• Fire Science and Engineering
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• v.32 no.4
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• pp.122-130
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• 2018

Recent urbanization, population densification, and the impact of global climate change are causing disasters to become larger and more complex. Meanwhile, in Korea, there is an emphasis on preventing, restoring, and recovering from disasters. However, disaster medical care, which is absolutely necessary to maintain life in a disaster, is being ignored. Therefore, in this study, we selected Seoul as the study area where flood damage is frequent and underground housing is densely populated. Assuming underground housing in the immersion history area as the emergency patient site, transfer distance and transfer time were analyzed. This study considered both accessibility to emergency medical facilities and disaster sites and accessibility from emergency services to disaster sites. Therefore, it seems to be meaningful as basic data for the improvement of emergency medical services.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.3
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• pp.1-11
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• 2014

Recently, major cities in Korea are suffering from frequent urban flooding caused by heavy rainfall. Such urban flooding mainly occurs due to the limited design capacity of the current drainage network, which increases the vulnerability of the cities to cope with intense precipitation events brought about by climate change. In other words, it can be interpreted that runoff exceeding the design capacity of the drainage network and increased impervious surfaces in the urban cities can overburden the current drainage system and cause floods. The study presents the green roof as a sustainable solution for this issue, and suggests the pre-design using the LID controls model in SWMM to establish more specific flood prevention system. In order to conduct the computer simulation in connection with Korean climate, the study used the measured precipitation data from Cheonan Station of Korea Meteorological Administration (KMA) and the forecasted precipitation data from RCP 8.5 scenario. As a result, Extensive Green Roof System reduced the peak runoff by 53.5% with the past storm events and by 54.9% with the future storm events. The runoff efficiency was decreased to 4% and 7%. This results can be understood that Extensive Green Roof System works effectively in reducing the peak runoff instead of reducing the total stormwater runoff.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1625-1630
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• 2021

In Bangkok, Thailand, there is an increasing concern for ground subsidence with the rapid urbanization. Given the presence of flood vulnerability due to the flat low-lying topography and proximity to the river delta, it is particularly significant to monitor deformation that can potentially augment flood hazards. In this paper, we have applied persistent scatterer interferometric synthetic aperture radar (PSInSAR) technique to investigate subsidence in Bangkok with the use of Sentinel-1 acquisitions spanning from June 2018 to October 2021. The vertical displacement velocity obtained from both ascending and descending orbits revealed regional-scale subsidence at rates up to 30 mm/yr. In addition, ongoing subsidence was observed in the suburb areas with the localized vertical subsidence exceeding 80 mm. The areas are primarily industrial and agricultural sectors, thus, the ground subsidence detected is probably caused by groundwater withdrawal. However, further work is needed to diagnose the trends of aquifer resources.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2B
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• pp.131-139
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• 2009

Recently frequent occurrences of heavy rainfall and increases of rainfall intensity resulted in severe flood damage in Korea. In order to mitigate the vulnerability of flood, it is necessary to estimate proper design rainfalls considering the increasing trend of extreme rainfalls for hydrologic planning and design. This study focused the estimation of design rainfalls in a design target year. Tests of trend indicated that there are 7 sites showing increasing trends among 56 sites which have hourly data more than 30 years in Korea. This study analyzed the relationship between mean of annual maximum rainfalls and parameters of the Gumbel distribution. Based on the relationship, this study estimated the probability density function and design rainfalls in a design target year, and then constructed the rainfall-frequency curve. The proposed method estimated the design rainfalls 6-20% higher than those from the stationary rainfall frequency analysis.

• Journal of Korea Water Resources Association
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• v.49 no.2
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• pp.95-106
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• 2016

Water Management Resilience Index (WMRI) was developed as a policy measure of adaptability to withstand water stresses and to set up water management strategies mainly in mid-small scale tributaries, and then evaluated on 117 sub-basins in South Korea. The index consists of 3 sub-indices such as vulnerability, robustness and redundancy sub-indices, each including indicators of 3 sectors: water use, flood mitigation, and river environment. Total number of indicators selected for the index was 31. Taking into account the stream order and control capability of river flow discharge, sub-basins were categorized into 3: 1 for mainstreams of lower large dams, 2 and 3 for tributaries, respectively without and with flow discharge regulation. As a result of the evaluation, resilience index scores in Category 2 and 3 are much lower than that of Category 1, especially with very poor score of redundancy. Although there was no significant difference between mainstream and tributaries in vulnerability and robustness sub-indices, results of redundancy sub-index in tributaries were lower than those in mainstream. Thus, it is conceived that the variety of water management schemes should be considered to improve their resilience in the face of future uncertainty. Addressing comprehensive stability of river basin against internal and external impacts, WMRI in this study can also be used for the prioritization of water management plans.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.5
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• pp.253-264
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• 2019

Storm surges caused by a typhoon occur during the summer season, when the sea-level is higher than the annual average due to steric effect. In this study, we analyzed the sea-level pressure and tidal data collected in 1 h intervals at Incheon, Kunsan, Mokpo, Seogwipo stations on the Yellow Sea coast to analyze the summer season storm surge and wave overtopping. According to our analyses, the summer mean sea-level rise on the west and south coasts is approximately 20 cm and 15 to 20 cm higher than the annual mean sea-level rise. Changes in sea-level rise are closely related to changes in seasonal sea-level pressure, within the range of 1.58 to 1.73 cm/hPa. These correlated mechanisms generates a phase difference of one month or more. The 18.6 year long period tidal constituents indicate that in 2090, the amplitude of the $M_2$ basin peaks on the southwest coast. Therefore, there is a need to analyze the target year for global warming and sea-level rise in 2090. Wave overtopping was simulated considering annual mean sea-level rise, summer sea level rise, the combined effect of nodal factor variation, and 100-year frequency storm surge. As a result, flooding by wave overtopping occurs in the area of Suyong Bay, Busan. In 2090, overtopping discharges are more than doubled than those in Marine City by the recent typhoon Chaba. Adequate coastal design is needed to prepare for flood vulnerability.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.289-293
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• 2008

