Abstract:

Flood is one of the great threats for regional sustainable development. As the global climate changes, accelerating process of urbanization and agglomeration of population and economic make flood loss become increasingly serious. Based on land use data, digital elevation data, grid size was set (grid size was 30 m×30 m) and the flood loss assessment basic flow was put out in this paper. According to the water level measured data, watershed digital elevation model and GIS spatial analysis technology, flood submerged area and water depth were calculated. GIS grid and socioeconomic attribute data grid superimposed to form flood disaster assessment grid. The grid not only included GIS topology information, but also included floodrelated information (such as water depth, velocity, duration, etc.) and land use information. Flood loss estimation model was built using the grid data. Based on field survey, combined with the facts of the study area and results of previous studies, agriculture, forestry, animal husbandry, fishery, household property, industrial and mining enterprises loss rates were determined. Based on spatial grid computing unit and flood monitoring data and GIS spatial analysis technology, flood loss was estimated in Chaohu basin in 2003. The results showed that flooded inundated area was 2 12504 km2 in Chaohu basin in 2003, submergences in the 0-05 m, 05-1 m, 1-2 m, 2-3 m, 3 m above area were 44533 km2, 48744 km2, 38146 km2, 42859 km2, 38222 km2. From the view of land use patterns, flooded area of paddy field was the largest, which was 1 71924 km2; flooded grassland was the smallest, only 1086 km2; flooded area of rural residential land, water, dry land, urban construction land, forest land were 18579 km2, 12609 km2, 471 km2, 2339 km2, 1257 km2, respectively. From the administrative region, flooded area of Wuwei County was the largest,  69785 km2; flooded area of Hefei City was the smallest, 4272 km2. Total value of flood loss was 1 948 280 000 yuan. Compared with the statistical data, the error was 619%. Flood loss was larger in Wuwei County, Hefei City and Lujiang County, 522 700 000 yuan, 284 150 000 yuan and 242 230 000 yuan respectively; less loss of Shucheng County and Feixi County was respectively 67 810 000 yuan and 94 480 000 yuan. Judging from the type of asset, economic losses of agriculture and industrial and mining enterprises were large, 662 790 000 yuan and 477 720 000 yuan respectively; forestry loss was the smallest, only 3 620 000 yuan. The flood loss estimation model was proved to be effective through the verification. The evaluation model could meet regional scale assessment of flood loss. Remote sensing data was broadly applied to carry out multiscale dynamic damage assessment