Recently a sudden increment of natural disasters occurred due to unusual weather. There are 17,569 reservoirs in South Korea, and since 1964 urgent maintenance has been required for 74.2% of deteriorated reservoirs. Concerns should also be taken about rising social demand and economic impact related to the deterioration of dam, and it is necessary to ensure the flood hazard mapping as a shelter.
Analysis is carried out to compare the hazard mapping, and flood hazard model data coming out from the field survey after the collapse of Sandae reservoir located in Gyeongju Angang Sandae Avenue. Besides, a comparative analysis is also performed to check the accuracy between the real and modeling data. Water flow curve was taken from the previous research, whereas the topographical mapping data were taken from the National Geography Institute with the scale of 1:5000. For the model in this study, the grid is set 5m X 5m. The ground surface properties were collected from the Land Covering Map and Soil Map. Coefficient of roughness, permeability coefficient, and soil suction value were computed.
The extent of damage for hazard map model results using FLO-2D model and field hazard map survey was determined. For the field hazard model, the extent of damage area was 177,750m2, and that of hazard map survey was 196,400m2. Despite of a difference of 10.5% between the 2 models, while performing the analysis by combining the 2 maps, field hazard mapping survey and the hazard mapping model, the depth of water measured at 10 differences places was beyond limit and the water level average was of 4cm. Due to such collapse dam disaster, loss of human life and individual properties are ruined. By carrying out this simulation, this work focused on making signs about flood information and evacuation signal information (limited spatial extent of Flood starting point, flooding depth, and clearway for evacuation) on the ground surface when there is collapse deteriorated reservoir. Compared to other developed countries, Flood Risk Map is very well used and fabricated in South Korea. Therefore, through this research, the flood risk map is provided.