The Evaluation Of The Situation Of Ecological Environment Based On GIS

Ecological environment is fundamental to human existence and development. A viable and accurate method of ecology evaluation is an important ecological problem to be solved. Qinghai province located in Qinghai-Tibet plateau is much sensitive and fragile to environmental change, thus a focus of climate and environmental change. The source regions of the three rivers there is of strategic significance to the sustainable development of agriculture and society in China.Following assessment system of the "Technological Standard for Evaluation of ecological environment (Trial Version)" (HJ/T192-2006), with assessment unit combined with polygon assessment unit from vector spatial data, and point assessment unit from grid spatial data, using spatial statistics and spatial analyst tool of ArcMap software, comprehensively evaluated the situation of ecological environment of each counties of Qinghai province in three years of 2004, 2006, 2007.Achievement and conclusion are as follows:1) Several spatial databases were built for each counties of Qinghai province in 2004, 2006, 2007, which include five index factors of biomass abundance index, vegetation cover index, soil degradation index, river density index and environmental quality index.2) The length of river and area of lakes (reservoir)were calculated in each grid based on administrative boundary map and water system map with spatial statistic and spatial analyst tools of ArcMap software.3)The statistical data of water source, SO₂ exhaust, COD exhaust, which are distributed based on area scale and population proportion were spatialized.4) The ecological indices in these three years in Qinghai province range from 18 to 66, mean EI in these three years are 27.43, 27.73, 29.97.5) The distribution of EI of Qinghai province show obvious zonation, which increase from northwest to southeast. The zonation are mainly presented as follows: the EI of the counties in Haixi region are low, environmental situation is worse; the environmental situation is better in most areas of Jiuzhi coutny, Banma county and Gande county, southeast and northeast part of Dari couty, southeast and southwest part of Maqin county of Guoluo region, and Datong county, southwest part of Menyuan county, central part of Qilian county of Haidong region; the EI are moderate in other counties.6) In 41 counties of Qinghai during 2004 - 2005, there are 7 counties with slightly changed EI, and more than 50% changed area; 15 counties with significant changed EI, and more than 50% changed area. There is no significant EI change in all counties of Qinghai province during 2006 - 2007.