| At the beginning of 1980 s,Guangxi after 30 years’ comprehensive management of small watershed,has made a significant contribution on reducing the sediment deposition in lake,improving the soil and the production capacity of land,conserving water,improving biodiversity,protecting ecological environment,increasing people’s income and improving the residents living.However,in the actual production and construction,Due to the lack of understanding of the distribution and basic condition at small watershed,small watershed management also showed some problems,including the management mechanism of small watershed construction is lagging behind,management planning and design are not professional,which influenced the comprehensive management of small watershed.In view of this,depend on the special survey of soil and water conservation in Guangxi,with the support of remote sensing and GIS technology,this research processed the multi-source data,then divided the border regions and build the spatial catalog database construction of small watershed,and established the evaluation indicators and evaluation model of small watershed preferentially management.At last,divided the management areas,provided a reference for the future development of the comprehensive management of small watershed according to the results of evaluation.The main conclusions of this study are as follows:(1)Refer to the Specification for Division and Encoding of Small Watershed,this study totally divided 9631 small watersheds,the area of which were between 3.13km2 and 98.01km2.Then check the topology relation of small watersheds data and attribute encoding,established the spatial database of small watersheds.As this research,we can find out the basic distribution of Guangxi small region,to solve the previous problem of the soil and water conservation in small watershed.(2)Catalogue multi-source geospatial data according to Geographic Features Cataloging Methodology and Specification for Data Catalog Compiling.This study set the small watershed catalogued as primary directory,the second-level directory includes basic information,natural environment,social economy,soil and water conservation,and the third-level directory includes 45 indicators such as the name of small watersheds,land types,population density,soil erosion modulus and so on.Finally,this study established the small watershed basic data catalog and the small watershed spatial cataloging database.(3)Based on small watershed spatial cataloging database,set the small watershed priority management evaluation as the goal,this study used principal component analysis and correlation analysis to establish evaluation system of small watershed priority management,whose second-level indicators contained natural environment,social economy,land use and soil and water conservation,and third-level indicators contained Thirteen parts.(4)This paper further utilized AHP to determine the weight of the indicators base on the evaluation system of small watershed priority management.Sorted 4 aspect affecting small watershed priority management by weight,there were soil and water conservation,the weight is 0.3672,followed by land use,the weight is 0.3319,again is the social economy(0.2272),the last is natural the environment(0.0731).Then Sorted 13 indicators by weight,top 3 were proportion of slope farmland(0.2489),Soil erosion ratio(0.2339),traffic(0.1634)。(5)By establishing the evaluation model,calculating the value of 9631 small watersheds,and build grading standards of small watershed priority management.The small watersheds in Guangxi were divided into 4 levels: priority governance(222),key governance(627),normal governance(2872),general governance(5910).According to the distribution of small watershed in all levels,the control area is divided into two regions: contiguous governance areas of Zuojiang river basin,contiguous governance area of central Guangxi;six small partitions: Tieshan river basin,Tianyang& Tiandong area,Napo area.Longlin&Xilin area,Huanjiang area and Fuchuan area.According to the characteristics of the target area,this paper puts forward some suggestions for the development of soil and water conservation in Guangxi. |
