洪水过程下双峰寺水库水动力特征及污染物迁移规律研究

Hydrodynamic Characteristics and Pollutant Shifting Law of Shuangfengsi Reservoir under Flood Process

为有效控制水体污染提供理论依据,同时为水库水动力-水质联合模拟及调控提供技术支撑。以双峰寺水库为研究对象,借助MIKE21构建了水动力-水质耦合模型,模拟在1962年典型洪水过程的工况条件下水动力特征及污染物迁移规律,输出结果表明:在典型洪水过程的工况下,库区内流场变化导致污染物浓度波动剧烈,随洪水过程的进行,其中BOD和DO浓度变化曲线相似,在洪水初期污染物浓度迅速下降,降低为某一数值时,下降坡度突然变缓直至过程结束;NH_(4)和PO_(4)浓度变化曲线相似,在洪水初期,三点浓度成上升趋势,并且越远离入库位置的点,浓度增加越迅速且时间越长,并随着浓度上升至最高点后迅速下降;NO_(3)浓度变化曲线较为特殊,在洪水来临时呈短暂的平稳趋势,随后猛然增加到最大值2.5 mg/L左右,并在其附近上下波动。可见在洪水作用下,库区各污染物的运移规律会随着洪水过程而呈现一定的变化。

This paper aims to provide a theoretical basis for effective control of water pollution and technical support for joint simulation and control of reservoir hydrodynamic and water quality.It takes Shuangfengsi Reservoir as the research object and builds a hydrodynamic and water quality coupling model in virtue of MIKE21 to simulate the hydrodynamic characteristics and pollutant migration rule of a typical flood process in 1962.The output results show that in a typical flood process,the change of flow field in the reservoir area leads to drastic fluctuation of pollutant concentration.As the flood process progresses,the change curves of BOD and DO concentration are similar.Pollutant concentration drops rapidly at the initial stage of the flood,and when it drops to a certain value,the descending slope suddenly slows down until the end of the process.The change curves of NH_(4)and PO_(4)concentrations are similar.At the early stage of the flood,the concentrations at three points show an upward trend.As the point is further away from the storage location,the concentration increases faster and longer,and it rapidly decreases after rising to the highest point.The change curve of NO_(3)concentration is special.It shows a transient stable trend when the flood comes,and then increases abruptly to the maximum value of 2.5 mg/L and fluctuates up and down around it.The migration of pollutants in the reservoir area under the action of flood will change with the flood process.