Water quality variation in Lake Wuliangsuhai, 2005-2014

为了确定乌梁素海湖泊水质变化特征，选取乌梁素海2005-2014年6-9月长序列的水质实测数据，分析溶解氧、化学需氧量、总氮、总磷及氟化物的年际变化特征.采用灰色模式识别模型对乌梁素海2005-2014年的水质进行评价，并结合乌梁素海的实际状况，从外源污染、入湖污染物负荷量及入湖水量3个方面对其水质变化的影响因素进行分析.结果表明：2005-2014年间，水质状况转好；除总磷外，各污染指标浓度均有不同程度的下降；灰色综合指数表明乌梁素海水质正向良性方向发展；总磷治理应成为乌梁素海污染治理的主要方面；外源污染的削减、入湖污染物负荷量的降低及入湖水量的增加是乌梁素海水质转好的主要影响因素.;To identify the water quality variation in the Lake Wulansuhai, the observation data on the water quality during June and September from 2005 to 2014, is analyzed using a Grey Model, based on factors including dissolved oxygen,chemical oxygen demand, total nitrogen, total phosphorus, and fluoride. The driving force analysis on the water quality variation is carried out in terms of exogenous pollution, pollutant loading and the quantity of water input to the lake. The results show that during the period of 2005 to 2014, the water quality of the Lake Wuliangsuhai was getting better. The concentration of each pollution index, except total phosphorus, was decreased with different degrees. The grey comprehensive index shows that the water quality of the Lake Wuliangsuhai was improved and the governance of total phosphorus should be the main manner of pollution controls. The key driving factors of the water quality of the Lake Wuliangsuhai getting better are due to the increasing the quantity of water input to the lake and the reduction quantity of input pollutant quantity as well as the reduction of exogenous pollution.