Uploaded on 2019-02-20 by Chi Zhang

People - According to the 2015 census, among the total population of 22 million, about 8 million people come from other cities or provinces. In the Spring Festival of every year, they go back to their own hometown, and then come back, which demonstrates a flow of people. During the year, like the indigenous residents, they work and live within Beijing, as a stock of people. Population Density - change in the past 30 years. The density in the old city has dropped slightly (due to the decline of residential area). The density in the suburban areas has doubled. The biggest change is in the Haidian, Fengtai and Chaoyang districts (used to be suburban areas). The density is more than three times of that in the past. This shows the density as a flow. Water - The South-to-North Water Diversion Project has solved the water problem of Beijing. It transports water from the Yangtze River to Beijing over 4350 kilometers, which indicates a flow of water. Then the water, as a stock, is stored in reservoirs and used by the the residents in Beijing. This project is updating and will bring more benefits, like more sufficient supply, better quality.