基于ENVI的大纵湖流域土地利用变化及其对水质影响研究

Land Use Change and Its Impact on Water Quality in Dazong Lake Basin Based on ENVI

为定量研究大纵湖流域土地利用类型与水质之间的关系,利用ENVI对大纵湖流域2012年和2016年Landsat TM遥感图像解译,采用监督分类法将土地分为6种类型,并与水质进行灰色关联。结果表明:①大纵湖流域以耕地和建设用地为主,两者比例超过总面积的70%。从2012-2016年,耕地和未利用地面积不断减少,主要流入林地和水域。②2012-2016年大纵湖水质指标总体均呈现先略有下降后缓慢改善的趋势。③湖泊水质整体上与土地利用类型的灰色关联度最大的是建设用地,其次是未利用地和水域,林地、耕地和草地的灰色关联度相对较低;各水质指标与土地利用的灰色关联度差异较大。研究表明,林地、草地对水质改善有着积极作用,因此在大纵湖流域上游多植树种草,有利于维护生态环境健康。

In order to quantitatively investigate the relationship between land-use change and water quality in the Dazong Lake basin,Landsat TM images from 2012 and 2016 were interpreted by using ENV. In this paper,the research area is divided into six types by using supervised classification and the grey correlation analysis method is used to evaluate water quality. The results show that: ① Dazong Lake basin is dominated by farmland and construction land accounting for more than 70% of the total area. From 2012 to 2016,the farmland and unused land had been converted to woodland and water area. ②Generally,from 2012 to 2016,the water quality of Dazong Lake was deteriorated and then improved. ③The order from large to small of the grey relational degree between water quality of lake and land-use is construction land,unused land,water area,woodland or farmland or grassland;the grey correlation between water quality indexes and land use is quite different;woodland and grassland play an active role in improving water quality. Therefore,planting more trees and grass in the upper Dazong lake basin is conductive to the maintenance of ecological health.