The method of extracting fresh groundwater in many Pacific islands, particularly atolls, often involves the installation of horizontal or inclined perforated pipes, connected to an extraction well/sump containing a pump. These “infiltration galleries” (or skimming wells) skim fresh groundwater from shallow depths while minimizing saltwater upconing beneath thin freshwater lenses, which are typically 3–21 m thick. This study summarizes the state of knowledge of infiltration galleries in the Pacific, including their design and performance, to share the decades-long experience of Pacific hydrogeologists with the global groundwater community. Our review compiles information on infiltration gallery layout, pipe characteristics and pumping rates, as well as the performance of infiltration galleries (pumping rates and salinities), among other aspects. Notably, we found a lack of investigations optimizing gallery design in terms of the aforementioned characteristics, leaving this as a critical area for future research effort. While many studies have examined horizontal wells in other contexts, the specific conditions of small islands, especially atolls, places unique demands on infiltration galleries. For example, infiltration gallery assessments should account for freshwater lost as discharge to the sea and through mixing with saltwater – key components of the water budget often overlooked in atoll island water-balance analyses. The insights gained from applying infiltration galleries to Pacific atolls offers opportunities for more widespread applications within continental aquifers, in particular to capture submarine fresh groundwater discharge that is otherwise lost through mixing with seawater and to mitigate seawater intrusion, thereby contributing to global groundwater management strategies.

中文翻译：

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渗透廊道（撇渣井）的建设和性能：太平洋环礁岛屿应用综述


在许多太平洋岛屿，特别是环礁，提取新鲜地下水的方法通常涉及安装水平或倾斜的穿孔管，这些管道连接到包含泵的提取井/集水坑。这些“渗透通道”（或撇去井）从浅层撇去淡水地下水，同时最大限度地减少薄淡水透镜体（通常为 3-21 m 厚）下的盐水上升。本研究总结了太平洋渗透廊道的知识状况，包括其设计和性能，以与全球地下水界分享太平洋水文地质学家数十年的经验。我们的综述汇编了有关渗透通道布局、管道特性和抽水速率以及渗透通道性能（抽水速率和盐度）等方面的信息。值得注意的是，我们发现缺乏根据上述特征优化画廊设计的调查，使其成为未来研究工作的关键领域。虽然许多研究已经检查了其他情况下的水平井，但小岛屿，尤其是环礁的特殊条件，对渗透廊道提出了独特的要求。例如，渗透廊道评估应考虑到淡水因排放到海洋和与盐水混合而损失的淡水——这是环礁岛屿水平衡分析中经常被忽视的水预算的关键组成部分。 将渗透廊道应用于太平洋环礁所获得的见解为在大陆含水层中更广泛地应用提供了机会，特别是捕获因与海水混合而损失的海底淡水地下水排放，并减轻海水入侵，从而为全球地下水管理战略做出贡献。