摘要
为定量讨论单一水闸的多闸门调度对下游COD浓度衰减的影响,采用2009—2011年在北运河杨洼闸上下游进行的实地监测数据,通过结合人工神经网络与修正的一维污染物衰减模型,建立了单一水闸多闸门调度对下游水体COD衰减影响的数学模型;并使用权值分析法、Sobol法对该模型进行全局敏感性分析,分别得到上游来水COD浓度、纵向距离、水闸开孔数、开闸高度的一阶敏感性指数和总敏感性指数。结果表明:Sobol方法在神经网络模型敏感度分析中的定量化结果与权值分析法一致;杨洼闸对水流的控制作用明显,且增减开闸孔数比升降闸门高度可更有效地控制流量大小;降解系数与弥散系数的变化对河道内COD的衰减过程影响很小,且通过闸门调度改变水力条件也不会显著提高两者的影响力,COD浓度的衰减主要依靠稀释作用;影响COD降解过程的因素排序为:上游来水COD浓度,纵向距离,水闸开孔数,开闸高度。
To quantitatively examine the influence of muti-water gate operation on the decay of COD concentration in downstream water, a model was set up by coupling the BP neural network and modified one-dimensional decay model based on monthly monitoring data （from 2009 to 2011 ） of upstream and downstream reaches of the Yangwa water gate in the North Canal in Beijing. The sensitivities of the variables of the model were calculated using weight analysis and the Sobol method. The first-order and global sensitivity indices of the COD concentration in downstream water, longitudinal distance, and the number and height of open water gates were obtained. It was found that the variable sensitivities obtained from the Sobol method was consistent with those obtained from weight analysis ; the flow was under effective control of the Yangwa water gate, and the number of open water gates （ WG number） could more effectively control the flow rate than the height of the water gates （ WG height） ; the changes of the degradation coefficient and dispersion coefficient had little influence on the decay of COD concentration in the canal, and the influence could not be significantly improved by the water gate operation; the decay of COD concentration was mainly attributed to the dilution effect; and the main factors affecting the decay of COD concentration were the upstream COD concentration, longitudinal distance, WG number, and WG height.
出处
《水资源保护》
CAS
2013年第5期45-51,共7页
Water Resources Protection
基金
国家水体污染控制与治理重大专项(2008ZX07209
2009ZX07212-002)
国家自然科学基金(40971258)
