• Title/Summary/Keyword: ILLUDAS모형

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Effects of Calculation Method of Surface Runoff on the Estimation of Flood in Urban Drainage Basin (지표면유출 해석방법이 도시 유역의 홍수량 산정에 미치는 영향)

  • Lee, Jong Tae;Yoon, Sei Eui;Kim, Jung Hwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.5
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    • pp.1167-1175
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    • 1994
  • The effects of the calculation method of surface runoff on the estimation of flood in urban drainage basin were analyzed in this study. In comparing with surface runoff methods. RUNOFF, ILLUDAS, SBUH and RRL were investigated. To route the flow in sewer/conduits EXTRAN was applied. The Kings Creek and Gray Haven drainage basin's measured data of rainfall and runoff were used in comparing the computed results. The results show that the greatest effect factor on surface runoff in urban small area is the concentration time. The results estimated by each model which are composed with EXTRAN show that the scheme for surface runoff gives considerable effect on the flood hydrograph in urban drainage system. RUN-EX method gives the most similar simulation results among the surface runoff models, and is more applicable for paved and unpaved basins than others.

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A Technique of Inland Drainage Control Considering flood Characteristics of the Han River (한강홍수특성을 고려한 내배수 처리기법)

  • Lee, Won Hwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.11 no.1
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    • pp.99-108
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    • 1991
  • Rapid changes of urban hydrologic events need new management operation rule of detention reservoir which is essential outflow control system in urban area. Therefore, this study is to develop the outflow management method of Seoul city considering the Han river flood characteristics, to analyze the inundation of detention reservoir according to variation of design storm patterns, and to examine the safety of gate due to design flood water level. From this study, new operation rule is presented. The design storm patterns are determined by instantaneous intensity method and Huff's quartile method. And the inflow hydrograph of detention reservoir is obtained by applying ILLUDAS model and RRL method. The operation rule of existing drainage pump is designed to have linear relation between storage and pumping discharge. But in this study, it is effective for preventing inundation when the operation rule of drainage pump have Gaussian function which is combined the storage of detention reservoir with its inflow according to increasing or decreasing of inflow hydrograph.

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Development and Verification of Inundation Modeling with Urban Flooding Caused by the Surcharge of Storm Sewers (도시배수체계와 연계한 내수침수모형의 개발 및 검증)

  • Kim, Ji-Sung;Han, Kun-Yeun;Lee, Chang-Hee
    • Journal of Korea Water Resources Association
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    • v.39 no.12 s.173
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    • pp.1013-1022
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    • 2006
  • Urban flooding is usually caused by the surcharge of storm sewers. For this reason, previous studies on urban flooding are mainly concentrated on the simulation of urban drainage systems. However these approaches that find the pipes which have insufficient drainage capacity are very approximate and unreasonable ways in establishing both flood prevention and flood-loss reduction planning. In this study, a two-dimensional model linked the existing ILLUDAS model is developed to calculate the accurate and resonable solution about urban flood inundation and it is verified by using the simulation of July 2001 flood in Seoul. In the urban area with a small difference of ground elevations, the two-dimensional flood propagation phases must be considered to make a accurate analysis for inundated area and depth. The result of this study can be used to construct fundamental data for a flood control plan and establish a urban flood forecasting/warning system.

Critical Duration of Design Rainfall for the Design of Storm Sewer in Seoul (우수관거 설계를 위한 계획강우의 임계지속기간 -서울 지역을 중심으로-)

  • 이재준;이정식;전병호;이종태
    • Water for future
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    • v.26 no.2
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    • pp.49-57
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    • 1993
  • A hydrological method is performed to determine the critical duration of design rainfall for the design of storm sewer in Seoul. To seize the effect of the duration and the temporal distribution of the rainfall to the peak discharge of the storm sewer, the Huff's quartile method is used as a temporal pattern for the design rainfall of any durations (9 cases for 20-240 min.) with 10 years return period. The critical duration of design rainfall is determined as the duration which maximizes the peak discharge. This study is applied to 18 urban drainage systems in Seoul. The ILLUDAS model is applied to runoff analysis, and the result shows that the duration which maximizes peak discharge is 30, 60 minutes generally. The relation diagram between peak discharge for the critical duration and watershed area is prepared for the design of storm sewer.

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A New Control Technique of Drainage Pump Based on Fuzzy Control (퍼지제어기법을 사용한 우수배제 펌프의 조작기법 개발)

  • Lee, Won Hwan;Cho, Won Cheol;Shim, Jae Hyun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.3
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    • pp.107-114
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    • 1992
  • With the increasing of impervious area and shortening of travel time, the risk of flooding in urban area becomes a serious problem in Seoul metropolitan area, and its alternatives are needed. In this study, one of urban flood alternatives, a fuzzy control technique is applied in pumping station to test its drainage capacity of inland inflow, and compared with existing pumping criteria (controled by water level). Three design rainfalls(10, 30, and 50 year) are applied to ILLUDAS model to calculate inflow in detention reservoir. To check the efficiency of fuzzy control, two fuzzy rules are used in the operation of pumping station. In these results, fuzzy control rules, based on the experiences of experts, show applicability in practice and effectiveness in inland flooding prevention.

