大型浅水湖泊纳污能力核算的风场设计条件分析

分析了东南风、西北风及东北风3种不同主导风场下太湖的风生湖流形态特征、环流结构及湖流流速大小变化，研究了不同风生湖流特征条件下环湖入湖污染物的输移扩散规律和湖区水质空间分布特征差异，以及在不同主导风场和常年主导风向下风速变化对太湖各主要湖湾纳污能力的影响。同时，参照水情设计条件要求，选择相对不利的主导风向和保证率为90％时的风速，对太湖进行了纳污能力计算。计算结果表明：在平均风速1.0m/s的西北风和枯水年型设计来水条件下，太湖的CODMn、TP、TN指标纳污能力分别为29732t/年、393t/年和7550t/年，较常年主导风向及多年平均风速条件下的纳污能力分别减小13.5％、 11.3％、23.6％。

Analysis on designed wind field condition for pollution capacity calculation in a large_scale shallow lake

The pattern, circulation structure and velocity change of the flow induced by the southeast, northeast and northwest wind in Taihu Lake were analyzed. The law of pollution transportation and diffusion and the spatial distribution characteristics of water quality of lake under the influence of different wind fields were studied. The influence of the change of wind fields on water pollution capacity in the Taihu Lake and main arm_of_lakes was quantitatively analyzed. Referred to the designed condition of water occurrence, the relatively worst wind direction and the frequency of wind velocity equal of 90% were taken as the condition of wind field in the calculation of water pollution capacity of lake. Northwest wind and the wind velocity of 1.0m/s could be the designed condition of wind field in the calculation of pollution capacity of CODMn, TP and TN in Taihu lake are 29732t/a, 393t/a, 7550t/a respectively under the designed wind field, the designed water occurrence and the current water quality.