Preliminary Discussion Of The Evaluation Index System And Methods For The Aquatic Ecosystem Of The Healthy Yangtze River

River is one of the most interrupted ecosystems on earth. Many years ago, the environment of Yangtze River was well, but now it was deeply polluted because of the development of industry and agriculture and the construction of urbanization. Consequently, the evaluation index system for aquatic ecosystem of Yangtze River was brought forward to evaluate the river health.Aquatic ecosystem index system is now the focuses in the field of ecology and environment science. In this thesis, river management history in various countries was reviewed, five components of stream condition were presented in this thesis to characterize river health: aquatic environment conditions, hydrobios, physical forms, hydrological regime and river bank zones. According to the nature condition, the river was divided into five sections: river head, upriver, middle river, lower reaches of river and estuary; according to the density of people activities, the evaluation was developed by urban stretch, un-urban stretch and typical stretch of river. In this thesis, the connotation of the Healthy Yangtze, as well as the constituents, was well defined. An index system for the aquatic ecosystem of the Healthy Yangtze River with 5 sub-indices and 15 indications was brought forward where an evaluation model was developed. Weight was determined for each index and the evaluation standards were established. The evaluations were explored by collecting historical literature and field monitoring and Hubei Wuhan as urban stretch, Hunan Pengze as un-urban stretch, Chongqing Wanzhou as typical stretch were studied to conclude the evaluation index system for aquatic ecosystem of Yangtze River.The results showed that Wuhan stretch and Pengze stretch were in sub-health, the main problem of these stretches were that the rivers and lakes were in bad connectivity, the biotope for rare aquatic animals was poor, the vegetation of river bank was in low coverage and the river bend in little degree. Wanzhou stretch was in health which was still nearly keeping in natural state and the Three Gorges made infect unobviously on this stretch on aquatic ecological environment. From which we can know that the aquatic ecosystem of the Yangtze River is sub-health. It could conclude that these conclusions were according to our recognization and the index system could reflect the aquatic ecological healthy situation perfectly. This could provide technology support for the further all-around research on the main stream of Yangtze River.