• Title/Summary/Keyword: urban flood mitigation

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Application of Urban Hydrologic Monitoring System for Urban Runoff Analysis (도시유출해석을 위한 도시수문 모니터링 기법 적용)

  • Seo, Kyu-Woo
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.2 s.17
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    • pp.37-44
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    • 2005
  • It reflects well feature of slope that is characteristic of urban river basin of Busan local. In this study, process various hydrological data and basin details data which is collected through basin basis data, hydrological monitoring system(EMS-DEU) and automatic water level equipment(AWS-DEU) for urban flood disaster prevention and use as basin input data of ILLUDAS, SWMM and HEC-HMS in order to examine outflow feature of experiment basin and then use in reservoir design of experiment basin through calibration and verification about HEC-HMS. Inserted design rainfall for 30 years that is design criteria of creek into HEC-HMS and then calculated design floods according to change aspect of the impermeable rate. Capacity of reservoir was determined on the outflow mass curve. Designed detention pond(volume $54,000m^3$) at last outlet upper stream of experiment basin, after designing reservoir. It could be confirmed that the peak flow was reduced resulting from examining outflow aspect. Designing reservoir must decrease outflow of urban areas.

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.

Assessing the resilience of urban water management to climate change

  • James A. Griffiths
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.32-32
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    • 2023
  • Incidences of urban flood and extreme heat waves (due to the urban heat island effect) are expected to increase in New Zealand under future climate change (IPCC 2022; MfE 2020). Increasingly, the mitigation of such events will depend on the resilience of a range Nature-Based Solutions (NBS) used in Sustainable Urban Drainage Schemes (SUDS), or Water Sensitive Urban Design (WSUD) (Jamei and Tapper 2019; Johnson et al 2021). Understanding the impact of changing precipitation and temperature regimes due climate change is therefore critical to the long-term resilience of such urban infrastructure and design. Cuthbert et al (2022) have assessed the trade-offs between the water retention and cooling benefits of different urban greening methods (such as WSUD) relative to global location and climate. Using the Budyko water-energy balance framework (Budyko 1974), they demonstrated that the potential for water infiltration and storage (thus flood mitigation) was greater where potential evaporation is high relative to precipitation. Similarly, they found that the potential for mitigation of drought conditions was greater in cooler environments. Subsequently, Jaramillo et al. (2022) have illustrated the locations worldwide that will deviate from their current Budyko curve characteristic under climate change scenarios, as the relationship between actual evapotranspiration (AET) and potential evapotranspiration (PET) changes relative to precipitation. Using the above approach we assess the impact of future climate change on the urban water-energy balance in three contrasting New Zealand cities (Auckland, Wellington, Christchurch and Invercargill). The variation in Budyko curve characteristics is then used to describe expected changes in water storage and cooling potential in each urban area as a result of climate change. The implications of the results are then considered with respect to existing WSUD guidelines according to both the current and future climate in each location. It was concluded that calculation of Budyko curve deviation due to climate change could be calculated for any location and land-use type combination in New Zealand and could therefore be used to advance the general understanding of climate change impacts. Moreover, the approach could be used to better define the concept of urban infrastructure resilience and contribute to a better understanding of Budyko curve dynamics under climate change (questions raised by Berghuijs et al 2020)). Whilst this knowledge will assist in implementation of national climate change adaptation (MfE, 2022; UNEP, 2022) and improve climate resilience in urban areas in New Zealand, the approach could be repeated for any global location for which present and future mean precipitation and temperature conditions are known.

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Assessing the capability of HEC-RAS coupled 1D-2D model through comparison with 2-dimensional flood models

  • Dasallas, Lea;An, Hyunuk
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.158-158
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    • 2019
  • Recent studies show the possibility of more frequent extreme events as a result of the changing climate. These weather extremes, such as excessive rainfall, result to debris flow, river overflow and urban flooding, which post a substantial threat to the community. Therefore, an effective flood model is a crucial tool in flood disaster mitigation. In recent years, a number of flood models has been established; however, the major challenge in developing effective and accurate inundation models is the inconvenience of running multiple models for separate conditions. Among the solutions in recent researches is the development of the combined 1D-2D flood modeling. The coupled 1D-2D river flood modeling allows channel flows to be represented in 1D and the overbank flow to be modeled over two-dimension. To test the efficiency of this approach, this research aims to assess the capability of HEC-RAS model's implementation of the combined 1D-2D hydraulic simulation of river overflow inundation, and compare with the results of GERIS and FLUMENS 2D flood model. Results show similar output to the flood models that had used different methods. This proves the applicability of the HEC-RAS 1D-2D coupling method as a powerful tool in simulating accurate inundation for flood events.

