Ecological Environment Quality Evaluation Of Small Watershed Of Hetuo Gold Mine Area Of Min County Of Gansu Province

With the rapid development of society,the carrying capacity of my country’s ecological environment has gradually increased,and ecological environmental issues have become more and more significant,which has become an important factor hindering my country’s economic development.Due to the impact of the 7.22 earthquake and long-term irregular mining of minerals in the study area,the ecological environment in the area has become fragile.Natural resources such as vegetation and waters have been damaged to varying degrees,which seriously threatens the safety of the small watershed ecosystem in the study area.Therefore,it is particularly important to improve the ecological environment of small watersheds.This study uses medium and high resolution remote sensing images as the basic data,combined with other statistical data,and uses the advantages of RS and GIS technology,According to the ecological environment of the study area,10 indicators such as slope and land use have been selected to construct this research evaluation system.On this basis,put forward the weighting method and ecological environment quality evaluation method based on this research evaluation system,in order to provide reference for the small watershed ecological environment quality evaluation.The main achievements of this resaerch are as follows:(1)Taking the small watershed of the Hetuo gold mining area in Minxian County,Gansu Province as the research object,conduct an in-depth analysis of the ecological environment quality evaluation results.Use analytic hierarchy process,principal component analysis method and AHP-PCA combined evaluation method for weight calculation,based on GIS technology,use graph overlay method and comprehensive index method to evaluate ecological environment quality.The results show that PCA and AHP-PCA methods are both suitable for research AHP is not suitable for district empowerment work;the overall ecological environment of the study area is of good quality,and there are many areas greater than level 4,accounting for about 75% of the area of the study area.(2)Based on RS,GIS and mathematical statistics,the effect of sub-item evaluation indicators on the ecological environment quality of small watersheds is studied.The analysis results show that the intensity of land use and development in the small watershed is relatively high,and the structure is unreasonable,which is not conducive to the preservation of water and soil and the restoration of the natural environment in the small watershed,and has a greater impact on the ecological environment of the small watershed;There is a trend of gradual restoration.A small amount of vegetation degradation is mainly related to human engineering activities.The main factor affecting the restoration of soil ecological conditions is human factors.(3)High-precision remote sensing monitoring of vegetation damage areas in small watersheds.The remote sensing monitoring results show that there are 116 ecological damages in the study area,including 34 extremely severe damages,23 severe damages,22 moderate damages,23 mild damages,and 14 ecological damages caused by mining and debris flow before the earthquake.From the spatial distribution,it can be seen that the pre-earthquake ecological damage areas were mainly concentrated in gold mining areas near Zhaishang Village and Shuguang Village,and extremely severe and severe ecological damage were mostly seen on the steep slopes along the axis between Lalu Village and Suigu Village.The vegetation damage in the area is mainly caused by human engineering activities and earthquake-induced factors,and the ecological damage caused by human engineering activities has hardly recovered.