Flood Risk Assessment Based On GIS

The flood disaster risk assessment is to have comprehensive evaluation of the loss degree created by possible different extent of hazard to study areas made by flood disaster. It is the synthetic reflection of the flood disaster natural quality and the social economy attribute, which is veiy important regarding the decision-making and the management of disaster reduction and prevention. This article is based on the GIS method application, which is to discuss one fast, simple and more accurate assessment method of the flood disaster risk. It takes the flood disaster which happened once in 100 years in Chen Jiaqiao Town on July 17,2007 for example. After the inundation analysis of the GIS digital elevation model and the actual flood level, the study shows this method can simulate the accurate flooding area, and calculate the inundated depth distribution. According to different water depth target, the application of GIS tool completed partition of flood disaster danger. This research uses remote sensing picture and through visual classification to make vector quantization carried on different disaster bodies and to establish space attribute database of geographic information system. It carries on the vulnerability appraisal according to the property damage target and thus has completed risk assessment of the flood disaster. The findings indicated that the effect of method based on the GIS and carried on the flood disaster risk assessment is good. This method is helpful in the reasonable arrangement of flood prevention area, the scientific management of flood-stricken area, raises the resident's consciousness of flood prevention and disaster reduction and is worth promoting and applying in other flood-hit areas.The full text includes six sections as the following:The first section is introduction, which mainly introduces the background and senses of the selected subject, the present situation of research at home and abroad, the main content and methods of the research.The second part primarily introduces related theory research of the flood disaster risk assessment, whose concept; basic procedures, content and methods are also included.The third part represents the flood disaster risk assessment of Chenjiaqiao in Sha pingba districts, which is based on the GIS. It also introduces concept of the flood disaster, location of the research districts, historical flood situation and causes of formation in the research districts. By making use of the function of analysis module in software space and after carrying out inundation analysis of the digital elevation model and the actual flood level in Chen jiaqiao Town, the flooding scope can be known and the inundated depth distribution can be calculated. According to different water depth target, the application of GIS tool has accomplished the dangerous partition of the flood disaster.The content of the forth part is flood's vulnerability appraisal in the research districts. By using remote sensing picture, classifying through visual and making vector quantization of different disaster bodies, the space attribute database of geographic information system can be established, and after carrying on the vulnerability appraisal according to the property damage target, the flood risk assessment can be completed thereby.The fifth mainly describes the overall risk assessment and risk zone of the flood disaster in the research districts. The study has constructed the flood risk assessment model R=0.5H* 0.5V, carried on risk assessment and partition in the research districts and conducted confirmation and discussion to the result.The sixth part includes the measures of flood prevention and disaster reduction in Chenjiaqiao. according the flood disaster situation.The last section is the main conclusion.