Assessment Of The Ecological Health Status Of Qijiang Watershed Of Chongqing Based On RS And GIS Methods

Watershed ecological health evaluation has went on for a long time. But in the past, the main contents of the Watershed ecological health evaluation only focus on the water body’s health of watershed, namely the river ecosystem health assessment. More and more researches show that with the increasing pace of human activities and the intensity of human impacts on the watershed, its health now is not simply be reflected in the watershed’s linear geographic features, but on the planar ecological elements. Studies at the basin scale evaluation of the ecological health has become a new hotspot of ecology research and get the attention of a growing number of scholars. But most studies are only for the physical and chemical properties of rivers and lakes and related indicators of aquatic organisms recently, while researches on the natural ingredients, integrated assessment of the impact on the ecological health of the Watershed and the economic component of the social composition are less.In this study we use Remote Sensing technology and Geographic Information Systems technology as research tools, taking lakes ecological health assessment method and principle as example, combining the principles of ecology and landscape ecology, Analytic Hierarchy Process(AHP, Analytic Hierarchy Process) methods, selecting multiple natural state parameters such as the impact of human activities, socio-economic and other aspects which reflect the ecological health of the Qijiang Watershed. those parameters contains sub-indexes such as watershed vegetation coverage statues, wetlands area changing ratios, the degree of watershed urbanization, hydro-ecological processes, water environmental quality indicators(Dissolved oxygen, oxygen consumption organics, heavy metals), aquatic biodiversity indicators, chemical fertilizer usage per unit, watershed rainfall and other parameters indicators, from the ecological health of the Watershed surface features characteristic features and line features state-level ecological health Qijiang Watershed of Chongqing were quantitatively evaluated.Evaluation shows that the ecological health state of the Qijiang Watershed of Chongqing scores 79.04 which is at sub-healthy level. Remote Sensing analysis indicates that Qijiang Watershed of Chongqing hold a higher degree of vegetation coverage, generally maintained at about 0.4, less inter-annual variation of vegetation coverage and are relatively stable. Basin annual urbanization degree is quite lower, but urbanization rate is relatively fast; watershed fertilizer usage is far behind the national average value, the relative balance of ecological processes hydrological basin without much volatility; the quality of the watershed water environment is high, watershed aquatic biodiversity is at a high level and the water ecological status is good, rainfall also relatively stable; shows a higher retention of wetland area and its changing rate is relatively low. But the study also shows that the current state of the ecological health of the Qijiang Watershed of Chongqing score is not too high, the ecological health of the watershed situation remains quite grim. Watershed faces more dangers and pressures of natural change impacts from human activities rather than natural environment and ecological situation watershed needs to be further improved.