西安市地下水污染敏感性分析研究

从"污染源排放→包气带传输→地下水污染"的系统概念出发,提出了地下水污染广义敏感性和狭义敏感性的概念,并构建了相应相对完善的评价指标;在广泛水文地质调查和污染源调查的基础上,以GIS空间分析为手段,完成了西安市地下水污染敏感性分析试验。结果显示:从纯水文地质条件出发,西安市地下水污染的狭义敏感性,以主河道、漫滩阶地、一级阶地和人工填土区最为敏感,与中心城区地下水污染的实际分布状况有较大偏离;考虑人类活动及污染源分布,广义敏感性为,西安市地下水污染的敏感性以建城区和北郊污灌区最为敏感,与地下水污染的现实分布格局相一致,但在广阔的农业区,使得敏感性等级不甚明显。进而得出,地下水污染狭义敏感性评价适合大尺度区、人类影响小或影响均一区的评价;广义敏感性评价适合小尺度区、人类影响大、影响不均一区的评价。本研究为地下水污染敏感性分析及西安市地下水污染防治提供了新的信息。

Analysis on Groundwater Vulnerability: A Case Study in Xi'an City, China

Based on"pollution discharge-vadose zone conveying—groundwater pollution" system,narrow sense of groundwater vulnerability concept and broad sense one are defined,and corresponding relatively perfect index system is built;According to investigation about hydrological geology and pollution,under support of GIS' spatial analysis,the test of groundwater vulnerability analysis is done.The conclusions are as follows: the narrow sense of groundwater vulnerability from nature hydrologic geology is that main river way,alluvial flat,second bottom and artificial earth fill are the most vulnerable,but this doesn't agree with real pollution distribution;Considering human behavior and distribution of pollution,the broad sense one is that city proper and north suburbs irrigation by polluted water are the most,this agrees with the real pollution distribution,but the grading contrast in broad agricultural region isn't obvious.It is drawed that narrow sense of grounderwater vulnerability evaluation suit for area of vast scale,less or different affected by human;broad sense one fit to one of small scale,more or same affected by human.The study offers new information for groundwater vulnerability analysis and control pollution in Xi'an