• Title/Summary/Keyword: Inland flood

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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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Evaluation of Inland Inundation Risk in Urban Area using Fuzzy AHP (Fuzzy AHP 기법을 이용한 도시지역의 내수침수위험도 평가)

  • Shin, Ji Yae;Park, Yei Jun;Kim, Tae-Woong
    • Journal of Korea Water Resources Association
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    • v.47 no.9
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    • pp.789-799
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    • 2014
  • This study presented how to evaluate the inland inundation risk considering the characteristics of inland flood. Fuzzy AHP (Analytic Hierarchy Process), which can deal with the uncertainty or ambiguousness of the decision-making process, was used to estimate the inundation risk. The criteria used for inland inundation risk include the physical index, social index and inland flood. Each index contains three detailed indicators then total nine indicators were employed in this study. The inundation risk evaluation was carried out for each node (manhole) within the drainage system, not to the administrative extent, which enabled us to point out nodes with high risk. The proposed Fuzzy AHP was applied to Geoje district in Busan. The results indicated that the junction of Oncheoncheon and Geojecheon has high risk which is consistent with the fact that this junction has already experienced floods in the past. The proposed method can be used for evaluating inland inundation risk and preparing flood prevention plans in inland flood-prone urban areas.

Comparing Methods for Determining Flood Protection Elevation in Urban Built-up Areas (도시지역 방어침수위 설정방법 비교분석)

  • Lee, Yang Jae;Shin, Sang Young;Lee, Chang Hee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.3B
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    • pp.271-281
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    • 2008
  • To determine the flood protection elevation (FPE) in urban built-up areas, this study examines four possible methods: using the highest flood elevation in the past, extending base flood elevations of nearby watercourse to inland, and two simulation methods of inland flood under the same rainfall used in the watercourse planning nearby. According to the case study of the Jang-An Drainage Area, Seoul, the highest flood elevation in the past and simulation results of inland flood under the same rainfall in the watercourse planning nearby tend to get similar results, while extending base flood elevations of nearby watercourse to inland shows much higher elevations than other results. Meanwhile, cost-benefit analysis, when regulating residential/commercial uses below the FPE by each of four methods, suggest that planners need to consider carefully the economic feasibility of FPE used to choose appropriate methods.

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.

Development of a Combined Model for Flood Inundation Simulation (홍수범람모의를 위한 내외수 연계모형 개발)

  • Yu, Jae-Hong;Kim, Hyung-Jun;Cho, Yong-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.4 s.19
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    • pp.1-8
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    • 2005
  • In this study, a numerical model combined by a river model and an inland model developed to simulated a flood event. The river model describing an inundation in a river solves the two-dimensional Saint Venant equations with a finite difference method. The inland model based on the ILLUDAS describes the conveyance capacity of a storm sewer system. The combined model is applied to a real situation. The model simulates reasonably the real flood event occurred in a river and inland simultaneously.

A Study on Inundation Analysis Considering Inland and River Flood (내수 및 외수영향을 고려한 침수해석에 관한 연구)

  • Cho, Wan-Hee;Han, Kun-Yeun;Kim, Hyeon-Sik;Kim, Jin-Soo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.18 no.1
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    • pp.74-89
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    • 2015
  • The objective of this study is to present countermeasures for mitigation of flood damage with inundation analysis considering the effect of inland and river flood and prediction of flood inundation area, depth and time against emergencies caused by abnormal flood and local torrential rainfall. In this study, 2-D inundation analysis was fulfilled on the basis of river flood analysis applying to HEC-HMS and FLDWAV model and inundation analysis applying to SWMM model for the area of Shineum-dong, Gimcheon-si. Also expected inundation depth and area about probable rainfall of 100 and 200 years frequency were suggested. If expected inundation depth and flooding area is presented on the basis of this inundation analysis considering the effect of inland and river flood, it would be an important preliminary data to establish structural and nonstructural countermeasures for flood prevention. Also if flood risk map is prepared based on the result of inundation analysis, it would be useful to evacuate residents in high-risk area and regulate road and vehicle.

Development of a Coupled Model for the Flood Inundation Simulation (홍수범람모의를 위한 내외수 연계모형 개발)

  • Kim Hyung-Jun;Cho Yong-Sik
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.1047-1052
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    • 2005
  • The purpose of this study is developing a coupled model for the flood analysis. Firstly, the model(river model) describing the inundation in a river solves the two-dimensional Saint Venant equations with a finite difference method and it is possible moving boundary treatment. The other model(inland model) in developed based on the ILLUDAS model to describe the conveyance capacity of a stormwater sewer system. Finally, a coupled model is applied to a real situation. The newly developed coupled model simulates reasonably the flood event occurred in a river and a inland simultaneously

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Combined Inland-River Operation Technique for Reducing Inundation in Urban Area: The Case of Mokgam Drainage Watershed (도시지역의 침수저감을 위한 내외수 연계 운영 기법 개발: 목감천 유역을 중심으로)

  • Kwon, Soon Ho;Jung, Hyun Woo;Hwang, Yoon Kwon;Lee, Eui Hoon;Kim, Joong Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.257-266
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    • 2021
  • Urban areas can often suffer flood damage because of the more frequent catastrophic rainfall events from climate change. Flood mitigation measures consist of (1) structural and (2) non-structural measures. In this study, the proposed method focused on operating an urban drainage system among non-structural measures. The combined inland-river operation technique estimates the inflow of pump stations based on the water level obtained from a preselected monitoring point, and the pump station expels the stored rainwater to the riverside based on those estimates. In this study, the proposed method was applied to the Mokgam drainage watershed, where catastrophic rainfall events occurred (i.e., 2010- and 2011-years), and severe flood damage was recorded in Seoul. Using the proposed method, the efficiency of flood reduction from the two rainfall events was reduced by 34.9 % and 54.4 %, respectively, compared to the current operation method. Thus, the proposed method can minimize the flood damage in the Mokgam drainage watershed by reserving the additional storage space of a reservoir. In addition, flooding from catastrophic rainfall can be prevented, and citizens' lives and property in urban areas can be protected.

Wetland Construction: Flood Control and Water Balance Analysis

  • Kim, Duck-Gil;Kwak, Jae-Won;Kim, Soo-Jun;Kim, Hung-Soo;Ahn, Tae-Jin;Singh, Vijay P.
    • Environmental Engineering Research
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    • v.15 no.4
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    • pp.197-205
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    • 2010
  • Recent years have witnessed increasing interest in wetland constructions in Korea as a flood control measure during the flood season and for consideration of the ecology during the non-flood season. In this study, hydraulic and hydrologic analyses were performed on a wetland construction plan for use as an alternative sustainable flood defense during the flood season, as well as a wetland that can protect the ecosystem during the non-flood season. The study area was the basin of the Topyeong-cheon stream, which is a tributary of the Nakdong River, including the Upo wetland, which is registered in the Ramsar Convention and the largest inland wetland in Korea. Wetlands were to be constructed at upstream and downstream of the Upo wetland by considering and analyzing seven scenarios for their constructions to investigate the effect of flood control during the flood season; it was found the best scenario reduced the flood level by 0.56 m. To evaluate the usefulness of the constructed wetlands during the non flood season, the water balance in the wetlands was analyzed, with the best scenario found to maintain a minimum water level of 1.3 m throughout the year. Therefore, the constructed wetlands could provide an alternative measure for flood prevention as well as an ecosystem for biodiversity.