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Relationship between Flood Characteristics and Underground Inundation (홍수특성과 지하공간침수의 관계 검토)

  • Lee, Dae-Young;Lee, Keon-Haeng;Kyoung, Min-Soo;Kim, Hung-Soo
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.367-370
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    • 2007
  • In recent, the utilization of underground in urban area is increased as subway, store, and others but we have done a few studies for the inundation of underground due to flooding. So, we investigate the examples of underground inundation and the causes of inundation for flood events. And the relationship between flood characteristics and underground inundation is analyzed through the frequency of rainfall which is made by annual multi maximum series. As a result, most of underground is inundated by high frequency of rainfall. And there are some cases that the underground is inundated by low frequency of rainfall because of poor drainage system and characteristics of location.

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A Study on the Estimation of the Urbanization Using GIS and Its Effect on the Runoff (GIS를 이용한 도시화 진행상황의 평가 및 유출에 미치는 영향에 관한 연구)

  • Kang, Sang-Hyeok;Kwon, Jae-Hyuk;Jun, Byung-Duk
    • Journal of the Korean Society of Hazard Mitigation
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    • v.1 no.2 s.2
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    • pp.85-92
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    • 2001
  • The flood damage due to heavy rainfall caused by not only geographical factor, but also social factors. In this paper we derived the flooding potential factors, and analyzed resident's understanding of flooding through the Tokai disaster of Japan, occurred in september 2000. Furthermore, the urban rate obtained by the data comparison between 1975 and 1985 using GIS is evaluated to estimate the effect of rainfall-runoff mechanism due to the urbanization. These efforts could be served as the information of flood damage for the communication with the residents and it would be helped the minimization of flood damage.

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Operational Improvement of Small Urban Storm Water Pumping Station (2) - Comparative Study to Reduce the Flooding Problems using Flood Simulation Model (도시 소유역 배수펌프장 운영개선 방안 연구 (2) - 침수범람모의에 의한 침수방지 방안 비교 연구)

  • Gil, Kyung-Ik;Han, Jong-Ok;Kim, Goo-Hyun
    • Journal of Korean Society on Water Environment
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    • v.22 no.1
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    • pp.110-115
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    • 2006
  • Flooding situation of Sutak basin was simulated and simulation seemed to be consistent with the real flooding situation in terms of high water levels and timings of flooding. The flood simulation model was used to evaluate alternatives to mitigate flooding problems in Sutak basin. From the evaluation of flood mitigation plans, it was found that combined operation of Sutak and Inchang pumping stations through partial diversion of inflow of Sutak pumping station to Inchang pumping station was the most effective one among the suggested mitigation plans. About 500 meter diversion channel will be needed to send 30% of Sutak pumping station inflow to Inchang pumping station. This will reduce overload of Sutak pumping station and the storage capacity of Inchang pumping station will be more efficiently utilized.

An Application Analysis of Vegetation Permission Map in Urban Stream in Korea (국내 도시하천에 대한 식수허가지도의 적용성 검토)

  • Lee, Joon-Ho;Yoon, Sei-Eui
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.3 s.18
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    • pp.47-55
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    • 2005
  • In order to design and manage the urban streams, the change of hydraulic characteristics by vegetation must be analyzed clearly. Planting criteria of vegetation in a urban stream were investigated and the design method of vegetation permission map was analyzed in this study. In addition, variations of water level due to vegetation are calculated by quasi two dimensional numerical model, HEC-RAS model and FESWMS model. Joongrang stream(Gunja bridge${\sim}$Jangan bridge reach) was selected as the case study stream. According to the criteria of vegetation, it is decided that vegetation density was $0.5{\sim}1.0$ tree/ha for selected tall tree in right floodplain and shrubs can be planted in the right and left floodplain area except the important hydraulic structures site. The selected shrubs planting simulations with three models show that water level in selected floodplain area increase approximately 12cm for the 100 year return period flood. The applicability of vegetation permission map in Korean urban stream was analyzed in this paper.

Development of Urban Inundation Analysis Model Using Dual-Drainage Concept (Dual-Drainage 개념에 의한 도시침수해석모형의 개발)

  • Lee, Chang Hee;Han, Kun Yeun;Noh, Joon Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4B
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    • pp.379-387
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    • 2006
  • An urban inundation model coupling an one-dimensional stormwater model, SWMM(Storm Water Management Model), and a two-dimensional inundation model was developed to simulate inundation caused by the surcharge of storm sewers in urban areas. The limitation of this model which can not simulate the interaction between drainage systems and surcharged flow was resolved by developing Dual-Drainage inundation analysis model which was based upon hydraulic flow routing procedures for surface flow and pipe flow. The Dual-Drainage inundation analysis model can simulate the effect of complex storm drainage system. The developed model was applied to Dorim, catchment. The computed inundated depth and area have good agreement with the observed data during the flood events. The developed model can help the decision support system of flood control authority for redesigning and constructing flood prevention structures and making the potential inundation zone, and establishing flood-mitigation measures.