• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.155-163
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• 2010

The past researches on flood inundation simulation mainly focused on development of numerical models based on unstructured mesh networks to improve model performances. However, despite the accurate simulation results, such models are not suitable for real-time flood inundation forecasting due to a huge computational burden in terms of geographic data processing. In addition, even though various types of vector and raster data are available to be compatible with flood inundation models for post-processes such as flood hazard mapping and flood inundation risk analysis, the unstructured mesh-based models are not effective to fully use such information due to data incommensurability. Therefore, this study aims to develop a raster-based two-dimensional inundation model; it guarantees computational efficiency because of direct application of DEM for flood inundation modeling and also has a good compatibility with various types of raster data, compared to a commercial model such as FLUMEN. We applied the model to simulate the BaekSan levee break in the Nam river during a flood period from August 10 to 13, 2002. The simulation results showed a good agreement with the field-surveyed inundation area and were also very similar with results from the FLUMEN. Moreover, the model provided physically-acceptable velocity vectors with respect to inundating and returning flows due to the difference of water level between channel and lowland.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.549-557
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• 2013

An flood inundation map is able to convey spatial distribution of inundation to a decision maker for flood risk management. A roughness coefficient with unclear values and a discharge obtained from the stage-discharge rating equation are key sources of uncertainty in flood inundation mapping by using a hydraulic model. Also, the uncertainty analysis needs an observation for the flood inundation, and satellite images is useful to obtain spatial distribution of flood. Accordingly, the objective of this study is to quantify uncertainty arising roughness and discharge in flood inundation mapping by using a hydraulic model and a satellite image. To perform this, flood inundations were simulated by HEC-RAS and terrain analysis, and ISODATA (Iterative Self-Organizing Data Analysis) was used to classify waterbody from Landsat 5TM imagery. The classified waterbody was used as an observation to calculate F-statistic (likelihood measure) in GLUE (Generalized Likelihood Uncertainty Estimation). The results from GLUE show that flood inundation areas are 74.59 $km^2$ for lower 5 % uncertainty bound and 151.95 $km^2$ for upper 95% uncertainty bound, respectively. The quantification of uncertainty in flood inundation mapping will play a significant role in realizing the efficient flood risk management.

• Journal of the Korean GEO-environmental Society
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• v.13 no.5
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• pp.59-68
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• 2012

The objective of this study is a comparison with simulation results of flood inundation by the construction techniques of river topography. For construction of river topography, the data used in this study are 1:5,000 topographic DEM, ASTER DEM and SRTM DEM provided by WMS. Also HEC-RAS and HEC-GeoRAS are applied to analyze of inundation depth and area. Flood inundations are simulated by 3 techniques in return periods and compared with the results. The results of this study are as follows; (1) Comparative analysis of the results shows that they have only a little difference in construction techniques of river topography at midsized catchment. (2) Flood inundations by ASTER DEM is to estimate larger than the other techniques in flood area (3) In case of SRTM DEM, the application can be expected to make use in the fields because of proper results in flood inundation analysis.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.59-66
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• 2007

The bridge crossing river is the one of the major factors causing backwater level rising. Furthermore, the bridges in the mountainous areas increase the flood damage in the upstream of the bridge due to the blockage by debris. In this research, the effects of debris to the magnitude of flood damage in the study river basin were simulated by using HEC-RAS and HEC-GeoRAS models. With assumption that the backwater caused by debris blocking the space between bridge piers is the only factor causing inundation, the unsteady flow simulation was carried out with various case studies. The potential inundation area with the overflow locations and volumes could be estimated as the results of simulation. However, the simulation results also reveal the limitations of inaccurate estimation of inundation area and depth. To overcome these hindrances, DEM and satellite images were applied to the simulation. By readjusting the inundation area using digital maps and satellite images and calibrating overflow volume and depth using DEM, the accuracy of simulation could be increased resulting more accurate flood damage estimation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.270-278
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• 2010

