Evaluation Of Water Conservation Function In Beijing Based On GIS

As the basic conditions for human survival and development,water resources have always been a major event in ruling the country.Based on the extreme shortage of water resources in Beijing,the water conservation functional areas in Beijing,Tianjin and Hebei is building by government.However,there has not been a unified standard and system for evaluating the function of water conservation.Therefore,takes Beijing as the study area to establish the evaluation index system of water conservation function.Used the Delphi method and Analytic hierarchy process(AHP)to evaluate the function of water conservation in Beijing,which has certain reference significance to the construction of water conservation function area and the protection of water resources in this area.The main achievements of this study are as follows:(1)The evaluation system of water conservation function is established.According to the characteristics of the study area,the evaluation indicators were selected.Vegetation factor,terrain factor,soil factor and climate factor were determined as evaluation criteria.Land use,vegetation coverage,vegetation type,slope,aspect,elevation,soil texture,soil thickness,the maximum water holding capacity of soil,average annual precipitation,annual average evaporation and annual average temperature were selected as evaluation indexes.(2)Using Analytic hierarchy process(AHP)and Delphi method to determine the weight of each Index.Then the evaluation model of water conservation function is established.Through the standardization of each index and GIS technology,obtained the spatial distribution map and standardized map of single index factor,finally get the distribution of multifactor comprehensive water conservation function in Beijing.(3)Evaluation of water conservation function in Beijing.Results showed that the study area has better water conservation function,the high score is 92.4178,the lowest is 17.4949,and the function of water conservation increases gradually from the plain area to the mountainous area.According to the classification,the water conservation function in Beijing is mainly composed of highly important(42.22%)and moderate important(39.79%).The extremely important area of water conservation function is consistent with the distribution of water system.Highly important areas are mainly scattered on woodland with an elevation of 100-500 m,and moderate important areas are mainly scattered in dryland and grassland.The mild important areas distributed mainly in urban areas.The general important areas are fewer than 0.1%.The evaluation results of various administrative districts showed that the areas with high water conservation function were Pinggu,Miyun,Yanqing,Huairou and Changping.The worst are Xicheng and Dongcheng,almost all are mild important.Based on the results,suggestions on strengthen the protection of ecosystems in areas with better water conservation functions,build ecological recycling economic belts,and improve regional water resources carrying capacity.