Groundwater flow and contaminant transport are strongly influenced by hydrogeological spatial variation. Understanding the textural heterogeneity of aquifer and aquitard units is critical for predicting preferential flow pathways, but is often hindered by sparse hydrogeological data, widely spaced data points, and complex stratigraphy. Here, we demonstrate the application of a relatively new air permeameter technology, providing a cost‐effective, rapid alternative for characterizing hydrostratigraphic units in the field. The aim of this research is to (1) characterize the variation of saturated hydraulic conductivity across shallow‐marine hydrostratigraphic units of the Whanganui Basin, New Zealand, and (2) assess the variation of saturated hydraulic conductivity within individual hydrostratigraphic units and relate these changes to facies and depositional environments. Results suggest heterogeneity within fine‐grained aquitard units is controlled by bioturbation, whereby burrowing, ingestion and defecation results in grain size segregation and differential micrite cementation. Coarse‐grained heterolithic aquifer facies display sharp changes in permeability across planar to cross‐bedded sets, related to current and wave energy fluctuations within shallow‐marine depositional settings. Bedding plane orientation creates high permeability zones that promotes down dip subsurface flow. Down dip gradation of coarse‐grained nearshore facies into fine‐grained shelf facies along the paleo shoreline‐shelf transect is suggested to promote lateral and vertical groundwater flow within the basin fill. Air permeameter techniques have potential for application within groundwater basins around the world, providing datasets that facilitate greater understanding of groundwater systems, informing practices and policies for targeted water quality management.

中文翻译：

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新西兰旺格努伊盆地露头尺度的饱和导水率变化

地下水流量和污染物运移受水文地质空间变化的强烈影响。了解含水层和阿奎塔尔单元的质地异质性对于预测优先流动路径至关重要，但通常因稀疏的水文地质数据，间隔较大的数据点和复杂的地层而受阻。在这里，我们演示了一种相对较新的空气渗透仪技术的应用，为表征现场水文地层单位提供了一种经济高效的快速替代方案。这项研究的目的是（1）表征新西兰旺格努伊盆地浅海水文地层单元中饱和导水率的变化，（2）评估各个水文地层单元内饱和导水率的变化，并将这些变化与相和沉积环境联系起来。结果表明，细粒阿基德单位内部的异质性受到生物扰动的控制，因此挖穴，食入和排便会导致晶粒尺寸偏析和微晶胶结。粗粒异质含水层相在平面到交叉层组的渗透率显示出急剧变化，这与浅海沉积环境中的电流和波能波动有关。顺层平面定向可形成高渗透率带，从而促进下倾地下流体流动。建议沿古海岸线-陆架断面将粗粒近岸相向下倾斜成细粒陆相，以促进盆地填充物中的横向和垂直地下水流。空气渗透仪技术在世界各地的地下水盆地中都有潜在的应用前景，它提供的数据集有助于人们更好地了解地下水系统，为有针对性的水质管理提供指导和政策依据。