Applicability of the MIKE21 model as a real time coupled tide-surge model had been examined at the previous study. In this study, another applicability of the model as an inundation model is also examined. Prior to real cases, effect of artificial structures on the inundation is analyzed. The results show that inundation depth is not altered, while inundation area is lessened as a result of decreased inundation speed. Comparative study between the coupled model and an uncoupled storm surge model is also carried out at the Masan coastal zone, which shows the coupled model is considered to be plausible at the time to maximum inundation, while both models show similar results at the inundation area and inundation depth.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.400-403
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• 2012

Laboratory experiments were conducted for tsunami inundation to an urban area with large building roughness. The waterfront portion of the city of Seaside which is located on the US Pacific Northwest coast, was replicated in 1/50 scale in the wave basin. Tsunami heights and velocities on the inundated land were measured at approximately 31 locations for one incident tsunami heights with an inundation height of approximately 10 m (prototype) near the shoreline. The inundation pattern and speed were more severe and faster in some areas due to the arrangement of the large buildings. Momentum fluxes along the roads were estimated using measure tsunami inundation heights and horizontal fluid velocities. As expected, the maximum momentum flux was near the shoreline and decreased landward. Inundation heights and momentum flux were slowly decreased through the road with buildings on each side. The results from this study showed that the horizontal inundation velocity is an important factor for the external force of coastal structures.

• Journal of Wetlands Research
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• v.12 no.1
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• pp.33-40
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• 2010

In this study, it has been intended to present the ways to improve some problems such as the difficulty of using the program which had got from the existing study, the computation and application of a lot of parameter and the complicated processing which need to be more simplified. Also It has been tried to bring up the ways to make a flood inundation map and a detailed inundation analysis which could reduce the risk factors. We selected an Anseong-Cheon basin, and wrote a flood inundation scenario based on extreme flood to exceed the planned frequency to consider only overflow and levee break and executed inundation simulation. Researchers conducted an analysis of overflow and levee break using function of HEC-RAS Storage with a One-Dimensional model. It applied Elevation versus Volume Curve for more correct inundation simulation than a method of Area-Time-Depth which used in popular. This study will suggest a mathematical method of SURFER with a little difference of inundation area more simplified and precise flood inundation than complicated Arcview 3.2a which used Query method of Arcview 3.2a.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.254-254
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• 2019

최근 가속화되는 온난화와 이상기후 현상으로 인하여 전 세계적으로 홍수 및 가뭄의 발생빈도가 증가하고 있다. 우리나라에서도 기상이변으로 인한 집중호우 및 이상강우 발생이 증가하고 있는 실정이며 이러한 이유로 하천 제방월류 및 댐 구조물의 붕괴 등 다양한 홍수피해가 발생하고 있다. 댐 구조물의 경우 붕괴 시하류에 직접적인 재산 및 인명피해가 발생할 수 있으며 이에 따른 정확한 해석이 필요하다. 기존의 댐 붕괴로 인한 하류하천 영향 및 홍수범람해석의 경우 하류하천 지형 및 기하학적 환경을 고려하지 못한 1차원적 해석에 그치고 있는 것이 사실이다. 본 연구에서는 전남 영광군에 위치한 불갑저수지를 대상으로 1:5000 DEM 및 하천측량 자료를 적용하여 GIS Tool인 HEC-RAS Mapper를 구성하기 위한 하류지역의 기하학적 자료(Terrain MAP)를 추출하였으며, 미국 공병단에서 개발한 HEC-RAS 2D 모형을 이용하여 댐 구조물 붕괴 시 하류영향 및 홍수범람도를 작성하였다. 댐 붕괴에 따른 유출수문곡선을 유도하기 위해서 도면과 보고서를 참고하여 붕괴지속기간, 붕괴부 평균폭의 변화에 따른 다양한 모의를 수행하였으며, 각각의 조건들이 붕괴파 형성에 미치는 영향을 분석하였다. 분석결과 댐 직하류를 포함함 전 구간에서 범람현상이 발생되었으며 하도의 특성 및 구조물의 영향으로 구간별 침수심이 다르게 분포되었다(3.0~5.1m). 또한 하류로 진행되며 홍수파 및 침수심의 영향은 감소하는 것으로 확인되었다. 이는 댐 직하류에 유입된 붕괴유출량이 제내지로 확산되어 하류지역의 홍수파 에너지가 감소되는 것으로 이러한 결과는 실제하천에서 일어날 수 있는 현상이며 제내지의 홍수범람을 양상이 반영된 결과로 판단된다. 향후 이러한 2D 범람해석 결과를 토대로 보다 더 세밀한 유역특성을 고려할 수 있는 홍수 범람해석 연구가 수행되어야 할 것이다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.1
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• pp.1-10
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• 2021

