考虑参数不确定性的地表水与地下水交换量的计算方法

Calculation method of the exchange volume between surface water and groundwater based on uncertainty of parameters

在计算地表水与地下水的交换量时,常规的方法是对实际获取的渗透系数采用集中式数学模型或者分布程度较低的分布式模型,使用以代表观测井为中心的泰森多边形划分计算区域。本研究在考虑实际获取的渗透系数基础上,进一步考虑参数空间分布的不确定性,利用渗透系数服从对数正态分布的已有研究成果,使用数字仿真技术,另外考虑地表水水位、地下水水位的动态变化对渗流方向的影响,在常规方法的基础上,基于D8算法提出改进,使用分布式模型计算地表水与地下水交换量,并与常规方法的结果进行对比。结果表明常规方法计算的交换量结果偏小,两者水位动态变化对渗流方向的影响显著。

As conventional method to calculate the exchange volume between surface water and groundwater, a calculation area was identified by a tessellation polygon surrounding an observation wells, in which obtained parameters of penetration was encompassed applying centralized models or low-distributed models. Based on the uncertainty of parameters, we presented an innovative calculation method to calculate the exact exchange volume between surface water and groundwater in this paper with applying numerical simulation and D8 arithmetic. The method counted the variability of seep direction combined the fluctuations of surface water and groundwater, and assumed the distribution modeling of hydraulic conductivity complying logarithm normal distribution. Therefore, exchange volume was calculated using innovation calculation method and compared with calculation result using conventional method. It was revealed that the seepage flow direction varied significantly accompanying with the fluctuations of water level and groundwater table.