Eco-health Assessment Based On Soil And Water Conservation In Headstream Area Of Oujiang Basin

In order to evaluate eco-health, and study the effect factors of the headstream area in Oujiang basin, we applied the ecology principles and soil and water conservation theries in this paper. And according to the actual circumstances of the study area, we constructed the ecosystem health evaluation index system for Oujiang River Source Area, including the indicators of ecological characteristics, functional role and socio-economics. To obtain highly accurate quantitative data, we collected 56 water samples and 96 soil samples and got some indicators through physical and chemical analysis. Meanwhile we obtained other indicators by data collection and means of GIS. Then we analyzed all evaluation factors of eco-health systematically, and constructed the system of eco-health evaluation criteria for the headstream area in Oujiang basin. Besides, comprehensive water quality identification index method and Principal Component Analysis were used to evaluate some indicators which were difficult to determine. Finally, the index weights were determined on the basis of Analytic Hierarchy Process to evaluate ecological health of the study area comprehensively. Eventually Soil and water conservation protection system was proposed based on the research findings, which can provide scientific basis for the ecological construction in hilly area of Southern source area. The main conclusions are as follows:(1) The ecological status reflected by the indicators of eco-health:the runoff is sufficient and the water quality belongs to the second class in study area. While,water quality still need to improve because the study area is the headstream area which plays a crucial role on the development of the whole basin. Good vegetation conditions and higher soil organic matter content, both provided a good ecological basis for the basin, but the soil water-stable aggregate stability of economic forest showed a greater difference. To conclude, the soil water-stable aggregate stability of economic forest was relatively poor, so the management of economic forest should be attached importance to.(2) The result of ecosystem health assessment of Oujiang River source area was sub-health. Among many influencing factors, the soil and water erosion intensity and the soil anti-erodibility rating are the main factors affecting the ecological health. The results showed that, the soil anti-erodibility was weak, and to some extent the soil and water erosion happened because of the disturbance of human activities. These carried away the sediment and top soil nutrient, and influenced the water quality, which in turn weakened the soil anti-erodibility and affected the ecological health in the study area. Therefore, although the study area has a good ecological basis, still can’t be on a healthy state.(3) According to the obvious vertical zoning geomorphological features and the current ecological situation of the study area, and following the principles of "local conditions" and "sustainable development", the area was divided into three different vertical zones which were as follows:the mountain regions of headstream based on ecological conservation, the piedmont hills sloping based on soil and water conservation, and riparian valley based on development and protection.