• Journal of The Geomorphological Association of Korea
• /
• v.23 no.3
• /
• pp.27-39
• /
• 2016

This study statistically investigates relationships between physical properties of rocks and topography by measuring and analyzing section, topographical and measured parameters of 58 bedrock outcrops at areas covered by gneiss, schist, granite, andesite, sandstone and limestone in the Korean Peninsula. Multiple linear regression analysis suggests that the joint spacing, joint continuity, weathering grade and maximum joint width of rocks among the measured parameters are related to the topographical parameters with statistical significances. Therefore, this study suggests that rock properties such as joint spacing, joint continuity, weathering grade and maximum joint width seem to greatly influence topography, although various factors can affect topographical parameters.

• Ecology and Resilient Infrastructure
• /
• v.3 no.1
• /
• pp.35-45
• /
• 2016

The correlation relationships and their corresponding equations between the geomorphological parameters and the Soil Water Assessment Tool (SWAT) model parameters by Sequential Uncertainty Fitting - version 2 (SUFI-2) algorithm of SWAT Calibration and Uncertainty Programs (SWAT-CUP) were developed at the Seom-river experimental watershed. The parameters of the SWAT model at the Soksa-river experimental watershed were estimated by the developed equations. The SWAT model parameters were estimated by SUFI-2 algorithm of SWAT-CUP with rainfall-runoff data from the Soksa-river experimental watershed from 2000 to 2007. Rainfall-runoff simulation of the SWAT model was carried out at the Soksa-river experimental watershed from 2000 to 2007 for the applicability of the estimated parameters by the developed equations. The root mean square errors (RMSE) between the observed and the simulated rainfall-runoffs using the estimated parameters by developed equations of correlation analysis and the optimum parameters by SUFI-2 of SWAT-CUP were $1.09m^3/s$ and $0.93m^3/s$ respectively at the Soksa-river experimental watershed from 2000 to 2007. Therefore, it is considered that the parameter estimation of the SWAT model by the geomorphological characteristics parameters has applicability.

• Journal of the Korean Geographical Society
• /
• v.33
• /
• pp.13-25
• /
• 1986

• Journal of Korea Water Resources Association
• /
• v.43 no.4
• /
• pp.399-408
• /
• 2010

The sensitivity of Nash model parameters is analyzed about characteristic velocities considering geomorphological dispersion in the present study. And changing shape of IUH compared and analyzed as variation of characteristic velocities through numerical experiment. Application watersheds are selected 4 subwatersheds which are located at main stream of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. And Nash model parameters are estimated with moments of path lengths and characteristic velocities. The changing trend about IUH which is derived Nash model parameters are compared as variation of characteristic velocities. The Major results of this study are summarized as follows. The Nash model parameters sensitively present changes about hillslope characteristic velocity. And the effect of the peak discharge and shape of recession in IUH dominate with hillslope's characteristic velocity, the effect of the peak time and shape of ascension in IUH dominate with channel's characteristic velocity.

• Journal of Korea Water Resources Association
• /
• v.42 no.1
• /
• pp.75-92
• /
• 2009

The development of the method for flood runoff analysis representing Korean mountain basins have been one of big concerns for Korean hydrologists for several decades. Several traditional methods dealing with unit hydrograph have been restricted to be used in Korea basins, because of its drawbacks due to its originality from other countries and the uncertainties of control parameters as well as its linearity assumption between rainfall and runoff relationship. In this paper, several geomorphological similarity relationships for Korean mountain basins was developed by using the experimental data over 40 Korean basins. Then those were applied directly to geomorphological unit hydrograph theory to meet Korean geomorphological unit hydrograph. The developed method was applied to Andong Dam basin. The results show the applicability and simplicity of the developed Korean geomorphological unit hydrograph generally for Korean mountain basins in future. It might be needed for more validations and applications of this method over Korean regions.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.21 no.1
• /
• pp.106-114
• /
• 2018

DEM(Digital Elevation Model) are now easily produced with advancing remote sensing technology. Depending on desired task, UAV can produce high resolution DEM. But high resolution comes with issues of data storage and processing time and cost. To check the effect of DEM resolution, this study compares six geomorphological parameters derived from different resolution DEM in a test area around Chuncheon, Korea. The comparison analysis was based on statistics of each derivatives of slope, curvature, flow direction, flow accumulation, flow length and basin. As a result, it was found that DEM remained unchanged and so did the flow accumulation area. However, slope, curvature, flow length and basin numbers were decreased with the normalization of increasing pixel size. DEM resolution should be carefully selected depending on the precision of application required.

