Analysis Of Vulnerability Of Groundwater Pollution And Space-time Change In Xi'an City From 1985 To 2003

Groundwater is the important source in production and living in city and somerespecial areas due to its cleanliness and steady etc. With development of urbanization andindustrialization and emission of the three wastes, groundwater pollution has become more andmore serious in city and industrial and mining area science establishing state. The monitoring,prediction, prevention and control of pollution is very urgent, of which the basic study is theanalysis of vulnerability of groundwater pollution and space-time dynamic change. With thesupport of the National Natural Science Foundation of China and graduate innovation projectionof Shaanxi normal university, we have systematically collected the information of hydrogeologyand monitored data of groundwater, and quantificationally analyzed the vulnerability ofgroundwater pollution and space-time dynamic change from 1985 to 2003 sustained GIS andtechnology of making models, the import contents and results is as follow:1, The analysis of vulnerability of groundwater pollution, especially the meanings of thepollution frangibility, conception model and GIS drawing method, provides the effects factors,indexes systems and classifications, weightings distributions and models selections of the generaland narrow vulnerability of groundwater, attains the evaluation chart of the general and narrowvulnerability of underground water using GIS Software, and compares the results with the realsituation of the pollution of underground water in Xi'an City. We find the narrow vulnerability issuitable for small scale and natural situation, and the general one is large and artificial ones.2, We introduces the monitoring and the models and methods of evaluation of the pollutionof underground water, especially analyses the measurement range of six important pollutants, thedistribution of the exceeding standard areas, the rule of the dynamic change of the pollutantsconcentrations and exceeding standard areas with time. The results are pollutiojns are devidedthree classifications: total solid, rigidity and nitrate are higher; fluoride, chloride and Cr6+ are inmiddle; and hydroxybenzene, arsenic and others are in lower; the exceeding standard area offormer six pollutants distribute in the central of the city, industry area in western suburb and areairrigated with polluted water in northern suburb, and the space distribution form a hilt figure;pollution index and exceeding standard area fall, These results indicate the groundwater totalqualities in Xi'an City become better gradually from 1985 to 2003.3, The simulation of the pollution change of underground water are done using space-timecombined model in Xi'an in these years, and the prediction of the development of the pollution change in the future. The space-time combined model includes the tendency, period and randomgradual simulation systems, and possesses integrated checkout methods, such as R coefficient,Post-test error ratio C and of small error and Probability P. We have attained 18 space-timecombined models of the pollution index, exceeding standard radio and exceeding standard area of 6pollutants, and check up the results using the above 3 checkout methods. In the whole investigation,we have combined the qualitative analysis and quantitative simulation using computer. It indecatespollution becoming smaller, and its cycle is 8-9 years. The results of this research will provide thescientific basis of the prediction of underground water pollution in Xi'an City.The outstanding contribution of the paper is as follow:â‘ distinguishing the general andnarrow vulnerability, building respectively index systems and models, introducing the method ofthe evaluation chart of the vulnerability distribution using GIS Software, and attaining thedistributions and adaptive conditions of the general and narrow vulnerabilityâ‘¡gathering andanalyzing the pollution datum in recent 20 years, understanding systematically the integratedchange rule.â‘¢building space-time conmbined models and complete checkout systems,establishing 18 models of 6 pollutants and 3 indexes of underground water pollution in Xi'an,revealing the period of change, and providing scientific basis for predicting and controllingunderground water pollution in Xi'an City...