasing the concentration time of the peak flow have been changed. Hence, the interest of an urban prevention against flood disasters has been centralized at the present day. The objectives of this study is to develop the suitable models to calculate the runoff characteristics from an urban basin. This study describes the properties of each urban hydrologic model and to determine suitable basin model using the ILLUDAS and SWMM models in the urban runoff models in the Yong-Ahm area at Chungju. The peak flow, concentration time and total runoff value of this area are compared and analyzed with regard to calculated and real values. After obtaining values appropriated from the ILLUDAS and SWMM models using 5 rainfall events in this areas, the peak flows, concentration times and total runoff values are compared with real values. As a result of this study, the Transport block of the SWMM is closely shown to real values.
Application of Improved Algorithm for Topographic Index Calculation
Kim, Sang-Hyeon ; Lee, Ji-Yeong ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 489~499
This research investigated the applicapability of an improved algorithm to calculate the topographic index, ln(
/tan B), for the topography of Korea employing channel initiation threshold area(CIT) and an exponent for the gradient(H). hanjaechun subwatershed in Cheongdochun and Dongok subwatershed in Wichun test watershed were selected as study areas. The digital elevation models(DEM) of study areas have been made with the resolution from 10m to 100m. Application of CIT to the traditional algorithm provide reasonable computation method in considering channel pixel impact. Introduction of the gradient exponent(H) made it possible to obtain better flow convergence effect in concave topography comparing with the traditional multiple flow direction algorithm. The improved algorithm shows the capability to relax the overestimation problem of rising limb of hydrograph through reducing overestimated high value of topographic index.
Effect of Land Use on the Water Quality of Small Agricultural Watersheds in Kangwon-do
Choe, Jung-Dae ; Lee, Chan-Man ; Choe, Ye-Hwan ;
Journal of Korea Water Resources Association, volume 32, issue 4, 1999, Pages 501~510
Stream and groundwater qualities of small agricultural watershed in Kangwon Probince, Korea were monitored 1 to 2 years, and the relationships between stream and groundwater qualities and seasonal water quality changes analyzed. Flooded paddy fields influenced groundwater level and quality during rice culture. The differences between groundwater levels during rice culture and non-culture spans were between 0.8 and 2.91 m. Seasonal changes of total nitrogen and nitrate nitrogen concentrations of stream and groundwater were very similar and groundwater quality was thought to have a profound impact on stream quality of the research watersheds. Suspended solids and BOD maintained the first degree stream water quality throughout the monitoring period except for a few and short flooding spans. The concentrations of total phosphorus and total bacteria of both waters showed wide variations and any seasonal trends were not observed. Long-term monitoring studies on small rural watersheds were recommended to understand the pattern of both stream and groundwater quality changes with respect to land use, season and cultural practice, and to apply the results to develop effective water quality management policies for large river and domestic water supply systems.