Development of Sediment Disaster Mitigation GIS by Using High-resolution Satellite Imagery and Forest Database

摘要

A new GIS for exact evaluation of the risk for sediment collapse and for counter measures to mitigate sediment disasters in mountain areas caused by heavy rainfall is shown in this paper. At first the characteristics of the sediment disaster in the mountain areas of Gifu Prefecture, Japan due to the 2000 Tokai Heavy Rainfall, are analyzed by the detailed records of sediment collapses obtained from high resolution satellite imagery and by the database for many features of the forests. Based on the results of the analysis the more exact risks for sediment flow and slope failures are evaluated in the area, and the reliability of the evaluation is confirmed. The practical counter measures for sediment disaster are demonstrated for different phases of the disaster, applying the GIS. Detailed evacuation plans are derived by the real time records of the precipitation and the evaluated risk. To recognize the disasters in the whole area, the sediment collapses mapdeveloped with high resolution satellite images, and the GIS data such as roads, are overlaid. In the plan for the dams to mitigate the disaster, the risk analysis is applied to determine the priority for the construction sites.