| Water is an indispensable element of human beings.In the urban ecosystems,the water resource is limited in a certain area,time and space.In recent years,with the population growing and economic developing,the impact of human activities on the natural environment has become increasingly prominent,and the water environment problem has become more and more serious.To solve the problem of water resource lacking,it is necessary to rationally develop water resources to adapt to the natural laws,which is the main problem of water environmental carrying capacity research.Due to the uneven distribution and unreasonable use of water resources,serious water pollution,unreasonable development of surface water,and over-exploitation of groundwater,the problem of water environment has become the factor to restrict the sustainable development of Changping District.The Central Line of the South-to-North Water Diversion Project has greatly alleviated the shortage of water resources in Changping District of Beijing,which has caused great changes in the water environment carrying capacity of Changping District.This paper takes the water environment carrying capacity of Changping District in Beijing as the research object,and constructs the water environment carrying capacity index system of Changping District by using the analytic hierarchy process.The weight value is calculated and the consistency test is carried out for each individual index,to obtain the weight and total ordering of levels of the corresponding indicators.Collecting,collating and analysing the individual indicators of water environmental carrying capacity from 2008 to 2017（especially,the ecological water demand of river and reservoir are estimated by Tennant method and biological space minimum demand method respectively）,forecasting for each indicator,and normalizing the indicators for all the data,to obtain the carrying capacity of each individual indicator over the years.The fuzzy comprehensive evaluation method is used to comprehensively evaluate the water environment carrying capacity.The results showed that:1)The water resources development and utilization rate,industrial water reuse rate and sewage treatment rate of Changping District have a greater impact on the water environment carrying capacity.2)The ecological environment water demand of the rivers and the Ming Tombs Reservoir in Changping District is 119.9062 million m3,which in 2020 is predicted to be 64.78 million m3,which is predicted to be 113.9 million m3 in 2035.3)Before the arrival of Southern Water in Beijing,the evaluation level of water environment carrying capacity of Changping District in 2014 was V1,the comprehensive evaluation value is 0.3151.In 2017,the evaluation level of water environment carrying capacity of Changping District was V4,and the comprehensive evaluation value is 0.5728.This indicated that the Central Line of the South-to-North Water Diversion Project has improved the water environment carrying capacity of Changping District,with an increase of 81.78%.4)It is predicted that after the East Line of South-to-North Water Diversion Project in Beijing in 2035,the evaluation level of water environment carrying capacity can reach V5 which is the best value in recent years.However,the predicted value of per capita domestic water consumption,population growth rate and vegetation coverage rate is lower in individual indicators.5)The direct contribution of the South-to-North Water Diversion Project to the water environment carrying capacity of Changping District is 9.35%.Through comprehensive evaluation of the water environment carrying capacity of Changping area,it can be seen that after the South Water arrived into Beijing,the water environment carrying capacity of the area is obviously improved,and the evaluation level was improved by three levels.Measures to control the population,and increase greening areas have a positive effect on the improvement of water environment carrying capacity in Changping. |
