不同水位期汉丰湖和高阳湖上覆水时空分异特征

为研究三峡库区不同水位条件下澎溪河流域永久性回水区高阳湖与城市内湖汉丰湖的水环境差异，确定影响湖库水环境变化的水质指标，于2018年11月~2019年10月，对两湖库上覆水进行逐月样品采集.以水质监测数据为基础，参照三峡水库调度的时间周期，将采样时间划分为蓄水期，消落期和泄水期3个时段，运用多元统计方法，分析了2个湖库的水环境时空分异特征.单因子水质评价结果显示，湖库水质等级具有时空分异性，浮游植物大量生长发育的3，4，5月及雨量充足的7，8月，2个湖大部分处于劣Ⅳ~劣Ⅴ类，而一年中其他时段主要达到地表水Ⅲ类标准.判别分析表明，透明度，溶氧，电导率，pH值，水温，水深（depth），总有机碳，总氮和氨氮均为两湖库水环境时空显著性差异的指示因子，泄水期，2个湖库水环境差异不大，但蓄水期和消落期，2个湖水环境具有明显的差异性.主成分分析显示，不同水位条件下，引起湖库水环境变化的主导因子不同，消落期水环境主要影响因子为TN，NH₃-N，水深和pH值；泄水期主要是TN，TP和EC；蓄水期主要影响因子为水深，TOC，TN，TP和NH₃-N.水体污染程度来看，汉丰湖：蓄水期 > 消落期 > 泄水期；空间表现为：HF3 < HF1 < HF2 < HF4 < HF5 < HF8 < HF7 < HF6.高阳湖：泄水期 > 消落期 > 蓄水期；空间表现为GY2 < GY3 < GY1 < GY5 < GY6 < GY4.

Spatial-temporal differentiation of water quality under different water level conditions of Hanfeng and Gaoyang Lakes in Three Gorges Reservoir

In order to understand the interactions between different water level conditions and water quality of Pengxi river, provide scientific supports for rivers ecological management of the Three Gorges Reservoir, we conducted a study to determine the spatial and temporal differentiation of water quality in Hanfeng and Gaoyang Lakes. We arranged 14 sampling sites in these two lakes and measured 10 water quality parameters once amonth from December 2018 to Octorber 2019 at these sites. Single pollution index results suggest that the water quality grade of Hanfeng and Gaoyang lakes were Class Ⅲ of the National Surface Water Standard in most months. As phytoplankton blooms occured, heavy rainfall made runoff increases, the water quality grade reached ClassⅣandⅤin spring and summer.Using the Discriminant Analysis(DA) and Analysis of Variance(ANOVA), water quality showed spatial and temporal differentiation pattern, SD, DO, EC, pH, T, depth, TOC, TN and NH₃-N were the indicative factors describing the significantly spatial-temporal difference in water environment. Using the Principal Component Analysis (PCA), pollution classification factors of water environment are TN, NH₃-N, depth and pH in flow period. Otherwise, TN, TP, EC were pollution classification factors in wet period and depth, EC, TOC, TP, TN, NH₃-N were pollution classification factors in dry period. In temporal terms, the order of pollution was storage period > falling stage > discharge period in Hanfeng Lake and discharge period > falling stage > storage period in Gaoyang Lake; the spatial pollution situation was HF3 < HF1 < HF2 < HF4 < HF5 < HF8 < HF7 < HF6; GY2 < GY3 < GY1 < GY5 < GY6 < GY4.