In intertidal zones, groundwater is often present as seepage that provides freshwater and nutrients to marine ecosystems. Point discharge or springs in intertidal zones have been observed in many locations, often in the form of sand boils. The spatial extent, temporal variability and source of intertidal springs are rarely documented and typically, not well understood. This study examined four intertidal groundwater springs at Sellicks Beach, South Australia, during May 2017, November 2019 and September 2020 using a combination of hydrogeophysical methods. A thermal infrared survey undertaken in 2017 showed springs as groupings of closely spaced sand boils that were warmer (15°C) than the surrounding saturated beach sediments (7°C). The four springs ranged in diameter from 0.20 to 0.45 m. Electromagnetic geophysical surveys identified a resistive anomaly (3.5 to 5.0 ohm.m), assumed to represent freshwater upwelling at the location of a spring, that extended 10 m horizontally and at least 6.7 m vertically. The average electrical conductivity of water discharging from the springs was 18.4 mS/cm, while seawater was 54.8 mS/cm. δ¹⁸O and δ²H data from the springs showed a variation between winter and spring, likely caused by variations in mixing ratios between seawater and groundwater. The springs are proximal to major regional fault systems that likely create preferential flow paths that control spring location and flow rates. The observations of spring characteristics highlight the critical role of seawater-groundwater mixing ratios, preferential flow paths and tidal variations in creating temporal variability in spring discharge and salinity.

在潮间带，地下水通常以渗漏的形式存在，为海洋生态系统提供淡水和养分。在许多地方都观察到潮间带的点状泄流或泉水，通常以沙疖的形式出现。潮间带泉水的空间范围、时间变化和来源很少被记录下来，通常也没有得到很好的理解。本研究结合水文地球物理方法，在 2017 年 5 月、2019 年 11 月和 2020 年 9 月期间检查了南澳大利亚塞利克斯海滩的四个潮间带地下水泉。2017 年进行的一项热红外调查显示，泉水是一组密集的沙子沸腾，比周围的饱和海滩沉积物 (7°C) 温度更高 (15°C)。四个弹簧的直径范围从 0.20 到 0.45 m。电磁地球物理调查发现了一个电阻异常（3.5 到 5.0 ohm.m），假定代表泉水位置的淡水上升流，水平延伸 10 m，垂直延伸至少 6.7 m。泉水排放的平均电导率为 18.4 mS/cm，而海水的平均电导率为 54.8 mS/cm。δ^{来自泉水的18} O 和 δ ² H 数据显示了冬季和春季之间的变化，这可能是由于海水和地下水混合比的变化造成的。这些泉水靠近主要的区域断层系统，这些断层系统可能会形成控制泉水位置和流速的优先流动路径。对泉水特征的观察突出了海水-地下水混合比、优先流动路径和潮汐变化在造成泉水流量和盐度的时间变化中的关键作用。