闸控河段氨氮浓度与主要影响因子的量化关系识别

Identification of quantitative relation of ammonia-nitrogen concentration and main influence factors in the river reaches controlled by sluice

闸门调度对河道内水流、底泥等环境要素具有强烈的扰动作用,闸控河段的水质变化过程较常规河道更为复杂。为了探析闸门调度在闸控河段水质演变中所起的作用,以槐店闸为研究对象,结合水闸调度影响实验与偏相关分析方法,识别了闸控河段氨氮浓度变化的主要影响因子;研制了考虑水闸调控作用的水动力模型和考虑内源释放的水质迁移转化模型,在大量情景模拟基础上构建了氨氮浓度变化率与主要影响因子的经验关系式。结果表明,在所选的9个指标中,闸前流速、上游来水浓度和闸门开度是氨氮浓度变化率的主要影响因子;水闸调度对氨氮浓度变化过程具有一定的影响,闸门大流量泄水使得闸后出流断面的氨氮浓度增加;氨氮浓度变化率与闸门开度、闸门开启个数、上游来水浓度之间呈对数关系,闸门开度的增大或开启个数的增多会使浓度变化率变小,来水浓度的增加会使浓度变化率逐步增大。

Sluice operation has a strong disturbance effect on environmental factors （such as water flow and sediment）, and the change process of water quality in the reaches controlled by sluice （RCS） is more complex than normal cases. Taking Huaidian Sluice as the research object,the effect of sluice operation on water quality evolution is studied. Main influence factors of change rate of ammonia-nitrogen （NH3-N） con- centration in RCS are identified by the sluice operation experiment and the partial correlation analysis meth- od. The hydrodynamic model considering sluice operation action and the water quality transportation and transform model considering endogenous substance exchange action are built. Based on scenario simulation, logarithmic relation expressions between the change rate and main influence factors are established. The re- search results show that the indexes （flow velocity, inflow＇s concentration and gate opening size） are main influence factors among the chosen 9 indexes; sluice operation has certain effects on the variation of NH3-N concentration in lower reaches; and the change rate of NH3-N concentration in RCS will be de- creased with the increase of gate opening size or number, and increased gradually with the increase of in- flow＇s concentration.