基于GIS的太湖流域主要生态风险源危险度综合评价研究

以太湖流域主要生态风险源为评价对象，充分考虑多类型多等级风险源作用强度的差异性，构建了风险源危险度评价模型，并在此基础上依据风险源发生机率、强度及作用范围等建立了太湖流域洪涝、干旱、极端气象、土壤侵蚀及污染排放等主要生态风险源的危险度评价指标体系。在ArcGIS技术支持下，创建了太湖流域1 606个网格和24个县市的风险源危险度统计数据库，采用AHP权重法确定指标权重，运用叠加分析、空间分析等技术方法最终实现太湖流域单要素及综合生态风险源危险度的定量评价。结果表明流域内生态风险源的分布存在明显的空间分异规律。其中，高生态风险源危险区集中分布在环太湖北部一带，面积约占流域面积的1172%；较高危险区主要呈“西北 北 东北 东”半环状分布格局，所占面积约2452%，危险度较低的区域集中在流域西南部的苕溪流域一带，面积占1566%。此外，不同区域主导生态风险源组成亦不同，约599%的区域是以污染排放为主导生态风险源，主要分布在镇江 宜兴 长兴 安吉一线以东的地区；2545%的区域主导生态风险源为干旱，主要集中在镇江 宜兴 长兴 安吉一线以西；1244%的区域是以洪涝灾害为主导风险源，集中分布在湖州、宜兴等地；而以水土流失、极端气象灾害作为主导风险源地区相对较为分散，所占比例较小

EVALUATION OF THE HAZARD DEGREE FOR THE MAIN ECOLOGICAL #br# RISK SOURCES IN TAIHU LAKE BASIN USING GIS

Located in the Yangtze River，the Taihu Lake watershed is one of the most economically developed regions in China，but is also a region with frequent natural disasters Regional development and social progress make the patterns，depth and intensity of land use constantly change in watershed，as a result，human land conflict is highlighted and the ecological environment is facing tremendous pressure，whats more，the ecosystem structure and function are strongly affected At present，study on the ecological risk of the Taihu Lake watershed is not plentitude，which only evaluates single risk sources such as heavy metal pollution，floods，etc，and is lacking of quantitative research Taking the main ecological risk sources of Taihu Lake Basin as the evaluation object，the article explored the mechanism of risk sources，and built a model of risk source assessment considering the differences of risk sources intensity in different grades and types Then according to the incidence，intensity and scope of ecological risk sources occurrence，this study established the hazard index system of ecological risk sources such as flood，drought，extreme weather，soil erosion and pollution emissions ArcGIS software was used to create the statistical database of risk source hazard including 1606 grids and 24 counties，and then to determine the weights of index by using AHP method At last，a quantitative assessment was conducted for single elements and comprehensive ecological risk by using the technology of overlay analysis，spatial analysis，and definite the leading ecological risk source Based on the hazard degree assessment of ecological risk source model，we used the probability analysis to assess the occurrence strength of floods，droughts，extreme weather，soil erosion，pollution and other natural disasters and human activities in the Taihu Lake watershed，and finally received the spatial distribution of comprehensive risk sourced High risk areas of risk source accounted for 1172% of the total area，mainly concentrated in the northern regions of the Taihu Lake watershed. Higher ecological risk areas appeared the “Northwest North Northeast East” semi circular distribution pattern，accounting for 2452% of the watershed，and lower risk source areas were concentrated in the Tiaoxi basin located in northwestern of Taihu watershed，accounting for 1566% of the watershed In different regions，the composition of ecological risk source and the dominant source was different In 599% of the region，the main risk source was pollution emission，mainly concentrated at the east of Zhenjiang yixing changxing anji Over 25% of the region took drought as the main risk source，mainly concentrated at the west of Zhenjiang yixing changxing anji For 1244% of the region,the main risk source was flood，concentrated at the huzhou，yixing The region taking the extreme weather and soil erosion as main risk source was relative dispersed and accounted for less percentage