현재 기후변화는 점점 가속화되고 있으며, 이로 인해 향후 홍수피해는 더욱 증가될 가능성이 높은 것으로 알려져 있다. 장기적이 측면에서 이러한 홍수피해에 대비하기 위해서는 유역별 홍수에 대한 취약성을 평가하고, 기후변화의 영향을 고려하여 유연한 적응 정책을 마련하는 것이 필요하다. 본 연구에서는 기후변화에 따른 국내유역의 홍수 취약성을 평가하는 방법으로 지표를 이용한 방법을 제안하였다. 이 방법은 기후변화에 따른 홍수 취약성을 민감도(sensitivity), 노출(exposure), 적응능력(adaptation)의 함수로 정의하고, 각 유역별 지표들을 이용하여 상대적인 취약성 정도를 평가하는 것이다. 본 연구에서는 유역의 민감도와 노출정도가 클수록 기후변화에 대한 홍수피해에 취약하고, 적응능력이 클수록 취약성이 낮다고 판단하였다. 본 연구에서 제안한 방법으로 국내 139개 유역에 대해 상대적인 홍수피해 취약성을 평가한 결과 과거 유역별 홍수 피해액의 분포와 유사한 것으로 나타났다. 또한, A2 시나리오를 이용하여 미래 기후변화 상황에서의 홍수피해 취약성에 대해 평가한 결과 국내 유역의 홍수피해는 증가될 가능성이 있는 것으로 전망되었으나 유역별 공간적인 취약성은 크게 변화지 않는 것으로 나타났다.

• Water Engineering Research
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• v.1 no.4
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• pp.267-277
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• 2000

This study reports an examination of the sensitivity of water resources in the Keum River basin to climate change. Assuming a doubling in $CO_2$ concentrations, a cooperative study provided four climate change scenarios for this study, which have been translated into temperature and precipitation scenarios on a basin scale. The study utilized these temperature and precipitation data for each climate change scenario as inputs to the NWS-PC model to generate the corresponding streamflow scenario over the Keum River basin. A reservoir simulation model for the Dae-Chung Dam in the Keum River basin has been developed with an object-oriented simulation environment, STELLA. For each streamflow scenario, the performance of the reservoir was assessed in terms of reliability, resiliency, and vulnerability. Although the simulation results are heavily dependent on the choice of the climate change scenarios, the following conclusions can be clearly concluded: (1) the future streamflow over the Dae-Chung Dam tends to decease during the dry period, which seriously increases competitive water use issues and (2) flood control issues predominate under the $2CO_2$-High case.

• Earthquakes and Structures
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• v.13 no.5
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• pp.497-507
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• 2017

Flooding induced scour has been long recognized as a major hazard to river-crossing bridges. Many studies in recent years have attempted to evaluate the effects of scour on the seismic performance of bridges, and probabilistic frameworks are usually adopted. However, direct and straightforward insight about how foundation scour affects bridges as a type of soil-foundation-structure system is usually understated. In this paper, we provide a comprehensive review of applied methods centering around seismic assessment of scoured bridges considering soil-foundation-structure interaction. When introducing these applied analysis and modeling methods, a simple bridge model is provided to demonstrate the use of these methods as a case study. Particularly, we propose the use of nonlinear modal pushover analysis as a rapid technique to model scoured bridge systems, and numerical validation and application of this procedure are given using the simple bridge model. All methods reviewed in this paper can serve as baseline components for performing probabilistic vulnerability or risk assessment for any river-crossing bridge system subject to flood-induced scour and earthquakes.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.47-51
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• 2010

본 연구의 목적은 기후변화에 따른 홍수 취약성 평가 방법을 제안하고 미래 기후시나리오를 이용하여 국내 5대강 유역에 대해 홍수취약지역을 시 공간적으로 평가하는 데에 있다. 이에 현 기후상태의 홍수 취약성을 평가하고자 유역의 지형, 인문 사회 정보를 수집하였으며, 관측 기상, 수문자료와 수문모형 모의로부터 유역평균강수량 및 유역별 유출량을 산정하였다. 이상의 자료를 토대로 홍수와 관련된 취약성 지표를 선정 및 산정하여 현재 기후상태(1971~2000년)에서의 홍수취약성을 평가하였다. 또한 기후변화 영향을 고려하기 위해 3개의 온실가스배출시나리오를 기반으로 생산된 13GCMs 별 미래 기후시나리오 자료를 수집하였으며, 3개의 유출모형에 적용, 다수의 유출시나리오를 생산하여 현재 기후상태(1971~2000년) 대비 미래 세기간 S1(2011~2040년), S2(2041~2070년), S3(2071~2100년)의 홍수 취약성을 평가하였다. 현재 기후상태에 따른 홍수취약지역을 평가한 결과 대체로 한강 중 하류지역과 영 섬강 하류 지역에서 높게 나타났으며, 낙동강 중 상류유역은 상대적으로 낮은 것으로 나타났다. 또한 기후변화시나리오를 적용할 경우 취약지역의 공간적인 분포는 기준기간과 유사했으나, 대부분의 유역에서 심도는 증가할 것으로 나타났다. 특히 낙동강 권역에서 가장 크게 변할 것으로 분석되었는데 이는 하천의 적응능력이 작아 상대적으로 기상 수문지표의 변화에 더욱 민감하게 반응하는 것으로 판단된다.