The Urban Flood Disaster Assessment Research Based On Fuzzy Evaluation Method

Extreme climate change and rapid urbanization around the world result in a rapid increasing number of urban flood disasters around the world in recent years.Urban flood usually causes tremendous loss of life and property because the urban area is the hub of population and economic activities.Urban flood assessment as the precondition of city flood management has become focus of municipal and hydraulic engineering.This study will be meaningful and helpful to prevent urban flood disaster and reduce the loss of urban flood.Firstly,this paper analyzing the cuases of urban flood disaster according to the global climate,urbanization,urban drainage system and flood forecasting system.In combination with risk difination,elements and properties therisk factors was identified.On account of selection principle,disaster-deducing factors fectures,determining the risk hydraological,social and economy indicators.Then,flooding risk assessment model was set up based on fuzzy evaluation method.A hydrodynamic model was built based on 2D shallow water equations to simulate process of the flood and acquiring the simulation results of water depth,inundation area.Meanwhile,analytic hierarchy process was used to calculate the weights of assessment indices and establishing subordinating degree function by referring to common functions.Based on above mature methods,a preliminary urban flood risk assessment method system was built.Moreover,the hydrodynamic model under five design rainfall conditons of Quzhou was set up to extract three hydrology elements data of water depth,inundation area and flooding time.According to local social and economic condition,the nine elements of density of population,urbanization rate,Gross Domestic Product,economic growth rate,industrial and mineral,transportation,electricity,communication and water conservancy were collected.Based on the index data,fuzzy assessment model was employed for comprehensive flood risk assessment of Quzhou urban area.The results was provided reference for department.Finally,a summary was given and some problems to be further studied are discussed.