Low-permeability aquitards are important sedimentary units that protect the underlying confined aquifers from contamination by seawater and anthropogenic sources in coastal leaky aquifer systems. Therefore, the integrity of the aquitard is of crucial importance. However, the aquitard integrity may be vulnerable to horizontal heterogeneities in the form of aquitard windows. In this study, an innovative analytical model was developed to describe groundwater flow in a coastal leaky aquifer system with horizontal heterogeneities in hydraulic properties of either the aquitard or the confined aquifer. Consequently, the effects of aquitard windows, which manifest as horizontally local heterogeneities in hydraulic conductivity and/or specific storage, on the tidal wave propagation can be considered in the analysis. Analytical solutions were derived for tidal-head or constant-flux inland boundary conditions. The derivation process avoided previous methodologies that involved the assembly of large-size matrices. The newly developed analytical model can cover multiple existing analytical models that are associated with the assumptions of homogeneity in hydraulic properties of the aquifer and the aquitard, infinite horizontal extent of the coastal leaky aquifer system, impermeability of the aquitard, or ignorance of aquitard storativity. Analytical investigations revealed that high-permeability aquitard windows acting as preferential-flow conduits tended to dampen the tide-induced head propagation within the underlying confined aquifer. Moreover, an aquitard with a higher storativity (but the same permeability) and of considerable size can result in an apparent propagation bias. The newly developed analytical model in this study was further corroborated through sandbox experiments. Both piezometer measurements and parameter estimates indicated the non-negligible effects of high-permeability aquitard windows on the tidal wave propagation. The sandbox investigation also highlighted the importance of geostatistical inverse modeling in characterizing local heterogeneities within the confined aquifer and in detecting the location and size of aquitard windows, when measurement data of tide-induced aquifer head fluctuations were provided.

低渗透性弱透水层是重要的沉积单元，可保护底层承压含水层免受沿海渗漏含水层系统中海水和人为来源的污染。因此，透水层的完整性至关重要。然而，弱透水层的完整性可能容易受到弱透水层窗口形式的水平异质性的影响。在这项研究中，开发了一个创新的分析模型来描述沿海渗漏含水层系统中的地下水流，该含水层系统的水力特性存在水平异质性，无论是弱透水层还是承压含水层。因此，在分析中可以考虑透水层窗口对潮波传播的影响，其表现为水力传导率和/或特定存储的水平局部异质性。针对潮头或恒定通量内陆边界条件推导了解析解。推导过程避免了以前涉及大型矩阵组装的方法。新开发的分析模型可以涵盖多个现有的分析模型，这些模型与含水层和弱透水层水力特性的同质性假设、沿海渗漏含水层系统的无限水平范围、弱透水层的不透水性或无视弱透水层蓄水性的假设相关联。分析研究表明，作为优先流管道的高渗透性隔水层窗口往往会抑制下伏承压含水层内由潮汐引起的水头传播。而且，具有较高储水性（但渗透率相同）且尺寸相当大的透水层会导致明显的传播偏差。通过沙盒实验进一步证实了本研究中新开发的分析模型。渗压计测量和参数估计都表明高渗透性隔水层窗对潮波传播的影响不可忽略。当提供潮汐引起的含水层水头波动的测量数据时，沙箱调查还强调了地质统计反演建模在表征承压含水层内的局部异质性以及检测弱透水层窗口的位置和大小方面的重要性。渗压计测量和参数估计都表明高渗透性隔水层窗对潮波传播的影响不可忽略。当提供潮汐引起的含水层水头波动的测量数据时，沙箱调查还强调了地质统计反演建模在表征承压含水层内的局部异质性以及检测弱透水层窗口的位置和大小方面的重要性。渗压计测量和参数估计都表明高渗透性隔水层窗对潮波传播的影响不可忽略。当提供潮汐引起的含水层水头波动的测量数据时，沙箱调查还强调了地质统计反演建模在表征承压含水层内的局部异质性以及检测弱透水层窗口的位置和大小方面的重要性。