Assessment Of Eco-environmental Sensitivity Of Duba River Basin In Beichuan County

The ecological environment sensitivity is the reflection of the ecological system on the changes of the natural environment and the intervention of human activities.It is the hot word that the geography and ecology scholars have paid attention to the study of regional ecosystem and ecological environment planning and ecological environment construction.It is of great practical significance to carry out the assessment of the ecological environment sensitivity of the river basin and to formulate the comprehensive management and protection policy of the ecological environment of the river basin.Beichuan County is located in the Longmenshan tectonic belt on the eastern margin of the Qinghai-Tibet Plateau,and the loose strata are exposed.The lithology of the strata is more complicated and the tectonic activity is strong.There are landslides,debris flow,collapse,unstable slopes and other geological disasters,and soil erosion is more serious,directly affecting the ecological security of mountainous areas.Based on the principle of regional differentiation and environmental carrying capacity of watershed,this paper takes the Duba River Basin as the research object of the ecological environment sensitivity evaluation.The aim of the study is to promote the development of this area,decide factors that influence sensitivity evaluation and construct the index system of sensitivity evaluation in Duba river.The entire basin of ecological sensitivity comprehensive evaluation was carried out by taking advantage of AHP and spatial analysis and 12 types of data including vegetation type,precipitation,soil type,topographic relief,geological hazard point density,strati graphic lithology,tectonic line,land use type,water buffer area,and road buffer.In order to get different spatial distribution of sensitive areas and to develop appropriate measures.The main conclusions are as follows:(1)Evaluation of the ecological sensitivity of the Duba River Basin was constructed,including 4 criterion layers and 12 index layers.Using the analytic hierarchy process to decide the weighted value of each evaluation index factor,the sensitivity of the soil erosion,the sensitivity of the geological disaster,the sensitivity of the habitat and the sensitivity of the human activities were obtained by the ArcGIS spatial analysis method(superposition analysis),based on which the comprehensive assessment chart of eco-environmental Sensitivity of the dam in River Basin wasobtained.(2)The sensitivity of soil erosion,the degree of sensitivity to geological disasters,the degree of habitat sensitivity and the degree of sensitivity of human activities in the Duba River Basin are obviously different.The sensitivity of soil erosion sensitivity is mainly moderate and highly sensitive,and the geological hazard and habitat and human activities are mildly sensitive.This indicates the comprehensive management of geological disasters,returning farmland to forests and basic farmland construction and other measures in Duba River Basin are significantly effective.(3)The ecological sensitivity of Duba River Basin is mainly mild and moderate sensitivity,accounting for 28.3% and 25.9% of the total area respectively.It is followed by high sensitivity and extreme sensitivity,accounting for 20.7% and 9.2% of the total area of the basin respectively.Highly sensitive areas are mainly distributed in the middle and lower reaches of the Dujiang River town of Yanyang town,Yunli and other two administrative villages and West River,old field,Longwan,Qinglin,Dazhu,Taihong and other administrative villages in Chenjiabai.(4)The extremely sensitive areas of the Duba River Basin are concentrated in the vicinity of the junction of Qushan Town and Chenjiaba Township and rivers.According to the spatial distribution characteristics and environmental problems in this area,a large number of debris flow accumulation sources have accumulated in the branch trenches.At present,the following cutting erosion is still dominant.It should be taken as an additional anti-erosion pile Lin,an additional adjustment dam and town protection embankment construction and other engineering measures.The agricultural sector can also make macro adjustments to land use methods,continue to implement the policy of returning farmland to forests,develop characteristic fruit forest bases,and transform low-yielding forests.