• Journal of the Korean Society of Hazard Mitigation
• /
• 제7권4호
• /
• pp.75-83
• /
• 2007

Urbanized area has complex terrain with many flow paths. Almost stormwater is drained through pipe network because most area is impervious. And overland flow from the pipe network reform the surface flow. Therefore, it should be considered the drainage system and surface runoff both in urban inundation analysis. It is analyzed by using MIKE FLOOD integrated 1 dimension - 2 dimension model about Incheon Gyo urbanized watershed and compared with the results of 1 dimension model and 2 dimension model. At the result this approach linking of 2 dimension and 1 dimension pipe hydraulic model in MIKE FLOOD give accuracy that offers substantial improvement over earlier approach and more information about inundation such as water dapth, velocity or risk of flood, because it is possible to present storage of overland flow and topographical characteristic of area.

• Journal of the Korean Professional Engineers Association
• /
• 제43권6호
• /
• pp.31-34
• /
• 2010

Recently, due to localized heavy rain and flash floods in urban areas is becoming more frequent flood damage. To prevent flood inundation damage, to formulate the diverse directions in connection with the drainage system of buildings, roads, sewerage, pump stations, detention (retention) pond, and streams is very important. In addition, it is important for the uniform design criteria, the consistent of hydrologic and hydraulic analysis method, and a flood disaster mitigation systems connected with structural and nonstructural measures. To accomplish this, the method such as installation of storage facilities, infiltration facilities, and underground water tank, the optimal size of the design gutter and grate of the road, ensure the capacity of pumping stations, and the installation of a flood control channel into the deep underground requires comprehensive measures dimension in urban areas.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.669-673
• /
• 2008

In this study, the new methodology which combines Kohonen self-organizing map(KSOM) neural networks model and the conventional neural networks models such as feedforward neural networks model and generalized neural networks model is introduced to forecast flood stage in Nakdong river, Republic of Korea. It is possible to train without output data in KSOM neural networks model. KSOM neural networks model is used to classify the input data before it combines with the conventional neural networks model. Four types of models such as SOM-FFNNM-BP, SOM-GRNNM-GA, FFNNM-BP, and GRNNM-GA are used to train and test performances respectively. From the statistical analysis for training and testing performances, SOM-GRNNM-GA shows the best results compared with the other models such as SOM-FFNNM-BP, FFNNM-BP, and GRNNM-GA and FFNNM-BP shows vice-versa. From this study, we can suggest the new methodology to forecast flood stage and construct flood warning system in river basin.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제26권5B호
• /
• pp.511-517
• /
• 2006

Flood damage is one of the most important and influential natural disaster which has an effect on human beings. Local concentrated heavy rainfall in urban area yields flood damage increase due to insufficient capacity of drainage system. When the excessive flood occurs in urban area, it yields huge property losses of public facilities involving roadway inundation to paralyze industrial and transportation system of the city. To prevent such flood damages in urban area, it is necessary to develop adequate inundation analysis model which can consider complicated geometry of urban area and artificial drainage system simultaneously. In this study, an urban flood analysis model adopting the unstructured computational grid was developed to simulate the urban flood characteristics such as inundation area, depth and integrated with subsurface drainage network systems. By the result, we can make use of these presented method to find a flood hazard area and to make a flodd evacuation map. The model can also establish flood-mitigation measures as a part of the decision support system for flood control authority.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.719-722
• /
• 2008

Forest management is done to keep ecological health of forest and to enhancement of its function. Nowadays, the abnormal climate and heavy rain happen frequently. Therefore, there are opinions that the thinning slash allowed in the mountain is flowed in rivers, which can influence in flood damage. This study, we grasp moving characteristics of thinning slash through field survey and achieved basic study about the effect of thinning slash on the discharge capacity of rivers and stream structure.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제32권5B호
• /
• pp.267-272
• /
• 2012

