不同时空尺度下土地利用对博斯腾湖水质的影响

Effects of Land Use on Water Quality of Bosten Lake at Different Spatiotemporal Scales

水资源是区域社会经济发展的重要战略资源,尤其在地表水资源稀缺的干旱区,湖泊的水文循环调节、水资源调蓄、水质净化等作用在干旱区显得尤为重要。为研究干旱地区不同空间尺度土地利用对内陆干旱湖泊水质的影响,以博斯腾湖为研究对象,分析湖泊水质时空变化特征,并通过与周边六期土地利用进行统计相关分析,阐明土地利用变化对不同水质指标的影响。结果表明:2005—2019年博斯腾湖水质有较大改善。根据标准,氨氮的浓度在地表水环境I~II类水水质标准之间,高锰酸盐指数和总磷处于地表水环境Ⅱ~Ⅲ类水水质标准之间,但湖水总矿化度仍大于1000 mg/L的淡水标准,属于微咸水。相关性分析表明:耕地、城市、未利用地等面积占比与水质指标之间具有强相关性;多元线性回归和冗余分析结果表明:有效改善水质主要需要从城市用地、耕地和草地三种土地类型规划和布局着手。

Water resources are important strategic resources for regional socio-economic development,especially in arid areas where surface water resources are scarce.The hydrological cycle regulation,water resource storage,and water quality purification of lakes are particularly important in arid areas.In order to study the influence of land use on the water quality of inland arid lakes at different spatial scales in arid regions,this study took Bosten Lake as the research object,analyzed the spatial and temporal variation characteristics of the water quality,and clarified the influence of land use on different water quality indicators through statistical correlation analysis with the surrounding 6 phases of land use.The results indicated that from 2005 to 2019,there had been an significant improvement in the water quality of Bosten Lake.According to the Environmental Quality Standards for Surface Water(GB 3838-2002),the concentration of ammonia nitrogen was between Class I to Class II of the water quality nation standards,while the concentration of permanganate index and total phosphorus generally remained within ClassⅡto ClassⅢof the nation standards.However,the concentration of the total mineralization of the lake was still higher than the freshwater standard of 1000 mg/L,which classified the lake as brackish water.Correlation analysis showed that the proportion of arable land,urban,unused land and other areas had a strong correlation with water quality indicators;multiple linear regression and redundancy analysis results showed that effective improvement of water quality mainly needed to start from planning and layout of urban land,arable land and grassland.