Analysis of the characteristics of water eco-environment and comprehensive countermeasure for typical cities in the Yangtze River Basin

The discharge loads of COD, NH₃-N, TN and TP from typical cities at the mainstream, tributary streams and around the lakes connected with the Yangtze River Basin were evaluated. The characteristics of urban water environment quality, water ecology, water resources and water security of the typical cities were analyzed. The results showed that 1937800, 155700, 310100 and 21800 tons of COD, NH₃-N, TN and TP, respectively, were discharged from 56 cities in the Yangtze River Basin for each year. The domestic source was the main pollution source for most cities in the Yangtze River Basin, and the pollution from industry and non-point sources was also nonnegligible. In recent years, the increasing non-point source proportion, the general damage of the urban water ecosystem, the shortage of water due to water quality and resources in some cities, the rough use of water and low utilization of unconventional water sources led to the prominent water ecological risk in these cities in the Yangtze River Basin. Finally, comprehensive countermeasures were proposed to improve the urban water eco-environment quality in the Yangtze River Basin in the 14th Five-Year Plan period.