滇西北高原湖泊剑湖演变过程及其生态环境效应分析

EVOLUTION OF JIANHU LAKE AND ITS ECO-ENVIRONMENTAL EFFECTS IN THE NORTHWESTERN YUNNAN PROVINCE

以滇西北高原湖泊剑湖为研究区,1974—2015年间8期遥感影像为数据源,运用遥感和地理信息系统技术,研究剑湖湖泊近40年间的时空演变过程,探析剑湖湖泊的入湖污染物及其生态环境效应变化。结果表明:近40年来剑湖湖泊面积呈现先明显减少再增加后缓慢减少的变化规律,由1974年的504.47 hm^2减至2015年的451.72 hm^2;目前剑湖水体中COD含量较低,符合地表水环境质量Ⅱ类标准;TP含量满足Ⅲ类标准;TN含量仅可满足IV类标准;剑湖入湖的主要污染源是农村生活污染和农业面源污染;随着时间的演变剑湖湖泊TN、TP污染物浓度呈上升趋势,剑湖湖泊生态系统受到极大干扰。

Taking the plateau lakes in Northwestern Yunnan as the study area and the remote sensing images of 1974—2015（ 8 periods） as data sources,the paper studied the spatial and temporal evolution of Jianhu Lake over the past 40 years,and further explored the lake pollution and changes in its eco-environmental effects. The results showed that： Over the past 40 years,the lake area of the Jianhu Lake first decreased significantly and then increased slowly and then decreased slowly. It decreased from 504. 47 hm^2 in 1974 to 451. 72 hm^2 in 2015. At the present,chemical oxygen demand concentration in the lake water was low,in accordance with the surface water environment quality II standards. Meanwhile,total phosphorus concentration met the III standards,and total nitrogen concentration only met the IV standard; rural domestic pollution and agricultural non-point source pollution were the main pollution sources into the Jianhu Lake; with the evolution of time,the concentration of TP and TN pollutants increased and the ecological system of Jianhu Lake was disturbed greatly.