The Evolution Trend Of Ecological Environment And Analysis Of Bearing Capacity Of Dongjiang Lake

Sustainable development, as a basic national policy of China's long-term development of society and economy, has become the theme of social development in the world. Water is not only a basic source of human survival and development of social civilization, but also an indispensably strategic resource of any country and region. Around the protection and use of water resources, from the perspective of the coordinated development of social, economic and environmental ecology, in our country especially in the recent 10 years has carried out many of the in-depth study of the theory and technology. Furthermore, related policy measures have been taken to establish a sound mechanism for ecological development of water resources and promote water conservation.In China, nearly 80 percent of urban water in lakes and 90 percent rivers was polluted by varying degrees. Hunan Province is faced with the problem of water security, a serious threat to the sustainable development of regional economy and the health of the people. Under the background of the "Lake Ecological Environment Protection Plan (2011-2020)", Hunan Dongjiang Lake was included in the scope of protection of the State in the 12th Five-Year Plan. Dongjiang Lake, with plenty of water in good condition, takes on not only the supply of the basin, but also the water security downstream of the Xiangjiang River.However, with the economic development around the Dongjiang Lake, the ecological and environmental protection bears increasing pressure especially the growing crisis of the water security. According to the monitoring data in recent years there, the environmental water quality shows the tendency of individual drop. On the basis of its social, economic and ecological survey, this dissertation will make predictions about the environmental evolution trend in Dongjiang Lake and through capacity analysis, put forward the corresponding pollution control priorities and objectives, to provide the appropriate basis for the Dongjiang Lake ecological environment.protection.According to research, the overall environmental quality of Dongjiang water is still in the global natural freshwater fairly basic clean level, with the partial minor contamination. The main indicators of drinking water source of primary reserve are better than I class while the indicator of total phosphorus is better than II class. The major indicators of secondary reserve are better than ? class, but total phosphorus, lead and arsenic are better than III class. In Dongjiang Lake, the environmental characteristic of the whole basin pollution is total phosphorus. Local watershed is under medium level of nutrition, in poor nutrition as whole. From the analysis of existing sources of pollution, there are five major aspects of environmental problems:Firstly, poor infrastructure environment, population and consumption growth aggravated domestic pollution; the second is mineral development which exacerbates soil erosion and the larger potential risk of heavy metal pollution; the third is the cage aquaculture pollution load, resulting in higher nutritional level of local waters; fourthly, industrial irrational; the fifth is that the environmental regulatory system and the system is not perfect and environmental monitoring capacity technology is weak.Based on social, economic and demographic development, with 2011 as the base year, there are predictions about the total phosphorus concentration variation characteristic pollutant trend.10% reduction or less can not meet ? water standards, in 15 percent reduction can be achieved at Class ? water standards. The ecological carrying capacity analysis of Dongjiang Lake shows its total phosphorus is beyond the capacity of the environment. COD, ammonia nitrogen, total nitrogen reveal surplus capacity. The land resource carrying capacity is between 70.65? 119.68 million people when the economic development do not accept the constraints of land resources. Based on the above research, this dissertation proposed that the ecological environment protection goal in Dongjiang Lake is, from 2012 to 2015, the water quality of reverse in Dongjiang Lake continues to surface water ? class standards and the overall water quality of the lake is better than ? class.The water quality at the backwater religions has markedly improved. The water quality of the river water into the lake steadily reached iii class. The local eutrophication trend has been effectively controlled and the whole lake is controled in poor nutritional status.