水库溶解氧的立面二维数值模拟

采用宽度平均的立面二维数学模型对水库水质进行数值模拟,通过对水位、水温的计算值与实测值的对比,验证了模型模拟水库水质的有效性.在此基础上,对库区的溶解氧浓度分布进行计算,结果表明,溶解氧的计算值与实测值整体吻合较好,基本能够反映水库中的溶解氧分布特性.对该水库水体中的饱和溶解氧率的计算分析表明,水库水体2007年全年的饱和溶解氧率多在90%以上,水体总体质量较好.在3-5月气温适宜的条件下,由于浮游植物生长旺盛,过饱和情况较为明显.而在夏季(6-9月),由于气温高,水体复氧能力较弱,同时同时期上游来水丰沛,随地表径流带来的面源污染也增加了水体的耗氧量,致使这一时期的溶解氧浓度较低,因此水库溶解氧受上游来流及气温的影响较为显著.

Vertical 2D numerical simulation of dissolved oxygen in reservoir

A width-averaged vertical 2D numerical model was adopted to simulate the water quality in a reservoir.Firstly,the water level and water temperature were predicted,and the agreement between the calculated results and the measured data proved that this model is effective in predicting the water quality in reservoir.Then the dissolved oxygen in the reservoir has been predicted,and saturated dissolved oxygen rates were calculated.Further analysis shows that most of the saturated dissolved oxygen rates in 2007 are higher than 90% which means that the water quality of this reservoir is satisfied.Oversaturation phenomenon appeared from March to May since the temperature was comfortable and the growth of aquatic vegetation was exuberant.During flooding season(June to September),the surface runoff into the reservoir carried a large number of non-point source pollution,which increased the dissolved oxygen consumption;at the same time,the high temperature during this season restained the reoxygenation process of the water body.The conclusion is that the inflow and air temperature are two main factors affecting the concentration of dissolved oxygen.