However, identifying localized regions of groundwater recharge remains challenging. Streams and ponds (Cuthbert et al., 2016 Scanlon et al., 2002, 2006). Occur in focused regions beneath perennial streams and lakes, and ephemeral In semi-arid areas, recharge has been shown to Understanding groundwater recharge mechanisms and surface-water–groundwaterĬonnectivity is crucial for sustainable groundwater management (Banks et al.,Ģ011 Brunner et al., 2009). Furthermore, we show that a combined geophysical approach can provide a perspective that helps shape the hydrogeological conceptualization of a semi-arid region. Our results suggest that recharge is localized and that small-scale ephemeral features may play an important role in groundwater recharge. The geophysical observations provide evidence to support a groundwater mound underneath a subtle ephemeral surface water feature. Separate geophysical surveys were used to obtain electrical conductivity measurements from time-domain electromagnetics and water contents from downhole nuclear magnetic resonance. The ratios between P-wave and S-wave velocities are used to calculate Poisson's ratio, which allow us to infer the position of the water table. We use a seismic survey to obtain P-wave velocity through travel-time tomography and S-wave velocity through the multichannel analysis of surface waves. We use a combination of well-established near-surface geophysical methods to provide evidence of a surface and groundwater connection under a small ephemeral recharge feature in a flat, semi-arid region near Adelaide, Australia. Identifying and quantifying recharge processes linked to ephemeral surface water features is challenging due to their episodic nature.
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