• Journal of the Korean Society of Hazard Mitigation
• /
• v.6 no.3 s.22
• /
• pp.57-68
• /
• 2006

The objective of this study is to analyze the temporal pattern characteristic of short-duration rainfall defined as a rainfall durations of 6 hours or less by the Huff's 4th quartile distribution. To analyze the temporal pattern characteristic of short-duration rainfall, the rainfall data are classified by rainfall duration and rainfall type(Changma, Typhoon, Severe rain storm, Frontal storm) and change of rainfall segment. Also, the results of this study compared with result of research work of Korea Institute of Construction Technology(1989) and Ministry of Construction & Transportation(2000). The conclusions of this study are as follows; (1) Short-duration rainfall with duration of 6 hours or less is found to be most prevalent frist-quartile storms. (2) In the case of rainfall type, Changma and Severe rain storms and Frontal storm is found second-quartile storms, and Typhoon is found third-quartile storms. (3) In the result by change of sixth segment storms, the type of temporal pattern of rainfall is found to be most prevalent two sixth parts, (4) Comparative analysis of the results shows that shapes of the dimensionless cumulative curves and values are different from those of existing researches.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.95-95
• /
• 2020

Urban flooding occurs in the form of internal-water inundation on roads and lowlands due to heavy rainfall. Unlike in the case of rivers, inundation in urban areas there is lacking in research on predicting and warning through measurement data. In order to analyze urban flood patterns and prevent damage, it is necessary to analyze flooding measurement data for various rainfalls. In this study, the pattern of urban flooding caused by rainfall was analyzed by utilizing the urban flooding measuring sensor, which is being test-run in the flood prone zone for urban flooding management. For analysis, 2019 rainfall data, surface water depth data, and water level data of a street inlet (storm water pipeline) were used. The analysis showed that the amount of rainfall that causes flooding in the target area was identified, and the timing of inundation varies depending on the rainfall pattern. The results of the analysis can be used as verification data for the urban inundation limit rainfall under development. In addition, by using rainfall intensity and rainfall patterns that affect the flooding, it can be used as data for establishing rainfall criteria of urban flooding and predicting that may occur in the future.

• Journal of Korea Water Resources Association
• /
• v.34 no.1
• /
• pp.67-80
• /
• 2001

This study is to propose temporal pattern of design rainfall which causes maximum peak discharge and to analyze the variation in peak discharge according to design rainfall durations. In this study, the Mononobe, the Yen and Chow triangular, the Huff's 4th quartiles and the Keifer and Chu methods are applied to estimate the proper temporal pattern of design rainfall and three rainfall-runoff models such as SCS, Nakayasu, and Clark methods are used to estimate the runoff hydrograph. And to examine the variability of peak discharge, the hydrologic characteristics from the rainfall-runoff models to which uniform rainfall intensity is applied are used as the standard values. The type of temporal pattern of design rainfall which causes maximum peak discharge in both of the watersheds and the rainfall-runoff models has resulted in Yen and Chow distribution method with the dimensionless vague of 0.75. On the basis of determined temporal pattern, the examination of the variability of peak discharge according to design rainfall durations shows that design rainfall duration varies greatly with the types of probable intensity formula, and the variation of peak discharge is more affected by the types of probable intensity formula and I-D-F currie than rainfall-runoff models.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.03a
• /
• pp.277-284
• /
• 1999

This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

• Water Engineering Research
• /
• v.2 no.1
• /
• pp.63-72
• /
• 2001

The variation of sampling errors was characterized using the Waymire-Gupta-Rodriguez-Iturbe multi-dimensional rainfall model(WGR model). The parameters used for this study are those derived by Jung et al. (2000) for the Han River Basin using a genetic algorithm technique. The sampling error problems considered are those for using raingauge network, satellite observation and also for both combined. The characterization of sampling errors was done for each month and also for the downstream plain area and the upstream mountain area, separately. As results of the study we conclude: (1) The pattern of sampling errors estimated are obviously different from the seasonal pattern of monthly rainfall amounts. This result may be understood from the fact that the sampling error is estimated not simply by considering the rainfall amounts, but by considering all the mechanisms controlling the rainfall propagation along with its generation and decay. As the major mechanism of moisture source to the Korean Peninsula is obviously different each month, it seems rather normal to provide different pattern of sampling errors from that of monthly rainfall amounts. (2) The sampling errors estimated for the upstream mountain area is about twice higher than those for the down stream plain area. It is believed to be because of the higher variability of rainfall in the upstream mountain arean than in the down stream plain area.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.187-192
• /
• 2000