• Journal of Korea Water Resources Association
• /
• v.36 no.1
• /
• pp.23-32
• /
• 2003

This study aims at the derivation of representative IUH considering geomorphological factors. Nash model has been combined with geomorphological IUH to estimate the parameters of representative IUH. For this purpose, total 18 storm events which have been recorded upstream parts of Sangye control point in Bocheong river watershed, one of the tributary of Keum river basin, have been analysed. The results show that n value is 3.17 and K value is 7.01. And the results also show that IUHs driven by the method of moments vary with each storm events significantly. As a result of this study the IUH could be median distribution which is representative IUH among each storm events. It is believed that this result considered geomorphological factors is more superior and physically meaningful comparing with the existing methods.

• Journal of The Geomorphological Association of Korea
• /
• v.27 no.2
• /
• pp.19-28
• /
• 2020

Grain size analysis is the most basic procedure for identifying the origin, transport and sedimentation processes of sediments, and is widely used in geomorphology and sedimentology. Traditionally, grain size was determined by a sieve-pippette method, but the use of automated analyzers is increasing in recent years. These analyzers have many advantages over traditional techniques, but the measurement results are not always the same. It is still difficult to solve the pretreatment problem such as incomplete diffusion and residual organic matter, and inappropriate results may be obtained. This study compared image-based grain size analysis and sieve analysis to verify its statistical reliability, and conducted experiments to enhance the measurement accuracy using shape parameters. The results showed that the image-based analysis overestimated the grain size of sand dunes by about 7% compared to the sieve analysis, but the two measurements were not statistically different. In addition, by using shape parameters, such as aspect ratio, sphericity, and convexity, improved statistics were obtained compared to the original data. Using the morphological properties of the individual grains is a complementary method to the incomplete pretreatment of the grain size analysis process, and at the same time, it will contribute to improving the accuracy and reliability of the results.

• Journal of Korea Water Resources Association
• /
• v.43 no.1
• /
• pp.1-13
• /
• 2010

For the first time, this study identifies Nash model parameters by GIUH theory based on grid of GIS with heterogeneity of drainage path. Identified parameters have advantages to improve accuracy and usefulness with considering hillslpoe-flow, geomorphological dispersion and easily extracting geomorphological factors by GIS in the watershed. Calculated results by identified parameters compare with observation data for verification of this model. The comparison is well correspondence between observed data and calculated results. And the comparison results of changing trends about lag time and the variance as hillslope and channel characteristic velocities sensitively present changes about hillslope characteristic velocity. Thus this model justifies that estimation of hillslope characteristic velocity demands with the great caution.

• Journal of Korean Society on Water Environment
• /
• v.26 no.3
• /
• pp.532-539
• /
• 2010

The synthetic unit hydrograph is developed and verified using Nash model and characteristic velocities considering geomorphological dispersion in this present study. Application watersheds are selected 5 subwatersheds of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. Characteristic velocities are calculated using estimated path lengths and moment characteristics of rainfall-runoff data. Characteristic velocities of random devised 7 ungauged watersheds are estimated through regional analysis of chracteristic velocities in guaged watershed. And Nash model parameters and IUH are derived using characteristic velocities and path length in the gauged and ungauged watershed. The result to compare of IUH about gauged watershed and random devised ungauged watershed in application watershed presents coherently hydrologic response characteristics that peak discharge is reduced and peak time is extended. In conclusion, Developed synthetic unit hydrograph in this study expects that it is useful method to estimate runoff discharge for managing of water pollution in ungauged watershed.