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Xian is one of the 40 serious groundwater shortages cities, many years of over-exploited coursed groundwater serious decline and trigger such as land subsidence and ground fissure, etc., resulting in the environmental geological problems, many ancient building have been damaged, some water supply, gas supply, drainage pipeline rupture, and people’s normal production and living suffered serious influence. In order to protect and conserve the groundwater resources, prevent the geological environment problems continue to deteriorate caused by phreatic water surface drops, and governance the appeared geological environment problems, Xi’an adopted a series of measures, including make use of surface water resource, close the self-prepare well. In order to protect and repair groundwater more scientific, this paper divides over-exploited groundwater area in Xi’an and research the calculation of ecological injection quantity and the effect of ground subsidence, this can provide reliable basis for the management and restoration of groundwater.On the basis of data collecting and investigate in Xi’an, this paper applied Probabilistic Neural Network and Mapgis, classified the over-exploited groundwater area in the use of analysis and calculation of every index of groundwater, analyse the result. Then analyzes the process of over-exploited, choosing the appropriate method to calculate the ecological injection quantity of research area. The main results as follows:①Through the groundwater area definitions and identification method of analysis, this paper consider permeability coefficient, groundwater level buried deep infiltration, the quantity of hydrogeological conditions of the influence of difference of over-exploited groundwater.②Introduced the classification method of groundwater vulnerability assessment in this paper, analyzes the advantages and disadvantages of each method, choose probability and neural network to classify the over-exploited groundwater area.③Through the analysis and calculation of over-exploited groundwater of Xi’an,there are 10 different degree of over-exploited area,and compare to the result of traditional methods, analyze this two results.⑤In the analysis of present situation and the history of groundwater exploitation of xian, this paper use well-precipitation volume method to calculate ecological injection quantity, and the total ecological injection quantity is 11.44 billion m3.
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