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Runoff Analysis for Urban Unit Subbasin Based on its Shape (유역형상을 고려한 도시 단위 소유역의 유출 해석)

  • Hur, Sung-Chul;Park, Sang-Sik;Lee, Jong-Tae
    • Journal of Korea Water Resources Association
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    • v.41 no.5
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    • pp.491-501
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    • 2008
  • In order to describe runoff characteristics of urban drainage area, outflow from subbasins divided by considering topography and flow path, is analyzed through stormwater system. In doing so, concentration time and time-area curve change significantly according to basin shape, and runoff characteristics are changed greatly by these attributes. Therefore, in this development study of FFC2Q model by MLTM, we aim to improve the accuracy in analyzing runoff by adding a module that considers basin shape, giving it an advantage over popular urban hydrology models, such as SWMM and ILLUDAS, that can not account for geometric shape of a basin due to their assumptions of unit subbasin as having a simple rectangular form. For subbasin shapes, symmetry types (rectangular, ellipse, lozenge), divergent types (triangle, trapezoid), and convergent types (inverted triangle, inverted trapezoid) have been analyzed in application of time-area curve for surface runoff analysis. As a result, we found that runoff characteristic can be quite different depending on basin shape. For example, when Gunja basin was represented by lozenge shape, the best results for peak flow discharge and overall shape of runoff hydrograph were achieved in comparison to observed data. Additionally, in case of considering subbasin shape, the number of division of drainage basin did not affect peak flow magnitude and gave stable results close to observed data. However, in case of representing the shape of subbasins by traditional rectangular approximation, the division number had sensitive effects on the analysis results.

A Study on the Variation of Runoff and Travel Time in Urban Stream due to Watershed Development (유역개발에 따른 도시하천에서의 유출량 및 도달시간 변화에 관한 연구)

  • 서규우;배덕효
    • Water for future
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    • v.29 no.3
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    • pp.207-216
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    • 1996
  • The subject research attempts to evaluate the variations of total runoff volume, peak flow, and travel time depending on the urbanhization, return periods and rainfall patterns under the situations that the preparation of a large residential site at the lowland areas of the downstream of Dongsu stream in Bupyung-Gu, Incheon city is progressed and the area will be eventually fully developed. The ILLUDAS model was used for the runoff analyses based on 3 differend steps of urbanization and 4 different types of Huff's quantile according to rainfall patterns is Huff's 4 quantile, Huff's 2 quantile, Huff's 3 quantile and Huff's 1 quantile. Under the 80 and 90 % of urbanization to the 70% of urbanization, the mean increasing ratio of total runoff volume for each case is 3.5 and 5.5 %, that of peak flow is 4.2 and 8.8%, and the mean decreasing ratio of travel time is 4.4 and 10.1%, respectively. The mean increasing ratio of total runoff volume according to the return periods is 3.0 and 5.4%, that of peak flow is 3.9 and 8.0% under the same conditions of urbanization.

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Development and Verification of Inundation Model Considering Storm Sewers in Urban Area (도시배수체계와 연계한 침수모형의 개발 및 검증)

  • Han, Kun-Yeun;Lee, Chang-Hee;Kim, Ji-Sung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.159-162
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    • 2005
  • Urban flooding is usually caused by the surcharge of storm sewers. For that reason, domestic studies about urban flooding are concentrated on the simulation of urban drainage system. However these approaches that find the pipes which have insufficient drainage capacity are very approximate and unreasonable ways. In this study, an accurate mathematical modeling is developed to analyze the impacts of an urban inundation for both flood prevention and flood-loss reduction planning and it is verified by using the simulation of July 2001 flooding in Seoul. The result of this study can be used to construct fundamental data for a flood control plan and establish a urban flood forecasting/warning system.

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Flood Runoff Characteristics in Urbanized Basin (도시화 유역에서의 홍수 유출 특성)

  • 한국희;이길춘
    • Water for future
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    • v.29 no.3
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    • pp.153-161
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    • 1996
  • This study is runoff analysis of the recently urbanized San Bon basin. The relationships between peak discharge and total discharge were examined by applying the ILLUDAS runoff analysis model to the measured data. In urbanized streams, it is found that channel adjustment had the most significant effect on the increase of peak discharge. Significant increases in the peak discharge occurred as rainfall duration or return period increases 10% and 7~16% increases in peak discharge were observed when the roughness coefficient were 0.04 and 0.015, respectively. When the natural river channel with n=0.04 was converted into a sewerage system of n=0.015 the peak discharge was greatly increased by 51~158%, Generally, flood peak discharge was increased during heavy rain, but in the case of urbanized basin, river stage was reduced owing to an increase of flow velocity by the adjustment of drainage system.

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A Study on the Risk - based Local Normal CSOs Curve Designs (위험도 기반 지역별 정규 CSOs 곡선 설계에 관한 연구)

  • Jo Deok-Jun
    • Journal of Korea Water Resources Association
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    • v.39 no.7 s.168
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    • pp.575-581
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    • 2006
  • This paper presents a systematic approach for the economical design of stormwater quality control systems. For the design of runoff quality control system (RQCS), the rainfall-runoff process requires the local rainfall data recorded continuously. In this study the rainfall probability distribution is assumed to follow an exponential decay function. Applying the exponential decay function, the normalized curves are derived to explain the non-exceedance probability distributions. The optimal curves for the determination of the RQCS size are derived based on the overflow risk. Comparison of the optimal capture volume and peak runoff rate to those computed by an urban rainfall-runoff model(ILLUDAS) demonstrates that the optimal CSOs(Combined Sewer Overflows) curves derived in this study can be utilized for the design of stormwater quality control systems in Korea avoiding an excessive computational effort based on over flow risks.