• Title/Summary/Keyword: Inland flooding

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Risk assessment for inland flooding in a small urban catchment : Focusing on the temporal distribution of rainfall and dual drainage model (도시 소유역 내 내수침수 위험도 평가 : 강우 시간분포 및 이중배수체계 모형을 중심으로)

  • Lee, Jaehyun;Park, Kihong;Jun, Changhyun;Oh, Jeill
    • Journal of Korean Society of Water and Wastewater
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    • v.35 no.6
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    • pp.389-403
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    • 2021
  • In this study, dual drainage system based runoff model was established for W-drainage area in G-si, and considering the various rainfall characteristics determined using Huff and Mononobe methods, the degree of flooding in the target area was analyzed and the risk was compared and analyzed through the risk matrix method. As a result, the Monobe method compared to the Huff method was analyzed to be suitable analysis for flooding of recent heavy rain, and the validity of the dynamic risk assessment considering the weight of the occurrence probability as the return period was verified through the risk matrix-based analysis. However, since the definition and estimating criteria of the flood risk matrix proposed in this study are based on the return period for extreme rainfall and the depth of flooding according to the results of applying the dual drainage model, there is a limitation in that it is difficult to consider the main factors which are direct impact on inland flooding such as city maintenance and life protection functions. In the future, if various factors affecting inland flood damage are reflected in addition to the amount of flood damage, the flood risk matrix concept proposed in this study can be used as basic information for preparation and prevention of inland flooding, as well as it is judged that it can be considered as a major evaluation item in the selection of the priority management area for sewage maintenance for countermeasures against inland flooding.

Numerical Comparisons of Flow Properties Between Indivisual and Comprehensive Consideration of River Inundation and Inland Flooding (하천범람과 내수침수의 개별적·복합적 고려에 따른 흐름 특성의 수치적 비교)

  • Choi, Sang Do;Eum, Tae Soo;Shin, Eun Taek;Song, Chang Geun
    • Journal of Convergence for Information Technology
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    • v.10 no.10
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    • pp.115-122
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    • 2020
  • Due to the climate change, torrential rain downpours unprecedentedly, and urban areas repeatedly suffer from the inundation damages, which cause miserable loss of property and life by flooding. Two major reasons of urban flooding are river inundation and inland submergence. However, most of previous studies ignored the comprehensive mechanism of those two factors, and showed discrepancy and inadequacy due to the linear summation of each analysis result. In this study, river inundation and inland flooding were analyzed at the same time. Petrov-stabilizing scheme was adopted to capture the shock wave accurately by which river inundation can be modularized. In addition, flux-blocking alrotithm was introduced to handle the wet and dry phenomena. Sink/source terms with EGR (Exponentially Growth Rate) concept were incorporated to the shallow water equations to consider inland flooding. Comprehensive simulation implementing inland flooding and river inundation at the same time produced satisfactory results because it can reflect the counterbalancing and superposition effects, which provided accurate prediction in flooding analysis.

An Application of Fuzzy Control Models to Inland Drainage Pumping Stations with Different Characteristics for Protection of Inland Flooding (상이한 제원특성을 가진 빗물펌프장에서의 퍼지제어모형 적용)

  • Shim, Jae Hyun;Lee, Won Hwan;Cho, Won Cheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.3
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    • pp.107-118
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    • 1993
  • Continuous increasing of impervious area due to urbanization and rainfall quantity due to environmental changes aggravate flooding risk in low land area. Therefore. Seoul municipal authorities go on securing an ample budget for reinforcement and establishment of inner water and inland drainage pumping facilities. But. there is no investment for developing optimal operation rules for appropriate application of existing facilities. In this study. fuzzy control techniques are developed. and applied to 57 stations of inner water and inland drainage pump for model assessment. In these results. fuzzy models have more efficiency in the inland flooding protection than the existing pump operation rule by water level in the same conditions.

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Numerical Investigation of Countermeasure Effects on Overland Flow Hydrodynamic and Force Mitigation in Coastal Communities

  • Hai Van Dang;Sungwon Shin;Eunju Lee;Hyoungsu Park;Jun-Nyeong Park
    • Journal of Ocean Engineering and Technology
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    • v.36 no.6
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    • pp.364-379
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    • 2022
  • Coastal communities have been vulnerable to extreme coastal flooding induced by hurricanes and tsunamis. Many studies solely focused on the overland flow hydrodynamic and loading mechanisms on individual inland structures or buildings. Only a few studies have investigated the effects of flooding mitigation measures to protect the coastal communities represented through a complex series of building arrays. This study numerically examined the performance of flood-mitigation measures from tsunami-like wave-induced overland flows. A computational fluid dynamic model was utilized to investigate the performance of mitigation structures such as submerged breakwaters and seawalls in reducing resultant forces on a series of building arrays. This study considered the effects of incident wave heights and four geometrically structural factors: the freeboard, crest width of submerged breakwaters, and the height and location of seawalls. The results showed that prevention structures reduced inundation flow depths, velocities, and maximum forces in the inland environment. The results also indicated that increasing the seawall height or reducing the freeboard of a submerged breakwater significantly reduces the maximum horizontal forces, especially in the first row of buildings. However, installing a low-lying seawall closer to the building rows amplifies the maximum forces compared to the original seawall at the shoreline.

