The Analyzing And Zoning Of Flood Disaster Risk In Minjiang River Valley Based On GIS

China is one of the countries in which flood occurs most frequently in the world. Every year, the direct economic loss caused by flood in china is more than billions. Especially after the 1990's, the loss by flood is increasing. As a non-construction measure, the risk analysis and evaluation of flood disaster is major part of flood control and protection system, which is very helpful to the landuse and development of flooded area, loss evaluation of flood disaster, assistant decision-making of flood control and protection, insurance of flood disaster, and criterion making of flood control.Flood disaster is one of the most serious disasters in Fujian, and Minjiang River is the main river of Fujian. So in this paper, the Minjiang River valley is the study area. This study based on the theories of flood disaster and its present acquired, used Zhouchenghu's method for reference, and with the help of Geographical Information Systems (GIS) technology analyzed the flood disaster risk of Minjiang River. For flood disaster risk analysis, a variety of methods have been developed and applied. Among them, flood disaster risk zoning is an effective one. With the method, every component element of risk should be taken into account, including flood hazard and socioeconomic vulnerability, GIS can be utilized as the key technique and cell as the basic unit. Risk zoning should be processed from bottom to top and step by step.In this article, ArcGIS has been chosen to quantitatively represent theinfluential factors, to spatialize the data into uniform grid system, and to transfer all the data item into the effect degrees on the probability of flooding. At last, with the support of Arc/Info GRID model, a categorical model for flood disaster risk has been put forward. The results show that the flood disaster risk of the lower reaches of the Minjiang River is more serious than that of the higher reaches, and the area of both sides of the river is more serious than other places. The results are accorded with the flood in the past, which shows that the GIS-based category models is effective in the analysis of flood disaster risk.