Basin aquifers are important groundwater sources in the Western United States that are increasingly stressed due to growing populations, increased resource use, and the impacts of climate change. These aquifers are mainly recharged through melting snowpack in the surrounding mountains that infiltrates to the water table and flows directly into the basin (Mountain Front Recharge), or through deeper groundwater pathways that flow from the mountains directly into the basin aquifer (Mountain Block Recharge). However, the dominant system of recharge remains uncharacterized in many mountain basin aquifers. To address this challenge, near-surface geophysical methods are being implemented to efficiently measure properties that govern groundwater storage and movement. This study infers groundwater storage and recharge to the Casper Aquifer around Laramie, WY, building off past studies that relied solely on sparse monitoring well data and observation of rainfall events. In this study, we use a clustering analysis on airborne electromagnetic data to define hydrogeophysical layers within the Casper Aquifer. These layers, which represent significant changes in bulk subsurface electrical resistivity, are integrated with existing hydrologic, lithologic, and smaller scale geophysical datasets to build a more representative hydrogeophysical model. Through this analysis, we define two sub-aquifers within the larger Casper Aquifer system that are connected through structurally induced fractures and faults. This research highlights the importance of integrating geophysical data at multiple scales for defining hydrogeophysical layers that provide both a more complete understanding of basin aquifer recharge dynamics and constrain more detailed hydrologic models.

中文翻译：

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利用多尺度地球物理学定义水文地球物理层，以加深对山区盆地补给的了解


流域含水层是美国西部地区重要的地下水源，由于人口增长、资源使用增加以及气候变化的影响，其压力日益增大。这些含水层主要通过周围山脉融化的积雪渗入地下水位并直接流入盆地（山前补给），或通过更深的地下水通道从山脉直接流入盆地含水层（山地块补给） 。然而，在许多山盆地含水层中，主要的补给系统仍然不具有特征。为了应对这一挑战，正在实施近地表地球物理方法来有效测量控制地下水储存和运动的特性。这项研究以过去仅依赖稀疏监测井数据和降雨事件观测的研究为基础，推断了怀俄明州拉勒米周围卡斯珀含水层的地下水储存和补给。在本研究中，我们使用机载电磁数据的聚类分析来定义卡斯珀含水层内的水文地球物理层。这些层代表了地下体电阻率的显着变化，与现有的水文、岩性和较小规模的地球物理数据集相集成，以构建更具代表性的水文地球物理模型。通过此分析，我们在较大的卡斯珀含水层系统中定义了两个地下含水层，它们通过结构引起的裂缝和断层连接。这项研究强调了整合多个尺度的地球物理数据对于定义水文地球物理层的重要性，这不仅可以更全面地了解盆地含水层补给动态，还可以约束更详细的水文模型。