• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.449-454
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• 2004

Nowadays, flood hazard maps have been generated to minimize the loss of human lives due to flooding domestically. To generate the flood hazard maps, LiDAR data have mainly been used to provide topographic data. The LiDAR data requires, however, relatively higher cost and processing time. Therefore, the needs of validating possible use of topographic maps as an alternative source of LiDAR, which have been already existed from the NGIS project over the nation, has been raised. In this background, this study has generated a DEM over City of Kuri as a pilot study using conventional 1:1,000 and 1:5,000 topographic maps emphasizing the linkage of river profile with breakline processing algorithm to build the essential topographic data as accurate as possible. The results showed that the RMSE from topographic maps and LiDAR were 3.49 and 2.282 meter, respectively. Further study needs to be made to decide possible use of topographic maps instead of LiDAR including more easier updating of topographic maps to support flood map generation. In addition, 1:1,000 topographic mapping, which is limited to the urban areas so far, needs to be extended to the river areas.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.389-393
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• 2010

The Objective of this study was to develop a system for visualizing inundation area by using 1-D numerical model analyzing damage information such as inundation area, facilities, land usages, population, building, loads. In this study, we have reviewed hydraulic models to select a flood model for simulation of discharges, water depths and velocities. The study area is Namhan River from Youngwol to Paldang Dam which had a flood damage on upper and below regions of Chungju Dam by a storm event in 2006. At the first, we developed the DB system base on GIS thematic map, ortho images, cadastral maps to analyze flood damages and support decisions making. Changing the boundary conditions such as discharge at the gauging stations, flood simulations were performed and then damages were extracted from the databases information support system based on 1-D numerical hydraulic model, it is expected to be able to analyze flood damages and support a decision making for reduce flood relate damages. In the future, the system developed in this study could be applied for flood forecasting system of small scaled streams.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.236-236
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• 2015

Flood is one of the major natural disasters affecting millions of people. Thailand also, frequently faces with this type of disaster. Especially, 2011 mega flood in Central Thailand, inundated highway severely attributed to the failure of national economic and risk to life. Lesson learned from such an extreme event caused flood monitoring and warning becomes one of the sound mitigations. The highway flood hazard mapping accomplished in this research is one of the strategies. This is due to highway flood is the potential risk to life and limb, and potential damage to property. Monitoring and warning therefore help reducing live and property losses. In this study, degree of highway flood hazard was assessed by weighting factors for each cause of the highway flood using Multi Criteria Analysis (MCA) based Analytic Hierarchy Process (AHP). These weighting factors are the essential information to classify the degree of highway flood hazard to enable pinpoint on flood monitoring and flood warning in hazard areas. The highway flood causes were then investigated. It was found that three major factors influence to the highway flood are namely the highway characteristics, the hydrological characteristics and the land topography characteristics. The weight of importance for each cause of the highway flood in the whole country was assessed by weighting 3 major factors influence to the highway flood. According to the result of MCA analysis, the highway, the hydrological and the land topography characteristics were respectively weighted as 35, 35 and 30 percent influence to the cause of highway flood. These weighting factors were further utilized to classify the degree of highway flood hazard. The Weight Linear Combination (WLC) method was used to compute the total score of all highways according to each factor. This score was later used to categorize highway flood as high, moderate and low degree of hazard levels. Highway flood hazard map accomplished in this research study is applicable to serve as the handy tool for highway flood warning. However, to complete the whole warning process, flood water level monitoring system for example the camera gauge should be installed in the hazard highway. This is expected to serve as a simple flood monitor as part of the warning system during such extreme or critical event.

• Journal of Korea Water Resources Association
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• v.54 no.spc1
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• pp.1119-1130
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• 2021

Urban flooding caused by localized heavy rainfall with unstable climate is constantly occurring, but a system that can predict spatial flood information with weather forecast has not been prepared yet. The worst flood situation in urban area can be occurred with difficulties of structural measures such as river levees, discharge capacity of urban sewage, storage basin of storm water, and pump facilities. However, identifying in advance the spatial flood information can have a decisive effect on minimizing flood damage. Therefore, this study presents a methodology that can predict the urban flood map in real-time by using rainfall data of the Korea Meteorological Administration (KMA), the results of two-dimensional flood analysis and random forest (RF) regression model. The Ujeong district in Ulsan metropolitan city, which the flood is frequently occurred, was selected for the study area. The RF regression model predicted the flood map corresponding to the 50 mm, 80 mm, and 110 mm rainfall events with 6-hours duration. And, the predicted results showed 63%, 80%, and 67% goodness of fit compared to the results of two-dimensional flood analysis model. It is judged that the suggested results of this study can be utilized as basic data for evacuation and response to urban flooding that occurs suddenly.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.74-88
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• 2010

In this study, the points of LiDAR were modified in order to generate various DEM resolutions by applying LiDAR data in Ulsan. Since the LiDAR data have points with 1m intervals, the number of points for each resolution was modified to the size of 1, 5, 10, 30, 50, 100m by uniformly eliminating the points. A runoff analysis was performed on Taehwa river and its tributary, Dongcheon, with 200 year rainfall exceedance probability. 2-dimensional inundation analysis was performed based on the density of LiDAR data using FLUMEN, which was used to establish domestic flood risk map. Once DEM data obtained from LiDAR survey are used, it is expected that the study results can be used as data in determining optimal grid spacing, which is economical, effective and accurate in establishing flood defence plans including the creation of flood risk map.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.383-392
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• 2014

The purpose of this study is to simulate inundation and evaluate the applicability of LISFLOOD model to the streams in South Korea by comparing with the inundation map using FLUMEN. The suggested levee breaching scenarios were applied to the LISFLOOD model, and the results obtained from scenarios were evaluated. The modeling results using LISFLOOD by appling the levee breaching scenarios showed 0.2% ~ 42% relative error with FLUMEN model in inundation area. But the relative error of maximum inundation area by overlapping all the flood analysis results from levee breaching scenarios such as the way making flood risk map was approximately 1.2% between two models. Meanwhile, LISFLOOD model was easy to construct input data, DEM as topographic data and discharge hydrograph as upper boundary conditions. And computing time of LISFLOOD was shorter than FLUMEN. Therefore LISFLOOD model can be applied usefully in the region that needs immediate inundation modeling.

• 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 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.

• Proceedings of the Korea Water Resources Association Conference
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• 2002.05b
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• pp.805-810
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• 2002

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.1
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• pp.63-71
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• 2017

Recently, there has been growing interest in public participation GIS (Geographic Information System) technology that enables spontaneous public response to increasingly frequent flood and drought events. Accordingly, social and economic demands are increasing on portal services that are designed to help cope with natural hazards such as earthquakes. By focusing on a specific hazard, urban flood, this study designed a prototype of a disaster response portal and its service system. The community map developed in this study is focused on prevention and mitigation of the urban flood damage by analyzing the vulnerable areas, and providing effective means to inspect the roads and sewer systems. By considering the compatibility with VGI (Volunteered Geographic Information) portals, the study created a system environment by employing universally used open-source software programs such as Apache Tomcat, GeoServer, GeoNetwork, and PostgreSQL/PostGIS.