Comprehensive Evaluation Of Small Watershed In Eco-environmental Quality Based On Rs And Gis

Water and soil resources are the basic material elements for mankind survival, and they are also the basic resources of the social economic development. We are one of the most serious soil erosion countries in the world. The soil erosion areas distribute extensively. And the loess plateau region is one of the most serious soil erosion regions in our country. Paying more attention to the prevention and control of soil erosion will have great significance in reasonable uses and valid protection of water resources, improving the agricultural conditions and the eco-environment, supporting the valley ecosystem safety. It will guarantee the society keeping on sustainable development, and moderate contradicts of population, resources, environment and economic development.The comprehensive management of the small watershed eco-environment is a basal work for water and soil protection in our country, and also it is the important eco-environment, society and economy project for the whole valley. Through the small watershed integrative protection we can collocate land structure reasonably, reduce sediment into river, decrease soil erosion, recover district eco-environment. For a long time, our country did great effort in small watershed improvement but we still week in the management and monitor which mainly depend on observed data statistic analysis from each hydrologic station generally. Because of the influence of every factor, the observation result has its limitation. In the last few years, the GIS and RS technique has been used in soil erosion investigation. It provides very economical and valid research tools on small watershed eco-environment research and monitor impact of the management. Remote Sensing has already played a very important role in soil and water protection, and it has already been one of the most advanced instruments in dynamic monitor of soil and water protection.This paper is supported by the project of"The water and soil protection monitor system for GuanTing and MiYun reservoirs". We take the DaWashan small watershed in ShanXi province TianZhen country as the study area. Based on GIS and RS technology, we analyze the middle and high resolution satellite images of 1987,2000,2002,2004 in this area. Then we monitor the indexes of land use,vegetation fraction,soil erosion,landscape to describe space structure,time process,regulation inside and class attribute of the region. And further more we assess eco-environment quality synthetically. Trough using the data and the analysis results it is provided credible references in water and soil protection monitor and management. The main conclusions of the research are:(1)According to the characteristics of the small watershed eco-environment we set up the index system for eco-environment quality evaluation by using the AHP method. In this method we selected 10 indexes to assess the quality of the eco-environment such as landuse/landcover, vegetation fraction, soil erosion, elevation, slope, equal precipitation of a year, >0℃'s accumulate temperature, landscape index etc.(2)The research takes the Remote Sensing data mainly to get the indexes of the eco-environment equality evaluation.(3)By contrasting the eco-environment equality of DaWashan small watershed from 1987 to 2004, we find that the eco-environment descend year by year before the year 2002 when the small watershed is started to comprehensive management, but in 2004 the average equality of eco-environment is increased after the improvement.(4)The small watershed land use structure is unreasonable. We can found that the area of high-quality lawn is small but the area of unused land especially weed is large. And we should be optimized the cultivate land structure and distribution area.(5)The small watershed eco-environment total condition is turning better year by year but still frangibility. The research indicates that the relational departments of our government should strengthen the small watershed management and monitor from now. And we must avoid the eco-environment would be destroyed by mankind factor again.