双塔水库水质对人类活动的响应分析

选取1993～2008年瓜州县人类活动数据及双塔水库水质指标年平均值进行主成分分析,去除冗余信息后进行多元线性回归分析,得到四组反映人类活动对水库水环境影响情况的回归方程。说明对双塔水库水质起主要影响作用的是农业活动和因农业活动引起的土地利用变化,农业活动的非点源污染是水库水质的主要污染源,水库水质仍存在富营养化的风险;工业活动对水库水质的影响没有在回归方程中体现出来。在农业活动过程中,耕地面积每增加10 000亩促使pH值上升0.062、溶解氧值下降0.046、高锰酸钾指数上升0.103、COD值上升0.617;而每增加10 000t的氮肥施用量会引起pH值升高1.837;总人口每增加1万人,COD值上升0.798。

Response of Water Quality in Shuangta Reservoir to Human Activities

Guazhou County is located in the downstream of the Shulehe River Basin. The principal components were used to analysis thedata of human activities in Guazhou County and the annual average water quality data in Shuangta Reservoir from 1993 to 2008, and the information representing human agricultural and industrial activities and the reservoir water quality situations was obtained. Then, the multiple linear regression analysis was used to calculate four regression equations reflecting the impacts of human activities and land use changeson pH index, dissolved oxygen index, potassium permanganate index and chemical oxygen demand index of water environment in the reservoir. The results show that the main impacts on water quality in the Shuangta Reservoir are human agricultural activities and land usechanges, and the major pollution sources of water quality in reservoir are non-point source pollution aroused by human agricultural activities. In addition, the impact of human industrial activities on water quality is not obvious in the regression equation. And the reservoir isstill facing the risk of eutrophication. In the course of human agricultural activities, each increase of 10 thousands mu of cultivated land willcause the pH index increasing by 0.062, dissolved oxygen index dropping by 0.046, potassium permanganate index increasing by 0.103,chemical oxygen demand index increasing by 0.617; and each increase of 10 thousands tons of nitrogen fertilizer will cause pH index increasing by 1.837, and if the total population increase by 10 thousands, then the chemical oxygen demand index will increase by 0.798 as well.