The Impact On Water Environment Due To Land Use Change Of Liangzi Lake Watershed

Land use is one of the most direct forms of human activities. Irrational land-use activities and management will lead to soil erosion and nutrient loss with surface runoff, therefore, causing a large area of non-point source pollution to watershed. From the point of view of the formation mechanism on non-point source pollution, it mainly depends on land use/land cover change model. So, with the constant deepening of LUCC research, the impact on water resources with land-use change are generally concerned. A lot of data at home and abroad indicate that land-use types have strong impact on the water environment. Therefore, predicting the intrinsic link between watershed land use and non-point source pollution load, analyzing the impact on non-point source pollution with the land use change, and bringing forward the best land use and management model to ensure service functions of the water are important to improve the quality of the water environment and to achieve sustainable development on ecological environment of watershed. With the improvement of control level on the industrial point source pollution, non-point source pollution has become the main source of water pollution. And human land-use is the main driving force for non-point source pollution.From angle of the land use pattern and optimal control measures to research non-point source pollution is the main tendency of non-point source pollution research. At present, it is a hot point of domestic and international research. From the comprehensive agricultural regionalization, Liangzi Lake watershed belongs to south of the Yangtze River mound subtype among Wuhan-Ezhou-Huangshi suburban agricultural area. And land use current condition is based on the principle of crop-farming and aquaculture. For agriculture, besides the traditional rice production, cotton, tea, ramie and other economic crops developed rapidly. Especially in Xian'an region, ramie processing industry is more concentrated. As a result, the environmental problem is very outstanding. Besides, aquaculture has a large scale. Its output value accounted for agriculture increases rapidly. This article takes an example of Liangzi Lake, through field investigation, historical material inspection, and the application of GIS technology, the author interpreted three phase(1987, 1995, 2005) TM images of Liangzi Lake basin; analyzed the change on land use of Liangzi Lake watershed; had access to changing-trend of water environment on Liangzi Lake watershed and landscape features. This thesis learns and applies the theory of landscape ecology and interrelated research methods, and explores the impact of watershed landscape characteristics on basin water-environment. From the perspective of need on the water environmental protection, it constructs water-environmental and ecological regionalization of Liangzi Lake watershed for the goal of the water environmental protection and non-point pollution control. And for the past 30 year's trend of watershed land use change, it puts forward corresponding management mode and the measures. Therefore, this thesis supplies not only a new view for resolving non-point pollution problem at watershed scale, but also a valid method for decreasing the threat of landscape type and pattern on water quality. It is beneficial to better achieve the goal of watershed economic development and protection of the water quality.