Monitoring Line Hole Well Field, San Salvador Island, Bahamas, 2015-2017

San Salvador Island is a small isolated carbonate platform on the southeastern edge of the Bahamian Archipelago. The Line Hole well field is located on an eogenetic karst aquifer on San Salvador Island's northern coast. The island's negative water budget and extensive lake cover have resulted in the upconing of saline water that has fragmented the once continuous freshwater lens. The Line Hole well field consists of several 15-cm diameter wells drilled into the fresh-water lens and arranged in a line perpendicular to the shore. The well field also has two monitoring wells (LH 1, and LH 13), that penetrate approximately 7 m below the water table into higher salinity groundwater. The well field was abandoned in 2016 upon saltwater intrusion to the aquifer. To evaluate the connectivity between the eogenetic karst aquifer monitored by the Line Hole well field and the ocean, we instrumented wells with HOBO U20L-04 loggers to measure pressure and temperature timeseries. We instrumented wells LH4, and LH8, in addition to the monitoring wells LH1 and LH13.

圣萨尔瓦多岛（San Salvador Island）是巴哈马群岛（Bahamian Archipelago）东南缘一处小型孤立碳酸盐岩台地（carbonate platform）。莱恩霍尔井场（Line Hole well field）坐落于该岛北海岸的早成喀斯特含水层（eogenetic karst aquifer）之上。该岛的水分负平衡与广泛分布的湖泊覆盖区，导致咸水发生上涌，使得原本连续分布的淡水透镜体（freshwater lens）发生破碎。莱恩霍尔井场包含多口直径15厘米的钻井，这些钻井钻入淡水透镜体中，并沿垂直于岸线的方向呈直线排布。该井场还设有两口监测井（LH 1与LH 13），其井深约达地下水位以下7米，穿透至高盐度地下水中。2016年，因含水层发生咸水入侵，该井场被废弃。为评估莱恩霍尔井场所监测的早成喀斯特含水层与海洋之间的连通性，本研究团队为钻井部署了HOBO U20L-04型记录仪（HOBO U20L-04 loggers），以采集压力与温度的时间序列数据。除监测井LH1与LH13外，研究人员还对LH4与LH8两口井进行了仪器部署。