To reduce the flood risk caused by unexpected heavy rainfall, many prediction methods for flood have been developed. A major constituent of flood prediction is an accurate rainfall estimation which is an input of hydrologic models. In this study, a regional-scale weather model which can provide relatively longer lead time for flood mitigation compared to the Nowcasting based on radar system will be introduced and applied to the Chongmi river basin located in central part of South Korea. The duration of application of a regional weather model is from July 11 to July 23 in 2006. The estimated rainfall amounts were compared with observations from rain gauges (Sangkeuk, Samjook, and Sulsung). For this rainfall event at Chongmi river basin, Thomson and Kain-Frisch Schemes for microphysics and cumulus parameterization, respectively, were selected as optimal physical conditions to present rainfall fall amount in terms of Mean Absolute Relative Errors (MARE>0.45).

• Journal of the Korean Society of Hazard Mitigation
• /
• 제9권2호
• /
• pp.59-68
• /
• 2009

Currently, building a small dam located 1.16 km downstream from Geumnam Bridge is being considered in order to improve the riverine scenery of the site for Sejong City and to create a hydrophilic space. The purpose of this research is to present the appropriate dimensions of a small dam by reviewing the flood control reliability of the Geum River after the small dam is built. To establish this purpose, changes in the flood water level were compared and analyzed by changing the installation height of a small dam using 1D and 2D models. 1D HEC-RAS and 2D FESWMS models were applied to perform the numerical analysis of the reach. The results showed that flood control reliability was guaranteed when the installation height of the small dam was 5 meters or lower. From the 2D model, a more accurate result can be developed because the model could provide a two dimensional numerical analysis. The results can be used to determine the appropriate dimensions of a small dam for Sejong City.

• Journal of the Korean Society of Hazard Mitigation
• /
• 제8권5호
• /
• pp.111-117
• /
• 2008

Recent climate changes have increased flood damage on bank and revetment. However design standard for revetment that is the one of the most important facility for flood protection is not enough in Korea. In this study, destruction of rock revetment in Guryecity caused by the flood on Aug 2007 was inquired by analysis using 2D hydraulic simulation model SMS and the propriety of established plan for protection of rock revetment was evaluated. For this purpose, the ranges of protection facility for revetment was calculated by two methods. The one is normal method to calculate range of pier scour protection facility, and the other is a method of the standard for river design in Korea. The results of both methods are compared to evaluate the established plan.

• Journal of the Korean Society of Hazard Mitigation
• /
• 제7권4호
• /
• pp.51-57
• /
• 2007

In this study, the flow in the spillway of Gun-nam flood control reservoir were simulated by using FLOW-3D model. The discharge in the overflow weir and flow stability in approach channel were investigated with the original design plan. The results show that the scale of spillway is unsuitable and the flow in approach channel is unstable. To solve this problem, therefore, the alternative design plan were formulated. The flow in the spillway were simulated with the alternative design plan. The results show that the scale of spillway is suitable and the flow in approach channel is stable.

• Journal of the Korean Society of Hazard Mitigation
• /
• 제10권2호
• /
• pp.143-149
• /
• 2010

The river master plan was established every 10 years in Korea. The basin characteristics of 62 small and medium size rivers of which master plans were recently established during the past three years in Gyeonggi-do were investigated, and design rainfalls and design floods in the past and the latest were compared and analyzed. It was predicted that basin data and flood estimating method changed design flood. The quantitative amount of design floods were analyzed for 6 basins like Gungunchen etc. As the results, the increasing factors of design flood were the application of critical duration time, temporal time of rainfall and the increase of CN value. The decreasing factors of design flood were the application of Huff's rainfall distribution instead of Mononobe one and the ARF. The application of critical duration time increased flood about 60% whereas the application of Huff's rainfall distribution method estimated less flood than Mononobe about 62%. Considering critical duration time and changing rainfall distribution were the most important factors of increasing or decreasing design flood. However, trends of flood variation were differently analyzed by factors in 6 basins because characteristics of topography, weather, hydrology and hydraulic were different, now that correlations were not found between factors and flood variation. Flood variation is evaluated by complex effects of factors so new flood recalculated by reasonable methods should be considered as design flood.