Abstract Shapes and boundary types of a groundwater basin play essential roles in the analysis of groundwater management and contaminant migration. Hydraulic tomography (HT), a recently developed new approach for high-resolution characterization of aquifers, is not only an inverse method but a logical strategy for collecting non-redundant hydraulic information. In this study, HT was applied to synthetic 2-D aquifers to investigate its feasibility to map the irregular shapes and types of the aquifer boundaries. We first used the forward model of VSAFT2 to simulate hydraulic responses due to HT surveys in the aquifer with irregular geometry and predetermined constant head conditions at some boundaries, and no-flow conditions at others. The SimSLE (Simultaneous Successive Linear Estimator) inverse model in VSAFT2 was then used to interpret the simulated HT data to estimate the spatial distribution of hydraulic properties of the aquifer using a domain with a wrong geometry surrounded by boundaries of a constant head condition. The inverse modeling experiment used steady-state and transient-states data from the HT forward simulations, and it used the same monitoring network as in the aquifer with irregular geometry to assess the ability of HT for detecting types and shapes of the boundary as well as heterogeneity in the aquifer. Results of the experiment show that no-flow boundaries, which were incorrectly treated as constant head boundaries in inverse models, were portrayed as low permeable zones of the aquifer near the boundaries. Overall, the results show that HT could delineate not only the irregular shape of the aquifer in general but also heterogeneity in the aquifer. Improvements of the estimation with prior information of transmissivity and storage coefficient was also investigated. The study shows that using homogeneous initial guess parameters resulted in a slightly better estimate than others. Moreover, this study employs Monte Carlo simulations to ensure statistically meaningful conclusions.

中文翻译：

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使用水力层析成像识别地下水盆地形状和边界

摘要 地下水流域的形状和边界类型在地下水管理和污染物迁移分析中起着至关重要的作用。水力断层扫描 (HT) 是最近开发的一种用于含水层高分辨率表征的新方法，它不仅是一种逆方法，而且是收集非冗余水力信息的逻辑策略。在这项研究中，HT 被应用于合成二维含水层，以研究其绘制不规则形状和类型的含水层边界的可行性。我们首先使用 VSAFT2 的前向模型来模拟由于在含水层中进行 HT 调查而导致的水力响应，在某些边界具有不规则的几何形状和预定的恒定水头条件，而在其他边界则为无流量条件。然后使用 VSAFT2 中的 SimSLE（同时连续线性估计器）反演模型来解释模拟的 HT 数据，以使用由恒定水头条件边界包围的具有错误几何形状的域来估计含水层的水力特性的空间分布。反演模拟实验使用来自 HT 正演模拟的稳态和瞬态数据，并使用与具有不规则几何形状的含水层相同的监测网络来评估 HT 检测边界类型和形状以及含水层的异质性。实验结果表明，在逆模型中被错误地视为恒定水头边界的无流量边界被描绘为边界附近含水层的低渗透区。全面的，结果表明，HT 不仅可以描绘含水层的一般不规则形状，还可以描绘含水层的非均质性。还研究了利用透射率和存储系数的先验信息对估计的改进。研究表明，使用同构初始猜测参数会产生比其他方法稍好的估计值。此外，本研究采用蒙特卡罗模拟来确保得出具有统计意义的结论。