In this study, Information for the case of seawater flooding and observation data over a period of 10 years (2009~2018) was collected. Using machine learning algorithms, the characteristics of the types of seawater flooding and observations by type were classified. Information for the case of seawater flooding was collected from the reports of the Korea Hydrographic and Oceanographic Agency (KHOA) and the Korea Land and Geospatial Informatics Corporation. Observation data for ocean and meteorological were collected from the KHOA and the Korea Meteorological Agency (KMA). The classification of seawater flooding incidence types is largely categorized into four types, and into 5 development types through combination of 4 types. These types were able to distinguish the types of seawater flooding according to the marine weather environment. The main characteristics of each was classified into the following groups: tidal movement, low pressure system, strong wind, and typhoon. Besides, in consideration of the geographical characteristics of the ocean, the thresholds of ocean factors for seawater flooding by region and type were derived.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.167-167
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• 2021

2018년 재해연보에 따르면 최근 10년간 자연재해는 태풍과 호우에 의한 평균피해액이(301,680백만원) 전체 재해평균피해액(344,124백만원)의 87.6%로 나타났다. 이처럼 물 관련 재해가 다른 재해에 비해 상대적으로 큰 비중을 차지하는 대표적 원인은 국지성 집중호우의 발달과 개발로 인한 불투수면적의 증가 및 지표면 유출량의 증가등이 있다. 이러한 요인들로 하천범람이 지속적으로 증가하고 있으며 이에 대응할 치수계획수립이 필요한 실정이다. 세종특별자치시의 하천기본계획(2020.01)에 따르면 세종특별자치시의 금남면 도남리의 도남천지구는 제방고 및 여유고 부족과 인명 및 재산피해 우려 지역으로 하천재해 위험지구로 선정되었다. 따라서 본 연구의 목적은 도남천지구에 강우-유출모형을 적용하여 빈도별 월류위치 파악과 하천범람지도를 작성하여 대피범위등 유역치수계획수립시 기초자료에 활용 되고자 한다. 강우분석을 위한 강우관측소 선정은 티센망 확인을 통하여 공주시(반포중) 강우관측소를 선정하였다. 강우분석은 자료기간이 짧은 강우관측소에서도 확률강우량을 산정할 수 있는 지역빈도해석을 하였으며 분석결과 적합한 확률분포형은 GEV인 것으로 나타났다. 빈도별 홍수량 산정을 위해 HEC-HMS모형을 이용하였으며 산정방법은 깅우-유출 관계 분석 방법에 의한 다양한 합성단위도 방법중 일관성과 객관성이 입증되어 온 Clark단위도 법을 사용하였다. 산정한 홍수량을 HEC-RAS모형에 적용하여 월류구간을 파악하였으며 월류위치 및 대피범위를 가시화 하기 위해 HEC-GeoRAS모형을 사용하여 빈도별 하천범람지도를 작성하였다. 본 연구는 도남천지구에 빈도별 하천범람지도를 작성 하였다. 이를 통하여 하천범람시 대피범위등 유역치수계획 수립 시 도움이 될 것으로 판단된다.