The severity of drought could be evaluated by the accumulative rainfall method, soil moisture condition method, storage ratio method, and water supply restriction intensity method, etc. The pattern of drought could be forecast with the most similar pattern of accumulative rainfall out of the file of past rainfall history. The information that how much rainfall should be expected to overcome the present drought could be obtained from the reservoir storage ratio and soil moisture condition.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2001.05a
• /
• pp.7-14
• /
• 2001

In this study, we characterized the variation of sampling errors using the Waymire-Gupta-rodriguez-Iturbe multi-dimensional rainfall model (WGR model). The parameters used for this study are those derived by Jung et al. (2000) for the Han River Basin using a genetic algorithm technique. The sampling error problems considering in this study are those far using raingauge network, satellite observation and also for both combined. The characterization of sampling errors was done for each month and also for the downstream plain area and the upstream mountain area, separately. As results of the study we conclude: (1) The pattern of sampling errors estimated are obviously different from the seasonal pattern of mentally rainfall amounts. This result may be understood from the fact that the sampling error is estimated not simply by considering the rainfall amounts, but by considering all the mechanisms controlling the rainfall propagation along with its generation and decay. As the major mechanism of moisture source to the Korean Peninsula is obviously different each month, it seems rather norma1 to provide different pattern of sampling errors from that of monthly rainfall amounts. (2) The sampling errors estimated for the upstream mountain area is about twice higher than those for the down stream plain area. It is believed to be because of the higher variability of rainfall in the upstream mountain area than in the down stream plain area.

• 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
• /
• 2009.05a
• /
• pp.540-544
• /
• 2009

Hydrologic pattern under climate change has been paid attention to as one of the most important issues in hydrologic science group. Rainfall and runoff is a key element in the Earth's hydrological cycle, and associated with many different aspects such as water supply, flood prevention and river restoration. In this regard, a main objective of this study is to evaluate design flood using simulation techniques which can consider a full spectrum of uncertainty. Here we utilize a weather state based stochastic multivariate model as conditional probability model for simulating the rainfall field. A major premise of this study is that large scale climatic patterns are a major driver of such persistent year to year changes in rainfall probabilities. Uncertainty analysis in estimating design flood is inevitably needed to examine reliability for the estimated results. With regard to this point, this study applies a Bayesian Markov Chain Monte Carlo scheme to the NWS-PC rainfall-runoff model that has been widely used, and a case study is performed in Soyang Dam watershed in Korea. A comprehensive discussion on design flood under climate change is provided.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.1B
• /
• pp.13-20
• /
• 2011

The spatio-temporal pattern in precipitation is a significant element in defining characteristics of precipitation. In this study, a new scheme on regionalization utilizing temporal information was introduced on the basis of existing approaches that is mainly based on simple moments of data and geographical information. Given the identified spatio-temporal pattern, this study was extended to characterize regional pattern of annual maximum rainfall over Korea. We have used circular statistics to characterize the temporal distribution on the precipitation, and the circular statistics allow us to effectively assess changes in timing of the extreme rainfall in detail. In this study, a modified K-means method was incorporated with derived temporal characteristics of extreme rainfall in order to better characterize hydrologic pattern for regional frequency analysis. The extreme rainfall was reasonably separated into five categories that considered most attributes in both quantitative and temporal changes in extremes. The results showed that the proposed approach is a promising approach for regionalization in term of physical understanding of extreme rainfall.