While the physical processes governing groundwater flow are well understood, and the computational resources now exist for solving the governing equations in three dimensions over continental‐scale domains, there remains substantial uncertainty about the subsurface distribution of the properties that control groundwater flow and transport for much of the contiguous United States (CONUS). The transmissivity of the shallow subsurface is a key parameter for the simulation of water table position, shallow groundwater flow, and base‐flow discharge, but is not well‐characterized at large regional to continental scales. We used a process‐based inversion of CONUS‐extent groundwater information to generate national data sets of (a) the transmissivity of the shallow groundwater system, (b) the depth to the water table, (c) groundwater discharge as base‐flow, and (d) long‐term average water content in the unsaturated zone. CONUS‐extent coverage was developed in the form of 75 subdomain models, with the spatial distribution of long‐term average transmissivity for each subdomain model calibrated against water‐levels derived from U.S. Geological Survey (USGS) observation wells, NHDPlusV2 first‐order perennial streams, and National Wetlands Inventory (NWI) freshwater wetlands. Estimated transmissivities were lower in the western CONUS than the eastern CONUS, and across the CONUS both transmissivity and depth to water correlate with recharge, elevation, and topographic slope. These generated data sets provide spatially distributed, long‐term average estimates of subsurface properties and hydrological states that we anticipate will complement other environmental modeling efforts as explanatory variables, boundary conditions, or transport pathways.

中文翻译：

---

连续美国长期平均地表水系统的校准模拟及其特征的空间分布

尽管人们已经很好地理解了控制地下水流动的物理过程，并且现在已经有了计算资源来求解大陆规模域中三维空间的控制方程，但是对于控制地下水流动和输送的属性的地下分布仍然存在很大的不确定性。连续的美国（CONUS）。浅层地下的透射率是模拟地下水位，浅层地下水流量和基流流量的关键参数，但在大型区域到大陆范围内却没有很好的特征。我们使用了基于过程的CONUS范围内的地下水信息反演，以生成以下国家数据集：（a）浅层地下水系统的透射率，（b）地下水位深度，（c）地下水作为基流的排放量，（d）非饱和区的长期平均水含量。CONUS范围的覆盖以75个子域模型的形式开发，每个子域模型的长期平均透射率的空间分布根据美国地质调查局（USGS）观测井，NHDPlusV2一阶多年生水流得出的水位进行了校准以及国家湿地清单（NWI）淡水湿地。西部CONUS的估计透射率低于东部CONUS，整个CONUS的透射率和对水的深度都与补给，海拔和地形坡度相关。这些生成的数据集提供了地下属性和水文状态的空间分布的长期平均估计值，我们预计这些估计值将补充其他环境建模工作，作为解释变量，