中文摘要：

湖泊承载力的计算一般建立在水环境容量的基础上,而水环境容量的确定涉及污染物降解系数。由于乌梁素海的挺水植物、浮水植物和沉水植物呈相间分布,时有共生,分布面积也各有差异,并伴生着多种藻类,因此该湖的降解系数的确定存在一定的难度。容量迭加的方法避开了降解系数确定的问题,其物理意义明确,容易操作。应用容量迭加的方法对乌梁素海2006年5-10月的COD、TN和TP的环境容量进行了计算。从结果可以看出,水生植物群落分布和水生植物量决定了湖区对污染物的降解能力,直接影响其水环境容量。在此基础上,确定了乌梁素海5-10月的水质承载力CCPZ,将当地的社会经济发展状况与湖泊水环境承载力结合起来。计算求得CCPZ=1.115＆gt;1.0（当CCPZ=1.0时,湖泊实际承载的社会发展与允许值平衡）,说明集水流域中的社会经济发展水平超过了湖泊所允许的水环境承载力,需要调整产业结构,从污染源控制污染物的排放,降低对湖区水环境的压力,实现社会、经济和环境协调可持续发展。

英文摘要：

To evaluate lake＇s carrying capacity normally requires an in vivo better understanding on water environmental capacity that usually needs the degradation coefficient. There are some difficulties in the determination of the degradation coefficient in Wuliangsuhai Lake because of its distribution complexity of aquatic plants and their degradation rates. However, superposition method has an advantage that is not necessary to determine the degradation coefficient. Meanwhile it has a clear physical meaning and is easy to obtain the necessary data. The environmental capacity of COD,TN and TP from May to October in 2006 were calculated using the superposition method. The results showed that the speces of the aquatic plans and their amount control the degradation capacity of the lake, which in turn affect the water environmental capacity. As a result of this, the water quality carrying capacity （CCPZ） of the lake was modeled based on the relationship between the data of economical development and the water environmental capacity of the lake. The result （CCPZ = 1. 115 〉 1.0） suggested that the lake is over loaded in terms of eutrophication, meaning the sources of the contaminants need to be controlled through either adjusting the local industrial structure or purifying the water that is discharged into the lake.