Establishment and Standardization of Evaluation Procedure for Urban Flooding Analysis Model Using Available Inundation Data (가용 침수 자료를 활용한 도심지 침수 해석 모형의 평가 절차 수립 및 표준화)

  • Shin, Eun Taek;Jang, Dong Min;Park, Sung Won;Eum, Tae Soo;Song, Chang Geun
    • Journal of the Korean Society of Safety
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    • v.35 no.2
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    • pp.100-110
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    • 2020
  • Recently, the frequency of typhoon and torrential rain due to climate change is increasing. In addition, the upsurge in the complexity of urban sewer network and impervious surfaces area aggravates the inland flooding damage. In response to these worsening situations, the central and local governments are conducting R&D tasks related to predict and mitigate the flood risk. Researches on the analysis of inundation in urban areas have been implemented through various ways, and the common features were to evaluate the accuracy and justification of the model by comparing the model results with the actual inundation data. However, the evaluation procesure using available urban flooding data are not consistent, and if there are no quantitative urban inundation data, verification has to be performed by using press releases, public complaints, or photos of inundation occurring through 'CCTV'. Because theses materials are not quantitative, there is a problem of low reliability. Therefore, this study intends to develop a comparative analysis procedure on the quantitative degree and applicability of the verifiable inundation data, and a systematic framework for the performance assessment of urban flood analysis model was proposed. This would contribute to the standardization of the evaluation and verification procedure for urban flooding modelling.

A Study on determining Flood Protection Elevation in Urban Area (도시지역 방어침수위 설정에 관한 연구)

  • Shin, Sang-Young;Lee, Yang-Jae
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.649-652
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    • 2008
  • In urban area, flood risk is getting higher because of inland flood risk has grown up by changing rainfall intensity, rainfall pattern, changing land use and so on. Urban area is needed higher flood protection level to protect accumulated people, buildings and other infrastructures. However, even though former flood protection has focused on overflow from river, there is not a guide line for evaluating proper flood protection level. Thus, it is necessary to protect flood from inland flooding as well as overflow from river and need a proper method to evaluating flood protection level. This study present a method of determining flood protection elevation by using GIS tools for deciding proper flood protection level. The study result may contribute to urban flood protection measures in which inland flood risk increases.

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Is It Possible the Period of Kyung-In Canal? (운하의 시대가 도래 하는가?)

  • Park, Sang-Kuk
    • Journal of the Korean Professional Engineers Association
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    • v.42 no.2
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    • pp.49-53
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    • 2009
  • The Kyung-In Canal is to protect Gulpo Stream Area from recursive flooding and to relief inland transportation congestion, in the Seoul Metropolitan Area. Enlarging and extending the Gulpo stream Drainage Canal operated only during rainy season. Kyung-in Canal will serve not only for preventiong flood, but for reducing logistics cost also in the Seoul Metropolitan Area

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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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A Warning and Forecasting System for Storm Surge in Masan Bay (마산만 국지해일 예경보 모의 시스템 구축)

  • Han, Sung-Dae;Lee, Jung-Lyul
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.5
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    • pp.131-138
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    • 2009
  • In this paper, a dynamic warning system to forecast inland flooding associated with typhoons and storms is described. The system is used operationally during the typhoon season to anticipate the potential impact such as inland flooding on the coastal zone of interest. The system has been developed for the use of the public and emergency management officials. Simple typhoon models for quick prediction of wind fields are implemented in a user-friendly way by using a Graphical User Interface (GUI) of MATLAB. The main program for simulating tides, depth-averaged tidal currents, wind-driven surges and currents was also vectorized for the fast performance by MATLAB. By pushing buttons and clicking the typhoon paths, the user is able to obtain real-time water level fluctuation of specific points and the flooding zone. This system would guide local officials to make systematic use of threat information possible. However, the model results are sensitive to typhoon path, and it is yet difficult to provide accurate information to local emergency managers.

Simulation of compound flooding using TUFLOW's 1D-2D coupling features (TUFLOW의 1-2차원 연계 기능을 활용한 복합 침수 모의)

  • Hwang, Donggyu;Kang, Teauk;Jin, Yongkyu;Lee, Sangho
    • Journal of Korea Water Resources Association
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    • v.57 no.7
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    • pp.451-460
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    • 2024
  • It is necessary to apply a rational urban flood simulation method to analyze the causes of frequent urban flooding and to develop appropriate countermeasures. Previous studies in Korea have performed flood simulations by inputting the results of manhole overflow from sewer systems and river overflow into two-dimensional flood flow simulation models. It, however, is reasonable to simulate flooding from river and manhole overflows in a complex manner. In this study, we used the 1D-2D coupling functionality of the TUFLOW module, which is a part of XP-SWMM, to simulate the compound flooding of rivers and urban areas. That method was applied to the lower basin of the Naengcheon River in Pohang City, Gyeongsangbuk-do, where both inland flooding and river overflow coincided due to Typhoon Hinnamnor on September 5 and 6, 2022, to verify its applicability.