Study On Flood Risk Zonation Assisted By Remote Sensing And Geographical Information System

Flood is a kind of serious natural disaster at the world range, and it makes severe personnel casualty and economical loss with plentiful occurring times. China is one of the most influenced countries by flood for Chinese spatial natural geographical conditions; its floods are frequent and have enormous expense.Floods fighting and disaster salvation are divided into structural and non-structural measures at present. Flood risk zonation is a type of the non-structural measures and it divides the area into different risk grades based on dangerous features of flood and referred to the social economical status and its enduring capability to flood disaster of this area. Thus sub-area of this area can be deal with different degrees, and serves for floods fighting and disaster salvation and supports decision-making.Geographical information system (GIS) and remote sensing (RS) develop rapidly recent years, this provides powerful safeguard for flood risk management. GIS has distinct advantage for spatial geographical data input, storage, query, search, analysis, display and output. RS is utilized for its advantage that it can attain the data the time of day and no touch, and it cans synchronously observe the object among wide range.Flood risk zonation assisted by RS and GIS will be studied in this paper. It will be began from the viewpoint of hazard system theory, indexes and factors such as disaster-pregnant environment, disaster-causing factors and disaster-bearing bodies will be used to describe the component of flood disaster, then it will be dissertated in detail that the attainment of those indexes and factors of flood risk zonation such asflood submerge range, flood frequency, disaster-causing factors and social economical factors.Flood risk zonation should utilize different indexes and factors and adopt different zonation methods according to different region and different environment. This paper single out two places of Beijiang River drainage basin ?Binjiang River small drainage basin and Pajiang River natural detention basin in Guangdong province to study flood risk zonation.Binjiang River is a branch of Beijiang River, it will be single out to carry through the study of drainage area flood risk zonation. Factors of relief, precipitation, social economy and flood frequency will be selected to process algebraic calculation in spatial range, and the whole Binjiang River drainage area will be divided into different sub-area marked secure and dangerous degree, then will analyze the result.Flood risk zonation method of Pajiang River natural detention basin is differ from Binjiang River small drainage basin, when store-floodwater and flood-detention project launched, some area must be submerged in this region and suffer losing. This paper will apply 2D unsteady flow equation to simulate numerically whole detention basin, and improve the equation with VORONOI diagram, according to the simulated result, spatial diversity will be pointed out such as when flood arrive, flood fastest velocity, whole time of flood submerge and flood depth and so on, at last flood risk zonation about disaster-causing factors will be done.Research of this paper is a part of DECISION-MAKING FOR FLOOD-PREVENTION 3S TECHNICAL SUPPORTING SYSTEM BEIJIANG RIVER GUANGDONG PROVINCE, so building of the flood risk management system include flood risk zonation sub-system is an important content of this paper. There is a whole chapter to debate integrating flood risk zonation with GIS, to design flood risk management system, besides flood risk cartography and flood risk analysis.