Glose Thomas J, Lowry Christopher S, Hausner Mark B
Department of Geology, University at Buffalo, North Campus, 126 Cooke Hall, Buffalo, NY, 14260-4130.
Division of Hydrologic Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno, NV, 89512-1095.
Ground Water. 2019 Sep;57(5):727-736. doi: 10.1111/gwat.12864. Epub 2019 Feb 12.
Numerical modeling of groundwater-surface water interactions provides vital information necessary for determining the extent of nutrient transport, quantifying water budgets, and delineating zones of ecological support. The hydrologic data that drive these models are often collected at disparate scales and subsequently incorporated into numerical models through upscaling techniques such as piecewise constancy or geostatistical methods. However, these techniques either use basic interpolation methods, which often simplifies the system of interest, or utilize complex statistical methods that are computationally expensive, time consuming, and generate complex subsurface configurations. We propose a bulk parameter termed "vertically integrated hydraulic conductivity" (K ), and defined as the depth-integrated resistance to fluid flow sensed at the groundwater-surface water interface, as an alternative to hydraulic conductivity when investigating vertical fluxes across the groundwater-surface water interface. This bulk parameter replaces complex subsurface configurations in situations dominated by vertical fluxes and where heterogeneity is not of primary importance. To demonstrate the utility of K , we extracted synthetic temperature time series data from a forward numerical model under a variety of scenarios and used those data to quantify vertical fluxes using the amplitude ratio method. These quantified vertical fluxes and the applied hydraulic head gradient were subsequently input into Darcy's Law and used to quantify K . This K was then directly compared to the equivalent hydraulic conductivity (K ) assuming an infinitely extending layer. Vertically integrated hydraulic conductivity allows for more accurate and robust flow modeling across the groundwater-surface water interface in instances where complex heterogeneities are not of primary concern.
地下水与地表水相互作用的数值模拟为确定养分运移范围、量化水量平衡以及划定生态支持区域提供了至关重要的信息。驱动这些模型的水文数据通常在不同尺度上收集，随后通过诸如分段常数或地质统计方法等尺度上推技术纳入数值模型。然而，这些技术要么使用基本插值方法，这往往会简化所关注的系统，要么利用计算成本高、耗时且会生成复杂地下结构的复杂统计方法。我们提出一个总体参数，称为“垂向综合水力传导率”（K ），定义为在地下水与地表水界面处感测到的流体流动的深度积分阻力，作为研究跨地下水与地表水界面的垂向通量时水力传导率的替代参数。在以垂向通量为主且非均质性并非首要因素的情况下，这个总体参数可替代复杂的地下结构。为证明K 的实用性，我们在各种情景下从一个正向数值模型中提取了合成温度时间序列数据，并使用这些数据通过振幅比方法量化垂向通量。随后将这些量化的垂向通量和应用的水头梯度输入达西定律，用于量化K 。然后将这个K 与假设为无限延伸层的等效水力传导率（K ）直接进行比较。在复杂非均质性并非主要关注点的情况下，垂向综合水力传导率能够实现跨地下水与地表水界面更准确、更稳健的水流模拟。
