• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.06a
• /
• pp.13-22
• /
• 2003

Train speed and infiltration of rainfall causes railway embankment to be unstable and may result in failure. Therefore, the variation in the safety factor of railway embankment should be analyzed as the function of rainfall intensity, rainfall duration, and train speed and the study is accomplished using numerical analysis program. Based on unsaturated soil engineering, the variables in the shear strength function and permeability function are also defined and used for the numerical model for evaluation of railway embankments under rainfall. As a result of the study, in order to secure the safety of train under rainfall, the variation in the safety factor of railway embankment is predicted as the function of rainfall intensity, duration time and the train load as a function of train speed. It is possible to ensure the safety of train under rainfall. Thereafter, the feasibility of the rail-transport operation control with engineering basis was established.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1798-1802
• /
• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation.The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall.The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• Journal of Industrial Technology
• /
• v.27 no.A
• /
• pp.95-102
• /
• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation. The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall. The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.4B
• /
• pp.315-322
• /
• 2011

This study reviewed the Weiss model, probably the only theoretical study available on the fixed- to true-interval rainfall conversion factor (CF), and implemented to propose a modified Weiss model. Also, the characteristics of the temporal distribution of rainfall were considered in the estimation of CF to overcome the problem of these two models, whose results were compared with those estimated empirically. As results, the CF was found to be differently estimated depending on the temporal distribution of rainfall. Especially, the theoretical CF estimate for the center-concentrated rainfall distribution was found to be very similar to that of empirical results of domestic and foreign studies.

• Journal of the Society of Disaster Information
• /
• v.14 no.4
• /
• pp.421-429
• /
• 2018

Purpose: This study conducted a slope stability study considering changes in the ground water level due to rain phenomena and the duration of rainfall, that is for the purpose of analyzing the stability of the slope surface of the cut section, seepage numerical analysis is performed by height of slope and rainfall accident, and the characteristics of rainfall was applied reasonably in order to determine the slope change during rain by analyzing rainfall and rainfall pattern due to climate change. Results: As a result of numerical analysis of stability for slope composed of the granite weathered soils according to the characteristics of rainfall(Uniform Rainfall, US Army Corps., Huff's method - 1/4, 4/4), Conclusion: The higher the slope, the smaller the safety factor of the slope, the smaller the elevation of the ground water level as the rainwater seepage does not reach the underground water level. In addition, the ground water level was assessed to be rose significantly in condition of case 3 Huff's method - 1/4, rain pattern with the largest initial rainfall duration, and the safety factor was analyzed to be small.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1324-1328
• /
• 2008

RUSLE(Revised Universal Soil Loss Equation) is one of empirical models for estimating the soil loss effectively, when there is no measured data from the study areas. It has been researching into application and estimation of the RUSLE parameters in Korea. As one of the RUSLE parameters, the rainfall-runoff erosivity factor R, is closely connected hydrologic characteristics of the study areas. It requires a continuous record of rainfall measurement at a minute time step for each storm to calculate an accurate R factor by the RUSLE methodology and it takes a lot of time to analyze it. For the more simplified and reasonable estimation of the rainfall erosivity, this study researched for correlation between the rainfall erosivity and mean annual precipitation used 122 data from the existing studies in Korea. Considering hydrologic homogeneity, new regression equations are presented and compared with other annual erosive empirical index for the test of application. As the results, the study presents the isoerodent map at 59 sites in Korea, using annual rainfall data by the Korea Meteorological Administration from 1978 to 2007.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.137-137
• /
• 2022

Evaluating interpolated rainfall uncertainty of hydrological models caused by different interpolation methods for basins where can not fully collect rainfall data are necessary. In this study, the adaptive MCMC method under effects of ILFs was used to analyze the interpolated rainfall uncertainty of the SURR model for Gunnam basin, Korea. Three events were used to calibrate and one event was used to validate the posterior distributions of unknown parameters. In this work, the performance of four ILFs on uncertainty of interpolated rainfall was assessed. The indicators of p_factor (percentage of observed streamflow included in the uncertainty interval) and r_factor (the average width of the uncertainty interval) were used to evaluate the uncertainty of the simulated streamflow. The results showed that the uncertainty bounds illustrated the slight differences from various ILFs. The study confirmed the importance of the likelihood function selection in the application the adaptive Bayesian MCMC method to the uncertainty assessment of the SURR model caused by interpolated rainfall.

• Journal of the Korean Geographical Society
• /
• v.44 no.5
• /
• pp.605-623
• /
• 2009

This study is aimed to classify rainfall regions in Pakistan. Classification of rainfall regions is essential to understand rainfall patterns in Pakistan. Rainfall patterns have been investigated using a factor and cluster analysis technique by 10-days rainfall parameter. The data used here have been obtained from 32 specific weather stations of PMD (Pakistan Meteorological Department) for the period of January 1980 to December 2006. The results obtained from factor analysis provide three factors and these three factors accounts for 94.60% of the total variance. For a better understanding of rainfall regions, cluster analysis method has been applied. The clustering procedure is based on the Wards method algorithm. Overall, these rainfall regions have been divided into six groups. The boundary of the region is determined by the topology such as Baluchistan plateau, Indus plain, Hindu Kush and Himalaya ranges.

• Journal of Korea Water Resources Association
• /
• v.35 no.2
• /
• pp.173-186
• /
• 2002

Rainfall-runoff model is usually used in estimating the design flood, and the most important elements in this model are probable rainfall and unit hydrograph. So, it is the most important step to estimate probable rainfall reasonably and exactly. If a basin area exceeds a certain scale, probable areal rainfall should be used as probable rainfall, but, Probable point- mean rainfall be usually used in Korea. Consequently, probable rainfall is used too high and unit hydrograph is used relatively too low. Thus the improvement is unavoidable. So, in this study, the parameters are proposed that transform the 1day, 2day rainfall to 24hr, 48hr rainfall, and areal rainfall data series are composed by using the same time rainfall data. Also, the areal reduction factor(ARF) is developed as the increase of area by the calculated probable point mean rainfall and probable areal rainfall by frequency analysis in Han-River basin. It can be the measure to easily transform probable point- mean rainfall to probable areal rainfall.

• Journal of Wetlands Research
• /
• v.10 no.2
• /
• pp.105-114
• /
• 2008

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Separated sewer overflows(SSO) have been considered as a major cause of water-quality deterioration of natural water-courses in the vicinity of the heavily urbanized areas. The factors defining the magnitude and occurrence of SSO are site-specific. It is important to know exact properties of pollutants contained in SSO to address water quality impacts that are caused by SSO inputs to the receiving waters. Site and event parameters found to have significant influences on urban runoff pollutant EMCs include total event rainfall, antecedent dry period, rainfall intensity. In this study, a field survey was carried out in some selected areas of Cheongju city. Literature from previous similar studies was consulted and some important factors affecting the runoff characteristics of urban drainage areas were analyzed for some selected survey points. It was found that the factors most affecting BOD are the number of dry days prior to rainfall and the intensity of the rainfall. The factor most affecting CODcr is the number of dry days prior to rainfall. The factors most affecting SS are the amount of rainfall and the number of dry days prior to rainfall. The factor most affecting TN is the amount of rainfall. The factor most affecting TP is the amount of rainfall and the number of dry days prior to rainfall.