Study On The Restoration Threshold Index System Of River Ecosystem In Huaihe River Basin (Henan Section)

River ecosystem is one of the most important ecosystem in the nature, and the origin of the development of human society. The relationship between humans and rivers can be devided into natural-cycled phase, engineering-regulated phase, pollution-controlled phase and ecological-rehabilitated phase. After the "Eleventh Five-Year" phase of river pollution, the water quality of Huaihe River basin (Henan Section) has been some improvement, some ditches for rivers had the ecological restoration of condition. But water environment problem of Huaihe River basin (Henan section) had not been fundamentally solved, the shortage of water resources, the poor of water purification capacity, water ecological function declined, reduction in biodiversity. Therefore, in the "Twelve Five" period, The study would to carry out aquatic ecosystem restoration research work and restore aquatic ecosystem health on the river, which meet the conditions for ecological restoration is the needs of our country and Henan province.The study relyed on water ecological restoration threshold definition Huaihe River basin (Henan section) of the major projects of the National Water Pollution Control and Treatment Technology, and made Huaihe River basin (Henan section) as the research object, and studied the water ecological restoration threshold system, which would provide scientific and technological support for resoration and determination of river ecosystem on Huaihe river basin (Henan scetion).Firstly, on the basis of researches and practices on the domestic and international ecological threshold of the river ecosystem restoration, study the theoretical basis of the threshold and the theoretical foundation of river restoration, which pointed out the range of river restoration. The research of pollution control and ecological restoration research was proposed, combined with the four phase of human and rivers, Contrast current water quality and aquatic life safe concentration range of Huaihe River basin (Henan Section), and selected water quality characterization factors of ecological restoration as DO, COD, ammonia nitrogen and heavy metal chromium, which calculate the range of values of ecological restoration of water quality conditions using statistical analysis, logarithmic function, the sort of toxicity percentage and species sensitivity distribution method in the water quality baseline study, and selected the river operated the ecological restoration in Huaihe River basin (Henan section).Next, basined in range of ecological restoration, the concept of river restoration threshold was proposed creatively, and use frequency analysis and theory analysis method to built the river ecological restoration threshold index system from the view of the ecosystem, and determined the threshold calculation methods of the various indicators. The study developed field survey investigation of the river ecosystem including the analysis of water quality and aquatic plant diversity, then devided river restoration system into different types.