地下水补给对河流水质扩散影响的数值模拟

为能够实时、量化研究地下水补给对河流水质扩散的影响,论文以某平原河流为研究对象,在地下水线源补给假定的基础上,通过基流分割方法对河流总流量进行了分割,借用MIKE11 AD对流扩散模块,分别建立了不考虑地下水补给作用的传统数值模型和加入分割后流量的新数值模型。通过分析河道沿程各点时间上的水质浓度变化过程,量化研究了两模型的差异及其产生原因。结果表明:在上游各点,两模型浓度曲线增长过程吻合度较高,但最终稳定值存在3%的差异;在下游各点,新模型浓度快速衰减,两模型浓度稀释差异巨大,可达到1000倍。由此得出结论,是否将河流流量进行分割研究对于河流水质扩散结果影响较大,这种影响会随地下水的沿程补给长度增加而快速变大。

Numerical simulation of effect of groundwater recharge on river concentration diffusion

In order to timely and quantively research the effect of groundwater recharge on river concentration diffusion,taking a plain river as study object,the paper cut apart the total flow of river by base flow separation method based on the suppose of line source supply.It built a traditional model which didn't consider the effect of groundwater recharge and a new model after the total flow was separated by the aid of AD module of MIKE 11. Through the analysis of the process of concentration diffusion in some points of the river on time,it researched the difference between two models and its cause in quantity. The results demonstrated that the difference of steady value of upstream concentration curve in two models is 3%,the growth process has higher anastomosis. The downstream concentration decays quickly in new model. The difference of concentration between two models is huge and reaches 1000 times. It has a huge impact on the result of river quality diffusion whether the river flow is studied in splitting.The impact can quickly become large with the increase of distance of groundwater recharge.