Flood Risk Assessment Based on Principal Component Analysis for Dongjiang River Basin

On the basis of the natural disaster system theory, this paper takes the danger of hazard inducing factors, stability of hazard inducing environment and vulnerability of hazard bearing body into consideration. Ten indexes including precipitation, typhoon, elevation, slope, river buffer, runoff, road, population, GDP and agricultural land are selected in this paper to evaluate the flood risk in Dongjiang River Basin, with the application of GIS technology and the Principal Component Analysis (PCA) method. The results show that the highest risk zones and higher risk zones occupy above 25% of the basin area while the lowest risk zones and lower risk zones make up about 45%. Flood disaster mainly concentrates in such regions as Shenzhen, Huizhou, Heyuan city; the results are objective and reasonable, compared with actual conditions. In sum, the PCA method is strict and convenient, which provides a reasonable, reliable way for flood risk assessment.