中文摘要：

近年来,长湖水质恶化,特别是以农业、水产养殖为主的非点源污染,加速了湖泊富营养化进程。为改善长湖的水质现状,文章建立了基于最大日负荷量（TMDL）计划的长湖水环境管理模式,估算了长湖COD、TP、TN的水环境容量和现状点源、非点源入湖污染负荷,明确了污染物削减百分比,提出了基于TMDL值的污染控制措施。结果表明,长湖COD、TP、TN的水环境容量分别为26 438.43、90.78、1 815.56 t/a,现状污染入湖量分别为14 137.74、271.23、2 485.24 t/a。长湖流域COD的现状负荷不需要进行削减,而富营养化因子TP、TN已经大大超过了其水环境容量,削减百分率分别高达68.20%、30.60%,而以农业、水产养殖为主的非点源负荷对TP、TN具有较大影响,亟需采取针对性的控污措施。

英文摘要：

In recent years, water quality in Changhu Lake has been deteriorating rapidly. The non-point source pollution caused mainly by agriculture and aquaculture in particular, accelerated the eutrophication process. To improve the water quality, a water environmental management mode based on total maximum daily load （TMDL） program is developed. Water environmental capacities of COD, TP, TN and the present point source and non-point source pollution load are estimated. Then, pollutants reduction rate are clearly determined and pollution control measures eventually put forward. The results show that the water environmental capacities of COD, TP, TN are 26 438.43, 90.78, 1 815.56 t/a respectively and the pollution load of COD, TP, TN into the Lake is 14 137.74, 271.23, 24 85.24 t/a respectively. COD need not be reduced, however, eutrophication factor TP, TN greatly exceed its standard and pollutants reduction rate for TP and TN reach up to 68.20% and 30.60% respectively. Particularly, non-point source pollution caused mainly by agriculture and aquaculture has such a great impact on TP and TN that targeted measures are urgently needed.